Bevacizumab Erlotinib Switch Maintenance in Chemo-Responsive Advanced Gallbladder and Cholangiocarcinoma (BEER BTC): A Multicenter, Open-Label, Randomized, Phase II Trial

PURPOSE Patients with chemotherapy-responsive advanced biliary tract cancers (BTCs) are usually observed after 6 months of gemcitabine-based therapy. There is limited prospective evidence for maintenance strategies after chemotherapy. METHODS This investigator-initiated, open-label, randomized, integrated phase II-III study enrolled adult patients with advanced BTC from two cancer centers in India. Patients with histologically confirmed advanced biliary tract adenocarcinoma who had at least disease stabilization after 6 months of gemcitabine-based chemotherapy were randomly assigned (1:1) to either active surveillance or switch maintenance, which was a combination of bevacizumab 5 mg/kg intravenous once every 21 days plus erlotinib 100 mg once daily. Both arms were continued until disease progression, unacceptable toxicity, or patient decision to withdraw. The primary end point of the phase II component of the trial was investigator-evaluated progression-free survival. This trial is registered with Clinical Trials Registry of India (CTRI/2019/05/019323I). RESULTS From May 2021 to November 2022, 98 patients were randomly assigned to active surveillance (n = 49) or bevacizumab-erlotinib (n = 49). A majority of patients had gallbladder cancer (80%). The median follow-up was 13.4 months. The median progression-free survival was 3.1 months (95% CI, 2.47 to 3.64) in the active surveillance group versus 5.3 months (95% CI, 3.53 to 7.04) in the bevacizumab-erlotinib group (hazard ratio, 0.51 [95% CI, 0.33 to 0·74]; P = .0013). The most common grade 3 class-specific adverse events associated with bevacizumab-erlotinib were acneiform rash 1 (2%) and oral stomatitis 1 (2%) with erlotinib and bleeding 1 (2%) with bevacizumab. CONCLUSION The combination of bevacizumab and erlotinib as switch maintenance improves progression-free survival with an acceptable safety profile compared with active surveillance in patients with advanced BTCs in this phase II study. The trial moves on to the phase III component to evaluate improvement in overall survival.