Convertible Preferred Stock and Stockholders' Equity (Deficit)	6 Months Ended
Jun. 30, 2026
Convertible Preferred Stock and Stockholders' Equity (Deficit)
Convertible Preferred Stock and Stockholders' Equity (Deficit)	6. Convertible Preferred Stock and Stockholders’ Equity (Deficit) At June 30, 2026, there were 6,737 shares of Series C Preferred stock outstanding. Certain material provisions of the Series C Preferred are as follows: Conversion: Each share of Series C Preferred is convertible into 400 shares of Company common stock, subject to the Beneficial Ownership Limitation (as defined below). Dividends: Shares of Series C Preferred participate in any dividends with common stockholders on an as-converted basis. Liquidation: In the event of the liquidation, dissolution, or winding up of the affairs of the Company, whether voluntary or involuntary, the holders of Series C Preferred shall rank on parity with common stockholders as to the distributions of assets. Beneficial Ownership Limitation: A holder of Series C Preferred is prohibited from converting its shares of Series C Preferred into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than 19.9% of the total number of shares of Company common stock issued and outstanding immediately after giving effect to such conversion (the “Beneficial Ownership Limitation”). At the Market Offering Agreement On March 10, 2025, the Company entered into an At the Market Offering Agreement (the “ATM Agreement”) with Citizens JMP Securities, LLC (“Citizens”), pursuant to which the Company may offer and sell shares of its common stock, having an aggregate sales price of up to $50,000,000 (subject to certain limitations set forth in the ATM Agreement), from time to time, to or through Citizens, acting as sales agent and/or principal. During the three and six months ended June 30, 2026, the Company sold and issued 103,513 and 1,193,513 shares of its common stock, under the ATM Agreement for net proceeds of $119,000 and $1,918,000, respectively. April 2026 Financing On April 15, 2026, the Company entered into a Securities Purchase Agreement for a private placement (the “April 2026 Financing”), which closed on April 16, 2026. At closing, the Company issued 5,982,919 shares of its common stock (including 989,507 pre-funded warrants issued in lieu thereof) for aggregate upfront gross proceeds of approximately $10,000,000, at a purchase price of $1.6730 per share ($1.6630 per accompanying pre-funded warrant, each pre-funded warrant having an exercise price of $0.01). The Company also issued (i) April 2026 Series A Warrants to purchase up to 5,982,919 shares of common stock, (ii) April 2026 Series B Warrants to purchase up to 5,982,919 shares of common stock, and (iii) April 2026 Series C Warrants to purchase up to 17,948,757 shares of common stock, each with an exercise price of $1.673 per share, subject to adjustment. If all such warrants are exercised for cash, the Company will receive additional gross proceeds of approximately $50,000,000. The April 2026 Series A Warrants become exercisable upon the Company’s receipt of approval from the Medicines and Healthcare products Regulatory Agency (“MHRA”) to conduct a human challenge trial in the United Kingdom (“UK”). The April 2026 Series B Warrants become exercisable upon the later of the announcement of data from the human challenge trial or receipt of Shareholder Approval. The April 2026 Series C Warrants become exercisable upon receipt of Shareholder Approval, have a three-year term, and are subject to a forced-exercise provision under which, if the closing price of the Company’s common stock is at or above 200% of the exercise price for an uninterrupted period of 30 trading days, the Company may call for cancellation of the unexercised April 2026 Series C Warrants for consideration of $0.001 per underlying share. Each warrant is subject to a beneficial ownership limitation of 4.99% (9.99% at the holder’s election). As of June 30, 2026, none of the April 2026 Series A Warrants, April 2026 Series B Warrants or April 2026 Series C Warrants were exercisable. The Company incurred placement agent fees and other offering costs in connection with the April 2026 Financing, including a cash fee equal to 6.0% of gross proceeds and reimbursement of certain placement agent expenses of up to $175,000, resulting in net proceeds of $9,390,000. On July 8, 2026, at the Company’s 2026 Annual Meeting of Stockholders, the Company’s stockholders approved, in accordance with Nasdaq Listing Rule 5635(d), the issuance of shares of common stock upon exercise of the April 2026 Series B Warrants and April 2026 Series C Warrants issued in the April 2026 Financing (the “Shareholder Approval”). As a result of the Shareholder Approval, the April 2026 Series C Warrants became exercisable, and the April 2026 Series B Warrants will become exercisable upon the announcement of data from the human challenge trial. Series A Warrants and Pre-funded Warrants On February 18, 2025, the Company and certain of the purchasers of Units in the equity offering that closed on December 31, 2024 (the “December 2024 Offering”) entered into amendments to the Series A Warrants (the “Series A Warrant Amendment”), pursuant to which the Series A Warrants issued to such purchasers were amended to (i) increase the threshold for a change of control, for purposes of determining whether a Fundamental Transaction (as defined in the Series A Warrants) has occurred, from 50% of the outstanding common stock of the Company to greater than 50% of the outstanding common stock of the Company, (ii) revise the expected volatility rate to be applied for purposes of determining the Black-Scholes Value of the Series A Warrants to be utilized for calculating consideration payable to the holders of the Series A Warrants in connection with a Fundamental Transaction that is not within the Company’s control, and (iii) remove Section 3(h) of the Series A Warrants, which, under certain circumstances, provided for adjustments to the exercise price of the Series A Warrants in the event of a reverse stock split, stock consolidation, or a recapitalization or similar event involving the Company’s common stock based on the volume weighted average price of the Company’s common stock over the eleven trading day period commencing five trading days immediately preceding such event and the five trading days immediately following such event. The Series A Warrant Amendment resulted in the reclassification of $4,196,000 in warrant liability into permanent equity during the six months ended June 30, 2025. During the first quarter of 2025, certain purchasers of Units in the December 2024 Offering exercised their pre-funded warrants for an aggregate of 1,382,559 shares of the Company’s common stock. On March 27, 2025, the Company and those purchasers holding all pre-funded warrants outstanding as of such date entered into amendments to the pre-funded warrants (the “PFW Amendment”), pursuant to which the pre-funded warrants issued to such purchasers were amended to increase the threshold for a change of control, for purposes of determining whether a Fundamental Transaction (as defined in the pre-funded warrants) has occurred, from 50% of the outstanding common stock of the Company to greater than 50% of the outstanding common stock of the Company. The PFW Amendment and exercises of pre-funded warrants resulted in the reclassification of $11,631,000 in warrant liability into permanent equity during the six months ended June 30, 2025.

