Table of Contents FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TEMPEST THERAPEUTICS, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 2834 45-1472564 (Primary Standard Industrial Code Number) As filed with the Securities and Exchange Commission on December 9, 2025 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 (I.R.S. Employer Identification Number) 2000 Sierr ...

Core Viewpoint - Tempest Therapeutics, Inc. has announced an all-stock acquisition of dual-targeting CAR-T programs from Factor Bioscience, aimed at expanding its clinical pipeline and extending its operational runway to mid-2027 [1][2][4] Group 1: Acquisition Details - The acquisition includes the first clinical-stage CD19/BCMA dual-CAR T program, TPST-2003, designed for patients with extramedullary disease [2][3] - Tempest will issue 8,268,495 shares of common stock to Factor, representing 65% of the outstanding shares post-transaction [9] - The transaction is expected to close in early 2026, pending stockholder approval and other customary conditions [12] Group 2: Pipeline Expansion - The acquisition will diversify Tempest's pipeline, which includes amezalpat (Phase 3-ready) and TPST-1495 (Phase 2 expected to start soon) [3][4] - TPST-2003 has completed Phase 1 trials in patients with relapsed multiple myeloma, with data expected in 2026 and a biologics license application planned for 2027 in China [4] - Tempest plans to continue developing additional preclinical and research-stage programs, including TPST-2206 and TPST-3003 [4] Group 3: Financial and Operational Outlook - Existing cash and an investment commitment from Factor are expected to support operations through mid-2027, including key development milestones [2][9] - The company plans to pursue business development discussions or additional financing to advance the pivotal development of amezalpat in first-line liver cancer [4] - The anticipated preclosing equity financing is expected to extend Tempest's runway and support significant milestones [3][4] Group 4: Leadership Changes - Upon closing, Matt Angel, Ph.D., will become the President and CEO, while Stephen Brady will transition to Chairman of the board [3][9] - Dr. Angel has extensive experience in biotechnology and cell therapy, having previously led Factor Bioscience and other cell therapy companies [8][10]

Core Viewpoint - Tempest Therapeutics, Inc. is focused on maximizing shareholder value through strategic alternatives while advancing its clinical pipeline, particularly the TPST-1495 Phase 2 trial in collaboration with the NCI [2][6]. Financial Results - As of September 30, 2025, Tempest reported cash and cash equivalents of $7.5 million, a decrease from $30.3 million on December 31, 2024, primarily due to cash used in operating activities [6][9]. - The net loss for the third quarter of 2025 was $3.5 million, or $0.79 per share, compared to a net loss of $10.6 million, or $5.32 per share, for the same period in 2024 [6][12]. - Research and development expenses for the quarter were $0.6 million, significantly lower than $7.6 million in the same quarter of 2024, reflecting a strategic re-prioritization [6][12]. - General and administrative expenses remained stable at $3.0 million for the quarter, consistent with the same period in 2024 [6][12]. - For the nine months ended September 30, 2025, the net loss was $22.2 million, or $5.71 per share, compared to $28.0 million, or $15.48 per share, for the same period in 2024 [6][12]. Company Overview - Tempest Therapeutics is a clinical-stage biotechnology company based in Brisbane, California, focusing on developing small molecule product candidates with tumor-targeted and immune-mediated mechanisms to treat various cancers [4].

Core Viewpoint - Tempest Therapeutics presented new data at the 2025 AACR Annual Meeting supporting the immune-mediated anti-cancer activity of amezalpat, reinforcing its potential as a novel cancer treatment [1][2]. Group 1: Amezalpat's Mechanism and Efficacy - Amezalpat reduces tumor-promoting immunosuppression by M2 macrophages and T regulatory cells, leading to immune activation [2]. - The drug is an inhibitor of PPAR-alpha, which regulates fatty acid oxidation, a pathway utilized by immunosuppressive cells associated with poor cancer prognosis [2]. - Clinical data indicate that amezalpat shows superiority in overall survival when combined with atezolizumab and bevacizumab in advanced HCC patients compared to standard care [3]. Group 2: Company Overview - Tempest Therapeutics is a clinical-stage biotechnology company focused on developing small molecule therapeutics with tumor-targeted and immune-mediated mechanisms [4]. - The company is headquartered in Brisbane, California, and is advancing a diverse portfolio of product candidates aimed at treating various tumors [4].