ADTX (NASDAQ: ADTX) raises at‑the‑market capacity to $53.4M

Rhea-AI Filing Summary

ADTX amends its shelf to increase its ATM capacity to $53,398,964. This prospectus supplement adds $36,800,000 of new ATM capacity, bringing the aggregate authorized amount under the sales agreement to $53,398,964, and leaves prior terms and the sales agreement unchanged.

The supplement states the company has previously sold approximately 398,950 shares for aggregate gross proceeds of $21,257,000, leaving about $16,500,000 of prior capacity before this increase. The filing also discloses the last reported Nasdaq sale price of the common stock was $0.81 per share as of March 27, 2026.

Insights

Equity Capital Markets Analyst

ATM supplement increases available equity capacity by $36.8M.

The company adds $36,800,000 to its at-the-market program, taking aggregate capacity to $53,398,964. The supplement confirms prior sales of 398,950 shares for $21,257,000, and leaves the sales agreement terms unchanged.

Practical dependence is on market conditions and dealer executions; actual issuance depends on future sales activity under the sales agreement and any market reception at prevailing prices.

Securities & Corporate Counsel

Filing is an administrative amendment to extend ATM capacity; no new covenants were disclosed.

The supplement explicitly states it "amends and supplements" prior prospectuses and that the sales agreement remains in full force and effect. It also notes the company is no longer subject to General Instruction I.B.6. limits on Form S-3.

Material qualifiers include reliance on the Prior Prospectuses; timing and cash-flow treatment of future sales are governed by the sales agreement and not specified here.

Filed pursuant to Rule 424(b)(5)

Registration No. 333-280757

SUPPLEMENT NO. 3 TO

PROSPECTUS SUPPLEMENT DATED OCTOBER 25, 2024

(To Prospectus dated August 6, 2024)

Up to $53,398,964

Common Stock

This prospectus supplement amends and supplements the prospectus dated August 6, 2024, filed as a part of our registration statement on Form S-3 (File No. 333-280757) as amended by our prospectus supplements dated October 25, 2024, April 3, 2025, and December 12, 2025 (the “Prior Prospectuses”). This prospectus supplement should be read in conjunction with the Prior Prospectuses, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the Prior Prospectuses. This prospectus supplement is not complete without, and may only be delivered or utilized in connection with, the Prior Prospectuses, and any future amendments or supplements thereto.

We filed the Prior Prospectuses to register the offer and sale of our common stock, par value $0.001 per share, from time to time pursuant to the terms of that certain At The Market Offering Agreement, or the sales agreement, between H.C. Wainwright & Co., LLC, or Wainwright, acting as the agent, and us (the “ATM Offering”).

We are filing this prospectus supplement to amend the Prior Prospectuses to increase the maximum aggregate gross sales price of our common stock that may be offered, issued and sold under the sales agreement from and after the date hereof by an additional $36,800,000 or up to $53,398,964 (the “ATM Offering Size Increase”), not including the shares of common stock previously sold. Under the prospectus supplement dated October 25, 2024, we initially registered up to $35,000,000 of our common stock for offer and sale pursuant to the sales agreement, which was reduced to $11,840,454 pursuant to the prospectus supplement dated April 3, 2025, and increased to $20,000,000 pursuant to the prospectus supplement dated December 12, 2025. As of the date of the filing of this prospectus supplement, we have sold approximately 398,950 shares of our common stock covered by the Prior Prospectuses pursuant to the sales agreement for aggregate gross sales proceeds of approximately $21,257,000, leaving approximately $16,500,000 remaining under the Prior Prospectuses. This prospectus supplement authorizes an additional $36,800,000 of common stock for offer and sale or up to $53,398,964 in the aggregate, representing the remaining available capacity under our registration statement to which this supplement forms a part.

The purpose of this prospectus supplement is to update the Prior Prospectuses to reflect the ATM Offering Size Increase. Except as modified by this prospectus supplement, the terms of the ATM Offering remain unchanged, and the sales agreement remains in full force and effect.

Our prior prospectus supplement dated April 3, 2025 indicated that we were, at that time, subject to General Instruction I.B.6. of Form S-3, which limited the amount that we were able to sell under the registration statement of which the prospectus forms a part. We are currently no longer subject to the offering limits imposed by General Instruction I.B.6. of Form S-3.

Our common stock is traded on The Nasdaq Capital Market under the symbol “ADTX.” On March 27, 2026, the last reported sale price of our common stock as reported on the Nasdaq Capital Market was $0.81 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

H.C. Wainwright & Co.

The date of this prospectus supplement is March 27, 2026.

FAQ

What change does ADTX's prospectus supplement make to the ATM program?

It increases the ATM capacity by $36,800,000, raising aggregate capacity to $53,398,964. The supplement amends prior prospectuses and leaves the sales agreement terms unchanged, authorizing additional common stock sales under the existing ATM arrangement.

How much common stock has ADTX already sold under the prior prospectuses?

ADTX has sold approximately 398,950 shares for aggregate gross proceeds of $21,257,000. That historical sale figure is presented in the supplement as the amount sold under the Prior Prospectuses prior to this capacity increase.

Does ADTX receive proceeds from these ATM sales?

Yes. The prospectus registers common stock for offer and sale under an ATM sales agreement under which the company may sell shares and receive gross proceeds. Specific future sales and timing depend on executions under the sales agreement.

What is ADTX's quoted market price disclosed in the supplement?

The last reported Nasdaq sale price disclosed is $0.81 per share as of March 27, 2026. That price is included in the supplement as a market-reference data point and does not indicate any executed sale amount in this filing.