[424B5] BeyondSpring Inc. Prospectus Supplement (Debt Securities)

Rhea-AI Filing Summary

BeyondSpring Inc. (BYSI) is conducting a primary offering of 800,000 ordinary shares to Ray Beauty Group Limited at $2.50 per share, raising an estimated $2 million in net proceeds after expenses. The company plans to use the cash to fund its research and development programs and for general corporate purposes, which may include clinical trial and commercial spending, working capital, debt repayment and potential acquisitions.

Shares outstanding are expected to increase from 40,322,320 to 41,122,320 as of the referenced date, modestly diluting existing holders. As of September 30, 2025, BeyondSpring reported a net tangible book value of $(0.49) per share, which would improve to $(0.43) per share on an as-adjusted basis after the offering, but investors buying in this deal face an immediate dilution of $2.93 per share. The company remains a clinical-stage biopharmaceutical developer centered on its lead oncology asset, Plinabulin, and additional preclinical immune agents.

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Filed Pursuant to Rule 424(b)(5)

Registration No. 333-280153

PROSPECTUS SUPPLEMENT

(To Prospectus dated August 18, 2025)

BeyondSpring Inc.

800,000

Ordinary Shares

We are offering 800,000 of our ordinary shares to Ray Beauty Group Limited pursuant to this prospectus supplement and the accompanying prospectus and a securities purchase agreement with such investor. The offering price is $2.50 per ordinary share. Our ordinary shares are listed on the Nasdaq Capital Market under the symbol “BYSI”. On November 14, 2025, the last reported sales price of our ordinary shares on the Nasdaq Capital Market was $2.09.

Investing in our ordinary shares involves a high degree of risk. Before buying any shares, you should review carefully the risks and uncertainties described under the heading “Risk Factors” beginning on page S-3 of this prospectus supplement, on page 5 of the accompanying prospectus, under “Risk Factors” in our most recent annual report on Form 10-K and under similar headings in the other documents that are incorporated by reference into this prospectus supplement.

			Per Share			Total
Offering price			$2.50			$2,000,000.00

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

Delivery of the ordinary shares is expected to be made on or about November 18, 2025 only in book-entry form.

Prospectus Supplement dated November 17, 2025.

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Prospectus Supplement

			Page
ABOUT THIS PROSPECTUS SUPPLEMENT			S-ii
SUMMARY			S-1
THE OFFERING			S-2
RISK FACTORS			S-3
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-6
USE OF PROCEEDS			S-8
DIVIDEND POLICY			S-9
DILUTION			S-10
CAPITALIZATION			S-11
LEGAL MATTERS			S-12
EXPERTS			S-13
ENFORCEABILITY OF CIVIL LIABILITIES			S-14
WHERE YOU CAN FIND MORE INFORMATION			S-15
INCORPORATION BY REFERENCE			S-16

Prospectus

ABOUT THIS PROSPECTUS			1
OUR COMPANY			2
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			3
RISK FACTORS			5
USE OF PROCEEDS			6
CAPITALIZATION			6
DESCRIPTION OF SHARE CAPITAL			7
PLAN OF DISTRIBUTION			16
WHERE YOU CAN FIND MORE INFORMATION			18
INCORPORATION BY REFERENCE			19
ENFORCEMENT OF CIVIL LIABILITIES			20
LEGAL MATTERS			21
EXPERTS			22

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ABOUT THIS PROSPECTUS SUPPLEMENT

A registration statement utilizing a shelf registration process relating to the securities described in this prospectus supplement was initially filed on Form F-3 with the Securities and Exchange Commission (the “SEC”) on June 12, 2024, and subsequently amended on Form S-3 (File No. 333-280153) on August 13, 2025 and declared effective on August 18, 2025. Under this shelf registration statement, of which this offering is a part, we may, from time to time, sell up to 10,000,000 of our ordinary shares.

This document contains two parts. The first part is this prospectus supplement, which describes the terms of this offering of our ordinary shares by us, and also adds, updates and changes information contained in the accompanying prospectus and the documents incorporated herein and therein by reference. The second part is the accompanying prospectus, which gives more general information about us, some of which may not apply to this offering. To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or any document filed prior to the date of this prospectus supplement and incorporated herein by reference, the information in this prospectus supplement will supersede and govern. In addition, this prospectus supplement and the accompanying prospectus do not contain all of the information provided in the registration statement that we filed with the SEC. For further information about us, you should refer to that registration statement, which you can obtain from the SEC as described elsewhere in this prospectus supplement under “Where You Can Find More Information” and “Incorporation by Reference.”

You should rely only on the information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with information that is different. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus supplement and the accompanying prospectus. This prospectus supplement is not an offer to sell or solicitation of an offer to buy these securities in any circumstances under which the offer or solicitation is unlawful. We are offering to sell, and seeking offers to buy, our securities offered hereby only in jurisdictions where offers and sales are permitted. You should not assume that the information we have included in this prospectus supplement or the accompanying prospectus is accurate as of any date other than the date of this prospectus supplement or the accompanying prospectus, respectively, or that any information we have incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus supplement or of any of our securities. Our business, financial condition, results of operations and prospects may have changed since those dates.

Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus supplement to:

“BeyondSpring,” the “Company,” the “Registrant,” “us,” “we,” “our” and similar designations refer to BeyondSpring Inc. and its consolidated subsidiaries.

“$” refers to United States Dollars.

“Exchange Act” refers to the Securities Exchange Act of 1934, as amended.

“Nasdaq” refers to the Nasdaq Capital Market.

“Our shares,” “ordinary shares” and similar expressions refer to the Registrant’s ordinary shares, par value $0.0001 per share.

“PRC” or “China” refer to the People’s Republic of China.

“SEC” or the “Commission” refers to the United States Securities and Exchange Commission.

“Securities Act” refers to the Securities Act of 1933, as amended.

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SUMMARY

This summary highlights information contained elsewhere or incorporated by reference into this prospectus supplement and the accompanying prospectus. This summary does not contain all of the information that you should consider before investing in our securities. You should carefully read the entire prospectus supplement and the accompanying prospectus, including the “Risk Factors” sections, starting on page S-3 of this prospectus supplement and page 5 of the accompanying prospectus and under “Risk Factors” in our most recent annual report on Form 10-K as well as the financial statements and notes thereto, and the other information incorporated by reference herein, before making an investment decision.

BeyondSpring Inc.

We are a clinical stage global biopharmaceutical company focused on developing innovative therapies to improve clinical outcomes for patients with high unmet medical needs. Our first-in-class lead asset, Plinabulin, which has been administered to over 700 cancer patients with generally good tolerability, is being developed as a potential “pipeline in a drug” in various cancer indications as a direct anti-cancer agent, and as a late stage clinical asset in second and third line NSCLC with epidermal growth factor receptor wild type, a severe unmet medical need. Plinabulin binds in a unique pocket of tubulin and activates the immune defense protein GEF-H1, which leads to indication of innate and adaptive immunity via dendritic cell maturation. We own global rights to Plinabulin in all countries except China. We own a 57.97% interest in our Chinese subsidiary, which owns 100% of the rights to Plinabulin in China. We are also developing three small molecule immune agents, which are currently in preclinical stages. In addition, we founded and continue to own an equity stake in SEED Therapeutics Inc. (“SEED”). SEED is utilizing a proprietary Targeted Protein Degradation (“TPD”) drug discovery platform, or “molecular glue” technology, to develop innovative therapeutic agents from internal research and development efforts and with our collaborators on currently undruggable protein targets. SEED is partnering with Eli Lilly and Co. and Eisai Co., Ltd. to discover and develop new chemical entities through this proprietary TPD platform which could produce therapeutic benefits to patients suffering from oncology and central nervous system disease, among others.

BeyondSpring Inc. was incorporated as an exempted company under the laws of the Cayman Islands on November 21, 2014. Our principal executive offices are located at 100 Campus Drive, West Side, 4th Floor, Suite 410, Florham Park, New Jersey 07932 and our telephone number is +1 (646) 305-6387. Our registered office in the Cayman Islands is located at the offices of Harneys Fiduciary (Cayman) Limited, 4th Floor, Harbour Place, 103 South Church Street, P.O. Box 10240, Grand Cayman KY1-1002, Cayman Islands. Our website is www.beyondspringpharma.com. The information contained on, or that can be accessed through, our website does not constitute part of this prospectus supplement and is not incorporated by reference herein.

For a further discussion of our business, we urge you to read the documents incorporated by reference herein, including our annual report on Form 10-K for the year ended December 31, 2024 and our quarterly reports on Form 10-Q for the quarters ended Mach 31, 2025, June 30, 2025 and September 30, 2025. See “Incorporation by Reference” and “Where You Can Find More Information.”

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THE OFFERING

Ordinary shares offered by us

800,000 shares.

Ordinary shares outstanding prior to the

offering

40,322,320 shares.

Ordinary shares to be outstanding after this offering

41,122,320 shares.

Use of proceeds

We estimate that the net proceeds from our issuance and sale of ordinary shares in this offering will be approximately $2 million, after deducting estimated offering expenses payable by us. We intend to use the net proceeds to fund our research and development and for general corporate purposes. See “Use of Proceeds” on page S-8 of this prospectus supplement.

Risk factors

This investment involves a high degree of risk. See “Risk Factors” beginning on page S-3 of this prospectus supplement, page 5 of the accompanying prospectus and in the documents incorporated by reference herein (including under “Risk Factors” in our most recent annual report on Form 10-K) for a discussion of the risks you should carefully consider before deciding to invest in our ordinary shares.

Nasdaq Capital Market symbol

“BYSI”

Unless otherwise stated, all information in this prospectus supplement is based on 40,322,320 ordinary shares outstanding as of September 30, 2025 and does not include, as of that date, the following outstanding awards under the 2017 Omnibus Incentive Plan, as amended and restated as of September 18, 2020 (the “2017 Incentive Plan”): 2,736,015 options, of which 2,060,833 were vested (with a weighted average exercise price of $4.86 per share) and 675,182 were unvested (with a weighted average exercise price of $5.46 per share) (of which 396,302 were subject to time-based vesting and 278,880 were subject to performance-based vesting).

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RISK FACTORS

Investing in our securities involves risks. Before making an investment decision, you should carefully consider the risks described below, on page 5 of the accompanying prospectus, under “Risk Factors” in our most recent annual report on Form 10-K, any subsequent quarterly reports on Form 10-Q and current reports on Form 8-K we file after the date of this prospectus supplement, together with all of the other information appearing in this prospectus supplement or the accompanying prospectus or incorporated by reference herein or therein, including in light of your particular investment objectives and financial circumstances. In addition to those risk factors, there may be additional risks and uncertainties of which management is not aware or focused on, or that management deems immaterial. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The trading price of our securities could decline due to any of these risks, and you may lose all or part of your investment.

Risks Related to Our Ordinary Shares and this Offering

The trading prices of our ordinary shares are likely to be volatile, which could result in substantial losses to you.

