First-Line Retifanlimab for Anal Cancer

Standard first-line chemotherapy for patients with advanced anal cancer combines carboplatin and paclitaxel. Immune checkpoint inhibitors have been endorsed for later-line therapy based on modest activity in phase 2 trials. Now, investigators report results of a global, placebo-controlled, randomized phase 3 trial of the anti-PD-1 agent retifanlimab plus carboplatin and paclitaxel in patients with advanced or metastatic anal squamous cell cancer. Among 308 participants, 72% were female, 70% had received prior radiotherapy, and 91% tested PD-L1–positive at 1% or higher.

Progression-free survival (the primary endpoint) was superior for the addition of retifanlimab versus placebo (9.3 vs. 7.4 months, HR 0.63). Preliminary analysis of median overall survival indicated a trend toward superiority of retifanlimab (29 vs. 23 months). Antitumor responses increased from 44% to 56% with retifanlimab. Incidence of serious treatment-related adverse events was greater with retifanlimab (16% vs 7%).