OS Therapies Announces Initial Closing of Warrant Exercise Inducement and Exchange Offer for Initial Gross Proceeds of Approximately $7.2 Million

The financing adds cash while issuing replacement warrants for up to 5,517,253 shares at $1.40 per share.

Rhea-AI Summary

OS Therapies (NYSE American: OSTX) completed an initial warrant inducement and exchange closing, raising approximately $7.2 million in gross proceeds. Seven holders exercised or pre-funded warrants covering 5,517,253 shares at $1.30 per share, or $1.299 for pre-funding. They received new warrants for up to 5,517,253 shares at $1.40 per share. Proceeds exclude solicitation agent fees and other offering expenses.

The company has accrued $7 million in refundable U.K. research and development tax credits, with filing expected in the fourth quarter of 2026 and receipt in early 2027. OS Therapies expects the financing and credits to support operations through upcoming milestones, including planned fourth-quarter 2026 Herlystic regulatory submissions in the U.S., U.K., EU and Australia. Net proceeds are intended to support filings and commercial preparation for preventing or delaying recurrence in fully resected, pulmonary metastatic osteosarcoma.

8 points · 1 major

MixediHow this balance works

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Rhea-AI gives every point it takes from this document a weight. Minor counts 1, Moderate 3 and Major 9, so one Major point outweighs several Minor ones. The bar adds up the weights on each side, and when neither side holds more than 65% of the total the balance reads Mixed.

It reads the document as published, with the same rules for every company, and it does not look at what the market expected or at how the stock traded, so a point can be objectively good on a day the stock falls.

Rhea-AI Sentiment measures something else, the tone of the wording.

How the balance worksHow Sentiment works

1 major · 5 points

Hollow bars mark forward-looking points. How the balance works

Positive

• Major pointInitial warrant closing raised approximately $7.2 million gross from seven participating holders. 12% of market cap
• Moderate point. Forward-looking: it has not happened yet and may not happen.Refundable U.K. tax credits total $7 million accrued; filing expected fourth-quarter 2026, receipt early 2027.
• Minor point. Forward-looking: it has not happened yet and may not happen.OS Therapies expects financing and tax credits to fund operations through upcoming milestones.
• Minor point. Forward-looking: it has not happened yet and may not happen.Herlystic filings and commercial preparation are the planned use of net proceeds.
• Minor point. Forward-looking: it has not happened yet and may not happen.Herlystic submissions in the U.S., U.K., EU and Australia remain planned for fourth-quarter 2026.

3 minor points

• Minor pointHerlystic holds FDA Orphan Drug, Fast Track and Rare Pediatric Disease designations.
• Minor pointHerlystic holds EMA Orphan Drug, PRIME and advanced therapy medicinal product designations.
• Minor pointFDA accepted the Commissioner's National Priority Voucher letter of intent; the regenerative medicine designation request was resubmitted.

Negative

• Major pointExercises or pre-funding cover 5,517,253 shares at $1.30 or $1.299, respectively, diluting existing holders.
• Minor point. Forward-looking: it has not happened yet and may not happen.New warrants add potential dilution of up to 5,517,253 shares at $1.40 per share.
• Minor pointExercise pricing was reduced to $1.30 per share; a significant majority previously carried $1.40 exercise prices.
• Minor pointGross proceeds are subject to solicitation agent fees and other offering expenses.
• Minor point. Forward-looking: it has not happened yet and may not happen.Potential Priority Review Voucher eligibility depends on approval of the company's U.S. biologics license application.

News Explained

If exercised, these warrants would add shares beyond the initial closing and reduce existing holders’ ownership percentages, absent offsetting changes.

The initial closing is complete; newly issued warrants can add up to 5,517,253 shares if exercised, beyond the shares covered by the initial exercise or pre-funding.

Although the release says the transaction minimizes dilution, those warrants cover up to the same number of shares as the initial exercise or pre-funding, so issuing them upon exercise would reduce existing holders’ percentage ownership absent offsetting changes.

As of June 30, 2026, reported cash and equivalents were $205,035. That balance equals 3.4 days of second-quarter operating cash outflow at that quarter’s reported rate.

