The BRAF inhibitor dabrafenib plus the MEK inhibitor trametinib show promising efficacy in BRAF V600E-mutant biliary tract cancer (BTC) and adenocarcinoma of the small intestine (ASI), according to the findings of a new phase 2 trial.
The study was presented at the joint European Organisation for Research and Treatment of Cancer (EORTC), the National Cancer Institute (NCI) and the American Association for Cancer Research (AACR) symposium on Molecular Targets and Cancer Therapeutics which took place in Dublin, Ireland, last week.
In the international open-label trial, 36 patients with BTC (n=33) and ASI (n=3) who had failed at least one prior line of systemic therapy, received continuous dabrafenib (150 mg BID) plus trametinib (2 mg QD) until unacceptable toxicity, disease progression or death.
At the data cut-off date, the overall response rate (ORR) was 41 per cent in the BTC cohort and 67 per cent in the ASI group. In the BTC arm, seven of 13 responses had a duration of response (DOR) of at least six months. Median progression-free survival (PFS) and overall survival were 7.2 months (95% CI 4.6-10.1) and 11.3 months (95% CI 7.3-17.6), respectively.
The results support BRAF mutational analysis for patients with BTC and ASI.