Afamitresgene autoleucel (Tecelra – Adaptimmune), a melanoma-associated antigen A4 (MAGE-A4)-directed genetically modified autologous T-cell immunotherapy, has received accelerated approval from the FDA for one-time treatment of adults with unresectable or metastatic synovial sarcoma who received prior chemotherapy and are HLA-A*02:01P, -A*02:02P, -A*02:03P, or -A*02:06P positive and whose tumor expresses the MAGE-A4 antigen. It is the first gene therapy to be approved in the US for treatment of synovial sarcoma. Accelerated approval of the immunotherapy was based on the overall response rate and duration of response.