[{"id":"cscc1-orr","name":"Objective Response Rate (ORR)","type":"PRIMARY","unit":"%","results":[{"notes":"47% ORR (95% CI 40-54%). CR 17%, PR 30%.","value":47,"arm_id":"cemiplimab-mcscc","arm_name":"Cemiplimab (combined)","ci_lower":40,"ci_upper":54}],"timepoint":"Best response","description":"Proportion of patients achieving confirmed complete or partial response by independent central review. Single-arm trial — no comparator."}]

EMPOWER-CSCC-1: 47% ORR (95% CI 40-54%) with 17% CR. Median DOR 41 months — durable responses. First systemic therapy showing activity in advanced CSCC.

EMPOWER-CSCC-1 (n=193, open-label): Fatigue 38%, rash 34%, MSK pain 33%, diarrhea 26%. SAEs 41%. Discontinuation due to AEs 12%. Typical PD-1 inhibitor safety profile.

EMPOWER-CSCC-1 was first-in-class for CSCC. 47% ORR with 41-month median DOR is impressive for a cancer with no prior systemic options. The high TMB from UV damage makes CSCC particularly IO-responsive. This established Libtayo as the default CSCC treatment.

Advanced CSCC had no approved systemic therapy. PD-1 inhibition rationale: UV-induced high tumor mutational burden → neoantigen generation → immune susceptibility.