The trading price of our ordinary shares is likely to be volatile and could fluctuate widely in response to a variety of factors, many of which are beyond our control. In addition, the performance and fluctuation of the market prices of other companies with business operations located mainly in China that have listed their securities in the United States may affect the volatility in the price of and trading volumes for our ordinary shares. Some of these companies have experienced significant volatility. The trading performances of these Chinese companies’ securities at the time of or after their offerings may affect the overall investor sentiment towards other Chinese companies listed in the United States and consequently may impact the trading performance of our ordinary shares.

In addition to market and industry factors, the price and trading volume for our ordinary shares may be highly volatile for specific business reasons, including:

• announcements of regulatory approval or a complete response letter, or specific label indications or patient populations for its use, or changes or delays in the regulatory review process;

• announcements of therapeutic innovations or new products by us or our competitors;

• adverse actions taken by regulatory agencies with respect to our clinical trials, manufacturing supply chain or sales and marketing activities;

• any adverse changes to our relationship with manufacturers or suppliers;

• the results of our testing and clinical trials;

• the results of our efforts to acquire or license additional product candidates;

• variations in the level of expenses related to our existing product candidates or preclinical studies and clinical trials;

• any intellectual property infringement actions in which we may become involved;

• announcements concerning our competitors or the pharmaceutical industry in general;

• achievement of expected product sales and profitability;

• manufacturing, supply or distribution shortages;

• variations in our results of operations;

• announcements about our earnings that are not in line with analyst expectations;

• publication of operating or industry metrics by third parties, including government statistical agencies, that differ from expectations of industry or financial analysts;

• research reports and changes in financial estimates by securities research analysts;

• announcements made by us or our competitors of new product and service offerings, acquisitions, strategic relationships, joint ventures or capital commitments;

• press reports, whether or not true, about our business;

• additions to, or departures of, our management;

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• fluctuations of exchange rates between the RMB and the U.S. dollar;

• release or expiry of lock-up or other transfer restrictions on our outstanding ordinary shares;

• sales or perceived potential sales of additional ordinary shares;

• sales of our ordinary shares by us, our executive officers and directors or our shareholders in the future;

• general economic and market conditions and overall fluctuations in the U.S. equity markets;

• changes in accounting principles; and

• changes or developments in the Chinese or global regulatory environment.

Any of these factors may result in large and sudden changes in the volume and trading price of our ordinary shares. In the past, following periods of volatility in the market price of a company’s securities, shareholders have often instituted securities class action litigation against that company. If we are involved in a class action suit, it could divert the attention of management, and, if adversely determined, have a material adverse effect on our financial condition and results of operations.

In addition, the stock market, in general, and small pharmaceutical and biotechnology companies have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our ordinary shares, regardless of our actual operating performance. Further, factors related to financial markets beyond our control may cause our ordinary shares price to decline rapidly and unexpectedly.

Sales or the availability for sales of substantial amounts of our ordinary shares in the public market could cause the price of our ordinary shares to decline significantly.

Sales of our ordinary shares or other equity securities in the public market after this offering, or the perception that these sales could occur, could cause the market price of our ordinary shares to decline significantly. Immediately after this offering, we will have 41,122,320 ordinary shares outstanding. All ordinary shares sold in this offering will be freely transferable by persons other than our “affiliates” without restriction or additional registration. As of September 30, 2025, we had 40,322,320 ordinary shares outstanding. Of these shares, 18,625,795 ordinary shares have been registered under the Securities Act, and are freely transferable by persons other than our “affiliates” without restriction or additional registration; the remaining shares outstanding have not been registered under the Securities Act and may be offered or sold only pursuant to an effective registration statement or pursuant to an available exemption from the registration requirements. If these shares are sold, or if it is perceived that they will be sold, in the public market, the trading price of our ordinary shares could decline.

We have broad discretion to determine how to use the funds raised in this offering, and may use them in ways that may not enhance our operating results or the price of our ordinary shares.

Our management team will have broad discretion as to the use of the net proceeds from our issuance of ordinary shares from this offering, and we could use such proceeds for purposes other than those contemplated at the date of this prospectus supplement. Accordingly, you will be relying on the judgment of our management team with regard to the use of those net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used effectively. The failure of our management team to use such funds effectively, if any, could have a negative impact on our business, financial condition, operating results and cash flows.

Because we do not expect to pay dividends in the foreseeable future, you must rely on price appreciation of the ordinary shares for return on your investment.

We intend to retain most, if not all, of our available funds and earnings to fund the development and growth of our business. As a result, we do not expect to pay any cash dividends in the foreseeable future. Therefore, you should not rely on an investment in our ordinary shares as a source for any future dividend income.

Our board of directors has significant discretion as to whether to distribute dividends. Our shareholders may, by ordinary resolution, declare dividends, but no dividend shall exceed the amount recommended by our board of directors. Even if our board of directors decides to declare and pay dividends, the timing, amount and form of future dividends, if any, will depend on, among other things, our future results of operations and cash flow, our capital requirements and surplus, the amount of distributions, if any, received by us from our subsidiaries, our financial

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condition, contractual restrictions and other factors deemed relevant by our board of directors. Accordingly, the return on your investment in our ordinary shares will likely depend entirely upon any future price appreciation of the ordinary shares. Our ordinary shares may not appreciate in value or even maintain the price at which you purchased the ordinary shares. You may not realize a return on your investment in the ordinary shares, and you may even lose your entire investment in the ordinary shares.

You will experience immediate and substantial dilution after giving effect to the net proceeds from this offering.

If you purchase ordinary shares in this offering, you will pay more for your ordinary shares than the amount paid by existing shareholders for their ordinary shares on a per ordinary share basis. As a result, you will experience immediate and substantial dilution of $2.93 per ordinary share, representing the difference between our as adjusted net tangible book value per ordinary share as of September 30, 2025, the issuance and sale of ordinary shares in this offering and the offering price of $2.50 per ordinary share, as set forth on the cover page of this prospectus supplement. In addition, you may experience further dilution to the extent that we make any grants of equity-based awards.

Future sales and issuances of our ordinary shares, including pursuant to our equity incentive plans, could result in additional dilution of the percentage ownership of our shareholders and could cause our share price to fall.

Additional capital will be needed in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our shareholders may experience substantial dilution. We may sell ordinary shares, convertible securities or other equity securities in one or more transactions at prices and in a manner we determine from time to time. If we sell ordinary shares, convertible securities or other equity securities in more than one transaction, our shareholders will experience additional dilution, and any such issuances may result in downward pressure on the price of our ordinary shares. We also cannot assure you that we will be able to sell shares or other securities in any other offering at a price per ordinary share that is equal to or greater than the price per share paid by the investor in this offering, and investors purchasing ordinary shares or other securities in the future could have rights superior to existing shareholders.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the documents incorporated by reference herein and any accompanying prospectus may contain or incorporate forward-looking statements that are based on our management’s belief and assumptions and on information currently available to our management. Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements.

All statements other than statements of historical facts are forward-looking statements. These forward-looking statements are made under the “safe harbor” provision under Section 27A of the Securities Act and 21E of the Exchange Act and as defined in the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue” or the negative of these terms or other comparable terminology. These statements are only predictions. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties and other factors, which are, in some cases, beyond our control and which could materially affect results. You should refer to the “Risk Factors” section of this prospectus supplement, the accompanying prospectus, and our periodic and current reports filed with the SEC for specific risks that could cause actual results to be significantly different from those expressed or implied by these forward-looking statements. If one or more of these risks or uncertainties occur, or if our underlying assumptions prove to be incorrect, actual events or results may vary significantly from those implied or projected by the forward-looking statements. No forward-looking statement is a guarantee of future performance. Forward-looking statements speak only as of the date made and we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. You should read this prospectus supplement, the accompanying prospectus and the documents that we reference in this prospectus supplement and have filed with the SEC as exhibits to the registration statement, of which this prospectus supplement is a part, completely and with the understanding that our actual future results may be materially different from any future results expressed or implied by these forward-looking statements.

Forward-looking statements in this prospectus supplement include, but are not limited to, statements about:

• the initiation, timing, progress and results of our studies in animals and clinical trials, and our research and development programs;

• our ability to advance our product candidates into, and successfully complete, clinical trials;

• our reliance on the success of our clinical-stage product candidates;

• the timing or likelihood of regulatory filings and approvals;

• our ability to address the concerns identified in the Complete Response Letter issued by the Food and Drug Administration, in November 2021 regarding the New Drug Application (“NDA”), seeking approval of Plinabulin in combination with granulocyte colony-stimulating factor for the prevention of chemotherapy-induced neutropenia;

• our ability to file the NDA submission for the non-small cell lung cancer indication with the National Medical Products Administration in China;

• the commercialization of our product candidates, if approved;

• our ability to develop sales and marketing capabilities;

• the pricing and reimbursement of our product candidates, if approved;

• the implementation of our business model, strategic plans for our business and technology;

• the scope of protection we are able to establish and maintain for intellectual property rights covering our product candidates and technology;

• our ability to operate our business without infringing the intellectual property rights and proprietary technology of third parties;

• costs associated with defending intellectual property infringement, product liability and other claims;

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• regulatory development in the United States, China and other jurisdictions;

• estimates of our expenses, future revenues, capital requirements and our needs for additional financing;

• the potential benefits of strategic collaboration agreements and our ability to enter into strategic arrangements;

• our ability to maintain and establish collaborations or obtain additional grant funding;

• the rate and degree of market acceptance of our product candidates;

• developments relating to our competitors and our industry, including competing therapies;

• our ability to effectively manage our anticipated growth;

• our ability to attract and retain qualified employees and key personnel;

• our future revenue, hiring plans, expenses, capital expenditures, capital requirements and share performance;

• the future trading price of our ordinary shares and impact of securities analysts’ reports on these prices;

• our ability to meet Nasdaq’s continued listing requirements;

• the impact of widespread health developments, and the responses thereto, which could materially and adversely affect, among other things, enrollment of patients in our clinical trials, timing and completion of regulatory or other required inspections, our expected timeline for data readouts of our clinical trials and certain regulatory filings for our product candidates, and the review and approval timeline of regulatory authorities; and

• other risks and uncertainties, including those listed under the caption “Risk Factors” in this prospectus supplement, the accompanying prospectus, and in our most recent annual report on Form 10-K.

The “Risk Factors” section of this prospectus supplement, the accompanying prospectus, and our reports filed with the SEC references the principal contingencies and uncertainties to which we believe we are subject, which should be considered in evaluating any forward-looking statements contained or incorporated by reference in this prospectus supplement.

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USE OF PROCEEDS

We estimate that the net proceeds from our issuance and sale of 800,000 ordinary shares in this offering will be approximately $2 million, after deducting estimated offering expenses payable by us. We intend to use the net proceeds from this offering to fund our research and development and for general corporate purposes. General corporate purposes may include the acquisition of companies or businesses, repayment and refinancing of debt, working capital, clinical trial expenditures, commercial expenditures and capital expenditures.

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DIVIDEND POLICY

We have never declared or paid cash dividends to our shareholders, and we do not intend to pay cash dividends in the foreseeable future. We intend to reinvest any earnings in developing and expanding our business. Any future determination relating to our dividend policy will be at the discretion of our board of directors and will depend on a number of factors, including future earnings, our financial condition, operating results, contractual restrictions, capital requirements, business prospects, our strategic goals and plans to expand our business, applicable law and other factors that our board of directors may deem relevant.

