eligibility_summary
Adults with advanced/metastatic melanoma, HCC, NSCLC, RCC, MSI‑H/dMMR, urothelial, ESCC, mesothelioma, SCCHN, or cervical cancer lacking standard options, prior PD‑1/PD‑L1, ECOG 0–1, adequate marrow/renal/hepatic labs, biopsyable disease (Part A evaluable/measurable, Part B measurable), negative pregnancy/contraception. Exclude: refusal of serial biopsies, recent therapy, active autoimmune, ≥G2 pneumonitis or >G1 irAEs, unstable CNS mets, major CV disease, uncontrolled HBV/HCV/HIV, >10% weight loss.
trial_source
clinical_trials.gov from Dec 2, 2025
annotation_status
ai
ai_summary
Interventions: MT-8421 (Engineered Toxin Body, biologic protein) as monotherapy or with nivolumab (anti–PD-1 IgG4 monoclonal antibody). Mechanisms: MT-8421 binds CTLA-4 and delivers a toxin-based kill signal to selectively deplete CTLA-4–expressing cells, aiming to dismantle the immunosuppressive tumor microenvironment, this primarily targets CTLA-4+ regulatory T cells and other CTLA-4+ immune cells within tumors. Nivolumab blocks the PD-1 checkpoint to reinvigorate exhausted effector T cells. Targets/pathways: CTLA-4 pathway (cell depletion) and PD-1/PD-L1 axis (checkpoint blockade) to enhance anti-tumor T-cell immunity.