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ASCO GI 2023: Quadruplet Regimen Under Study in Advanced Biliary Tract Cancer

By: Vanessa A. Carter, BS
Posted: Tuesday, January 24, 2023

Anthony B. El-Khoueiry, MD, of the University of Southern California Norris Comprehensive Cancer Center, Los Angeles, and colleagues conducted the IMbrave151 study to determine whether the monoclonal antibody atezolizumab with or without bevacizumab in combination with cisplatin and gemcitabine is an effective first-line treatment for advanced biliary tract cancer. Presented during the 2023 American Society of Clinical Oncology (ASCO) GI Cancers Symposium (Abstract 491), the data suggest that the quadruplet combination may provide “clinical benefit” in this patient population.

This phase II global study enrolled 162 patients with previously untreated advanced biliary tract cancer. Participants were randomly assigned to receive atezolizumab (n = 79) or placebo (n = 83) plus bevacizumab, cisplatin, and gemcitabine for up to eight cycles, until disease progression or unacceptable toxicity. Individuals were stratified by primary tumor location, disease status, and geographic region.

The median patient age was 63 years. Approximately 43% of patients identified as Asian, and 53% and 48% had an Eastern Cooperative Oncology Group performance status of 0 and 1, respectively. Most participants (82%) had metastatic disease, with primary tumor locations such as intrahepatic (54%) or extrahepatic (19%) cholangiocarcinoma as well as the gallbladder (27%).

The median progression-free survival was 8.4 months for those given atezolizumab plus bevacizumab, cisplatin, and gemcitabine and 7.9 months for those given atezolizumab plus placebo, cisplatin, and gemcitabine (hazard ratio = 0.76); the 6-month rates were 78% and 63%, respectively. Median overall survival was not reached. The confirmed objective response rate was similar in both treatment groups (24% vs. 25%). The duration of response was higher in the bevacizumab arm than in the placebo arm (89% vs. 47%). Of note, the frequency of grade 3 or 4 adverse events was similar in both groups (73% and 74%).

Disclosure: For full disclosures of the study authors, visit

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