Phase 2 Pembrolizumab PD-1 Inhibitor Study in Ultra-Rare Sarcomas

This minibasket study by Memorial Sloan Kettering assesses whether pembrolizumab—a PD-1 inhibitor that releases immune brakes—is safe and effective in ultra-rare sarcomas (including pleomorphic liposarcoma, epithelioid sarcoma, PEComa, CIC-rearranged sarcoma, and sclerosing epithelioid fibrosarcoma) in recurrent or metastatic settings after standard therapy failure, with patients receiving 6-week intravenous infusions to monitor clinical activity and immune response. Many of these histologies rely on doxorubicin/ifosfamide-based chemo or agents like trabectedin and pazopanib with modest ORR; this explores whether PD-1 blockade yields durable pockets of benefit.