See “Risk Factors—Risks Related to Our Ordinary Shares and This Offering—Because we do not expect to pay dividends in the foreseeable future, you must rely on price appreciation of the ordinary shares for return on your investment.”

We are a holding company incorporated in the Cayman Islands. We will rely to some extent on dividends from our U.S. and PRC subsidiaries for payment of any dividends to our shareholders. PRC regulations may restrict the ability of our PRC subsidiaries to make such dividend payments to us. See “Risk Factors—Risks Related to Our Doing Business in China—In the future, we may rely to some extent on dividends and other distributions on equity from our principal operating subsidiaries to fund offshore cash and financing requirements” and “Business—Government Regulation—Chinese Regulation—Regulations Relating to Foreign Exchange and Dividend Distribution—Regulation of Dividend Distribution” in our most recent annual report on Form 10-K, incorporated herein by reference.

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DILUTION

If you invest in our ordinary shares in this offering, your interest will be diluted to the extent of the difference between the offering price per ordinary share and the as adjusted net tangible book value per ordinary share immediately after this offering.

As of September 30, 2025, our net tangible book value was approximately $(19.81) million, or $(0.49) per ordinary share. Our net tangible book value represents our total tangible assets less our total liabilities. Our net tangible book value per ordinary share is our net tangible book value divided by the number of ordinary shares outstanding as of September 30, 2025.

After giving effect to our issuance and sale of 800,000 ordinary shares in this offering at an offering price of $2.50 per ordinary share, as set forth on the cover page of this prospectus supplement, and after deducting estimated offering expenses payable by us, our as adjusted net tangible book value as of September 30, 2025 would have been $(17.84) million, or $(0.43) per ordinary share. This amount represents an immediate increase in as adjusted net tangible book value of $0.06 per ordinary share to existing shareholders and an immediate dilution in net tangible book value of $2.93 per ordinary share to the investor purchasing ordinary shares in this offering, as illustrated in the following table:

Offering price per share						$2.50
Historical net tangible book value per share as of September 30, 2025			$(0.49)
Increase in net tangible book value per share attributable to the investor in this offering			$0.06
As adjusted net tangible book value per share after offering						$(0.43)
Dilution in net tangible book value per share to the new investor						$2.93

The number of ordinary shares shown as issued and outstanding above as of September 30, 2025 does not include 2,736,015 options, of which 2,060,833 were vested (with a weighted average exercise price of $4.86 per share) and 675,182 were unvested (with a weighted average exercise price of $5.46 per share) (of which 396,302 were subject to time-based vesting and 278,880 were subject to performance-based vesting) under the 2017 Incentive Plan.

To the extent that any additional equity awards are granted under our 2017 Incentive Plan in the future, you will experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities may result in further dilution to our shareholders.

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CAPITALIZATION

The following table sets forth our cash, investments and total capitalization as of September 30, 2025, as follows:

• on an actual basis; and

• as adjusted to give effect to our issuance and sale of 800,000 ordinary shares in this offering based on a price of $2.50 per ordinary share, as set forth on the cover page of this prospectus supplement, after deducting the estimated offering expenses.

This table should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our unaudited condensed consolidated financial statements and related notes, each included in our most recent quarterly report on Form 10-Q, incorporated herein by reference.

			As of September 30, 2025
			Actual			As Adjusted
			(Unaudited) (in thousands of U.S. Dollars (“$”), except share amounts)
Cash and Cash Equivalents			12,483			14,453
Shareholders’ deficit
Ordinary shares ($0.0001 par value; 500,000,000 shares authorized, 40,322,320 shares issued and outstanding as of September 30, 2025)			4			4
Additional paid-in capital			373,602			375,572
Accumulated deficit			(406,294)			(406,294)
Accumulated other comprehensive income			913			913
Noncontrolling interests			11,965			11,965
Total shareholders’ deficit			(19,810)			(17,840)
Total capitalization			(19,810)			(17,840)

The number of ordinary shares shown as issued and outstanding in the above table as of September 30, 2025 does not include 2,736,015 options, of which 2,060,833 were vested (with a weighted average exercise price of $4.86 per share) and 675,182 were unvested (with a weighted average exercise price of $5.46 per share) (of which 396,302 were subject to time-based vesting and 278,880 were subject to performance-based vesting) under the 2017 Incentive Plan.

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LEGAL MATTERS

The validity of the ordinary shares relating to Cayman Islands law will be passed upon for us by Maples and Calder (Hong Kong) LLP. Certain legal matters relating to Chinese law will be passed upon for us by Beijing Dacheng Law Offices, LLP. Certain legal matters relating to U.S. law will be passed upon for us by Skadden, Arps, Slate, Meagher & Flom LLP, New York, New York.

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EXPERTS

The consolidated financial statements of BeyondSpring Inc. as of and for the years ended December 31, 2024 and 2023 appearing in BeyondSpring Inc.’s Annual Report on Form 10-K for the year ended December 31, 2024 have been audited by Marcum LLP, independent registered public accounting firm, as set forth in their report thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

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ENFORCEABILITY OF CIVIL LIABILITIES

We are incorporated under the laws of the Cayman Islands as an exempted company with limited liability. We incorporated in the Cayman Islands because of certain benefits associated with being a Cayman Islands corporation, such as political and economic stability, an effective judicial system, a favorable tax system, the absence of foreign exchange control or currency restrictions and the availability of professional and support services. However, the Cayman Islands have a less developed body of securities laws that provide significantly less protection to investors as compared to the securities laws of the United States. In addition, Cayman Islands companies may not have standing to sue before the federal courts of the United States.

A portion of our assets, including certain Chinese patents, are located in China. In addition, some of our directors and officers are residents of jurisdictions other than the United States and all or a substantial portion of their assets are located outside the United States. As a result, it may be difficult for investors to effect service of process within the United States upon us or our directors and officers, or to enforce against us or them judgments obtained in United States courts, including judgments predicated upon the civil liability provisions of the securities laws of the United States or any state in the United States.

Maples and Calder (Hong Kong) LLP, our counsel as to Cayman Islands law, and Beijing Dacheng Law Offices, LLP, our counsel as to Chinese law, have respectively advised us that the courts of the Cayman Islands and China are, respectively, unlikely (1) to recognize and enforce judgments of United States courts obtained against us or our directors or officers that are predicated upon the civil liability provisions of the securities laws of the United States or any state in the United States, and (2) in original actions brought in the Cayman Islands to impose liabilities against us or our directors or officers that are predicated upon the civil liability provisions of federal securities laws of the United States or the securities laws of any state in the United States so far as the liabilities imposed by those provisions are penal in nature.

Maples and Calder (Hong Kong) LLP has further advised us that although there is no statutory enforcement in the Cayman Islands of judgments obtained in the United States (and the Cayman Islands are not a party to any treaties for the reciprocal enforcement or recognition of such judgments), the courts of the Cayman Islands will at common law, recognize and enforce a foreign money judgment of a foreign court of competent jurisdiction without any re-examination of the merits of the underlying dispute based on the principle that a judgment of a competent foreign court imposes upon the judgment debtor an obligation to pay the liquidated sum for which such judgment has been given, provided such judgment (1) is given by a foreign court of competent jurisdiction, (2) imposes on the judgment debtor a liability to pay a liquidated sum for which the judgment has been given, (3) is final and conclusive, (4) is not in respect of taxes, a fine or a penalty, (5) was not obtained in a manner and is not of a kind the enforcement of which is contrary to natural justice or the public policy of the Cayman Islands, (6) not inconsistent with a Cayman Islands judgement in respect of the same matter and (7) not impeachable on the grounds of fraud. A Cayman Islands Court may stay enforcement proceedings if concurrent proceedings are being brought elsewhere.

Beijing Dacheng Law Offices, LLP has advised us that the recognition and enforcement of foreign judgments are provided for under the PRC Civil Procedure Law. Chinese courts may recognize and enforce foreign judgments in accordance with the requirements of the PRC Civil Procedure Law based either on treaties between China and the country where the judgment is made or on principles of reciprocity between jurisdictions. Beijing Dacheng Law Offices, LLP has advised us further that under Chinese law, courts in China will not recognize or enforce a foreign judgment against us or our directors and officers if they decide that the judgment violates the basic principles of Chinese law or national sovereignty, security or social public interest. As there exists no treaty or other form of reciprocity between China and the United States governing the recognition and enforcement of judgments as of the date of this prospectus supplement, including those predicated upon the liability provisions of the United States federal securities laws, there is uncertainty whether and on what basis a Chinese court would enforce judgments rendered by United States courts. In addition, because there is no treaty or other form of reciprocity between the Cayman Islands and China governing the recognition and enforcement of judgments as of the date of this prospectus supplement, there is further uncertainty as to whether and on what basis a PRC court would enforce judgments rendered by a Cayman Islands court.

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WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement, of which this prospectus supplement is a part, with respect to the ordinary shares that we will offer. This prospectus supplement and any accompanying prospectus do not contain all the information contained in the registration statement, including its exhibits and schedules. You should refer to the registration statement, including the exhibits and schedules, for further information about us and the ordinary shares we may offer. Statements we make in this prospectus supplement and any accompanying prospectus about certain contracts or other documents are not necessarily complete. When we make such statements, we refer you to the copies of the contracts or documents that are filed as exhibits to the registration statement, because those statements are qualified in all respects by reference to those exhibits. The registration statement, including exhibits and schedules, is on file at the office of the SEC and may be inspected without charge.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC’s website at www.sec.gov. We maintain a corporate website at www.beyondspringpharma.com. We do not incorporate the information on our website into this prospectus supplement or any accompanying prospectus and you should not consider any information on, or that can be accessed through, our website as part of this prospectus supplement or any accompanying prospectus (other than those filings with the SEC that we specifically incorporate by reference into this prospectus supplement or any accompanying prospectus).

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information in documents we file with it. This means that we can disclose important information to you by referring you to those documents. Each document incorporated by reference is current only as of the date of such document, and the incorporation by reference of such documents shall not create any implication that there has been no change in our affairs since the date thereof or that the information contained therein is current as of any time subsequent to its date. The information incorporated by reference is considered to be a part of this prospectus supplement and should be read with the same care. When we update the information contained in documents that have been incorporated by reference by making future filings with the SEC, the information incorporated by reference in this prospectus supplement is considered to be automatically updated and superseded. In other words, in the case of a conflict or inconsistency between information contained in this prospectus supplement and information incorporated by reference into this prospectus supplement, you should rely on the information contained in the document that was filed later.

We incorporate by reference the documents listed below:

• our annual report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on March 27, 2025;

• our quarterly reports on Form 10-Q for the fiscal quarters ended March 31, 2025, June 30, 2025 and September 30, 2025, filed with the SEC on May 12, 2025, August 13, 2025 and November 12, 2025, respectively;

• our current reports on Form 8-K filed with the SEC on January 28, 2025, February 25, 2025, April 11, 2025, July 3, 2025, September 16, 2025 and September 23, 2025;

• the description of share capital contained in the Registration Statement on Form 8-A, as filed with the SEC on March 6, 2017 (File No. 001-38024), and including any amendments or reports filed for the purpose of updating such description; and

• with respect to each offering of ordinary shares under this prospectus supplement, all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date on which this registration statement is first filed with the SEC and until the termination or completion of that offering under this prospectus supplement.

