Adding bevacizumab to atezolizumab plus cisplatin and gemcitabine did not significantly improve the progression-free survival (PFS) of patients with newly diagnosed advanced biliary tract cancer (BTC), the phase 2 IMbrave 151 trial showed.

The phase 2 IMbrave 151 study evaluated atezolizumab and bevacizumab in combination with chemotherapy in newly diagnosed patients with advanced BTC (N=162).1 Patients who were randomized to the experimental arm received eight cycles of gemcitabine plus cisplatin chemotherapy and bevacizumab and atezolizumab until disease progression, unacceptable toxicity, or until there was no longer a clinical benefit. In the placebo arm, bevacizumab was replaced with placebo. PFS was the primary endpoint. Prof. Anthony El-Khoueiry (USC Norris Comprehensive Cancer Center) presented the main findings at ASCO-GI 2023.

PFS was not significantly improved in the bevacizumab arm compared with the control arm, although the investigators noticed a numerical benefit of the experimental arm over the control arm (median PFS, 8.3 months vs 7.9; HR, 0.76; 95% CI, 0.51–1.14). The overall survival (OS) data displayed a similar trend (median OS, ‘not reached’ vs 11.4 months; HR, 0.74; 95% CI, 0.43–1.27). Prof. El-Khoueiry mentioned that bevacizumab did not add substantial toxicity to the safety profile of the treatment regimen. The rates of grade 3 or 4 adverse events (AEs) during the chemotherapy phase were similar for the two treatment arms, with 69.2% and 70.4%, respectively. After the chemotherapy phase, these rates dropped to 31.5% in the bevacizumab arm and to 24.5% in the control arm.

Although the results of the IMbrave 151 study showed a modest improvement in PFS with the addition of bevacizumab to atezolizumab and chemotherapy in patients with newly diagnosed advanced BTC, this finding did not reach statistical significance.

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