Multinational phase 3 trial of retifanlimab plus chemotherapy for locally recurrent or metastatic squamous cell anal carcinoma

The phase 3 POD1UM trial, at 70 centers in 12 countries evaluated retifanlimab (anti-PD-1) versus placebo, both with carboplatin and paclitaxel, as first-line treatment for locally recurrent or metastatic squamous cell carcinoma of the anal canal. Patients in the placebo group could cross over to retifanlimab monotherapy on disease progression.The primary endpoint was centrally assessed progression-free survival. The median progression-free survival was 9.3 months in the retifanlimab group versus 7.4 months in the placebo group (HR 0.63; p=0.0006). Serious and grade 3 or worse adverse events were more frequent in the retifanlimab group than in the placebo group. The authors conclude that retifanlimab provides clinical benefit, with a manageable safety profile, when added to first-line chemotherapy in advanced squamous cell carcinoma of the anal canal.