Unless expressly incorporated by reference, nothing in this prospectus supplement shall be deemed to incorporate by reference information furnished to, but not filed with, the SEC. Copies of all documents incorporated by reference in this prospectus supplement, other than exhibits to those documents unless such exhibits are specially incorporated by reference in this prospectus supplement, will be provided at no cost to each person, including any beneficial owner, who receives a copy of this prospectus supplement on the written or oral request of that person made to:

BeyondSpring Inc.

100 Campus Drive, West Side, 4^th Floor, Suite 410

Florham Park, New Jersey 07932

Tel: +1 (646) 305-6387

Attention: Chief Executive Officer

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PROSPECTUS

BeyondSpring Inc.

10,000,000

Ordinary Shares

This prospectus relates to the offer and sale, from time to time, of up to 10,000,000 of our ordinary shares. The offer and sale of 8,728,813 of the ordinary shares was previously registered pursuant to our registration on Form F-3 (File No. 333-257639), which we filed with the U.S. Securities and Exchange Commission (the “SEC”) on July 2, 2021, and was declared effective by the SEC on July 13, 2021 (the “prior registration statement”). Pursuant to Rule 429 under the Securities Act of 1933, as amended (the “Securities Act”), this prospectus updates the prior registration statement and includes the ordinary shares previously registered by us pursuant to such prior registration statement.

We may offer the ordinary shares for sale directly to purchasers or through underwriters, dealers or agents to be designated at a future date. If any underwriters, dealers or agents are involved in the sale of any of the ordinary shares, their names, and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. See the “Plan of Distribution” and “About this Prospectus” sections for more information.

You should read this prospectus and the applicable prospectus supplement as well as the documents incorporated or deemed to be incorporated by reference in this prospectus carefully before you invest in our securities together with additional information described under the heading “Where You Can Find More Information.” Our ordinary shares are quoted on the Nasdaq Capital Market under the symbol “BYSI.” The closing price of our ordinary shares, as reported on the Nasdaq Capital Market on August 12, 2025, was $2.01.

Investing in our securities involves risks. Risks associated with an investment in our securities will be described in the applicable prospectus supplement and certain of our filings with the Securities and Exchange Commission, as described under “Risk Factors” on page 5 of this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

This Prospectus is dated August 18, 2025

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ABOUT THIS PROSPECTUS			1
OUR COMPANY			2
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			3
RISK FACTORS			5
USE OF PROCEEDS			6
CAPITALIZATION			6
DESCRIPTION OF SHARE CAPITAL			7
PLAN OF DISTRIBUTION			16
WHERE YOU CAN FIND MORE INFORMATION			18
INCORPORATION BY REFERENCE			19
ENFORCEMENT OF CIVIL LIABILITIES			20
LEGAL MATTERS			21
EXPERTS			22

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the SEC under the Securities Act with respect to our ordinary shares. The term registration statement means the prior registration statement and any and all amendments including the schedules and exhibits to the prior registration statement and this registration statement, which is combined with the prior registration statement pursuant to Rule 429 under the Securities Act, and is being amended by this Post-Effective Amendment No.1. We may, from time to time, offer and sell, in one or more offerings, up to 10,000,000 of our ordinary shares. The offer and sale of securities under this prospectus may be made from time to time, in one or more offerings, in any manner described under the section in this prospectus entitled “Plan of Distribution.”

This prospectus only provides you with a general description of our ordinary shares that we may offer. Each time we sell our ordinary shares, we will provide a prospectus supplement containing specific information about the offering, if required. Any such prospectus supplement may include a discussion of any risk factors or other special considerations that apply to that offering. The prospectus supplement may also add, update or change the information in this prospectus. If there is any inconsistency between the information in this prospectus and any prospectus supplement, you should rely on the information in that prospectus supplement. Before purchasing any of our ordinary shares, you should carefully read both this prospectus and any prospectus supplement together with additional information incorporated by reference herein and described under the headings “Where You Can Find More Information” and “Incorporation by Reference.”

The registration statement containing this prospectus, including exhibits to the registration statement, provides additional information about us and the securities offered under this prospectus. The registration statement can be read on the SEC website or at the SEC office mentioned under the heading “Where You Can Find More Information.”

When acquiring any ordinary shares described in this prospectus, you should rely only on the information provided in this prospectus and in any applicable prospectus supplement, including the information incorporated by reference. Neither we nor any underwriter, dealer or agent have authorized anyone to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not offering our ordinary shares in any jurisdiction where the offer or sale is prohibited. You should not assume that the information in this prospectus, any prospectus supplement or any document incorporated by reference is truthful or complete at any date other than the date mentioned on the cover page of any such document.

We may sell our ordinary shares to underwriters who will sell the securities to the public at a fixed offering price or at varying prices determined at the time of sale. The applicable prospectus supplement will contain the names of the underwriters, dealers or agents, if any, together with the terms of offering, the compensation of those underwriters, dealers or agents and the net proceeds to us. Any underwriters, dealers or agents participating in the offering may be deemed “underwriters” within the meaning of the Securities Act.

Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus to:

“BeyondSpring,” the “Company,” “our Company,” the “Registrant,” “us,” “we,” “our” and similar designations refer to Dalian Wanchun Biotechnology Co., Ltd. (the “Wanchun Biotech”), the former holding company of our U.S. subsidiary, and its consolidated subsidiaries, as a whole, prior to the completion of our internal corporate reorganization, and BeyondSpring Inc. and its consolidated subsidiaries, after the completion of our internal corporate reorganization on July 20, 2015.

“Our shares,” “ordinary shares” and similar expressions refer to the Registrant’s ordinary shares, par value $0.0001 per share.

“Dollars,” “U.S.$” or “$” refer to United States Dollars.

“PRC” or “China” refer to the People’s Republic of China.

“Exchange Act” refers to the Securities Exchange Act of 1934, as amended.

“Securities Act” refers to the Securities Act of 1933, as amended.

“FINRA” refers to the Financial Industry Regulatory Authority.

“Nasdaq” refers to the Nasdaq Capital Market.

“SEC” or the “Commission” refers to the United States Securities and Exchange Commission.

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OUR COMPANY

We are a clinical stage global biopharmaceutical company focused on developing innovative therapies to improve clinical outcomes for patients with high unmet medical needs. Our first-in-class lead asset, Plinabulin, which has been administered to over 700 cancer patients with generally good tolerability, is being developed as a potential “pipeline in a drug” in various cancer indications as a direct anti-cancer agent. Plinabulin binds in a unique pocket of tubulin and activates the immune defense protein GEF-H1, which leads to indication of innate and adaptive immunity via dendritic cell maturation. We own global rights to Plinabulin in all countries except China. We own a 57.97% interest in our Chinese subsidiary, which owns 100% of the rights to Plinabulin in China. We are also developing three small molecule immune agents, which are currently in preclinical stages. In addition, we founded and continue to own an equity stake in SEED Therapeutics Inc. (“SEED”). SEED is utilizing a proprietary Targeted Protein Degradation (“TPD”) drug discovery platform, or “molecular glue” technology, to develop innovative therapeutic agents from internal research and development efforts and with our collaborators on currently undruggable protein targets. SEED is partnering with Eli Lilly and Co. and Eisai Co., Ltd. to discover and develop new chemical entities through this proprietary TPD platform which could produce therapeutic benefits to patients suffering from oncology and central nervous system (CNS) disease, among others.

BeyondSpring Inc. was incorporated as an exempted company under the laws of the Cayman Islands on November 21, 2014. In July 2015, we completed our internal restructuring. Our principal executive offices are located at 100 Campus Drive, West Side, 4th Floor, Suite 410, Florham Park, New Jersey 07932 and our telephone number is +1 (646) 305-6387. Our registered office in the Cayman Islands is located at the offices of Harneys Fiduciary (Cayman) Limited, 4th Floor, Harbour Place, 103 South Church Street, P.O. Box 10240, Grand Cayman KY1-1002, Cayman Islands. Our website is www.beyondspringpharma.com. The information contained on, or that can be accessed through, our website does not constitute part of this prospectus or any accompanying prospectus supplement and is not incorporated by reference herein or therein.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, the documents incorporated by reference herein and any accompanying prospectus supplement may contain or incorporate forward-looking statements that are based on our management’s belief and assumptions and on information currently available to our management. Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements stated in or implied by these forward-looking statements.

All statements other than statements of historical facts are forward-looking statements. These forward-looking statements are made under the “safe harbor” provision under Section 27A of the Securities Act and 21E of the Exchange Act and as defined in the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue” or the negative of these terms or other comparable terminology. These statements are only predictions. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties and other factors, which are, in some cases, beyond our control and which could materially affect results. You should refer to the “Risk Factors” section of this prospectus, any accompanying prospectus supplement, and our periodic and current reports filed with the SEC for specific risks that could cause actual results to be significantly different from those stated in or implied by these forward-looking statements. If one or more of these risks or uncertainties occur, or if our underlying assumptions prove to be incorrect, actual events or results may vary significantly from those implied or projected by the forward-looking statements. No forward-looking statement is a guarantee of future performance. Forward-looking statements speak only as of the date made and we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. You should read this prospectus, any accompanying prospectus supplement and the documents that we reference in this prospectus and have filed with the SEC as exhibits to the registration statement, of which this prospectus is a part, completely and with the understanding that our actual future results may be materially different from any future results stated in or implied by these forward-looking statements.

Forward-looking statements in this prospectus include, but are not limited to, statements about:

• the initiation, timing, progress and results of our studies in animals and clinical trials, and our research and development programs;

• our ability to advance our product candidates into, and successfully complete, clinical trials;

• our reliance on the success of our clinical-stage product candidates;

• the timing or likelihood of regulatory filings and approvals;

• our ability to address the concerns identified in the Complete Response Letter issued by the Food and Drug Administration, in November 2021 regarding the New Drug Application (“NDA”), seeking approval of Plinabulin in combination with granulocyte colony-stimulating factor for the prevention of chemotherapy-induced neutropenia;

• our ability to file the NDA submission for the non-small cell lung cancer indication with the National Medical Products Administration in China;

• the commercialization of our product candidates, if approved;

• our ability to develop sales and marketing capabilities;

• the pricing and reimbursement of our product candidates, if approved;

• the implementation of our business model, strategic plans for our business and technology;

• the scope of protection we are able to establish and maintain for intellectual property rights covering our product candidates and technology;

• our ability to operate our business without infringing the intellectual property rights and proprietary technology of third parties;

• costs associated with defending intellectual property infringement, product liability and other claims;

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• regulatory development in the United States, China and other jurisdictions;

• estimates of our expenses, future revenues, capital requirements and our needs for additional financing;

• the potential benefits of strategic collaboration agreements and our ability to enter into strategic arrangements;

• our ability to maintain and establish collaborations or obtain additional grant funding;

• the rate and degree of market acceptance of our product candidates;

• developments relating to our competitors and our industry, including competing therapies;

• our ability to effectively manage our anticipated growth;

• our ability to attract and retain qualified employees and key personnel;

• our future revenue, hiring plans, expenses, capital expenditures, capital requirements and share performance;

• the future trading price of our ordinary shares and impact of securities analysts’ reports on these prices;

• our ability to meet Nasdaq’s continued listing requirements;

• the impact of widespread health developments, and the responses thereto, which could materially and adversely affect, among other things, enrollment of patients in our clinical trials, timing and completion of regulatory or other required inspections, our expected timeline for data readouts of our clinical trials and certain regulatory filings for our product candidates, and the review and approval timeline of regulatory authorities; and

• other risks and uncertainties, including those listed under the caption “Risk Factors” in this prospectus, any accompanying prospectus supplement, and in our most recent annual report on Form 10-K.

