Tempest Therapeutics, Inc. (Nasdaq: TPST) (the "Company"), a clinical-stage biotechnology company pioneering the development of advanced in vivo CAR-T therapies for cancer and autoimmune disease, today announced that it has entered into definitive agreements for the purchase and sale of an aggregate of 3,105,591 shares of common stock (or pre-funded warrant in lieu thereof), series C warrants to purchase up to 3,105,591 shares of common stock and series D warrants to purchase up to 3,105,591 shares of common stock, at a combined purchase price of $0.805 per share of common stock (or per pre-funded warrant in lieu thereof) and accompanying warrants in a private placement. The series C warrants and the series D warrants will have an exercise price of $0.805 per share and will be exercisable beginning on the effective date of stockholder approval of the issuance of the shares issuable upon exercise of the warrants (the "Stockholder Approval Date"). The series C warrants will expire six years from the later of the Stockholder Approval Date and the Effectiveness Date (as defined below) and the series D warrants will expire three years from the later of the Stockholder Approval Date and the Effectiveness Date. The private placement is expected to close on or about September 14, 2026, subject to the satisfaction of customary closing conditions.

H.C. Wainwright & Co. is acting as the exclusive placement agent for the offering.

The gross proceeds from the offering are expected to be approximately $2.5 million, prior to deducting placement agent fees and other offering expenses payable by the Company.