A Phase 2 Trial of Regorafenib as a Single Agent in Patients With Chemotherapy-Refractory, Advanced, and Metastatic Biliary Tract Adenocarcinoma

BACKGROUND: Biliary tract cancers are rare, aggressive neoplasms. Most patients present with advanced/unresectable or metastatic disease at diagnosis, and no second-line regimen has demonstrated clinical benefit. This was a phase 2 study evaluating the efficacy and safety of regorafenib in patients who had advanced/unresectable or metastatic disease after receiving standard therapy. METHODS: In this single arm-study, patients with advanced/unresectable or metastatic biliary tract cancer who failed at least 1 line of systemic chemotherapy received regorafenib once daily on a schedule of 21-days on/7-days off in a 28-day cycle. Patients initially received a standard 160mg dose. After toxicity assessments in the first 3 patients, the dose was reduced to 120 mg for subsequent patients, as preplanned. The primary endpoint was progression-free survival (PFS). Secondary objectives included overall survival (OS), the objective response rate, and the disease control rate. RESULTS:Forty-three patients received at least 1 dose of regorafenib, and 34 patients who received at least 1 cycle of treatment were evaluable for tumor response. The median PFS was 15.6 weeks (90% confidence interval, 12.9-24.7 weeks), and the median OS was 31.8 weeks (90% confidence interval, 13.3-74.3 weeks), with survival rates 40% at 12 months and 32% at 18 months. A partial response was achieved in 5 patients (11%), and 19 had stable disease (44%), for a disease control rate of 56%. The toxicity profile was as expected, with grade 3 and 4 adverse events reported in 40% of patients. The most common toxicities were hypophosphatemia (40%), hyperbilirubinemia (26%), hypertension (23%), and hand-foot skin reaction (7%). CONCLUSIONS: The current results suggest promising efficacy of regorafenib in patients with chemotherapy-refractory, advanced/metastatic biliary tract cancer, warranting further studies to confirm its clinical efficacy. There is a clear unmet need for effective therapies in patients who have advanced and metastatic biliary tract cancer. (c) 2018 American Cancer Society.