A New Immunotherapy Regimen for a Group of Rare Cancers  

The immune checkpoint inhibitor durvalumab was approved in combination with chemotherapy for certain biliary tract cancers that have spread.  

The U.S. Food and Drug Administration (FDA) has approved durvalumab (Imfinzi) in combination with the chemotherapeutics gemcitabine and cisplatin for patients with locally advanced or metastatic biliary tract cancer.  

Durvalumab is a type of immunotherapy that that increases the immune system’s ability to kill cancer cells by blocking the interaction of the immune-suppressing proteins PD-L1 and PD-1. Durvalumab is also approved to treat certain lung and liver cancers.  

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The latest approval is based on results from the randomized, double-blind, placebo-controlled, multiregional TOPAZ-1 phase III clinical trial. 

The TOPAZ-1 trial enrolled 685 patients with locally advanced unresectable or metastatic biliary tract cancers who had not previously received systemic therapy for advanced disease. Patients had intrahepatic cholangiocarcinoma (56 percent of patients), gallbladder cancer (25 percent), or extrahepatic cholangiocarcinoma (19 percent). Patients were randomly assigned to receive either durvalumab or placebo, in combination with gemcitabine and cisplatin.  

Twenty-seven percent of patients in the durvalumab arm responded to the treatment, compared with 19 percent of patients in the placebo arm. Overall survival was significantly higher in patients treated with durvalumab compared with those receiving placebo (12.8 months versus 11.5 months, respectively). Progression-free survival was also significantly greater among patients in the durvalumab arm (7.2 months) than those in the placebo arm (5.7 months).  

Common adverse reactions included fatigue, nausea, constipation, decreased appetite, abdominal pain, rash, and fever.  

Biliary tract cancers include various rare epithelial malignancies, including cancers of the gallbladder, ampulla of Vater, and bile ducts inside and outside the liver, and account for 3 percent of gastrointestinal cancers.  

The FDA rendered its decision on September 2, 2022.