eligibility_summary
Adults ≥18 with ECOG 0–1, Merkel cell carcinoma, somatostatin receptor–positive on Ga‑68 imaging, ≥1 measurable lesion, and RECIST progression after ≥2 doses of anti‑PD‑1/L1 (within 12 wks). Recovered from prior therapy, adequate organ function. HBV/HCV controlled, HIV suppressed on stable ART. Contraception required. Exclude active CNS mets, other recent cancers, immunosuppression/live vaccines, allogeneic transplant, pembrolizumab allergy, significant autoimmune/pneumonitis, active infection/TB, pregnancy, major cardiac disease.
trial_source
clinical_trials.gov from Dec 2, 2025
annotation_status
ai
ai_summary
NCT05583708: Single-arm phase II testing pembrolizumab plus lutetium Lu 177 dotatate (Lutathera) in Merkel cell carcinoma after progression on prior PD-1/L1 therapy. Drugs/Mechanisms: • Pembrolizumab – immune checkpoint inhibitor, humanized IgG4 monoclonal antibody against PD-1. Blocks PD-1 on T cells to prevent PD-1/PD-L1 inhibitory signaling, restoring antitumor cytotoxic T-cell activity. • Lutetium Lu 177 dotatate – peptide receptor radionuclide therapy (PRRT), a radiolabeled somatostatin analog (DOTA-TATE) that binds SSTR2 on tumor cells and delivers beta radiation, causing DNA damage and tumor cell death (theranostic pairing with Ga-68 DOTATATE imaging). Targets: • Tumor cell SSTR2 (direct, targeted radiotherapy to SSTR-positive MCC cells). • PD-1/PD-L1 immune checkpoint pathway in the tumor microenvironment (reactivates effector T cells). Combination aims for direct tumor kill plus immune activation/synergy.