The “Risk Factors” section of this prospectus, any accompanying prospectus supplement, and our periodic and current reports filed with the SEC references the principal contingencies and uncertainties to which we believe we are subject, which should be considered in evaluating any forward-looking statements contained or incorporated by reference in this prospectus or in any prospectus supplement.

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RISK FACTORS

Investing in our ordinary shares involves risks. Before making an investment decision, you should carefully consider the risks described under “Risk Factors” in the applicable prospectus supplement and in our most recent annual report on Form 10-K, any subsequent quarterly reports on Form 10-Q and current reports on Form 8-K we file after the date of this prospectus, together with all of the other information appearing in this prospectus or incorporated by reference into this prospectus and any applicable prospectus supplement, in light of your particular investment objectives and financial circumstances. In addition to those risk factors, there may be additional risks and uncertainties of which management is not aware or focused on or that management deems immaterial. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The trading price of our securities could decline due to any of these risks, and you may lose all or part of your investment.

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USE OF PROCEEDS

Our management will have broad discretion over the use of the net proceeds from the sale of our ordinary shares pursuant to this prospectus, both in terms of the purposes for which they will be used and the amounts that will be allocated for each purpose. We intend to use the net proceeds from the sale of any securities offered under this prospectus for funding our research and development and for general corporate purposes unless otherwise indicated in the applicable prospectus supplement. General corporate purposes may include the acquisition of companies or businesses, repayment and refinancing of debt, working capital, clinical trial expenditures, commercial expenditures and capital expenditures.

CAPITALIZATION

Our capitalization will be set forth in a prospectus supplement to this prospectus.

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DESCRIPTION OF SHARE CAPITAL

We are a Cayman Islands exempted company with limited liability and our affairs are governed by our memorandum and articles of association, as amended and restated from time to time and the Companies Act (As Revised) of the Cayman Islands, which is referred to as the Companies Act below, and the common law of the Cayman Islands.

As of June 30, 2025, our authorized share capital was $50,000, consisting of 500,000,000 ordinary shares, par value of U.S. $0.0001 each. As of June 30, 2025, 40,322,320 ordinary shares were issued and outstanding. All of our issued and outstanding ordinary shares are fully paid.

The following are summaries of material provisions of our current amended and restated memorandum and articles of association as adopted by a special resolution of our shareholders passed on February 24, 2017 and that became effective immediately prior to the completion of our initial public offering (“IPO”), in March 2017, insofar as they relate to the material terms of our ordinary shares.

Objects of Our Company

Under our amended and restated memorandum and articles of association, the objects of our Company are unrestricted and we have the full power and authority to carry out any object not prohibited by the law of the Cayman Islands.

Ordinary Shares

Our ordinary shares are issued in registered form and are issued when registered in our register of members. Our shareholders who are non-residents of the Cayman Islands may freely hold and vote their shares.

Dividends

The holders of our ordinary shares are entitled to such dividends as may be declared by our board of directors. In addition, our shareholders may by ordinary resolution declare a dividend, but no dividend may exceed the amount recommended by our directors. Under Cayman Islands law, dividends may be declared and paid only out of funds legally available therefor, namely out of either profit or our share premium account, provided that in no circumstances may a dividend be paid if this would result in our Company being unable to pay its debts as they fall due in the ordinary course of business.

Voting Rights

Voting at any shareholders’ meeting is by show of hands unless a poll (before or on the declaration of the result of the show of hands) is demanded. A poll may be demanded by the chairman of such meeting or any one or more shareholders who together hold not less than 10% of the voting share capital of our Company present in person or by proxy.

A quorum required for a meeting of shareholders consists of one or more shareholders present and holding not less than a majority of all voting share capital of our Company in issue. Shareholders may be present in person or by proxy or, if the shareholder is a legal entity, by its duly authorized representative. Shareholders’ meetings may be convened by our board of directors on its own initiative or upon a request to the directors by shareholders holding at the date of deposit of the requisition not less than ten percent of our voting share capital in issue. Advance notice of at least seven calendar days is required for the convening of our annual general shareholders’ meeting and any other general shareholders’ meeting.

An ordinary resolution to be passed at a meeting by the shareholders requires the affirmative vote of a simple majority of the votes attaching to the ordinary shares cast at a meeting, while a special resolution requires the affirmative vote of no less than two-thirds of the votes attaching to the ordinary shares cast at a meeting. Both ordinary resolutions and special resolutions may also be passed by a unanimous written resolution signed by all the shareholders of our Company, as permitted by the Companies Act and our amended and restated memorandum and articles of association. A special resolution will be required for important matters such as a change of name or making changes to our amended and restated memorandum and articles of association. Holders of the ordinary shares may, among other things, divide or combine their shares by ordinary resolution.

Transfer of Ordinary Shares

Subject to the restrictions set out below, any of our shareholders may transfer all or any of his or her ordinary shares by an instrument of transfer in the usual or common form or any other form approved by our board of directors.

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Our board of directors may, in its absolute discretion, decline to register any transfer of any ordinary share which is not fully paid up or on which we have a lien. Our board of directors may also decline to register any transfer of any ordinary share unless:

• the instrument of transfer is lodged with us, accompanied by the certificate for the ordinary shares to which it relates and such other evidence as our board of directors may reasonably require to show the right of the transferor to make the transfer;

• the instrument of transfer is in respect of only one class of shares;

• the instrument of transfer is properly stamped, if required;

• in the case of a transfer to joint holders, the number of joint holders to whom the ordinary share is to be transferred does not exceed four; and

• a fee of such maximum sum as the Nasdaq Capital Market may determine to be payable or such lesser sum as our directors may from time to time require is paid to us in respect thereof.

If our board of directors refuse to register a transfer they shall, within two months after the date on which the instrument of transfer was lodged, send to each of the transferor and the transferee notice of such refusal.

The registration of transfers may, after compliance with any notice required of the Nasdaq Capital Market, be suspended and the register closed at such times and for such periods as our board of directors may from time to time determine, provided, however, that the registration of transfers shall not be suspended nor the register closed for more than 30 days in any year as our board of directors may determine.

Restructuring

A company may present a petition to the Grand Court of the Cayman Islands for the appointment of a restructuring officer on the grounds that the company:

(a)
is or is likely to become unable to pay its debts; and

(b)
intends to present a compromise or arrangement to its creditors (or classes thereof) either pursuant to the Companies Act, the law of a foreign country or by way of a consensual restructuring.

The Grand Court may, among other things, make an order appointing a restructuring officer upon hearing of such petition, with such powers and to carry out such functions as the court may order. At any time (i) after the presentation of a petition for the appointment of a restructuring officer but before an order for the appointment of a restructuring officer has been made, and (ii) when an order for the appointment of a restructuring officer is made, until such order has been discharged, no suit, action or other proceedings (other than criminal proceedings) shall be proceeded with or commenced against the company, no resolution to wind up the company shall be passed, and no winding up petition may be presented against the company, except with the leave of the court. However, notwithstanding the presentation of a petition for the appointment of a restructuring officer or the appointment of a restructuring officer, a creditor who has security over the whole or part of the assets of the company is entitled to enforce the security without the leave of the court and without reference to the restructuring officer appointed.

Liquidation

On a return of capital on winding up or otherwise (other than on conversion, redemption or purchase of shares), assets available for distribution among the holders of ordinary shares shall be distributed among the holders of our ordinary shares on a pro rata basis. If our assets available for distribution are insufficient to repay all of the paid-up capital, the assets will be distributed so that the losses are borne by our shareholders proportionately.

Calls on Shares and Forfeiture of Shares

Our board of directors may from time to time make calls upon shareholders for any amounts unpaid on their shares in a notice served to such shareholders at least 14 days prior to the specified time or times of payment. The shares that have been called upon and remain unpaid are subject to forfeiture.

Redemption, Repurchase and Surrender of Ordinary Shares

We may issue shares on terms that such shares are subject to redemption, at our option or at the option of the holders thereof, on such terms and in such manner as may be determined, before the issue of such shares, by our board of directors. Our Company may also repurchase any of our shares (including any redeemable shares) provided that

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the manner and terms of such purchase have been approved by our board of directors or by ordinary resolution of our shareholders, or are otherwise authorized by our amended and restated memorandum and articles of association. Under the Companies Act, the redemption or repurchase of any share may be paid out of the company’s profits or out of the proceeds of a fresh issue of shares made for the purpose of such redemption or repurchase, or out of capital (including share premium account and capital redemption reserve) if the company can, immediately following such payment, pay its debts as they fall due in the ordinary course of business. In addition, under the Companies Act no such share may be redeemed or repurchased (a) unless it is fully paid up, (b) if such redemption or repurchase would result in there being no shares outstanding, or (c) if the company has commenced liquidation. In addition, our Company may accept the surrender of any fully paid share for no consideration.

Variations of Rights of Shares

The rights attached to any class or series of shares (unless otherwise provided by the terms of issue of the shares of that class or series) may, subject to our amended and restated memorandum and articles of association, be varied with the consent in writing of the holders of not less than two thirds of the issued shares of that class or series or with the sanction of a special resolution passed at a general meeting of the holders of the shares of that class or series. The rights conferred upon the holders of the shares of any class issued shall not, unless otherwise expressly provided by the terms of issue of the shares of that class, be deemed to be varied by the creation or issue of further shares ranking pari passu with such existing class of shares.

Issuance of Additional Shares

Our amended and restated memorandum and articles of association authorize our board of directors to issue additional ordinary shares from time to time as our board of directors shall determine, to the extent of available authorized but unissued shares.

Our amended and restated memorandum and articles of association also authorize our board of directors to establish from time to time one or more series of preferred shares and to determine, with respect to any series of preferred shares, the terms and rights of that series, including:

• the designation of the series;

• the number of shares of the series;

• the dividend rights, dividend rates, conversion rights, voting rights; and

• the rights and terms of redemption and liquidation preferences.

Our board of directors may issue preferred shares without action by our shareholders to the extent authorized but unissued. Issuance of these shares may dilute the voting power of holders of ordinary shares.

Inspection of Books and Records

Holders of our ordinary shares will have no general right under Cayman Islands law to inspect or obtain copies of our list of shareholders or our corporate records (save for our memorandum and articles of association, our register of mortgages and charges and special resolutions of our shareholders). However, we will provide our shareholders with annual audited financial statements. See “Where You Can Find Additional Information.”

