Vemurafenib in non-small-cell lung cancer patients with BRAF^V600 and BRAF^nonV600 mutations

Background: BRAF mutations occurring in 1%-5% of patients with non-small-cell lung cancer (NSCLC) are therapeutic targets for these cancers but the impact of the exact mutation on clinical activity is unclear. The French National Cancer Institute (INCA) launched the AcSe vemurafenib trial to assess the efficacy and safety of vemurafenib in cancers with various BRAF mutations. We herein report the results of the NSCLC cohort. Patients and methods: Tumour samples were screened for BRAF mutations in INCA-certified molecular genetic centres. Patients with BRAF-mutated tumours progressing after >= 1 line of treatment were proposed vemurafenib 960 mg twice daily. Between October 2014 and July 2018, 118 patients were enrolled in the NSCLC cohort. The primary outcome was the objective response rate (ORR) assessed every 8 weeks (RECIST v1.1). A sequential Bayesian approach was planned with an inefficacy bound of 10% for ORR. If no early stopping occurred, the treatment was of interest if the estimated ORR was >= 30% with a 90% probability. Secondary outcomes were tolerance, response duration, progression-free survival (PFS), and overall survival (OS). Results: Of the 118 patients enrolled, 101 presented with a BRAF(V600) mutation and 17 with BRAF(nonV600) mutations; the median follow-up was 23.9 months. In the BRAF(nonV600) cohort, no objective response was observed and this cohort was stopped. In the BRAF(V600) cohort, 43/96 patients had objective responses. The mean Bayesian estimated success rate was 44.9% [95% confidence intervals (CI) 35.2%-54.8%]. The ORR had a 99.9% probability of being >= 30%. Median response duration was 6.4 months, median PFS was 5.2 months (95% CI 3.8-6.8), and OS was 10 months (95% CI 6.8-15.7). The vemurafenib safety profile was consistent with previous publications. Conclusion: Routine biomarker screening of NSCLC should include BRAF(V600) mutations. Vemurafenib monotherapy is effective for treating patients with BRAF(V600)-mutated NSCLC but not those with BRAF(nonV600) mutations.