CAMBRIDGE, Mass., August 5, 2026
Obsidian Therapeutics announced the enrollment of the first patient in the registration-enabling cohort of the Phase 1/2 Agni-01 clinical trial evaluating amsokigene autoleucel (amsoki-cel, formerly OBX-115) for patients with immune checkpoint inhibitor (ICI)-resistant advanced or metastatic melanoma. Following discussions with the U.S. Food and Drug Administration (FDA), the company will pursue a single-arm trial design intended to support a future Biologics License Application (BLA) under the accelerated approval pathway. Topline data from the registration-enabling cohort are expected by the end of 2027.
Phase 1/2 Results Demonstrated Strong Response Rates in Difficult-to-Treat Melanoma
The registration-enabling study follows encouraging Phase 1/2 Agni-01 results, where amsoki-cel achieved a 67% objective response rate (ORR) at the recommended Phase 2 dose (10 of 15 patients), including two complete responses, in patients with advanced melanoma who had progressed after immune checkpoint inhibitor therapy. The engineered tumor-infiltrating lymphocyte (TIL) cell therapy also demonstrated a favorable safety profile, with no dose-limiting toxicities, treatment-related deaths, immune effector cell-associated neurotoxicity syndrome (ICANS), or ICU transfers. The ongoing registration-enabling cohort will continue evaluating safety and efficacy, with ORR serving as the primary endpoint.
Engineered TIL Therapy Designed for Broader Patient Accessibility
Amsoki-cel is an investigational engineered TIL cell therapy incorporating pharmacologically regulatable membrane-bound IL15 (mbIL15) using Obsidian Therapeutics’ proprietary cytoDRiVE® protein-regulation platform. Unlike conventional TIL therapies, the treatment is designed to eliminate the need for high-dose IL-2, utilize low-dose lymphodepletion, and allow less-invasive core needle biopsy for tumor collection. These features may improve treatment accessibility and support outpatient administration while maintaining strong anti-tumor activity in patients with advanced melanoma.
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Obsidian Expands Cell Therapy Pipeline Beyond Melanoma
The initiation of the registration-enabling cohort represents a significant regulatory milestone for Obsidian Therapeutics as it advances amsoki-cel toward potential accelerated approval in advanced melanoma. The company is also evaluating the therapy in non-small cell lung cancer (NSCLC) through the ongoing Agni-01 study, with Phase 1 NSCLC data expected during the first half of 2027. If successful, amsoki-cel could become a differentiated next-generation engineered TIL therapy for multiple solid tumors.
Source: Obsidian Therapeutics press release
