For patients with BRAF V600E-mutated metastatic non-small cell lung cancer, first-line treatment has long sat at the intersection of two powerful but very different strategies. On one side are BRAF plus MEK inhibitors, a biologically direct approach that targets the MAPK pathway and can produce rapid tumor shrinkage. On the other side are immune checkpoint inhibitors, with or without chemotherapy, which may deliver less immediate cytoreduction in some patients but can generate more durable immune-mediated disease control.
The FRONT-BRAF study brings new weight to this unresolved question. In this multicenter retrospective cohort study, first-line immunotherapy-based treatment was associated with longer overall survival than BRAF plus MEK inhibition in patients with stage IV, treatment-naive, BRAF V600E-mutated NSCLC. The finding is not definitive, because the study was retrospective and non-randomized, but it is clinically important because it challenges the reflexive assumption that targeted therapy must always come first in oncogene-driven lung cancer (Di Federico et al., 2025). The FRONT-BRAF as the largest real-world comparison in this setting, involving 17 international centers and 284 patients.
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Why This Question Matters
BRAF V600E mutations are rare in NSCLC, accounting for only a small minority of cases, but they define a biologically distinct subgroup. The mutation constitutively activates MAPK signaling, making combined BRAF and MEK inhibition a rational and effective treatment strategy. Drugs such as dabrafenib plus trametinib, and more recently encorafenib plus binimetinib, have established targeted therapy as a highly active option.
Yet BRAF V600E-mutated lung cancer does not behave exactly like EGFR- or ALK-driven NSCLC. Many patients have a smoking history, higher PD-L1 expression, and a more immunogenic tumor profile. These features create a biologic argument for immunotherapy, especially in patients whose tumors already carry clinical markers of ICI sensitivity.
That dual identity is what makes this disease so difficult to sequence. It is both targetable and potentially immunotherapy-responsive.
FRONT-BRAF Study Design
FRONT-BRAF was a retrospective cohort study conducted across 17 centers in the United States, Italy, France, and Brazil. The study included adults with stage IV, treatment-naive, metastatic BRAF V600E-mutated NSCLC and ECOG performance status 0–3 who started first-line systemic treatment between January 2015 and July 2024.
Patients received either immune checkpoint inhibitors with or without chemotherapy or BRAF plus MEK inhibitors. The ICI group included PD-1 or PD-L1 inhibitors with or without platinum-based chemotherapy. The targeted therapy group included dabrafenib plus trametinib or encorafenib plus binimetinib.
The primary endpoint was overall survival.
A total of 284 patients were included. Of these, 88 patients received ICIs with or without chemotherapy, while 196 patients received BRAF and MEK inhibitors. The median age was 68 years, and the cohort was almost evenly balanced by sex, with 52% female and 48% male participants.
Baseline Imbalances Matter
The two treatment groups were not identical, and that is essential for interpreting the results. Patients treated with first-line immunotherapy were more likely to have a smoking history, at 83% versus 60% in the BRAF/MEK inhibitor group. They were also more likely to have high PD-L1 expression. A PD-L1 tumor proportion score of ≥50% was seen in 66% of the immunotherapy group compared with 39% of the targeted therapy group.
These differences could bias outcomes in favor of immunotherapy, because smoking history and higher PD-L1 expression are both associated with greater likelihood of response to checkpoint blockade. This does not invalidate the study, but it means the findings must be read carefully. FRONT-BRAF is not a randomized trial; it is a real-world analysis that reflects how clinicians selected treatment in practice.
Survival Favored First-Line Immunotherapy
At a median follow-up of 45.0 months, first-line ICIs with or without chemotherapy were associated with significantly longer overall survival than BRAF plus MEK inhibitors.
Median overall survival was 40.9 months with immunotherapy-based treatment compared with 25.2 months with BRAF/MEK inhibition. This corresponded to a hazard ratio of 0.69 and a statistically significant p value of 0.039.
The approximately 16-month difference in median overall survival is clinically meaningful. It suggests that, for selected patients, starting with immunotherapy may create a longer disease-control trajectory than beginning with targeted therapy.
