Organization and Description of Business	12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. ORGANIZATION AND DESCRIPTION OF BUSINESS Description of Business Tempest Therapeutics, Inc. (“Tempest” or the “Company”) is a clinical-stage biotechnology company advancing a diverse portfolio of targeted and immune-mediated product candidates with the potential to be first-in-class to treat a wide range of cancers. Tempest’s portfolio includes both cell therapy and small molecule product candidates spanning discovery through late-stage development. The Company is headquartered in Brisbane, California. Reverse Stock Split On December 3, 2024, the Company’s stockholders approved a proposal to effect an amendment to the Company’s Restated Certificate of Incorporation to implement a reverse stock split. On April 4, 2025, the Company filed a certificate of amendment to the Company’s Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect the one-for-thirteen (1:13) reverse stock split of its outstanding common stock (the "Reverse Stock Split"). On April 8, 2025, the Company effected the Reverse Stock Split. Pursuant to their terms, a proportionate adjustment was made to the per share exercise price and number of shares issuable under all of the Company’s outstanding options and warrants, and the number of shares authorized for issuance pursuant to the Company’s equity incentive plans have been reduced proportionately. The Reverse Stock Split did not reduce the number of authorized shares of common stock and did not alter the par value. No fractional shares were issued as a result of the Reverse Stock Split. Stockholders of record who would have otherwise been entitled to receive a fractional share received a cash payment in lieu thereof. The Reverse Stock Split affected all stockholders proportionately and did not affect any stockholder’s percentage ownership of the Company’s common stock (except to the extent that the Reverse Stock Split resulted in any stockholder owning only a fractional share). Liquidity and Going Concern The Company has incurred operating losses since inception. As of December 31, 2025, the Company had $7.7 million of cash and cash equivalents. While the Company implemented cost reductions in 2025, the Company has finite cash resources available to fund its operations. In April 2025, the Company announced plans to explore a full range of strategic alternatives to advance its promising clinical stage programs and maximize stockholder value. The Company retained MTS Health Partners, L.P., an internationally recognized financial advisor with substantial experience in the biotechnology industry, to support it with the strategic evaluation process. As part of the cost reductions, the Company reduced its workforce by 21 of 26 full-time employees, which became effective April 30, 2025. Further, in support of such efforts, on June 5, 2025, each of Stephen Brady, the Company’s Chief Executive Officer and President, Samuel Whiting, the Company’s Executive Vice President and Chief Medical Officer, and Nicholas Maestas, the Company’s Chief Financial Officer and Head of Corporate Strategy, transitioned to consulting arrangements with the Company, pursuant to which they continued to serve the Company in their respective executive roles. The Company incurred $3.2 million of one-time cash severance payments, benefits and other related costs (excluding non-cash charges associated with stock-based compensation), with the majority of such costs incurred in the second quarter of 2025. On February 3, 2026, the Company closed the Asset Acquisition (as defined below). See Note 13, Subsequent Events. Pursuant to the Asset Purchase Agreement (as defined below), Factor (as defined below) has made the Funding Commitment (as defined below) to provide the Company with financial support for at least 18 months following the closing of the Asset Acquisition, up to a maximum amount of $20.0 million that is inclusive of any amounts raised and received by the Company after the date of the Asset Purchase Agreement, on the terms and subject to the conditions and other provisions of a funding commitment letter contemplated by and entered into concurrently with the Asset Purchase Agreement. However, there is significant uncertainty as to whether we will be able to satisfy the terms and conditions and other provisions set forth in the funding commitment letter, and, if we are unable to do so, we may be limited in the amount of funding that we are able to access under the Funding Commitment or we may not be able to access any funds under the Funding Commitment. The timing of any additional funding from Factor is uncertain. The Company expects that its existing cash and cash equivalents will fund the Company’s projected operating expense requirements through less than 12 months from the date our consolidated financial statements were available to be issued. Accordingly, there is substantial doubt about the Company’s ability