FDA Grants RMAT Designation to OBX-115 for Treatment-Resistant Metastatic Melanoma

The FDA has given Regenerative Medicine Advanced Therapy (RMAT) appointment to OBX-115, a new treatment developed by Obsidian Therapeutics for patients with unresectable or metastatic melanoma resistant to ICI. OBX-115 is an engineered tumour-infiltrating cell therapy that uses membrane-bound IL-15 to boost antitumor activity and persistence. This therapy is also pharmacologically regulated by the FDA-approved drug acetazolamide.

Melanoma is a dangerous skin cancer often caused by UV light exposure, with a high risk of metastasis if not detected early. Once metastatic, treatment usually involves PD-1 inhibitors, but outcomes can be poor for patients who are resistant to these therapies. OBX-115 aims to address this unmet need to resistant patients by enhancing the efficacy and safety of TIL therapy.

The RMAT election follows OBX-115’s FDA Fast Track designation granted in July 2024. It is based on data from a Phase 1 study presented at the 2024 American Society of Clinical Oncology’s yearly meeting, which showed a favourable safety profile compared to traditional IL-2-dependent TIL therapy. Obsidian Therapeutics are currently researching through a Phase 1/2 open-label study to further determine the safety and efficiency of OBX-115 in patients with advanced solid tumours.