Tremelimumab in combination with microwave ablation in patients with refractory biliary tract cancer (BTC).

365Background: Treatment option for patients with advanced BTC is limited and prognosis is poor with a median survival of less than 1 year in the locally advanced or metastatic setting. It has been shown deregulation of the immune system plays an important role in the pathogenesis of BTC. This study aimed to investigate whether tremelimumab (Treme), anti-CTLA4, could be combined safely and feasibly with microwave ablation therapy to enhance the effect of anti-CTLA4 treatment in patients with advanced BTC. Methods: Patients with refractory BTC were enrolled in a study of monthly Treme (10mg/kg, IV, 6 doses), followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal microwave ablation. Staging image was performed every 8 weeks. Adverse events (AEs) were collected and managed. Tumor samples and peripheral blood samples were collected to perform immune monitoring. Results: Twenty patients with refractory BTC were enrolled. Male: female ratio was 10:10 with m...