Stockholders' equity

12 Months Ended

Dec. 31, 2025

Stockholders' equity

Stockholders' equity

7. Stockholders’ equity

The total number of shares of all classes of capital stock that the Company is authorized to issue is 440,000,000 shares, consisting of 400,000,000 shares of common stock, par value $0.001 per share and 40,000,000 shares of preferred stock, par value $0.001 per share.

Series A Preferred Stock

As of December 31, 2025, a total of 31,194 shares of Series A Preferred Stock remained outstanding, which are convertible into 15,596 shares of common stock. In April 2025, a total of 25,033 shares of Series A Preferred stock were converted into 12,516 shares of common stock.

Common Stock

The holders of common stock are entitled to one vote for each share of common stock. In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company, after the payment or provision for payment of all debts and liabilities of the Company, the holders of common stock shall be entitled to share in the remaining assets of the Company available for distribution, if any.

Shelf Registration Statement

On January 26, 2024, the Company filed a shelf registration statement (the “2024 Shelf Registration Statement”) with the SEC for issuance of common stock, preferred stock, warrants, rights, debt securities and units up to an aggregate of $150.0 million, including a prospectus for the sale of $1.0 million of shares of common stock under the ATM Agreement, as discussed below, which was declared effective on February 2, 2024. The Company subsequently filed a prospectus supplement to the 2024 Shelf Registration Statement for the sale of up to $2.0 million of shares of common stock pursuant to the ATM Agreement. On January 26, 2024, the Company entered into an At the Market Offering Agreement (the “ATM Agreement”) with H.C. Wainright & Co., LLC (“HCW”). Pursuant to the ATM Agreement and the prospectus supplement filed in connection therewith, the Company was able, from time to time, in its sole discretion, to issue and sell through HCW, acting as sales agent and/or principal, up to $2.0 million of shares of common stock. The Company did not make any sales under the ATM Agreement and in March 2024, the Company terminated the ATM Agreement with HCW.

On November 8, 2024, the Company filed a prospectus supplement to the 2024 Shelf Registration Statement with the SEC for the sale of up to $3.0 million pursuant to the 2024 ATM Agreement, as discussed below. On November 8, 2024, the Company entered into an At the Market Offering Agreement (the “2024 ATM Agreement”) with HCW. Pursuant to the 2024 ATM Agreement and the prospectus supplement filed in connection therewith, the Company may, from time to time, in its sole discretion, issue and sell through HCW, acting as sales agent and/or principal, up to $3.0 million of shares of common stock. During the year ended December 31, 2024, the Company issued and sold 41,152 shares of common stock under the 2024 ATM Agreement resulting in net proceeds to the Company of approximately $0.1 million after deducting approximately $6,000 in issuance costs. During the year ended December 31, 2025, the Company issued and sold 1,337,948 shares of common stock under the 2024 ATM Agreement resulting in net proceeds to the Company of approximately $1.9 million after deducting approximately $76,000 in issuance costs.

March 2024 Private Placement

On March 11, 2024, the Company entered into a securities purchase agreement with certain purchasers (the “March Purchasers”) pursuant to which the Company agreed to issue and sell to the March Purchasers in a private placement offering exempt from registration under the Securities Act of 1933, as amended, or the Securities Act, and the March Purchasers agreed to purchase from the Company (i) 1,687,712 shares of the Company’s common stock at a purchase price of $7.29 per share (the “March 2024 Shares”), (ii) pre-funded common stock purchase warrants at a purchase price of $7.289 to purchase an aggregate of up to 507,076 shares of the Company’s common stock at an exercise price of $0.001 per share (the “March 2024 Pre-Funded Shares”), (iii) tranche A common stock purchase warrants to purchase up to 1,097,394 shares of the Company’s common stock at an exercise price of $7.29 per share (the “Tranche A Warrants”), and (iv) tranche B common stock purchase warrants to purchase up to 1,097,394 shares of the Company’s common stock at an exercise price of $9.1125 per share (the “Tranche B Warrants”). The Tranche A Warrants will be exercisable until the earlier of (i) the three-year anniversary of issuance and (ii) 30 days after the Company announces the recommended Phase 2 dose for ATRN-119, and, following such announcement, the daily volume weighted average price of the Company’s common stock equals or exceeds $14.58 for 30 consecutive trading days. The Tranche B Warrants will be

