CAMBRIDGE, Mass. — Obsidian Therapeutics has enrolled the first patient in a registration-enabling cohort of its Phase 1/2 Agni-01 study evaluating amsoki-cel in patients with advanced or metastatic melanoma that has resisted immune checkpoint inhibitor treatment.
The company said it plans to pursue a single-arm trial design following discussions with the U.S. Food and Drug Administration. The study is intended to support a future biologics license application and a potential accelerated approval pathway.
Amsoki-cel, formerly known as OBX-115, is an engineered tumor-infiltrating lymphocyte therapy designed with a pharmacologically regulated form of membrane-bound interleukin-15.
“We have obtained alignment with the FDA across key trial design and manufacturing considerations, including drug potency assay, to proceed with the registration-enabling cohort in support of the single-arm accelerated approval pathway for amsoki-cel in advanced melanoma,” Chief Medical Officer Parameswaran Hari, M.D., M.S., said.
“Enrolling the first patient in this cohort is an important step toward bringing a patient-centric TIL treatment regimen to patients with difficult-to-treat ICI-resistant advanced melanoma,” Hari added.
The registration-enabling cohort is part of the ongoing multicenter Agni-01 study and will further evaluate the safety and efficacy of amsoki-cel at the recommended Phase 2 dose.
The study’s primary endpoint is objective response rate, assessed under RECIST criteria by blinded independent central review. Obsidian expects to complete enrollment by the end of the first quarter of 2027 and report topline data by the end of 2027.
The new cohort follows earlier Phase 1/2 results in which amsoki-cel produced a 67 percent objective response rate at the recommended Phase 2 dose. Ten of 15 patients responded, including two who achieved complete responses.
Obsidian said the therapy also demonstrated a favorable safety profile with low-dose lymphodepletion and no interleukin-2 included in the treatment regimen.
The company reported no dose-limiting toxicities, treatment-related deaths, immune effector cell-associated neurotoxicity syndrome or transfers to intensive care.
Obsidian said the therapy could potentially serve a broad patient population because it uses an IL-2-free regimen, allows tumor tissue collection through a less-invasive core needle biopsy and relies on low-dose lymphodepletion that may be compatible with outpatient administration.
The company is also evaluating amsoki-cel in patients with non-small cell lung cancer as part of the Agni-01 trial. Phase 1 data from that group are expected in the first half of 2027.
