Triple Therapy in BRAF-Mutated Melanoma: Progression-Free Survival Increased from 3.4 Months to 33 Months

Adding Targeted Therapy to Immunotherapy: STARBOARD Doubled the Response Rate in BRAF-Mutant Melanoma, but What About Survival?

In the phase 3 STARBOARD trial, adding encorafenib and binimetinib to first-line pembrolizumab in advanced BRAF V600-mutant melanoma raised the response rate from 32.7% to 70% and extended the time until disease progression from 3.4 months to 33 months. The results were presented on October 23, 2026, at the ESMO Congress in Madrid (Abstract 2071O). However, serious side effects rose markedly with the triplet, and overall survival data are not yet mature. We have previously discussed why starting with immunotherapy is more effective in BRAF-mutant melanoma and first-line treatment options in advanced melanoma.

Why does this matter?

About half of patients with melanoma have a V600 mutation in the BRAF gene in their tumor; the same mutation also occurs in other cancers and is targeted in a tissue-agnostic manner. Melanoma arising in the eye (uveal melanoma) is a different disease and is outside the scope of this article. These patients have two powerful treatment options: immunotherapy, which activates the immune system (such as pembrolizumab, nivolumab, ipilimumab and relatlimab), and targeted drugs that block the BRAF and MEK proteins (dabrafenib + trametinib, vemurafenib + cobimetinib, encorafenib + binimetinib). Targeted drugs produce rapid, high response rates, but responses often end within one to two years as resistance develops. Immunotherapy has a lower response rate, but in a substantial proportion of responders the response lasts for years.

The DREAMseq and SECOMBIT trials showed that starting with immunotherapy and switching to targeted therapy at progression leads to longer survival than the reverse sequence. For this reason, the 2025 ESMO melanoma guideline recommends first-line immunotherapy. The question is whether giving both treatments together from the start is better than giving them in sequence. STARBOARD is the trial that has provided the strongest positive answer to this question so far.

What is triplet therapy in BRAF-mutant melanoma?

Triplet therapy means giving one immunotherapy drug (pembrolizumab in STARBOARD) together with two targeted drugs (the BRAF inhibitor encorafenib and the MEK inhibitor binimetinib). The aim is to combine the rapid tumor shrinkage of targeted drugs with the ability of immunotherapy to produce durable responses. In STARBOARD, it markedly increased the response rate and progression-free survival, but side effects also increased.

There is also a biological rationale for the triplet: BRAF and MEK inhibitors can increase immune cells around the tumor and make the tumor more "visible" to the immune system. This may enhance the effect of immunotherapy.

How was STARBOARD conducted?

In the safety lead-in that preceded the trial, two encorafenib doses were tested; because the response rate was higher at 450 mg, this dose was used in phase 3.

Results

The trial met both its primary and key secondary endpoints. Tumors shrank substantially in 7 of every 10 patients receiving the triplet, compared with about 1 in 3 of those receiving pembrolizumab alone.

Median progression-free survival was 33 months with the triplet and 3.4 months in the pembrolizumab + placebo arm. This corresponds to a 67% reduction in the risk of disease progression or mortality (HR 0.33; 90% confidence interval 0.24–0.46). Overall survival data are not yet mature; a favorable trend toward the triplet was reported.

Side effects

Grade 3–4 adverse events were markedly more frequent with the triplet. The most common were nausea, diarrhea, vomiting, fatigue and elevated liver enzymes; these are known, manageable side effects of BRAF-MEK inhibitors and immunotherapy. No new safety signals and no treatment-related mortality was reported. However, in the trial's safety lead-in, up to half of patients had serious adverse events, and pembrolizumab was permanently discontinued due to side effects in up to 25% of patients, encorafenib or binimetinib in up to 15%. With the triplet, it can be harder to tell which drug is causing certain side effects, such as fever, diarrhea or elevated liver enzymes.

How should the results be interpreted?

Strengths

• Double-blind, placebo-controlled, randomized phase 3 design.
• Immunotherapy control arm: in line with current practice, the question was framed as "adding targeted therapy to immunotherapy" rather than "adding immunotherapy to targeted therapy."
• The differences in response rate and progression-free survival are very large and statistically robust.