Sources and calculations

• OS Therapies press release (2026-10-19)
• Dilution definition (version supplied)
• OS Therapies second-quarter 2026 fundamentals (2026-06-30)

• Available liquidity against the last reported quarterly operating outflow, in days at that rate $205,035 / ($5,532,872 / 91) = 3.4 days

Key Figures

Gross proceeds: $7.2 million Shares purchased through warrant exercises or pre-funding: 5,517,253 shares Reduced exercise price: $1.30 per share cash exercise; $1.299 per share pre-funding +5 more

Gross proceeds

$7.2 million

Initial closing; before solicitation agent fees and other offering expenses

Shares purchased through warrant exercises or pre-funding

5,517,253 shares

Initial closing

Reduced exercise price

$1.30 per share cash exercise; $1.299 per share pre-funding

Existing warrants

New warrants

Up to 5,517,253 shares at $1.40 per share

Issued to participating holders

Accrued refundable R&D tax credits

$7 million

Through the U.K. subsidiary

Offer expiration

October 30, 2026, at 11:59 p.m. Eastern time

Unless extended or earlier terminated

Planned regulatory submissions

Fourth quarter of 2026

Herlystic early market access submissions

Expected tax credit receipt

Early 2027

U.K. R&D tax credits

Key Terms

biologics license application, accelerated approval, priority review voucher, orphan drug designation, +2 more

6 terms

biologics license application regulatory

"submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration"

A biologics license application is a formal request submitted to regulatory authorities seeking approval to market a new biological medicine, such as vaccines or treatments made from living organisms. It is a comprehensive review process that evaluates the safety, effectiveness, and manufacturing quality of the product. For investors, receiving approval signals that a biological therapy can be sold to the public, potentially leading to revenue growth and market success.

accelerated approval regulatory

"under the Accelerated Approval Program"

Accelerated approval is a process that allows new medical treatments to be approved more quickly than usual if they address serious or life-threatening conditions and show promising early results. For investors, it signals that a treatment may reach the market sooner, potentially boosting a company's prospects, but it also involves some uncertainty since full evidence of effectiveness is still being gathered.

priority review voucher regulatory

"may become eligible to receive a Priority Review Voucher (PRV)"

A priority review voucher is a transferable regulatory incentive that lets a company move a future drug or device application to the front of the review line, shortening the review period by several months. For investors it matters because the voucher can speed up market access for a high-value product or be sold to other companies for significant cash, acting like a tradable fast-pass that can accelerate revenue or create immediate financial upside.

orphan drug designation regulatory

"has received Orphan Drug Designation (ODD)"

Orphan drug designation is a special status given to medicines developed to treat rare diseases affecting only a small number of people. This status often provides benefits like faster approval processes and financial incentives, making it more attractive for companies to develop these drugs. For investors, it signals potential for exclusive market rights and reduced competition, which can impact the drug’s profitability.

fast track designation regulatory

"Fast Track Designation (FTD)"

Fast track designation is a status the U.S. Food and Drug Administration grants to drugs intended to treat serious conditions and address an unmet medical need. It gives the developer more frequent communication with the FDA and can allow parts of the application to be reviewed on a rolling basis, and it may pave the way to priority review or accelerated approval. It can shorten development timelines, though it does not guarantee approval.

private placement financial

"were offered and issued in a private placement"

A private placement is a sale of securities directly to a selected group of investors, typically institutions or accredited investors, instead of through a public offering. It lets a company raise money faster and with fewer regulatory steps; for existing shareholders it matters because the newly issued shares, often sold at a discount, increase the share count and can dilute their ownership.

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• Proceeds from the initial closing, together with accrued refundable U.K. R&D tax credits, expected to provide operating runway through major upcoming milestones
• Company expects to complete early market access regulatory approval submissions for Herlystic™ ("OST-HER2" or "daznelimgene lisbac") in the U.S., U.K., Europe and Australia in the fourth quarter of 2026