to continue to operate as a going concern for a period of 12 months from the date of issuance of these consolidated financial statements. The accompanying financial statements were prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. These financial statements do not include any separate adjustments relating to the recovery of recorded assets or the classification of liabilities; however, such adjustments may be necessary in the future when the Company is unable to continue as a going concern. ATM Program On July 23, 2021, the Company entered into a sales agreement with Jefferies LLC (“Jefferies”), pursuant to which the Company may sell, from time to time at its sole discretion through Jefferies, as its sales agent, shares of its common stock having, up to an aggregate sales price of $100.0 million of its common stock through Jefferies (the “Prior ATM Program”). As of June 20, 2024, the Company had sold an aggregate 9,017,110 shares of its common stock for gross proceeds of $42.7 million ($41.5 million net of commissions and estimated expenses) under the Prior ATM Program. On June 20, 2024, the Company and Jefferies terminated the Prior ATM Program and entered a new Open Market Sale Agreement (the “Sales Agreement”) to sell shares of common stock from time to time through Jefferies acting as sales agent (the “ATM Program”). The Company will pay Jefferies a commission up to 3.0% of the gross sales proceeds of any shares of its common stock sold through Jefferies under the ATM Program and also has provided Jefferies with indemnification and contribution rights. Pursuant to the prospectus supplement dated June 20, 2024 filed by the Company with the U.S. Securities and Exchange Commission (“SEC”), the Company was able to offer and sell up to $205.0 million of its shares of common stock pursuant to the Sales Agreement. On February 6, 2025, the Company filed a prospectus supplement with the SEC limiting the availability under the ATM Program to $14.5 million. On June 11, 2025, in connection with the RDO (as defined below), the Company delivered written notice to Jefferies that it was suspending and terminating the prospectus supplement, dated February 6, 2025, related to the ATM Program (the “ATM Prospectus”). The Company will not make any sales of its securities pursuant to the Sales Agreement, unless and until a new prospectus, prospectus supplement or a new registration statement is filed. Other than the termination of the ATM Prospectus, the Sales Agreement remains in full force and effect. Under current SEC regulations, if at any time the Company's public float is less than $75.0 million, and for so long as the Company’s public float remains less than $75.0 million, the amount the Company can raise through primary public offerings of securities in any 12-month period using shelf registration statements is limited to an aggregate of one-third of the Company's public float, which is referred to as the baby shelf rules. As of the year ended December 31, 2025, the Company has sold an aggregate of 312,830 shares of its common stock for proceeds of $2.8 million, pursuant to the ATM Program. Registered Direct Offerings On June 11, 2025, the Company sold an aggregate of 405,000 shares of the Company’s common stock and pre-funded warrants to purchase 334,000 shares of its common stock (the “June 2025 Pre-Funded Warrants”) in a registered direct offering (“June RDO”). The offering price was $6.25 per share of common stock and $6.249 per June 2025 Pre-Funded Warrant, which is the price of each share of common stock sold in the RDO, minus the $0.001 exercise price per June 2025 Pre-Funded Warrant. The net proceeds from the RDO were approximately $4.1 million, after deducting placement agent fees and offering expenses payable by the Company. As of December 31, 2025, all June 2025 Pre-Funded Warrants had been exercised. On November 24, 2025, the Company sold an aggregate of 487,000 shares of the Company's common stock, pre-funded warrants to purchase 685,414 shares of its common stock (the “November 2025 Pre-Funded Warrants”) and warrants to purchase an aggregate of 1,172,414 shares of common stock (the “Common Warrants”) in a registered direct offering (the “November RDO”). The combined purchase price of each share of common stock and accompanying Common Warrant was $3.625. The combined purchase price of each November 2025 Pre-Funded Warrants and accompanying Common Warrant was $3.624 (equal to the combined purchase price per share of common stock and accompanying Common Warrant, minus $0.001) The exercise price of the Common Warrants is $3.50 per share. The net proceeds from the RDO were approximately $3.8 million, after deducting placement agent fees and estimated offering expenses payable by the Company. As of December 31, 2025, all November 2025 Pre-Funded Warrants and Common Warrants remained outstanding. All November 2025 Pre-Funded Warrants were subsequently exercised in January and February 2026.

