Immatics announces updated Phase 1a dose escalation data for IMA402, IMA401

Immatics (IMTX) announced updated Phase 1a dose escalation data from both product candidates in its TCR Bispecific pipeline, IMA402 PRAME Bispecific and IMA401 MAGEA4/8 Bispecific, as well as next steps for clinical development. IMA402 showed favorable tolerability across a wide dose range in the 80 patients treated. The most frequent treatment-related adverse events were expected and transient lymphopenia, consistent with the mechanism of action, and low-grade cytokine release syndrome: Grade 1: 33%, Grade 2: 5%, Grade 3: 0%, Grade 4: 1%. No ICANS or IMA402-related Grade 5 events occurred. Tolerability across all doses was consistent with tolerability at the RP2D range. Several patients dosed with IMA402 at the RP2D range were observed to have deep and durable responses. All 6 confirmed objective responses were ongoing as of data cutoff, including two complete metabolic responses in cutaneous and uveal melanoma, ongoing at 8 and 18 months, respectively, as well as one confirmed partial response in ovarian carcinoma with -100% reduction in target lesions. All responders with ovarian carcinoma were platinum-resistant, and all responders with melanoma were immune checkpoint inhibitor-resistant.