Grasonville, Maryland--(Newsfile Corp. - October 19, 2026) - OS Therapies Inc. (NYSE American: OSTX) ("OS Therapies" or the "Company"), the world leader in gene-edited, Listeria-based cancer immunotherapies, today announced the initial closing of a warrant exercise inducement and exchange offer that was made to nine accredited investors (the "Holders") that beneficially owned common stock purchase warrants (the "Existing Warrants") to exercise, or pre-fund the exercise of, their Existing Warrants for cash at a reduced exercise price of $1.30 per share (or $1.299 per share for a pre-funding). At the initial closing, seven Holders exercised, or pre-funded the exercise of, Existing Warrants to purchase an aggregate of 5,517,253 shares of common stock, resulting in a total of $7.2 million in gross proceeds to the Company, before deducting solicitation agent fees and other offering expenses payable by the Company. A significant majority of the Existing Warrants exercised or pre-funded by the seven Holders had an exercise price of $1.40 per share, reflecting strong support for the Company's mission while minimizing dilution to existing stockholders.

In consideration for such exercise or pre-funding, the Company issued to the participating Holders new common stock purchase warrants to purchase up to an aggregate of 5,517,253 shares of common stock at an exercise price of $1.40 per share. The offer, which is scheduled to expire at 11:59 p.m., Eastern time, on October 30, 2026, unless extended or earlier terminated, was made only to the Holders and is not available to any other person. A description of the material terms of the offer is included in the Company's Current Report on Form 8-K filed with the Securities and Exchange Commission.

Additionally, the Company has accrued $7 million in refundable research and development tax credits through its U.K. subsidiary ("R&D Tax Credits"). The tax credit filing with His Majesty's Revenue and Customs, the UK's tax authority, is expected to be submitted during the fourth quarter of 2026, with receipt of the credit expected in early 2027.

The Company expects to use the net proceeds to support regulatory filings and commercial preparation activities related for Herlystic™ in the prevention or delay of recurrence in fully resected, pulmonary metastatic osteosarcoma in the U.S., U.K., European Union (EU) and Australia (the "Human Metastatic Osteosarcoma Program"), and for general corporate purposes.

"We expect the proceeds from this warrant inducement transaction to provide the Company with the capital needed to advance our pending Herlystic™ early market access submissions with regulators in the U.S., U.K., Europe and Australia," said Chair & CEO Paul Romness. "We remain steadfast in our mission of improving treatment options for osteosarcoma patients."

The Company reiterates its intention to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) under the Accelerated Approval Program (Accelerated Approval) and Conditional Marketing Authorisation Applications (CMAAs) to the U.K. Medicines and Healthcare products Regulatory Authority (MHRA), the European Medicines Agency (EMA) and the Australian Therapeutic Goods Administration (TGA) in the fourth quarter of 2026.

Herlystic™ has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the FDA, as well as ODD, PRIME (European FTD equivalent) and ATMP from the EMA. Under the RPDD program, if the Company's BLA is approved, the Company may become eligible to receive a Priority Review Voucher (PRV), which it intends to sell. The most recent PRV sale occurred in October 2026 for $203 million. There can be no assurance that the Company will receive a PRV or realize a comparable value, if any, from any future PRV sale. OS Therapies has completed resubmission of a Regenerative Medicine Advanced Therapy (RMAT) designation request and the Company's Commissioner's National Priority Voucher (CNPV) letter of intent has been accepted by FDA.

No Offer to Sell or Solicit

This press release is for informational purposes only and does not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of these securities in in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. The new common stock purchase warrants and the shares of common stock issuable upon exercise thereof were offered and issued in a private placement in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended (the "Securities Act"), and/or Rule 506(b) of Regulation D promulgated thereunder, have not been registered under the Securities Act or applicable state securities laws, and may not be offered or sold in the United States absent registration with the Securities and Exchange Commission or an applicable exemption from such registration requirements.

About OS Therapies

OS Therapies is a clinical stage oncology company focused on the identification, development, and commercialization of treatments for Osteosarcoma and other solid tumors. The Company is the world leader in gene-edited, Listeria-based cancer immunotherapies. Herlystic™, the Company's lead asset, is an immunotherapy leveraging the immune-stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. Herlystic™ is designed to target two mutated extracellular epitopes and one mutated intracellular epitope of the HER2 oncogene, requiring only one of these three epitopes to be present in a tumor (or micro-metastasis) to trigger the desired immune response. Herlystic™ has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the U.S. Food & Drug Administration and has received ODD, FTD and Advanced Therapy Medicinal Products (ATMP) from the European Medicines Agency.