Points to consider

• Overall survival is unknown: As ESMO discussant Olivier Michielin emphasized, this strategy uses two effective treatment options together from the start that could otherwise be used in sequence. Whether the progression-free survival benefit will translate into longer survival is uncertain.
• Control arm: Pembrolizumab alone is a less effective option than nivolumab + ipilimumab dual checkpoint blockade, which many centers prefer today for BRAF-mutant patients. Whether the triplet is superior to dual checkpoint blockade was not tested.
• Short progression-free survival in the control arm: The median progression-free survival of 3.4 months in the control arm appears shorter than results reported for anti-PD-1 monotherapy in earlier trials. This may have inflated the size of the difference; the full publication and subgroup analyses are awaited.
• Side effects: Grade 3–4 adverse events nearly doubled. Long-term use of two oral drugs together with immunotherapy may affect quality of life and treatment adherence.
• What comes next: It is unknown which treatment will be effective in patients who progress on the triplet, because both immunotherapy and targeted therapy will already have been used.

What does this mean in practice?

• Early-stage disease is separate: These results apply to unresectable or metastatic disease; treatment of stage 3 melanoma and preoperative immunotherapy are separate topics.
• The current standard has not changed: In advanced BRAF V600-mutant melanoma, first-line immunotherapy (nivolumab + ipilimumab or nivolumab + relatlimab for most patients, anti-PD-1 monotherapy for some) is recommended, with a BRAF-MEK inhibitor at progression.
• Who might be considered for the triplet: If approved in the future, it could be a strong option for patients with high tumor burden, symptomatic disease, a need for rapid response, or elevated LDH. In these patients, rapid tumor shrinkage matters for quality of life.
• Brain metastases: STARBOARD has not yet reported data specific to patients with brain metastases; in these patients the evidence for dual checkpoint blockade is strong.
• Testing is essential: Every patient with advanced melanoma should have the tumor tested for a BRAF mutation; next-generation sequencing can be used if needed.
• Managing side effects: If the triplet is chosen, fever, diarrhea, and liver and eye side effects should be closely monitored; immunotherapy side effects (including kidney and persistent skin side effects) must be distinguished from those of the targeted drugs.

Practical tips for patients and families

• If you have been diagnosed with advanced melanoma, ask whether your tumor has been tested for a BRAF mutation.
• If you have a BRAF mutation, discuss with your oncologist whether to start with immunotherapy, targeted therapy or both together, as well as the benefits and side effects of each option.
• While taking targeted drugs, report symptoms such as fever, chills, diarrhea, blurred vision, skin rash or jaundice without delay.
• Protect yourself from the sun and regularly check for changes in your skin; have your moles monitored; if melanoma runs in your family, ask about familial melanoma risk.
• If you are eligible, consider taking part in clinical trials; seek a second opinion if needed.

Frequently asked questions

What is the STARBOARD trial?

It is a phase 3 trial in advanced BRAF V600-mutant melanoma comparing the addition of encorafenib and binimetinib versus placebo to first-line pembrolizumab. Its results were presented at the ESMO Congress in October 2026: the response rate rose from 32.7% to 70%, and median progression-free survival increased from 3.4 months to 33 months.

Is triplet therapy now the standard of care in BRAF-mutant melanoma?

No. Overall survival data are not yet mature, and the triplet was not compared with dual checkpoint blockade, the most effective immunotherapy option. The current recommendation is first-line immunotherapy, with targeted therapy at progression.

What are the side effects of triplet therapy?

In STARBOARD, 70% of patients had grade 3–4 adverse events (39% with pembrolizumab alone). The most common were nausea, diarrhea, vomiting, fatigue and elevated liver enzymes. No treatment-related mortality was reported.

Is this treatment available in Türkiye?

The triplet combination is not yet approved. In Türkiye, its use may only be possible with off-label approval, and it is not expected to be covered by the SGK.

Glossary

BRAF V600 mutation

A genetic change found in about half of melanomas that continuously stimulates cell growth.

BRAF-MEK inhibitors

Oral targeted drugs that block this growth signal at two points.

Immunotherapy (immune checkpoint inhibitor)

Drugs that release the "brakes" preventing the immune system from attacking cancer cells.

Objective response rate

The proportion of patients whose tumors shrink substantially or disappear.

Progression-free survival

The time during which the disease does not progress and the patient remains alive.

Overall survival

The length of time patients live from the start of treatment.

Grade 3–4 adverse event

Serious or potentially life-threatening side effects that usually require interrupting treatment.