Organization and Description of Business

12 Months Ended

Dec. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Description of Business

1. ORGANIZATION AND DESCRIPTION OF BUSINESS

Description of Business

Tempest Therapeutics, Inc. (“Tempest” or the “Company”) is a clinical-stage biotechnology company advancing a diverse portfolio of targeted and immune-mediated product candidates with the potential to be first-in-class to treat a wide range of cancers. Tempest’s portfolio includes both cell therapy and small molecule product candidates spanning discovery through late-stage development. The Company is headquartered in Brisbane, California.

Reverse Stock Split

On December 3, 2024, the Company’s stockholders approved a proposal to effect an amendment to the Company’s Restated Certificate of Incorporation to implement a reverse stock split. On April 4, 2025, the Company filed a certificate of amendment to the Company’s Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect the one-for-thirteen (1:13) reverse stock split of its outstanding common stock (the "Reverse Stock Split").

On April 8, 2025, the Company effected the Reverse Stock Split. Pursuant to their terms, a proportionate adjustment was made to the per share exercise price and number of shares issuable under all of the Company’s outstanding options and warrants, and the number of shares authorized for issuance pursuant to the Company’s equity incentive plans have been reduced proportionately. The Reverse Stock Split did not reduce the number of authorized shares of common stock and did not alter the par value.

No fractional shares were issued as a result of the Reverse Stock Split. Stockholders of record who would have otherwise been entitled to receive a fractional share received a cash payment in lieu thereof. The Reverse Stock Split affected all stockholders proportionately and did not affect any stockholder’s percentage ownership of the Company’s common stock (except to the extent that the Reverse Stock Split resulted in any stockholder owning only a fractional share).

Liquidity and Going Concern

The Company has incurred operating losses since inception. As of December 31, 2025, the Company had $7.7 million of cash and cash equivalents. While the Company implemented cost reductions in 2025, the Company has finite cash resources available to fund its operations. In April 2025, the Company announced plans to explore a full range of strategic alternatives to advance its promising clinical stage programs and maximize stockholder value. The Company retained MTS Health Partners, L.P., an internationally recognized financial advisor with substantial experience in the biotechnology industry, to support it with the strategic evaluation process. As part of the cost reductions, the Company reduced its workforce by 21 of 26 full-time employees, which became effective April 30, 2025. Further, in support of such efforts, on June 5, 2025, each of Stephen Brady, the Company’s Chief Executive Officer and President, Samuel Whiting, the Company’s Executive Vice President and Chief Medical Officer, and Nicholas Maestas, the Company’s Chief Financial Officer and Head of Corporate Strategy, transitioned to consulting arrangements with the Company, pursuant to which they continued to serve the Company in their respective executive roles. The Company incurred $3.2 million of one-time cash severance payments, benefits and other related costs (excluding non-cash charges associated with stock-based compensation), with the majority of such costs incurred in the second quarter of 2025.

On February 3, 2026, the Company closed the Asset Acquisition (as defined below). See Note 13, Subsequent Events. Pursuant to the Asset Purchase Agreement (as defined below), Factor (as defined below) has made the Funding Commitment (as defined below) to provide the Company with financial support for at least 18 months following the closing of the Asset Acquisition, up to a maximum amount of $20.0 million that is inclusive of any amounts raised and received by the Company after the date of the Asset Purchase Agreement, on the terms and subject to the conditions and other provisions of a funding commitment letter contemplated by and entered into concurrently with the Asset Purchase Agreement. However, there is significant uncertainty as

to whether we will be able to satisfy the terms and conditions and other provisions set forth in the funding commitment letter, and, if we are unable to do so, we may be limited in the amount of funding that we are able to access under the Funding Commitment or we may not be able to access any funds under the Funding Commitment. The timing of any additional funding from Factor is uncertain.

The Company expects that its existing cash and cash equivalents will fund the Company’s projected operating expense requirements through less than 12 months from the date our consolidated financial statements were available to be issued. Accordingly, there is substantial doubt about the Company’s ability to continue to operate as a going concern for a period of 12 months from the date of issuance of these consolidated financial statements. The accompanying financial statements were prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. These financial statements do not include any separate adjustments relating to the recovery of recorded assets or the classification of liabilities; however, such adjustments may be necessary in the future when the Company is unable to continue as a going concern.