The Company reported positive data in its Phase 2b clinical trial of Herlystic™ in the prevention or delay of recurrence in fully resected, pulmonary metastatic osteosarcoma, demonstrating clinically significant benefit in the 12-month event free survival (EFS) primary endpoint of the study and the overall survival (OS) secondary endpoint. The Company intends to submit a Biologics License Application (BLA) request to the U.S. FDA for Herlystic™ in osteosarcoma in 2026 and, if approved, would become eligible to receive a Priority Review Voucher that it could then sell. The Company also anticipates requesting Conditional Marketing Authorisation Applications from the U.K.'s Medicines and Healthcare products Regulatory Agency (MHRA) the European Medicines Agency (EMA) and the Australian Therapeutic Goods Administration (TGA) for Herlystic™ in the fourth of 2026. Herlystic™ has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing preclinical efficacy data in various models of breast cancer. Herlystic™ was previously conditionally approved by the U.S. Department of Agriculture for the treatment of canines with osteosarcoma. The Company has also completed dosing in a Phase 1 study of OST-504 for castration-resistant prostate cancer.

In addition, OS Therapies is advancing its next-generation Antibody Drug Conjugate (ADC) and Drug Conjugates (DC), known as tunable ADC (tADC), which features tunable, tailored antibody-linker-payload candidates. This platform leverages the Company's proprietary silicon Si-Linker and Conditionally Active Payload (CAP) technology, enabling the delivery of multiple payloads per linker. For more information, please visit www.ostherapies.com.

Forward-Looking Statements

Statements in this press release regarding future expectations, plans, prospects or performance, as well as any other statements that are not historical facts, may constitute forward-looking statements within the meaning of the federal securities laws. Forward-looking statements are generally identified by words such as "anticipate," "believe," "could," "expect," "intend," "may," "plan," "potential," "should," "will" and similar expressions, although not all forward-looking statements contain these words. Forward-looking statements in this press release include, without limitation, statements regarding any subsequent closings of the warrant inducement and exchange offer, the expected use of net proceeds, the Company's expected cash runway, the receipt of R&D Tax Credits, the timing of regulatory submissions and the potential receipt and sale of a PRV. These statements are based on the current expectations and assumptions of OS Therapies and its management and are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such forward-looking statements. Such risks and uncertainties include, but are not limited to: whether additional Holders exercise or pre-fund their Existing Warrants; the Company's ability to obtain additional financing; the timing and receipt of R&D Tax Credit refunds; the timing and outcome of regulatory submissions and potential approval of Herlystic™ by the U.S. FDA and applicable foreign regulatory authorities; and other risks and uncertainties described under the heading "Risk Factors" in the Company's most recent Annual Report on Form 10-K and in its other filings with the Securities and Exchange Commission. The forward-looking statements contained in this press release speak only as of the date of this press release, and OS Therapies undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law.

OS Therapies Contact Information:

INVESTOR CONTACT
Harrison Seidner, PhD
WaterSeid Partners
OSTX@waterseid.com

MEDIA CONTACT
Steven Weiss
Executive Vice President
Rubenstein Public Relations
sweiss@rubensteinpr.com
212-805-3062

https://x.com/OSTherapies
https://www.instagram.com/ostherapies/
https://www.facebook.com/OSTherapies/
https://www.linkedin.com/company/os-therapies/

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/319689

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How much did OS Therapies raise in its initial warrant inducement closing?

OS Therapies raised approximately $7.2 million in gross proceeds before solicitation agent fees and other offering expenses. Seven holders exercised or pre-funded existing warrants covering 5,517,253 shares at $1.30 per share, or $1.299 per share for pre-funding.

When does the OS Therapies warrant inducement offer expire, and who can participate?

The offer is scheduled to expire at 11:59 p.m. Eastern time on October 30, 2026, unless extended or earlier terminated. It was made only to nine accredited investors holding existing warrants and is not available to other people.

Could OS Therapies sell a Priority Review Voucher following Herlystic approval?

OS Therapies may become eligible for a Priority Review Voucher if its U.S. biologics license application is approved, and intends to sell any voucher received. The most recent voucher sale occurred in October 2026 for $203 million, but that transaction does not establish what OS Therapies would receive.