Anti-Takeover Provisions

Some provisions of our amended and restated memorandum and articles of association may discourage, delay or prevent a change of control of our Company or management that shareholders may consider favorable, including provisions that: authorize our board of directors to issue preferred shares in one or more series and to designate the price, rights, preferences, privileges and restrictions of such preferred shares without any further vote or action by our shareholders; and limit the ability of shareholders to requisition and convene general meetings of shareholders.

However, under Cayman Islands law, our directors may only exercise the rights and powers granted to them under our memorandum and articles of association for a proper purpose and for what they believe in good faith to be in the best interests of our Company.

General Meetings of Shareholders and Shareholder Proposals

Our shareholders’ general meetings may be held in such place within or outside the Cayman Islands as our board of directors considers appropriate.

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As a Cayman Islands exempted company, we are not obliged by the Companies Act to call shareholders’ annual general meetings. Our amended and restated memorandum and articles of association provide that we may (but are not obliged to) hold a general meeting in each year as our annual general meeting.

Shareholders’ annual general meetings and any other general meetings of our shareholders may be convened by a majority of our board of directors. Our board of directors shall give not less than seven calendar days’ written notice of a shareholders’ meeting to those persons whose names appear as members in our register of members on the date the notice is given (or on any other date determined by our directors to be the record date for such meeting) and who are entitled to vote at the meeting.

Cayman Islands law provides shareholders with only limited rights to requisition a general meeting, and does not provide shareholders with any right to put any proposal before a general meeting. However, these rights may be provided in a company’s articles of association. Our amended and restated memorandum and articles of association allow our shareholders holding shares representing in aggregate not less than ten percent of our voting share capital in issue, to requisition an extraordinary general meeting of our shareholders, in which case our directors are obliged to call such meeting and to put the resolutions so requisitioned to a vote at such meeting; however, our amended and restated memorandum and articles of association do not provide our shareholders with any right to put any proposals before annual general meetings or extraordinary general meetings not called by such shareholders.

Exempted Company

We are an exempted company with limited liability under the Companies Act. The Companies Act distinguishes between ordinary resident companies and exempted companies. Any company that is registered in the Cayman Islands but conducts business mainly outside of the Cayman Islands may apply to be registered as an exempted company. The requirements for an exempted company are essentially the same as for an ordinary company except that an exempted company:

• does not have to file an annual return of its shareholders with the Registrar of Companies;

• is not required to open its register of members for inspection;

• does not have to hold an annual general meeting;

• may issue shares with no par value;

• may obtain an undertaking against the imposition of any future taxation (such undertakings are usually given for a period of up to 30 years);

• may register by way of continuation in another jurisdiction and be deregistered in the Cayman Islands;

• may register as a limited duration company; and

• may register as a segregated portfolio company.

“Limited liability” means that the liability of each shareholder is limited to the amount unpaid by the shareholder on the shares of the company (except in exceptional circumstances, such as involving fraud, the establishment of an agency relationship or an illegal or improper purpose or other circumstances in which a court may be prepared to pierce or lift the corporate veil).

Register of Members

Under Cayman Islands law, we must keep a register of members and there should be entered therein:

• the names and addresses of the members, together with a statement of the shares held by each member, and such statement shall confirm (i) the amount paid or agreed to be considered as paid, on the shares of each member (ii) the number and category of shares held by each member, and (iii) whether each relevant category of shares held by a member carries voting rights under the articles of association of the company, and if so, whether such voting rights are conditional;

• the date on which the name of any person was entered on the register as a member; and

• the date on which any person ceased to be a member.

Under Cayman Islands law, the register of members of our Company is prima facie evidence of the matters set out therein (i.e. the register of members will raise a presumption of fact on the matters referred to above unless

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rebutted) and a member registered in the register of members should be deemed as a matter of Cayman Islands law to have legal title to the shares as set against its name in the register of members. Once our register of members has been updated, the shareholders recorded in the register of members should be deemed to have legal title to the shares set against their name.

If the name of any person is incorrectly entered in, or omitted from, our register of members, or if there is any default or unnecessary delay in entering on the register the fact of any person having ceased to be a member of our company, the person or member aggrieved (or any member of our Company or our Company itself) may apply to the Cayman Islands Grand Court for an order that the register be rectified, and the Court may either refuse such application or it may, if satisfied of the justice of the case, make an order for the rectification of the register.

History of Securities Issuances

The following is a summary of our securities issuances for the past three years.

From January 1, 2022 to December 31, 2024, we issued (i) an aggregate of 15,970 ordinary shares upon the exercise of share options granted to our executive officers and employees, with a weighted average exercise price of $0.95 per share; (ii) an aggregate of 101,098 restricted shares to our executive officers and non-employee directors, all of which are fully vested as of the date of this prospectus; (iii) an aggregate of 76,014 ordinary shares upon the achievement of certain time-based and performance-based conditions with respect to research and development progress to one former employee, with a total fair market value equal to RMB 800,000 (approximately $112,000); (iii) 1,271,187 ordinary shares to an investor in a registered offering. The gross proceeds from the offering were approximately $3.0 million, before deducting expenses.

In connection with our initial public offering, we adopted the 2017 Omnibus Incentive Plan to provide additional incentives to selected directors, officers, employees and consultants, and to enable our Company to obtain and retain the services of these individuals. In March 2021, the shareholders approved the 2017 Omnibus Incentive Plan, as amended and restated effective September 18, 2020 (the “Amended 2017 Plan”), to permit the grant of “incentive stock options.” The Amended 2017 Plan enables us to grant options (including incentive stock options), restricted shares or other awards to our directors, employees and consultants. We authorized 5,277,197 ordinary shares to be available for grant pursuant to awards under the Amended 2017 Plan, and as of June 30, 2025, there were 1,458,297 ordinary shares remaining available for grant. As of June 30, 2025, there were the following outstanding awards under the Amended 2017 Plan: (i) 5,500 unvested restricted shares, all of which were subject to time-based vesting; (ii) 2,737,797 options, of which 2,047,499 were vested (with a weighted average exercise price of $4.88 per share) and 690,298 were unvested (with a weighted average exercise price of $5.38 per share) (of which 411,418 were subject to time-based vesting and 278,880 were subject to performance-based vesting).

Differences in Corporate Law

The Companies Act is derived, to a large extent, from the older Companies Acts of England but does not follow recent United Kingdom statutory enactments, and accordingly there are significant differences between the Companies Act and the current Companies Act of England. In addition, the Companies Act differs from laws applicable to United States corporations and their shareholders. Set forth below is a summary of the significant differences between the provisions of the Companies Act applicable to us and the laws applicable to companies incorporated in the United States and their shareholders.

Mergers and Similar Arrangements

The Companies Act permits mergers and consolidations between Cayman Islands companies and between Cayman Islands companies and non-Cayman Islands companies. For these purposes, (a) “merger” means the merging of two or more constituent companies and the vesting of their undertaking, property and liabilities in one of such companies as the surviving company and (b) a “consolidation” means the combination of two or more constituent companies into a combined company and the vesting of the undertaking, property and liabilities of such companies to the consolidated company. In order to effect such a merger or consolidation, the directors of each constituent company must approve a written plan of merger or consolidation, which must then be authorized by (a) a special resolution of the shareholders of each constituent company and (b) such other authorization, if any, as may be specified in such constituent company’s articles of association. The written plan of merger or consolidation must be filed with the Registrar of Companies together with a declaration as to the solvency of the consolidated or surviving company, a declaration as to the assets and liabilities of each constituent company and an undertaking that

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a copy of the certificate of merger or consolidation will be given to the members and creditors of each constituent company and that notification of the merger or consolidation will be published in the Cayman Islands Gazette. Dissenting shareholders have the right to be paid the fair value of their shares (which, if not agreed between the parties, will be determined by the Cayman Islands court) if they follow the required procedures, subject to certain exceptions. Court approval is not required for a merger or consolidation which is effected in compliance with these statutory procedures.

In addition, there are statutory provisions that facilitate the reconstruction and amalgamation of companies, provided that the arrangement is approved by (a) 75% in value of the shareholders or class of shareholders, as the case may be, or (b) a majority in number representing 75% in value of the creditors or each class of creditors, as the case may be, with whom the arrangement is to be made, and that are, in each case, present and voting either in person or by proxy at a meeting, or meetings, convened for that purpose. The convening of the meetings and subsequently the arrangement must be sanctioned by the Grand Court of the Cayman Islands. While a dissenting shareholder has the right to express to the court the view that the transaction ought not to be approved, the Grand Court can be expected to approve the arrangement if it determines that:

• the statutory provisions as to the required majority vote have been met;

• the shareholders have been fairly represented at the meeting in question and the statutory majority are acting bona fide without coercion of the minority to promote interests adverse to those of the class;

• the arrangement is such that may be reasonably approved by an intelligent and honest man of that class acting in respect of his interest; and

• the arrangement is not one that would more properly be sanctioned under some other provision of the Companies Act.

When a takeover offer is made and accepted by holders of 90% of the shares affected within four months, the offeror may, within a two-month period commencing on the expiration of such four month period, require the holders of the remaining shares to transfer such shares on the terms of the offer. An objection can be made to the Grand Court of the Cayman Islands, but this is unlikely to succeed in the case of an offer which has been so approved unless there is evidence of fraud, bad faith or collusion.

If an arrangement and reconstruction is thus approved, the dissenting shareholder would have no rights comparable to appraisal rights, which would otherwise ordinarily be available to dissenting shareholders of Delaware corporations, providing rights to receive payment in cash for the judicially determined value of the shares.

Shareholders’ Suits

In principle, we will normally be the proper plaintiff to sue for a wrong done to us as a company and a derivative action may ordinarily not be brought by a minority shareholder. However, based on English authority, which would in all likelihood be of persuasive authority in the Cayman Islands, the Cayman Islands courts can be expected (and have had occasion) to follow and apply the common law principles (namely the rule in Foss v. Harbottle and the exceptions thereto) so that a minority shareholder may be permitted to commence a representative action against, or derivative actions in the name of, our Company to challenge:

• an act which is ultra vires the company or illegal and is therefore incapable of ratification by the shareholders,

• an act which constitutes a fraud against the minority where the wrongdoers are themselves in control of the company, or

• an act which requires a resolution with a qualified (or special) majority (i.e. more than a simple majority) which has not been obtained.

Indemnification of Directors and Executive Officers and Limitation of Liability

Cayman Islands law does not limit the extent to which a company’s memorandum and articles of association may provide for indemnification of officers and directors, except to the extent any such provision may be held by the Cayman Islands courts to be contrary to public policy, such as to provide indemnification against civil fraud or the consequences of committing a crime. Our amended and restated memorandum and articles of association require us to indemnify every director, alternate director, secretary, assistant secretary, or other officer for the time being and

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from time to time of our Company (but not including our auditors) and the personal representatives of the same against all actions, proceedings, costs, charges, expenses, losses, damages or liabilities incurred or sustained by such indemnified person, other than by reason of such indemnified person’s own dishonesty, willful default or fraud, in or about the conduct of our Company’s business or affairs (including as a result of any mistake of judgment) or in the execution or discharge of his duties, powers, authorities or discretions, including without prejudice to the generality of the foregoing, any costs, expenses, losses or liabilities incurred by such indemnified person in defending (whether successfully or otherwise) any civil proceedings concerning us or our affairs in any court whether in the Cayman Islands or elsewhere. This standard of conduct is generally the same as permitted under the Delaware General Corporation Law for a Delaware corporation.

