Business Description

Overview We are a clinical-stage biotechnology company advancing a diversified portfolio of cell therapy and small molecule product candidates. In February 2026, we expanded our pipeline through a strategic transaction under which we acquired rights to a portfolio of dual-targeting chimeric antigen receptor T-cells (“CAR-T”) product candidates with the potential to treat certain blood cancers, solid tumors and immunology indications, including TPST-2003, an autologous CD19/B-cell maturation antigen (“BCMA”) CAR-T therapy currently in clinical development for relapsed or refractory multiple myeloma (“rrMM”). Our portfolio also includes two clinical-stage small molecule product candidates with the potential to treat certain cancer indications. One of our small-molecule product candidates, amezalpat (previously known as TPST-1120), has completed a Phase 2 study in first-line hepatocellular carcinoma (“HCC”). Amezalpat remains Phase 3-ready in HCC and we plan to pursue business development discussions to advance pivotal development. Our second small-molecule product candidate is TPST-1495, which we plan to initiate a Phase 2 study for in familial adenomatous polyposis (“FAP”), with first patient enrollment expected in 2026. The study is expected to be funded by the National Cancer Institute (“NCI”) and conducted through the Cancer Prevention Clinical Trials Network (“CP-CTNet”), enabling advancement with limited internal capital deployment. Our mission is to develop therapeutic products with the potential to address high unmet medical needs by identifying promising clinical-stage candidates and advancing their development to create products that will improve patients’ lives. Recent Developments Strategic Acquisition of Dual-Targeting CAR-T Programs On November 19, 2025, we executed an Asset Purchase Agreement (the “Asset Purchase Agreement”) with Erigen LLC, a Delaware limited liability company (“Erigen”), and Factor Bioscience Inc., a Delaware corporation (together with Erigen, “Sellers”), pursuant to which Sellers agreed to sell and transfer to the Company all right, title and interest of Sellers, worldwide outside of China, Russia, India, and Turkey, in and to all of the assets primarily related to (a) the autologous BCMA/CD19 dual-targeting CAR T-cell therapy known as TPST-2003 currently being evaluated in a Phase 1/2a clinical study in patients with rrMM, a Phase 1/2 investigator-initiated trial (“IIT”) in patients with rrMM, and a Phase 1 clinical study in patients with POEMS Syndrome (“POEMS”), a rare blood disorder caused by abnormal plasma cells, (b) the autologous CD70/CD70 dual-targeting CAR T-cell therapy known as TPST-2206, (c) the allogeneic BCMA/CD19 dual-targeting CAR T-cell therapy with a gene edit in the TRAC locus that inactivates the T cell receptor known as TPST-3003, and (d) the allogeneic CD70/CD70 dual-targeting CAR T-cell therapy with a gene edit in the TRAC locus that inactivates the T cell receptor known as TPST-3206 (collectively referred to herein as the “Assets”), in exchange for an aggregate purchase price of 8,268,495 shares of our common stock issued to Erigen on behalf of both Sellers. Pursuant to the Asset Purchase Agreement, at Closing we assumed Erigen’s rights and obligations under each of the Novatim License Agreement and the Restated Factor License Agreement (each as defined below under “— License and Collaboration Agreements ”). Under the Novatim License Agreement, we obtained an exclusive license to specified patents and know-how in all fields worldwide, but excluding Greater China, India, Turkey, and Russia, to exploit the TPST-2003 and TPST-2206 programs and allogeneic CAR-T therapies based on the TPST-2003 and TPST-2206 programs. We also received a right of first negotiation to negotiate a license to exploit allogeneic CAR-T therapies and in vivo CAR-T therapies in Greater China. Under the Restated Factor License Agreement, we obtained an exclusive license to specified patents in all fields worldwide, but excluding Greater China, India, Turkey, and Russia, to exploit the TPST-3003 and TPST-3206 programs.…