Immatics (IMTX) announced the presentation of expanded data from the ongoing Phase 1b clinical trial evaluating IMA203 PRAME cell therapy in heavily pretreated patients with metastatic melanoma. The longer follow-up of patients demonstrates a consistent and favorable tolerability profile as well as durable responses with a confirmed ORR of 56%. In addition, the Company provided details from a Trial in Progress poster on SUPRAME, the ongoing Phase 3 clinical trial evaluating IMA203 in patients with unresectable or metastatic cutaneous melanoma who have received prior treatment with a checkpoint inhibitor. The most frequent treatment-emergent adverse events were anticipated cytopenias associated with lymphodepletion. Expected and manageable cytokine release syndrome was mostly Grades 1 and 2, which is consistent with the mechanism of action. The expected median PFS in this post-checkpoint inhibitor patient population6 is 2-3 months, and the IMA203 Phase 1b data presented today at ASCO indicate a continued median PFS of greater than or equal to 6 months.