Features and efficacy of triple-targeted therapy for patients with EGFR-mutant non-small-cell lung cancer with acquired BRAF alterations who are resistant to epidermal growth factor receptor tyrosine kinase inhibitors

Background

The recommended first-line treatment for advanced epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC) patients is EGFR-tyrosine kinase inhibitors (EGFR-TKIs). BRAF alterations have been identified as resistance mechanisms. We aimed to identify features of and subsequent treatment strategies for such patients.

Patients and methods

We conducted a systematic literature review of NSCLC patients harboring acquired BRAF alterations. Additionally, BRAF-altered NSCLC patients who progressed from EGFR-TKIs at West China Hospital of Sichuan University were screened. Patient characteristics, treatment options, and outcomes were analyzed.

Results

A total of 104 patients were included, 2 of whom came from our center. Seventy-five patients (72.1%) harbored BRAF mutations (57 class I mutations, 7 class II mutations, 9 class III mutations, and 2 non-class I-III mutations), and 29 (27.9%) harbored BRAF fusions. Eighteen patients received triple-targeted therapy, including prior EGFR-TKIs plus dabrafenib and trametinib, and 23 patients received other treatments. The median progression-free survival was significantly longer in patients receiving triple-targeted therapy than in those receiving other treatments (8.0 versus 2.5 months, P < 0.001). Similar findings were observed in patients with BRAF mutations (9.0 versus 2.8 months, P = 0.004), particularly in those with BRAF class I mutations (9.0 versus 2.5 months, P < 0.001). A potential benefit was also observed among patients with BRAF fusions (5.0 versus 2.0 months, P = 0.230). Twenty patients (48.8%) experienced adverse events. Dose reduction of RAF or MEK inhibitor was required in five patients (12.2%). Five patients (12.2%) permanently discontinued treatment (three on triple-targeted therapy; one on prior EGFR-TKI plus vemurafenib; one on prior EGFR-TKI plus trametinib).

Conclusions

BRAF alterations, specifically BRAF mutations and BRAF fusions, facilitate resistance to EGFR-TKIs. Triple-targeted therapy is effective and safe for patients with EGFR-mutant NSCLC with acquired BRAF alterations, mainly among patients with BRAF class I mutations and potentially in patients with BRAF fusions.