Interim results of a phase II study of the BRAF inhibitor (BRAFi) dabrafenib (D) in combination with the MEK inhibitor trametinib (T) in patients (pts) with BRAF V600E mutated (mut) metastatic non-small cell lung cancer (NSCLC).

8006 Background: In 78 BRAF V600E mut NSCLC pts, single agent D induced an overall response rate (ORR) of 32%. The combination of D and T (DT) has demonstrated significant improvements in efficacy compared with BRAFi monotherapy in BRAFV600 mut metastatic melanoma. Here, we report interim safety (33 pts) and efficacy (24 pts) data for NSCLC pts enrolled in this phase II DT study. Methods: This single-arm, 2-stage, phase II study was in advanced BRAFV600E mut NSCLC pts who failed at least 1 line of chemotherapy. D was dosed at 150 mg orally twice daily and T at 2 mg once daily. The primary endpoint was investigator-assessed ORR per RECIST 1.1 criteria. A minimum response rate ( ≥ 6 out of first 20 pts) was required to continue into the second stage. Results: Median age of 33 pts was 66 yrs (range 49–88 yrs). Most pts were female (64%), White (82%), former smokers (73%), and had adenocarcinoma (88%). Twenty-seven pts (82%) remain on therapy, and 6 have stopped (4 with disease progression, 2 due to adverse e...