POD1UM-303/InterAACT-2
POD1UM-303 showed that adding the immunotherapy retifanlimab to the standard carboplatin-paclitaxel chemotherapy for advanced anal cancer delayed progression by about two months in median terms and reduced the risk of progression by 37 percent, making it the first immunotherapy to improve first-line treatment of this cancer.
Overview
POD1UM-303/InterAACT-2 was a global double-blind phase 3 trial by Incyte that randomised 308 patients with untreated inoperable locally recurrent or metastatic anal squamous cell carcinoma to carboplatin and paclitaxel with retifanlimab 500 mg every four weeks or placebo. The primary endpoint was progression-free survival by blinded independent review.
Median progression-free survival was 9.3 months with retifanlimab against 7.4 months with placebo (hazard ratio 0.63), and interim overall survival also favoured the antibody; grade 3 or worse adverse events were 83.1 against 75.0 percent, with neutropenia and anaemia most common. Retifanlimab with carboplatin-paclitaxel was approved in the United States in May 2025 for this indication, and the corpus's metastatic anal cancer page lists it as the first-line standard with carboplatin-paclitaxel alone (InterAACT) where the antibody is unavailable.
- Median 9.3 vs 7.4 months with Retifanlimab + carboplatin + paclitaxel compared with Placebo + carboplatin + paclitaxel; about 1.9 months longer for half the group.
- A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
- Put another way, the treated group had about 37 percent lower chance of the event at any given time (hazard ratio 0.63, likely range 0.47 to 0.84).
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- 83.1 vs 75 out of 100 reached this endpoint with Retifanlimab + carboplatin + paclitaxel compared with Placebo + carboplatin + paclitaxel; 8.1 more per 100.
- On this measure the first group did worse, not better.
- This endpoint is not one of the standard survival or response measures; read it alongside the trial's primary result.
- 47.4 vs 38.8 out of 100 reached this endpoint with Retifanlimab + carboplatin + paclitaxel compared with Placebo + carboplatin + paclitaxel; 8.6 more per 100.
- On this measure the first group did worse, not better.
- This endpoint is not one of the standard survival or response measures; read it alongside the trial's primary result.
- These results apply to the people the trial enrolled: Untreated inoperable locally recurrent or metastatic squamous cell carcinoma of the anal canal: carboplatin and paclitaxel with the PD-1 antibody retifanlimab or placebo (double-blind), with progression-free survival as the primary endpoint. People in a different situation may not see the same effect.
- The trial selected people by a biomarker (PD-1); the result should not be assumed for people whose cancer does not have it.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
308 enrolled.
95% CI 7.5 to 11.3 · 95% CI 7.1 to 7.7
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Progression-free survival (blinded independent central review)primary | Retifanlimab + carboplatin + paclitaxel | 154 | 9.3 months | 0.63 (0.47 to 0.84) | 0.0006 (one-sided) | link |
| Placebo + carboplatin + paclitaxel | 154 | 7.4 months | ||||
| Grade 3 or worse adverse events | Retifanlimab + carboplatin + paclitaxel | 154 | 83.1% | - | - | link |
| Placebo + carboplatin + paclitaxel | 154 | 75% | ||||
| Serious adverse events | Retifanlimab + carboplatin + paclitaxel | 154 | 47.4% | - | - | link |
| Placebo + carboplatin + paclitaxel | 154 | 38.8% |
Similar pages
not linked directly; found by shared links- TrialInterAACT
Shares Metastatic and recurrent anal squamous cell carcinoma, Anal cancer (squamous cell carcinoma), Paclitaxel / nab-paclitaxel, Carboplatin and the tag soc-trials.
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- TrialAURELIA
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Shares Paclitaxel / nab-paclitaxel, Cytotoxic chemotherapy and the tag soc-trials.