In the SPEARHEAD-1 trial, 44 heavily pretreated adults with advanced synovial sarcoma who had the HLA-A*02 genotype and had tumour expression of melanoma-associated antigen 4 (MAGE-A4) received a single dose of afamitresgene autoleukcal, a genetically modified autologous T-cell receptor immunotherapy targeting MAGE-A4, resulting in a 39% response rate with a median duration of response of 6 months [210]. The gene discussed is MAGEA4; the disease is synovial sarcoma.