In addition, we have entered into indemnification agreements with each of our directors and executive officers that provide such persons with additional indemnification beyond that provided in our amended and restated memorandum and articles of association.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to our directors, officers or persons controlling us under the foregoing provisions, we have been informed that in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

Directors’ Fiduciary Duties

Under Delaware corporate law, a director of a Delaware corporation has a fiduciary duty to the corporation and its shareholders. This duty has two components: the duty of care and the duty of loyalty. The duty of care requires that a director act in good faith, with the care that an ordinarily prudent person would exercise under similar circumstances. Under this duty, a director must inform himself of, and disclose to shareholders, all material information reasonably available regarding a significant transaction. The duty of loyalty requires that a director acts in a manner he reasonably believes to be in the best interests of the corporation. He must not use his corporate position for personal gain or advantage. This duty prohibits self-dealing by a director and mandates that the best interest of the corporation and its shareholders take precedence over any interest possessed by a director, officer or controlling shareholder and not shared by the shareholders generally. In general, actions of a director are presumed to have been made on an informed basis, in good faith and in the honest belief that the action taken was in the best interests of the corporation. However, this presumption may be rebutted by evidence of a breach of one of the fiduciary duties. Should such evidence be presented concerning a transaction by a director, the director must prove the procedural fairness of the transaction, and that the transaction was of fair value to the corporation.

As a matter of Cayman Islands law, a director of a Cayman Islands company is in the position of a fiduciary with respect to the company and therefore it is considered that he owes the following duties to the company — a duty to act in good faith in the best interests of the company, a duty not to make a personal profit based on his position as director (unless the company permits him to do so), a duty not to put himself in a position where the interests of the company conflict with his personal interest or his duty to a third party and a duty to exercise powers for the purpose for which such powers were intended. A director of a Cayman Islands company owes to the company a duty to act with skill and care. It was previously considered that a director need not exhibit in the performance of his duties a greater degree of skill than may reasonably be expected from a person of his knowledge and experience. However, English and Commonwealth courts have moved towards an objective standard with regard to the required skill and care and these authorities are likely to be followed in the Cayman Islands.

Shareholder Action by Written Consent

Under the Delaware General Corporation Law, a corporation may eliminate the right of shareholders to act by written consent by amendment to its certificate of incorporation. Cayman Islands law and our amended and restated articles of association provide that shareholders may approve corporate matters by way of a unanimous written resolution signed by or on behalf of each shareholder who would have been entitled to vote on such matter at a general meeting without a meeting being held.

Shareholder Proposals

Under the Delaware General Corporation Law, a shareholder has the right to put any proposal before the annual meeting of shareholders, provided it complies with the notice provisions in the governing documents. A special meeting may be called by the board of directors or any other person authorized to do so in the governing documents, but shareholders may be precluded from calling special meetings.

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Cayman Islands law provides shareholders with only limited rights to requisition a general meeting, and does not provide shareholders with any right to put any proposal before a general meeting. However, these rights may be provided in articles of association. Our amended and restated articles of association allow our shareholders holding not less than ten percent of all voting power of our share capital in issue to requisition a shareholder’s meeting, in which case our board of directors is obliged to call such meeting and to put the resolutions so requisitioned to a vote at such meeting. Other than this right to requisition a shareholders’ meeting, our amended and restated articles of association do not provide our shareholders other right to put proposal before a meeting. As an exempted Cayman Islands company, we are not obliged by law to call shareholders’ annual general meetings.

Cumulative Voting

Under the Delaware General Corporation Law, cumulative voting for elections of directors is not permitted unless the corporation’s certificate of incorporation specifically provides for it. Cumulative voting potentially facilitates the representation of minority shareholders on a board of directors since it permits the minority shareholder to cast all the votes to which the shareholder is entitled on a single director, which increases the shareholder’s voting power with respect to electing such director. There are no prohibitions in relation to cumulative voting under the laws of the Cayman Islands but our amended and restated articles of association do not provide for cumulative voting. As a result, our shareholders are not afforded any less protections or rights on this issue than shareholders of a Delaware corporation.

Removal of Directors

Under the Delaware General Corporation Law, a director of a corporation with a classified board may be removed only for cause with the approval of a majority of the outstanding shares entitled to vote, unless the certificate of incorporation provides otherwise. Under our amended and restated articles of association, directors may be removed with or without cause, by an ordinary resolution of our shareholders.

Transactions with Interested Shareholders

The Delaware General Corporation Law contains a business combination statute applicable to Delaware corporations whereby, unless the corporation has specifically elected not to be governed by such statute by amendment to its certificate of incorporation, it is prohibited from engaging in certain business combinations with an “interested shareholder” for three years following the date that such person becomes an interested shareholder. An interested shareholder, generally, is a person who, or a group which, owns or owned 15% or more of the target’s outstanding voting share within the past three years. This has the effect of limiting the ability of a potential acquirer to make a two-tiered bid for the target in which all shareholders would not be treated equally. The statute does not apply if, among other things, prior to the date on which such shareholder becomes an interested shareholder, the board of directors approves either the business combination or the transaction which resulted in the person becoming an interested shareholder. This encourages any potential acquirer of a Delaware corporation to negotiate the terms of any acquisition transaction with the target’s board of directors.

Cayman Islands law has no comparable statute. As a result, we cannot avail ourselves of the types of protections afforded by the Delaware business combination statute. However, although Cayman Islands law does not regulate transactions between a company and its significant shareholders, it does provide that such transactions must be entered into bona fide in the best interests of the company and for a proper purpose and not with the effect of constituting a fraud on the minority shareholders.

Dissolution; Winding up

Under the Delaware General Corporation Law, unless the board of directors approves the proposal to dissolve, dissolution must be approved by shareholders holding 100% of the total voting power of the corporation. Only if the dissolution is initiated by the board of directors may it be approved by a simple majority of the corporation’s outstanding shares. Delaware law allows a Delaware corporation to include in its certificate of incorporation a supermajority voting requirement in connection with dissolutions initiated by the board.

Under Cayman Islands law, a company may be wound up by either an order of the courts of the Cayman Islands or by a special resolution of its members or, if the company is unable to pay its debts as they fall due, by an ordinary resolution of its members. The court has authority to order winding up in a number of specified circumstances

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including where it is, in the opinion of the court, just and equitable to do so. Under the Companies Act and our amended and restated articles of association, our Company may be dissolved, liquidated or wound up by a special resolution of our shareholders, or by an ordinary resolution on the basis that our Company is unable to pay its debts as they fall due.

Variation of Rights of Shares

Under the Delaware General Corporation Law, a corporation may vary the rights of a class of shares with the approval of a majority of the outstanding shares of such class, unless the certificate of incorporation provides otherwise. Under Cayman Islands law and our amended and restated articles of association, if our share capital is divided into more than one class of shares, we may vary the rights attached to any class with the written consent of the holders of not less than two thirds of the issued shares of that class or with the sanction of a special resolution passed at a general meeting of the holders of the shares of that class.

Amendment of Governing Documents

Under the Delaware General Corporation Law, a corporation’s governing documents may be amended with the approval of a majority of the outstanding shares entitled to vote, unless the certificate of incorporation provides otherwise. Under Cayman Islands law, our amended and restated memorandum and articles of association may only be amended with a special resolution of our shareholders.

Rights of Non-resident or Foreign Shareholders

There are no limitations imposed by our amended and restated memorandum and articles of association on the rights of non-resident or foreign shareholders to hold or exercise voting rights on our shares. In addition, there are no provisions in our amended and restated memorandum and articles of association governing the ownership threshold above which shareholder ownership must be disclosed.

Transfer Agent and Registrar

The transfer agent and registrar for our ordinary shares is Continental Stock Transfer & Trust Company.

Listing

Our ordinary shares are listed on the Nasdaq under the symbol “BYSI.”

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PLAN OF DISTRIBUTION

We may sell or distribute our ordinary shares from time to time in one or more public or private transactions:

• through underwriters;

• through agents;

• to dealers;

• directly to one or more purchasers;

• in “at the market” offerings, within the meaning of Rule 415(a)(4) of the Securities Act, to or through a market maker or into an existing trading market on an exchange or otherwise;

• in block trades;

• through a combination of any of the above; and

• any other method permitted pursuant to applicable law.

Any sale or distribution may be effected by us:

• at market prices prevailing at the time of sale;

• at varying prices determined at the time of sale; or

• at negotiated or fixed prices.

At any time a particular offer of the ordinary shares is made, a prospectus supplement, if required, will be distributed and set forth the terms of each specific offering, including the name or names of any underwriters or agents, the purchase price of the ordinary shares and the proceeds to us from such sales or distribution, any delayed delivery arrangements, any underwriting discounts and other items constituting underwriters’ compensation, any initial public offering price and any discounts or concessions allowed or re-allowed or paid to dealers. Any initial public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

In addition, we may distribute the ordinary shares as a dividend or in a rights offering to our existing security holders. In some cases, we or dealers acting for us or on behalf of us may also repurchase the ordinary shares and reoffer them to the public by one or more of the methods described above.

Through Underwriters

If underwriters are used in a sale or distribution, the ordinary shares will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The ordinary shares may be offered to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. The underwriter or underwriters with respect to a particular underwritten offering and, if an underwriting syndicate is used, the managing underwriter or underwriters will be set forth on the cover of such prospectus supplement. Unless otherwise set forth in the prospectus supplement, the underwriters will be obligated to purchase all the ordinary shares if any are purchased.

During and after an offering through underwriters, the underwriters may purchase and sell or distribute the ordinary shares in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters also may impose a penalty bid, under which selling concessions allowed to syndicate members or other broker-dealers for the ordinary shares they sell or distribute for their account may be reclaimed by the syndicate if the syndicate repurchases the ordinary shares in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the ordinary shares, which may be higher than the price that might otherwise prevail in the open market, and, if commenced, may be discontinued at any time.

Through Agents or to Dealers

We may sell or distribute the ordinary shares directly or through agents we designate from time to time. Unless otherwise indicated in a prospectus supplement, any such agent will be acting on a best efforts basis for the period of its appointment.

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If dealers are used in any of the sales or distribution of the ordinary shares covered by this prospectus, we will sell those ordinary shares to dealers as principals. The dealers may then resell the ordinary shares to the public at varying prices the dealers determine at the time of resale.

Direct Sales

We may sell or distribute the ordinary shares directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale thereof.

Delayed Delivery

If so indicated in a prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase the ordinary shares from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. These contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth the commission payable for solicitation of such contracts.