exercisable until the earlier of (i) the five-year anniversary of issuance and (ii) 30 days after the Company announces the recommended Phase 2 dose for APR-1051 and, following such announcement, the daily volume weighted average price of the Company’s common stock equals or exceeds $18.225 for 30 consecutive trading days. To the extent that the exercise of a Tranche A Warrant or Tranche B Warrant would result in the holder beneficially owning greater than 4.99% (or, at the election of the holder, greater than 9.99%) of the Company’s outstanding common stock immediately following such exercise, the holder will instead receive pre-funded warrants in substantially the same form as the pre-funded warrants issued at closing. The aggregate upfront gross proceeds from the issuance of common stock and pre-funded common stock purchase warrants totaled approximately $16.0 million, before deducting placement agent fees and offering costs of approximately $1.3 million. The gross proceeds from potential future warrant cash exercises are expected to be up to approximately $18.0 million, before deducting placement agent fees. In April 2024, the Company registered on Form S-3 the resale of the March 2024 Shares, the March 2024 Pre-Funded Shares and the shares underlying the Tranche A Warrants and Tranche B Warrants.

December 2025 Private Placement

On December 8, 2025, the Company entered into a securities purchase agreement with certain purchasers (the “Purchasers”) pursuant to which the Company agreed to issue and sell to the Purchasers in a private placement offering exempt from registration under the Securities Act of 1933, as amended, or the Securities Act, and the Purchasers agreed to purchase from the Company (i) 26,459 shares of the Company’s common stock at a purchase price of $1.165 per share (the “December 2025 Shares”), (ii) pre-funded common stock purchase warrants at a purchase price of $1.164 to purchase an aggregate of up to 2,596,564 shares of the Company’s common stock at an exercise price of $0.001 per share (the “December 2025 Pre-Funded Shares”), (iii) common stock purchase warrants to purchase up to 2,880,533 shares of the Company’s common stock at an exercise price of $1.04 per share, including this issuance of a warrant to purchase up to 257,510 shares of the Company’s common stock to the placement agent (the “December 2025 Warrants”). The December 2025 Warrants will be exercisable until the five-year anniversary of issuance. To the extent that the exercise of a December 2025 Warrant would result in the holder beneficially owning greater than 4.99% (or, at the election of the holder, greater than 9.99%) of the Company’s outstanding common stock immediately following such exercise, the holder will instead receive pre-funded warrants in substantially the same form as the pre-funded warrants issued at closing. The aggregate upfront gross proceeds from the issuance of common stock and pre-funded common stock purchase warrants totaled approximately $3.1 million, before deducting placement agent fees and offering costs of approximately $0.4 million. In December 2025, the Company registered on Form S-3 the resale of the December 2025 Shares, the December 2025 Pre-Funded Shares and the shares underlying the December 2025 Warrants.

The Company evaluated the terms of the warrants issued in the March 2024 and December 2025 Private Placements and determined that they should be classified as equity instruments within additional paid-in capital. As of December 31, 2025 and 2024, none of the Tranche A Warrants or Tranche B Warrants have been exercised. During 2025, 91,206 warrants to purchase March 2024 Pre-Funded Shares were exercised for proceeds of $91 and 1,198,700 warrants to purchase December 2025 Pre-Funded Shares were exercised for no proceeds. No warrants to purchase March 2024 Pre-Funded Shares were exercised during 2024.

A summary of warrants outstanding as of December 31, 2025 is as follows:

		Exercise
	Number of	price per		Expiration
Description	warrants	share		date
March 2024 Tranche A Warrants	1,097,394	$	7.2900	3/11/2027
March 2024 Tranche B Warrants	1,097,394	$	9.1125	3/11/2029
March 2024 pre-funded warrants	415,870	$	0.0010	n/a
December 2025 pre-funded warrants	1,397,864	$	0.0010	n/a
December 2025 warrants	2,880,533	$	1.0400	12/10/2030
Total	6,889,055