First-line immunotherapy with or without chemotherapy versus BRAF plus MEK inhibitors in BRAFV600E-mutated metastatic non-small-cell lung cancer (FRONT-BRAF): a multicentre, retrospective cohort study

Abstract

Background: Patients with BRAF^V600E (ie, Val600Glu)-mutated non-small-cell lung cancer (NSCLC) can be treated with BRAF and mitogen-activated protein kinase (MEK) inhibitors, or with immune checkpoint inhibitors (ICIs) with or without chemotherapy. We aimed to investigate which initial systemic treatment should be prioritised in this population.

Methods: In this retrospective cohort study conducted across 17 centres in the USA, Italy, France, and Brazil, clinicopathological data were collected from participants aged 18 years and older with stage IV, treatment-naive, metastatic BRAF^V600E-mutated NSCLC and with an Eastern Cooperative Oncology Group performance status of 0-3, who started first-line treatment with ICIs with or without chemotherapy (PD-1 or PD-L1 inhibitors with or without platinum-based chemotherapy) or BRAF and MEK inhibitors (dabrafenib and trametinib or encorafenib and binimetinib) between Jan 2, 2015, and July 11, 2024. The primary endpoint was overall survival with first-line ICIs with or without chemotherapy versus with BRAF and MEK inhibitors.

Findings: 284 participants were identified for this study, of whom 88 (31%) received ICIs with or without chemotherapy and 196 (69%) received BRAF and MEK inhibitors. The median age of participants was 68 years (IQR 61-74), and 148 (52%) participants were female and 136 (48%) male. Participants in the ICIs with or without chemotherapy group had a higher history of smoking (73 [83%] vs 118 [60%]; p=0·0002) and a higher PD-L1 expression (≥50% in 58 [66%] vs 76 [39%], 1-49% in 16 [18%] vs 67 [34%], and <1% in eight [9%] vs 31 [16%]; p=0·0003) than those in the BRAF and MEK inhibitor group. At a median follow-up time of 45·0 months (95% CI 39·0-55·7), ICIs with or without chemotherapy were associated with improved median overall survival compared with BRAF and MEK inhibitors (40·9 months [95% CI 33·3-not reached] vs 25·2 months [19·9-31·1]; hazard ratio [HR] 0·69 [0·49-0·98], p=0·039). In subgroup analyses, ICIs with or without chemotherapy, compared with BRAF and MEK inhibitors, were associated with longer median overall survival in participants with a history of smoking (HR 0·60 [0·40-0·90], p=0·013), with a PD-L1 tumour proportion score of ≥1% or higher (HR 0·66 [0·45-0·98], p=0·039), aged 70 years or older (HR 0·54 [0·31-0·94], p=0·029), with TP53 co-mutations (HR 0·46 [0·27-0·79], p=0·0048), and without brain metastases (HR 0·66 [0·45-0·99], p=0·045). With BRAF and MEK inhibitors, frequencies of adverse events of any grade and of grade 3 and higher were similar whether administered as first-line therapy or as second-line therapy following ICIs with or without chemotherapy.

Interpretation: First-line ICIs with or without chemotherapy were associated with improved overall survival compared with BRAF and MEK inhibitors in participants with metastatic BRAF^V600E-mutated NSCLC, particularly among specific subpopulations. These findings, although suggesting potential clinical relevance, remain exploratory and require confirmation from prospective studies.

Funding: NextGenerationEU.