ATM Program

On July 23, 2021, the Company entered into a sales agreement with Jefferies LLC (“Jefferies”), pursuant to which the Company may sell, from time to time at its sole discretion through Jefferies, as its sales agent, shares of its common stock having, up to an aggregate sales price of $100.0 million of its common stock through Jefferies (the “Prior ATM Program”). As of June 20, 2024, the Company had sold an aggregate 9,017,110 shares of its common stock for gross proceeds of $42.7 million ($41.5 million net of commissions and estimated expenses) under the Prior ATM Program. On June 20, 2024, the Company and Jefferies terminated the Prior ATM Program and entered a new Open Market Sale Agreement (the “Sales Agreement”) to sell shares of common stock from time to time through Jefferies acting as sales agent (the “ATM Program”). The Company will pay Jefferies a commission up to 3.0% of the gross sales proceeds of any shares of its common stock sold through Jefferies under the ATM Program and also has provided Jefferies with indemnification and contribution rights. Pursuant to the prospectus supplement dated June 20, 2024 filed by the Company with the U.S. Securities and Exchange Commission (“SEC”), the Company was able to offer and sell up to $205.0 million of its shares of common stock pursuant to the Sales Agreement. On February 6, 2025, the Company filed a prospectus supplement with the SEC limiting the availability under the ATM Program to $14.5 million. On June 11, 2025, in connection with the RDO (as defined below), the Company delivered written notice to Jefferies that it was suspending and terminating the prospectus supplement, dated February 6, 2025, related to the ATM Program (the “ATM Prospectus”). The Company will not make any sales of its securities pursuant to the Sales Agreement, unless and until a new prospectus, prospectus supplement or a new registration statement is filed. Other than the termination of the ATM Prospectus, the Sales Agreement remains in full force and effect.

Under current SEC regulations, if at any time the Company's public float is less than $75.0 million, and for so long as the Company’s public float remains less than $75.0 million, the amount the Company can raise through primary public offerings of securities in any 12-month period using shelf registration statements is limited to an aggregate of one-third of the Company's public float, which is referred to as the baby shelf rules. As of the year ended December 31, 2025, the Company has sold an aggregate of 312,830 shares of its common stock for proceeds of $2.8 million, pursuant to the ATM Program.

Registered Direct Offerings

On June 11, 2025, the Company sold an aggregate of 405,000 shares of the Company’s common stock and pre-funded warrants to purchase 334,000 shares of its common stock (the “June 2025 Pre-Funded Warrants”) in a registered direct offering (“June RDO”). The offering price was $6.25 per share of common stock and $6.249 per June 2025 Pre-Funded Warrant, which is the price of each share of common stock sold in the RDO, minus the $0.001 exercise price per June 2025 Pre-Funded Warrant. The net proceeds from the RDO were approximately $4.1 million, after deducting placement agent fees and offering expenses payable by the Company. As of December 31, 2025, all June 2025 Pre-Funded Warrants had been exercised.

On November 24, 2025, the Company sold an aggregate of 487,000 shares of the Company's common stock, pre-funded warrants to purchase 685,414 shares of its common stock (the “November 2025 Pre-Funded Warrants”) and warrants to purchase an aggregate of 1,172,414 shares of common stock (the “Common Warrants”) in a registered direct offering (the “November RDO”).

The combined purchase price of each share of common stock and accompanying Common Warrant was $3.625. The combined purchase price of each November 2025 Pre-Funded Warrants and accompanying Common Warrant was $3.624 (equal to the combined purchase price per share of common stock and accompanying Common Warrant, minus $0.001) The exercise price of the Common Warrants is $3.50 per share. The net proceeds from the RDO were approximately $3.8 million, after deducting placement agent fees and estimated offering expenses payable by the Company. As of December 31, 2025, all November 2025 Pre-Funded Warrants and Common Warrants remained outstanding. All November 2025 Pre-Funded Warrants were subsequently exercised in January and February 2026.