Retifanlimab improves progression-free survival in advanced squamous cell anal carcinoma

1. Progression-free survival was significantly greater in retifanlimab compared to placebo.

2. Serious and grade 3 or more adverse events were more common in the retifanlimab group.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Squamous cell carcinoma of the anal canal (SCAC) is a rare cancer that can progress despite standard platinum-based chemotherapy. Retifanlimab, a PD-1 inhibitor, has shown promise in previously treated, PD-L1-positive SCAC. This randomized controlled trial aimed to evaluate whether adding retifanlimab to carboplatin–paclitaxel improves outcomes in patients with inoperable SCAC. The primary outcome of this study was progression-free survival, while key secondary outcome was safety. According to study results, retifanlimab significantly improved median progression-free survival compared to placebo, with a manageable safety profile. Although this study was well done, it was limited by crossover to retifanlimab in the placebo group, which may have confounded overall survival outcomes.

Click to read the study in The Lancet

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In-depth [randomized controlled trial]: Between Nov 12, 2020, and Jul 3, 2023, 376 patients were assessed for eligibility across 70 centers in 12 countries. Included were patients aged ≥ 18 years with locally recurrent or metastatic SCAC, an ECOG status of 0 or 1, and no prior systemic therapy. Altogether, 308 patients (154 each in retifanlimab plus carboplatin–paclitaxel or placebo plus carboplatin–paclitaxel) were included in the final analysis. The primary outcome of progression-free survival was significantly longer in retifanlimab compared to placebo (median 9.3 months vs. 7.4 months, hazard rate [HR] 0.63, p<0.05). The secondary outcome of safety showed higher rates of serious and grade ≥ 3 adverse events in the retifanlimab group (47.4% vs. 38.8% and 83.1% vs. 75.0%). Findings from this study suggest that adding retifanlimab to chemotherapy improves outcomes for advanced SCAC.

Image: PD

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