Derivative Transactions and Hedging

We and the underwriters may engage in derivative transactions involving the ordinary shares. These derivatives may consist of short sale transactions and other hedging activities. The underwriters may acquire a long or short position in the ordinary shares, hold or resell ordinary shares acquired and purchase options or futures on the ordinary shares and other derivative instruments with returns linked to or related to changes in the price of the ordinary shares. In order to facilitate these derivative transactions, we may enter into security lending or repurchase agreements with the underwriters. The underwriters may carry out the derivative transactions through sales or distributions of the ordinary shares to the public, including short sales, or by lending the ordinary shares in order to facilitate short sale transactions by others. The underwriters may also use the ordinary shares purchased or borrowed from us or others (or, in the case of derivatives, ordinary shares received from us in settlement of those derivatives) to directly or indirectly settle sales of the ordinary shares or close out any related open borrowings of the ordinary shares.

Loans of Securities

We may loan or pledge the ordinary shares to a financial institution or other third party that in turn may sell the ordinary shares using this prospectus and an applicable prospectus supplement.

General

Agents, dealers and direct purchasers that participate in the distribution of the offered ordinary shares may be underwriters as defined in the Securities Act and any discounts or commissions they receive from us and any profit on the resale of the offered ordinary shares by them may be treated as underwriting discounts and commissions under the Securities Act. Agents, dealers and underwriters may be entitled under agreements entered into with us to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which such agents, dealers or underwriters may be required to make in respect thereof. Agents, dealers and underwriters may be customers of, engage in transactions with, or perform services on our behalf.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a registration statement we filed with the SEC, with respect to the ordinary shares we will offer. For purposes of this section, the term registration statement means the prior registration statement and any and all amendments including the schedules and exhibits to the prior registration statement and this registration statement, which is combined with the prior registration statement pursuant to Rule 429 under the Securities Act, and is being amended by this Post-Effective Amendment No.1. This prospectus and any accompanying prospectus supplement do not contain all the information contained in the registration statement, including its exhibits and schedules. You should refer to the registration statement, including the exhibits and schedules, for further information about us and the ordinary shares we may offer. Statements we make in this prospectus and any accompanying prospectus supplement about certain contracts or other documents are not necessarily complete. When we make such statements, we refer you to the copies of the contracts or documents that are filed as exhibits to the registration statement, because those statements are qualified in all respects by reference to those exhibits. The registration statement, including exhibits and schedules, is on file at the office of the SEC and may be inspected without charge.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC’s website at www.sec.gov. We maintain a corporate website at www.beyondspringpharma.com. We do not incorporate the information on our website into this prospectus or any supplement to this prospectus and you should not consider any information on, or that can be accessed through, our website as part of this prospectus or any supplement to this prospectus (other than those filings with the SEC that we specifically incorporate by reference into this prospectus or any supplement to this prospectus).

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information in documents we file with it. This means that we can disclose important information to you by referring you to those documents. Each document incorporated by reference is current only as of the date of such document, and the incorporation by reference of such documents shall not create any implication that there has been no change in our affairs since the date thereof or that the information contained therein is current as of any time subsequent to its date. The information incorporated by reference is considered to be a part of this prospectus and should be read with the same care. When we update the information contained in documents that have been incorporated by reference by making future filings with the SEC, the information incorporated by reference in this prospectus is considered to be automatically updated and superseded. In other words, in the case of a conflict or inconsistency between information contained in this prospectus and information incorporated by reference into this prospectus, you should rely on the information contained in the document that was filed later.

We incorporate by reference the documents listed below:

• our annual report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on March 27, 2025;

• our quarterly reports on Form 10-Q for the fiscal quarters ended March 31, 2025 and June 30, 2025, filed with the SEC on May 12, 2025 and August 13, 2025, respectively;

• our current reports on Form 8-K filed with the SEC on January 28, 2025, February 25, 2025, April 11, 2025 and July 3, 2025;

• the description of share capital contained in the Registration Statement on Form 8-A, as filed with the SEC on March 6, 2017 (File No. 001-38024), and including any amendments or reports filed for the purpose of updating such description; and

• with respect to each offering of ordinary shares under this prospectus, all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date on which this registration statement is first filed with the SEC and until the termination or completion of that offering under this prospectus.

Unless expressly incorporated by reference, nothing in this prospectus shall be deemed to incorporate by reference information furnished to, but not filed with, the SEC. Copies of all documents incorporated by reference in this prospectus, other than exhibits to those documents unless such exhibits are specially incorporated by reference in this prospectus, will be provided at no cost to each person, including any beneficial owner, who receives a copy of this prospectus on the written or oral request of that person made to:

BeyondSpring Inc.

100 Campus Drive, West Side, 4^th Floor, Suite 410

Florham Park, New Jersey 07932

Tel: +1 (646) 305-6387

Attention: Chief Executive Officer

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ENFORCEMENT OF CIVIL LIABILITIES

We are incorporated under the laws of the Cayman Islands as an exempted company with limited liability. We incorporated in the Cayman Islands because of certain benefits associated with being a Cayman Islands corporation, such as political and economic stability, an effective judicial system, a favorable tax system, the absence of foreign exchange control or currency restrictions and the availability of professional and support services. However, the Cayman Islands have a less developed body of securities laws that provide significantly less protection to investors as compared to the securities laws of the United States. In addition, Cayman Islands companies may not have standing to sue before the federal courts of the United States.

A portion of our assets, including certain Chinese patents, are located in China. In addition, some of our directors and officers are residents of jurisdictions other than the United States and all or a substantial portion of their assets are located outside the United States. As a result, it may be difficult for investors to effect service of process within the United States upon us or our directors and officers, or to enforce against us or them judgments obtained in United States courts, including judgments predicated upon the civil liability provisions of the securities laws of the United States or any state in the United States.

Maples and Calder (Hong Kong) LLP, our counsel as to Cayman Islands law, and Beijing Dacheng Law Offices, LLP, our counsel as to Chinese law, have respectively advised us that the courts of the Cayman Islands and China are, respectively, unlikely (1) to recognize and enforce judgments of United States courts obtained against us or our directors or officers that are predicated upon the civil liability provisions of the securities laws of the United States or any state in the United States, and (2) in original actions brought in the Cayman Islands to impose liabilities against us or our directors or officers that are predicated upon the civil liability provisions of federal securities laws of the United States or the securities laws of any state in the United States so far as the liabilities imposed by those provisions are penal in nature.

Maples and Calder (Hong Kong) LLP has further advised us that although there is no statutory enforcement in the Cayman Islands of judgments obtained in the United States (and the Cayman Islands are not a party to any treaties for the reciprocal enforcement or recognition of such judgments), the courts of the Cayman Islands will at common law, recognize and enforce a foreign money judgment of a foreign court of competent jurisdiction without any re-examination of the merits of the underlying dispute based on the principle that a judgment of a competent foreign court imposes upon the judgment debtor an obligation to pay the liquidated sum for which such judgment has been given, provided such judgment (1) is given by a foreign court of competent jurisdiction, (2) imposes on the judgment debtor a liability to pay a liquidated sum for which the judgment has been given, (3) is final and conclusive, (4) is not in respect of taxes, a fine or a penalty, (5) was not obtained in a manner and is not of a kind the enforcement of which is contrary to natural justice or the public policy of the Cayman Islands, (6) not inconsistent with a Cayman Islands judgement in respect of the same matter and (7) not impeachable on the grounds of fraud. A Cayman Islands Court may stay enforcement proceedings if concurrent proceedings are being brought elsewhere.

Beijing Dacheng Law Offices, LLP has advised us that the recognition and enforcement of foreign judgments are provided for under the PRC Civil Procedure Law. Chinese courts may recognize and enforce foreign judgments in accordance with the requirements of the PRC Civil Procedure Law based either on treaties between China and the country where the judgment is made or on principles of reciprocity between jurisdictions. Beijing Dacheng Law Offices, LLP has advised us further that under Chinese law, courts in China will not recognize or enforce a foreign judgment against us or our directors and officers if they decide that the judgment violates the basic principles of Chinese law or national sovereignty, security or social public interest. As there exists no treaty or other form of reciprocity between China and the United States governing the recognition and enforcement of judgments as of the date of this prospectus, including those predicated upon the liability provisions of the United States federal securities laws, there is uncertainty whether and on what basis a Chinese court would enforce judgments rendered by United States courts. In addition, because there is no treaty or other form of reciprocity between the Cayman Islands and China governing the recognition and enforcement of judgments as of the date of this prospectus, there is further uncertainty as to whether and on what basis a PRC court would enforce judgments rendered by a Cayman Islands court.

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LEGAL MATTERS

The validity of the ordinary shares relating to Cayman Islands law will be passed upon for us by Maples and Calder (Hong Kong) LLP. Certain legal matters relating to Chinese law will be passed upon for us by Beijing Dacheng Law Offices, LLP. Certain legal matters relating to U.S. law will be passed upon for us by Skadden, Arps, Slate, Meagher & Flom LLP, New York, New York.

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EXPERTS

The consolidated financial statements of BeyondSpring Inc. as of and for the years ended December 31, 2024 and 2023 appearing in BeyondSpring Inc.’s Annual Report on Form 10-K for the year ended December 31, 2024 have been audited by Marcum LLP, independent registered public accounting firm, as set forth in their report thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

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800,000 Shares

BEYONDSPRING INC.

Ordinary Shares

PROSPECTUS SUPPLEMENT

November 17, 2025

FAQ

What is BeyondSpring Inc. (BYSI) offering in this 424B5 filing?

BeyondSpring Inc. is offering 800,000 ordinary shares to Ray Beauty Group Limited at an offering price of $2.50 per share in a primary issuance of new stock.

How much cash will BeyondSpring (BYSI) receive from the 800,000-share offering?

BeyondSpring estimates net proceeds of approximately $2 million from the issuance and sale of 800,000 ordinary shares, after deducting estimated offering expenses.

How does this offering affect BeyondSpring’s (BYSI) shares outstanding and dilution?

Ordinary shares outstanding are expected to increase from 40,322,320 to 41,122,320. As adjusted net tangible book value would move from $(0.49) to $(0.43) per share, resulting in immediate dilution of $2.93 per share to the new investor.

What will BeyondSpring use the proceeds of this $2 million offering for?

BeyondSpring intends to use the net proceeds to fund research and development and for general corporate purposes, which may include acquisitions, debt repayment, working capital, clinical trial spending, commercial expenditures and capital expenditures.

What risks does BeyondSpring highlight related to this BYSI share offering?

The company notes that its ordinary shares can be highly volatile, that substantial future share sales may pressure the price, that it has broad discretion over use of proceeds, and that investors will experience immediate and substantial dilution from buying in this offering.

Does BeyondSpring (BYSI) expect to pay dividends on its ordinary shares?

BeyondSpring states that it has never paid cash dividends and does not intend to pay dividends in the foreseeable future, preferring to reinvest earnings to develop and expand its business.

What is BeyondSpring’s core business focus mentioned in the prospectus?

BeyondSpring is a clinical-stage global biopharmaceutical company focused on innovative therapies for high unmet medical needs, led by its oncology drug candidate Plinabulin and additional small-molecule immune agents, plus an equity stake in SEED Therapeutics’ TPD platform.