Convertible Preferred Stock and Stockholders' Equity (Deficit)

6 Months Ended

Jun. 30, 2026

Convertible Preferred Stock and Stockholders' Equity (Deficit)

Convertible Preferred Stock and Stockholders' Equity (Deficit)

6. Convertible Preferred Stock and Stockholders’ Equity (Deficit)

At June 30, 2026, there were 6,737 shares of Series C Preferred stock outstanding. Certain material provisions of the Series C Preferred are as follows:

Conversion: Each share of Series C Preferred is convertible into 400 shares of Company common stock, subject to the Beneficial Ownership Limitation (as defined below).

Dividends: Shares of Series C Preferred participate in any dividends with common stockholders on an as-converted basis.

Liquidation: In the event of the liquidation, dissolution, or winding up of the affairs of the Company, whether voluntary or involuntary, the holders of Series C Preferred shall rank on parity with common stockholders as to the distributions of assets.

Beneficial Ownership Limitation: A holder of Series C Preferred is prohibited from converting its shares of Series C Preferred into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than 19.9% of the total number of shares of Company common stock issued and outstanding immediately after giving effect to such conversion (the “Beneficial Ownership Limitation”).

At the Market Offering Agreement

On March 10, 2025, the Company entered into an At the Market Offering Agreement (the “ATM Agreement”) with Citizens JMP Securities, LLC (“Citizens”), pursuant to which the Company may offer and sell shares of its common stock, having an aggregate sales price of up to $50,000,000 (subject to certain limitations set forth in the ATM Agreement), from time to time, to or through Citizens, acting as sales agent and/or principal. During the three and six months ended June 30, 2026, the Company sold and issued 103,513 and 1,193,513 shares of its common stock, under the ATM Agreement for net proceeds of $119,000 and $1,918,000, respectively.

