4-Year Benefit of Durvalumab in BTC: JAMA Oncol | July 2026

Introduction:

The TOPAZ-1 trial established durvalumab combined with gemcitabine and cisplatin (GemCis) as the first immunotherapy-based first-line standard of care for advanced biliary tract cancer (BTC). However, long-term survival outcomes and durability of benefit beyond the initial analysis remained uncertain. This post hoc analysis reports efficacy and safety after more than four years of follow-up.

Why was this study needed?:

. Long-term survival data for immunotherapy in advanced BTC were lacking.

. The durability of benefit with durvalumab beyond the primary analysis required confirmation.

. Long-term safety with prolonged immunotherapy exposure remained uncertain.

. Extended follow-up was needed to validate durvalumab plus GemCis as the standard first-line regimen.

Results:

After more than four years of follow-up, durvalumab plus GemCis continued to demonstrate a sustained overall survival advantage over chemotherapy alone. Long-term survival rates remained consistently higher with the addition of durvalumab, confirming durable clinical benefit in a subset of patients. Importantly, the safety profile remained stable over time, with no increase in treatment-related serious adverse events or treatment discontinuations compared with chemotherapy alone. These findings reinforce the long-term efficacy and tolerability of the regimen.

Clinical Impact:

This extended analysis provides compelling evidence that adding durvalumab to GemCis delivers durable survival benefits without compromising long-term safety. The persistence of a meaningful survival advantage beyond four years strengthens confidence in immunotherapy as the foundation of first-line treatment for advanced biliary tract cancer and provides reassurance regarding prolonged treatment outcomes.

Bottom Line:

More than four years of follow-up confirms that durvalumab plus gemcitabine–cisplatin provides durable survival benefit with a manageable long-term safety profile, reinforcing its role as the standard first-line treatment for advanced biliary tract cancer.