On May 15, 2025, the FDA approved retifanlimab-dlwr for the first-line treatment of adult patients with inoperable locally recurrent or metastatic squamous cell carcinoma of the anal canal (SCAC). This approval covers its use in combination with carboplatin and paclitaxel, as well as a single agent for those with disease progression or intolerance to platinum-based chemotherapy.
Mechanism of action:
Retifanlimab-dlwr is a monoclonal antibody that targets PD-1
Dosing:
The recommended dose is 500 mg intravenously every four weeks for both combination therapy and monotherapy. For combination therapy, treatment is limited to one year,
Clinical trial results- Combination therapy:
In the randomized double-blind POD1UM-303/InterAACT 2 trial was a randomized, double-blind trial showed that patients receiving the combination progression-free survival (PFS) compared to those on chemotherapy alone. Specifically, the median PFS was 9.3 months with retifanlimab-dlwr compared to 7.4 months with chemotherapy alone. The overall response rate (ORR) was also higher in the retifanlimab-dlwr arm (56%) compared to chemotherapy alone (44%).
Clinical trial results- Monotherapy:
Retifanlimab-dlwr was also approved as a single agent for patients with locally recurrent or metastatic SCAC who have progressed on or are intolerant to platinum-based chemotherapy, based on results from the POD1UM-202 trial. A study from the American Association for Cancer Research (AACR) showed that 14% of evaluable patients experienced tumor responses to retifanlimab-dlwr in this setting, with half of those responses lasting at least 9.5 months.