April 2026 Financing

On April 15, 2026, the Company entered into a Securities Purchase Agreement for a private placement (the “April 2026 Financing”), which closed on April 16, 2026. At closing, the Company issued 5,982,919 shares of its common stock (including 989,507 pre-funded warrants issued in lieu thereof) for aggregate upfront gross proceeds of approximately $10,000,000, at a purchase price of $1.6730 per share ($1.6630 per accompanying pre-funded warrant, each pre-funded warrant having an exercise price of $0.01). The Company also issued (i) April 2026 Series A Warrants to purchase up to 5,982,919 shares of common stock, (ii) April 2026 Series B Warrants to purchase up to 5,982,919 shares of common stock, and (iii) April 2026 Series C Warrants to purchase up to 17,948,757 shares of common stock, each with an exercise price of $1.673 per share, subject to adjustment. If all such warrants are exercised for cash, the Company will receive additional gross proceeds of approximately $50,000,000.

The April 2026 Series A Warrants become exercisable upon the Company’s receipt of approval from the Medicines and Healthcare products Regulatory Agency (“MHRA”) to conduct a human challenge trial in the United Kingdom (“UK”). The April 2026 Series B Warrants become exercisable upon the later of the announcement of data from the human challenge trial or receipt of Shareholder Approval. The April 2026 Series C Warrants become exercisable upon receipt of Shareholder Approval, have a three-year term, and are subject to a forced-exercise provision under which, if the closing price of the Company’s common stock is at or above 200% of the exercise price for an uninterrupted period of 30 trading days, the Company may call for cancellation of the unexercised April 2026 Series C Warrants for consideration of $0.001 per underlying share. Each warrant is subject to a beneficial ownership limitation of 4.99% (9.99% at the holder’s election). As of June 30, 2026, none of the April 2026 Series A Warrants, April 2026 Series B Warrants or April 2026 Series C Warrants were exercisable.

The Company incurred placement agent fees and other offering costs in connection with the April 2026 Financing, including a cash fee equal to 6.0% of gross proceeds and reimbursement of certain placement agent expenses of up to $175,000, resulting in net proceeds of $9,390,000.

On July 8, 2026, at the Company’s 2026 Annual Meeting of Stockholders, the Company’s stockholders approved, in accordance with Nasdaq Listing Rule 5635(d), the issuance of shares of common stock upon exercise of the April 2026 Series B Warrants and April 2026 Series C Warrants issued in the April 2026 Financing (the “Shareholder Approval”). As a result of the Shareholder Approval, the April 2026 Series C Warrants became exercisable, and the April 2026 Series B Warrants will become exercisable upon the announcement of data from the human challenge trial.

Series A Warrants and Pre-funded Warrants

On February 18, 2025, the Company and certain of the purchasers of Units in the equity offering that closed on December 31, 2024 (the “December 2024 Offering”) entered into amendments to the Series A Warrants (the “Series A Warrant Amendment”), pursuant to which the Series A Warrants issued to such purchasers were amended to (i) increase the threshold for a change of control, for purposes of determining whether a Fundamental Transaction (as defined in the Series A Warrants) has occurred, from 50% of the outstanding common stock of the Company to greater than 50% of the outstanding common stock of the Company, (ii) revise the expected volatility rate to be applied for purposes of determining the Black-Scholes Value of the Series A Warrants to be utilized for calculating consideration payable to the holders of the Series A Warrants in connection with a Fundamental Transaction that is not within the Company’s control, and (iii) remove Section 3(h) of the Series A Warrants, which, under certain circumstances, provided for adjustments to the exercise price of the Series A Warrants in the event of a reverse stock split, stock consolidation, or a recapitalization or similar event involving the Company’s common stock based on the volume weighted average price of the Company’s common stock over the eleven trading day period commencing five trading days immediately preceding such event and the five trading days immediately following such event. The Series A Warrant Amendment resulted in the reclassification of $4,196,000 in warrant liability into permanent equity during the six months ended June 30, 2025.

During the first quarter of 2025, certain purchasers of Units in the December 2024 Offering exercised their pre-funded warrants for an aggregate of 1,382,559 shares of the Company’s common stock. On March 27, 2025, the Company and those purchasers holding all pre-funded warrants outstanding as of such date entered into amendments to the pre-funded warrants (the “PFW Amendment”), pursuant to which the pre-funded warrants issued to such purchasers were amended to increase the threshold for a change of control, for purposes of determining whether a Fundamental Transaction (as defined in the pre-funded warrants) has occurred, from 50% of the outstanding common stock of the Company to greater than 50% of the outstanding common stock of the Company. The PFW Amendment and exercises of pre-funded warrants resulted in the reclassification of $11,631,000 in warrant liability into permanent equity during the six months ended June 30, 2025.