Obsidian Therapeutics Gets FDA RMAT Designation for OBX-115 to Treat Advanced Melanoma

Obsidian Therapeutics, Inc., a biotechnology firm in the clinical stage, has received Regenerative Medicine Advanced Therapy (RMAT) designation from the U.S. Food and Drug Administration (FDA) for its innovative treatment, OBX-115. This treatment is designed for patients with unresectable or metastatic melanoma that does not respond to immune checkpoint inhibitor (ICI) therapy. OBX-115 is a specially engineered autologous T cell immunotherapy derived from tumors and enhanced with membrane-bound IL15 (mbIL15), which is controlled using the FDA-approved drug acetazolamide. This RMAT designation follows an earlier Fast Track designation granted to OBX-115 in July 2024.

Dr. Parameswaran Hari, Chief Development Officer at Obsidian, emphasized the significance of the RMAT designation, stating it underscores the critical need for new treatments in cases where melanoma is resistant to ICI therapy. Initial Phase 1 data, presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting, indicated that OBX-115 has a favorable safety profile compared to non-engineered TIL cell therapy dependent on IL2. It also showed promising efficacy in heavily pre-treated patients and compatibility with core needle biopsy tumor tissue procurement rather than requiring surgical procedures. Obsidian plans to continue working closely with the FDA to advance the clinical development of OBX-115 for both melanoma and non-small cell lung cancer (NSCLC).

The RMAT designation was introduced under the 21st Century Cures Act and offers benefits similar to those of Fast Track and Breakthrough Therapy designations. It aims to speed up the development and review process for promising drug candidates, including cell therapies. To qualify for RMAT, a cell therapy must be regenerative medicine that treats, modifies, reverses, or cures a serious or life-threatening condition and must show preliminary clinical evidence of addressing unmet medical needs. The RMAT designation allows for early and frequent interaction with the FDA, providing intensive guidance on drug development. It also opens the possibility for Accelerated Approval and Priority Review.

OBX-115 is part of Obsidian’s lead cytoTIL15™ program. It is a novel T cell immunotherapy derived from tumors and enhanced with mbIL15, which can be pharmacologically regulated. The goal of OBX-115 is to offer a significant therapeutic option for patients with advanced or metastatic melanoma and other solid tumors. This is achieved by leveraging the expected benefits of mbIL15 and Obsidian’s unique manufacturing process to improve the persistence, antitumor activity, and clinical safety of TIL cell therapy. OBX-115 is currently being tested in a multicenter trial for patients with advanced melanoma or relapsed/refractory NSCLC (NCT06060613).

Obsidian Therapeutics, Inc. is at the forefront of developing engineered cell and gene therapies, aiming to deliver transformative outcomes for patients with difficult-to-treat diseases. The company’s proprietary cytoDRiVE® technology allows for precise regulation of protein function timing and levels using FDA-approved small-molecule drugs. Headquartered in Cambridge, MA, Obsidian has established collaborations with major pharmaceutical companies Bristol Myers Squibb and Vertex Pharmaceuticals.