Adjuvant use of combination therapy with dabrafenib plus trametinib resulted in a significantly lower risk of recurrence in patients with stage III melanoma with BRAF V600E or V600K mutations than the adjuvant use of placebo and was not associated with new toxic effects. (Funded by GlaxoSmithKline and Novartis; COMBI-AD ClinicalTrials.gov, NCT01682083 ; EudraCT number, 2012-001266-15 .).

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Background BRAF mutations act as an oncogenic driver via the mitogen-activated protein kinase (MAPK) pathway in non-small cell lung cancer (NSCLC). BRAF inhibition has demonstrated antitumor activity in patients with BRAF V600E (Val600Glu)–mutant NSCLC. Dual MAPK pathway inhibition with BRAF and MEK inhibitors in BRAF V600E–mutant NSCLC may improve efficacy over BRAF-inhibitor monotherapy based on observations in BRAF V600–mutant melanoma. Methods In this phase 2, multicenter, nonrandomized, open-label study of patients with pretreated metastatic BRAF V600E–mutant NSCLC, antitumor activity and safety of oral dabrafenib (150 mg twice daily) plus oral trametinib (2 mg once daily) were evaluated. Adult patients (≥ 18 years) with documented progression following at least one prior platinum-based chemotherapy and no more than three prior systemic anticancer therapies were enrolled. Patients with prior BRAF or MEK inhibitor treatment were ineligible. Patients with brain metastases were permitted to enroll only if the lesions were asymptomatic, untreated (or stable > 3 weeks after local therapy if treated), and measured < 1 cm. The primary endpoint was investigator-assessed overall response, which was assessed by intention-to-treat in the protocol-defined population (≥ second-line); safety was also assessed in this population. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT01336634. Findings Fifty-seven patients previously treated with systemic chemotherapy for metastatic BRAF V600E–mutant NSCLC were enrolled. The investigator-assessed overall response was 63·2% (36 of 57; 95% CI 49·3–75·6). Serious adverse events were reported in 32 (56%) of 57 patients and included pyrexia (16%; 9 of 57), anemia (5%; 3 of 57), confusional state (4%; 2 of 57), decreased appetite (4%; 2 of 57), hemoptysis (4%; 2 of 57), hypercalcemia (4%; 2 of 57), nausea (4%; 2 of 57), and cutaneous squamous cell carcinoma (4%; 2 of 57). Common grade 3/4 AEs included neutropenia (9%; 5 of 57), hyponatremia (7%; 4 of 57), and anemia (5%; 3 of 57). Interpretation Dabrafenib plus trametinib represents a new targeted therapy with robust antitumor activity and a manageable safety profile in patients with BRAF V600E–mutant NSCLC. Funding GlaxoSmithKline.