AstraZeneca said that Imfinzi (durvalumab) in combination with standard-of-care chemotherapy doubled the overall survival (OS) rate at three years for patients with advanced biliary tract cancer (BTC) in the TOPAZ-1 Phase 3 trial.
Imfinzi is designed to bind to the PD-L1 protein and prevent it from interacting with the PD-1 and CD80 proteins.
TOPAZ-1, which is a randomised, double-blind, placebo controlled, multicentre study, assessed the human monoclonal antibody in combination with gemcitabine plus cisplatin as chemotherapy against placebo plus chemotherapy as a first-line treatment.
The late-stage trial evaluated 685 adult patients with unresectable, locally advanced, or metastatic BTC.
The primary endpoint was overall survival and important secondary endpoints included progression-free survival (PFS), objective response rate, and safety.
According to the results, Imfinzi along with chemotherapy lowered the mortality risk by 26% versus chemotherapy alone at a median follow-up of 41.3 months.
The median overall survival for Imfinzi plus chemotherapy was found at 12.9 months compared to 11.3 months for chemotherapy alone.
Additionally, more than twice as many patients on the Imfinzi-based regimen were still alive after three years when compared to chemotherapy alone.
At a scheduled interim analysis, the TOPAZ-1 trial achieved its primary endpoint of overall survival in October 2021, demonstrating that the combination lowered the risk of death by 20% when compared to chemotherapy alone.
AstraZeneca oncology R&D executive vice president Susan Galbraith said: “TOPAZ-1 raised the bar for the treatment of advanced biliary tract cancer, showing a remarkable survival benefit for Imfinzi added to chemotherapy with a well-tolerated regimen.
“These data represent the longest survival follow-up reported for immunotherapy in this setting, and the three-year landmark survival improvement underscores our commitment to improving long-term outcomes in gastrointestinal cancers.”
In November last year, Imfinzi with chemoradiotherapy failed to meet the PFS endpoint in the PACIFIC-2 Phase 3 trial of patients with Stage 3 non-small cell lung cancer (NSCLC).