This is especially important because targeted therapy may still produce faster and higher response rates. FRONT-BRAF reminds us that early tumor shrinkage is not always the same as longer survival.
Which Patients Benefited Most?
The subgroup findings are among the most clinically useful parts of FRONT-BRAF. Immunotherapy-based treatment was associated with longer overall survival in several biologically plausible groups.
Patients with a history of smoking had better outcomes with ICIs, with an HR of 0.60. Patients with PD-L1 expression ≥1% also appeared to benefit, with an HR of 0.66. The signal was even stronger among patients with TP53 co-mutations, where the HR was 0.46, suggesting a marked survival advantage with immunotherapy-based therapy.
Older patients, particularly those aged 70 years or older, also appeared to benefit from first-line ICIs, with an HR of 0.54. Patients without brain metastases had improved survival with immunotherapy as well, with an HR of 0.66.
These findings suggest that BRAF V600E-mutated NSCLC is not a single clinical category. Smoking status, PD-L1 expression, TP53 co-mutation, age, and CNS involvement may all influence the optimal first-line approach.
Where Targeted Therapy Still Matters
FRONT-BRAF does not remove BRAF/MEK inhibitors from the treatment algorithm. Targeted therapy remains essential, particularly when rapid disease control is needed.
Patients with symptomatic bulky disease, impending organ compromise, or active brain metastases may still require the speed and predictability of BRAF/MEK inhibition. The study’s subgroup data suggest that the immunotherapy advantage was clearest in patients without baseline brain metastases, meaning CNS disease remains a major factor in treatment selection.
This is the practical clinical message: immunotherapy may be the better first-line strategy for immunogenic tumors, but targeted therapy remains highly relevant when immediate cytoreduction is the priority.
Sequencing Appears Feasible
One of the important safety findings was that BRAF/MEK inhibitors appeared similarly tolerable whether given first line or after prior immunotherapy. Frequencies of adverse events of any grade and grade 3 or higher events were similar when targeted therapy was used upfront or as second-line treatment after ICIs.
This matters because clinicians often worry that giving immunotherapy first may complicate later targeted therapy. In FRONT-BRAF, that concern was not strongly supported. The data suggest that an ICI-first strategy may preserve the ability to use BRAF/MEK inhibition later.
What Makes This Different From EGFR and ALK Disease?
In EGFR- and ALK-driven NSCLC, first-line targeted therapy clearly dominates because these tumors are often less immunogenic and respond poorly to checkpoint inhibitors. BRAF V600E disease appears different. Many tumors arise in smokers, express PD-L1, and may carry co-mutations such as TP53 that increase genomic instability.
That difference may explain why immunotherapy has a stronger role here than in other oncogene-driven subtypes. FRONT-BRAF does not mean that all driver-mutated NSCLC should be approached with immunotherapy first. It means BRAF V600E-mutated NSCLC may need its own sequencing logic.
Limitations
The key limitation is the retrospective design. Treatment was not randomly assigned, and baseline differences between groups may have influenced outcomes. The immunotherapy group had more smokers and higher PD-L1 expression, both of which could contribute to improved survival.
The study also spans nearly a decade, during which lung cancer treatment changed substantially. Immunotherapy regimens, targeted therapy access, diagnostic practices, and subsequent lines of treatment may not have been uniform across centers or time periods.
For these reasons, FRONT-BRAF should be viewed as strong hypothesis-generating evidence rather than a final practice-changing answer. Prospective randomized studies are still needed.
Clinical Takeaway
FRONT-BRAF provides the most compelling real-world evidence to date that first-line immunotherapy with or without chemotherapy may improve overall survival compared with upfront BRAF plus MEK inhibition in patients with metastatic BRAF V600E-mutated NSCLC.
The signal appears strongest in patients with smoking history, PD-L1 expression ≥1%, TP53 co-mutation, older age, and absence of brain metastases. For these patients, immunotherapy-first treatment deserves serious consideration.
At the same time, BRAF/MEK inhibition remains an important option for patients who need rapid tumor shrinkage or CNS disease control. The future of this space is unlikely to be one universal sequence. It will be a biomarker-guided strategy that matches treatment order to tumor biology and clinical urgency.