Biliary tract cancers are a rough group of diseases. They include tumors in the bile ducts and gallbladder, and they often get diagnosed late, when surgery is no longer an option. That is a big reason researchers keep chasing better systemic treatments. Even with recent progress, these cancers still behave like the final boss who somehow has three extra health bars and a legal team. Reviews and consensus papers over the past few years keep landing on the same point: we have more tools now, but we still do not have enough lasting wins, especially outside biomarker-selected groups (Banales et al., 2026; Kalyan et al., 2022).
That is why dual checkpoint blockade is interesting. Nivolumab and ipilimumab have shown real punch in some cancers, and earlier biliary studies hinted that a subset of patients - especially those with intrahepatic cholangiocarcinoma or gallbladder cancer - might benefit (Klein et al., 2020; Ahn et al., 2024).
What this study actually found
The MoST-CIRCUIT trial enrolled 60 patients total - 37 with intrahepatic cholangiocarcinoma and 23 with gallbladder cancer - most of whom had already received prior treatment. Everyone got the same regimen, so this was a single-arm study, not a head-to-head cage match against another therapy.
The overall response rate was 12%. That included 2% complete responses and 10% partial responses. Median overall survival was 7 months, and 27% of patients were progression-free at 6 months. Severe immune-related side effects showed up in 20% of patients (Nagrial et al., 2026).
Now for the part that makes researchers lean forward in their chair.
The results were not evenly spread. In intrahepatic cholangiocarcinoma, the response rate was just 3%. In gallbladder cancer, it was 26%. In patients who had not previously received immunotherapy, the overall response rate rose to 19%, and the gallbladder subgroup hit 38% (Nagrial et al., 2026).
So the big headline is not "dual immunotherapy works great for everyone." It very much does not. The more honest headline is "this looked disappointing overall, but gallbladder cancer may be a different story."
Why that matters more than it sounds
Cancer research loves a clean answer and then immediately refuses to provide one. Biliary tract cancers are not one disease wearing different hats. They are a messy family of related cancers with different biology, different mutation patterns, and apparently different immune behavior. Gallbladder cancer may be more vulnerable to this two-drug immune approach than intrahepatic cholangiocarcinoma, and that is exactly the kind of clue worth chasing.
That matters because the field has already shifted. Chemo plus PD-1 or PD-L1 blockade is now standard first-line treatment for many patients with advanced biliary tract cancer after trials like TOPAZ-1 and KEYNOTE-966 showed survival gains over chemotherapy alone (Oh et al., 2024; Kelley et al., 2023). In other words, the easy sequel has already been released. The question now is who needs a different script.
This study suggests one answer: maybe patients with gallbladder cancer deserve a more focused look at dual checkpoint blockade, especially before prior immunotherapy muddies the waters.
The catch, because there is always a catch
This is not practice-changing on its own. The trial was single-arm, the subgroups were small, and the toxicity was not trivial. Immune-related side effects are the kind of plot twist oncologists take seriously because they can affect the liver, gut, skin, endocrine organs, and more. Twenty percent severe toxicity is not nothing. That is not "oops, mild rash, carry on." That is "everyone in the room needs to know what they are doing."
Still, negative-ish studies can be useful when they fail in an informative way. This one says the combo probably is not the broad answer for advanced biliary tract cancers as a whole. But it also says gallbladder cancer may not belong in the same immunotherapy bucket as everything else. And in oncology, separating one bucket into two better buckets is often how progress actually happens - less fireworks, more sorting hat.
References
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Nagrial A, Carlino MS, Gunjur A, et al. Nivolumab and ipilimumab combination treatment in patients with advanced intrahepatic cholangiocarcinoma and gallbladder cancer: Results from the phase II MoST-CIRCUIT trial. Clinical Cancer Research. 2026. DOI: 10.1158/1078-0432.CCR-25-4009
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Banales JM, Rodrigues PM, Affo S, et al. Cholangiocarcinoma 2026: status quo, unmet needs and priorities. Nature Reviews Gastroenterology & Hepatology. 2026;23:65-96. DOI: 10.1038/s41575-025-01153-w
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Kalyan A, Khosla H, Kim RD. Immunotherapy in Biliary Tract Cancers: Where Are We? Current Oncology Reports. 2022;24(12):1821-1828. DOI: 10.1007/s11912-022-01328-7
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Klein O, Kee D, Nagrial A, et al. Evaluation of Combination Nivolumab and Ipilimumab Immunotherapy in Patients With Advanced Biliary Tract Cancers: Subgroup Analysis of a Phase 2 Nonrandomized Clinical Trial. JAMA Oncology. 2020;6(9):1405-1409. DOI: 10.1001/jamaoncol.2020.2814
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Ahn DH, Bekaii-Saab T, O'Neil BH, et al. SWOG 1609 Cohort 48: Anti-CTLA-4 and Anti-PD-1 for Advanced Gallbladder Cancer. Cancer. 2024;130(17):2918-2927. PMCID: PMC11309904 DOI: 10.1002/cncr.35243
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Oh DY, He AR, Qin S, et al. Durvalumab or placebo plus gemcitabine and cisplatin in participants with advanced biliary tract cancer (TOPAZ-1): updated overall survival from a randomised phase 3 study. Lancet Gastroenterology & Hepatology. 2024;9(8):694-704. DOI: 10.1016/S2468-1253(24)00095-5
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Kelley RK, Ueno M, Yoo C, et al. Pembrolizumab in combination with gemcitabine and cisplatin compared with gemcitabine and cisplatin alone for patients with advanced biliary tract cancer (KEYNOTE-966): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2023;401:1853-1865. DOI: 10.1016/S0140-6736(23)00727-4
Disclaimer: The image accompanying this article is for illustrative purposes only and does not depict actual experimental results, data, or biological mechanisms.