STARBOARD Extends Median PFS to 33 Months in Melanoma

By Sophie Lindqvist

In the phase 3, randomized, double-blind STARBOARD trial, first-line encorafenib, binimetinib and pembrolizumab extended median progression-free survival (PFS) to 33.0 months in unresectable locally advanced or metastatic BRAF V600–mutant melanoma, versus 3.4 months with placebo plus pembrolizumab.

The 220-patient analysis found a confirmed objective response rate (ORR) of 70.0% with the triplet versus 32.7% with pembrolizumab alone; the PFS hazard ratio was 0.33 (90% CI, 0.24–0.46). Disease control also improved.

Dirk Schadendorf, MD, professor of dermatology and oncology and director of the Department of Dermatology and the West German Cancer Center at University Hospital Essen in Germany, presented the final results at the 2026 European Society for Medical Oncology Congress, October 23–27 in Madrid, as abstract 2071O.

The trial is registered as NCT04657991. The abstract lists Schadendorf, Dummer, Sullivan and colleagues.

What did STARBOARD test?

The triplet combined encorafenib (Braftovi), a BRAF inhibitor, with binimetinib (Mektovi), a MEK inhibitor, and pembrolizumab (Keytruda), a PD-1 inhibitor. The control was placebo plus pembrolizumab, reflecting the first-line standard of PD-1 monotherapy in many countries.

Schadendorf described the approach as combining two treatment types available over the previous 10 years: targeted BRAF/MEK inhibition and checkpoint blockade. Earlier prospective trials had tested triplet regimens against BRAF/MEK inhibition alone and found only limited clinical benefit.

The unanswered question was whether adding BRAF/MEK inhibition to checkpoint blockade could outperform checkpoint blockade alone. STARBOARD tested that combination against the established first-line comparator.

Why did the trial change midstream?

STARBOARD began as a planned 600-patient registrational study. Recruitment ran from mid-2022 to early 2024, an 18-month stretch shaped by the post-COVID period and changing conditions; roughly 200 patients had been included when Pfizer, the sponsor, redesigned the study.

Ultimately, 220 patients were randomized. Pfizer made confirmed ORR the primary endpoint and PFS a key secondary endpoint, with blinded independent central review for both.

The early closure left overall-survival data immature despite the sizable response and PFS differences. That distinction matters because response and PFS can establish biological and clinical activity without settling the long-term survival benefit.

What did the efficacy results show?

“We saw impressive results. The confirmed response rate was 70% for the triplet therapy, in contrast to almost 33% for checkpoint blockade,” Schadendorf said.

Median PFS was 33.0 months with the triplet and 3.4 months with pembrolizumab monotherapy; the HR of 0.33 (90% CI, 0.24–0.46) favored the combination. He described both the response and PFS differences as statistically significant.

Overall survival favored the triplet numerically but remained immature: HR 0.71 (90% CI, 0.48–1.05), an estimated 29% reduction in the hazard of death that narrowly missed statistical significance. Schadendorf suggested that another six months of follow-up or 50 additional patients might have yielded a positive result; that remains a projection, not an observed finding.

How much additional toxicity came with the benefit?

Grade 3 or 4 treatment-emergent adverse events occurred in 70.0% of the triplet arm versus 39.1% of the control arm. Schadendorf characterized the triplet as more toxic, making treatment selection inseparable from the magnitude of benefit.

“Easy-to-treat patients who are PD-L1 positive are probably still well served with PD-1 monotherapy or checkpoint blockade alone, but everyone else should also be considered for triplet therapy, in my view,” he said.

That remains Schadendorf’s proposed clinical judgment, not a reported STARBOARD subgroup analysis. He described the triplet as an interesting first-line option with benefits across multiple endpoints, even without official registration, while acknowledging the toxicity burden and uncertain survival result.

What does this change for first-line melanoma care?

For unresectable locally advanced or metastatic BRAF V600–mutant melanoma, STARBOARD provides a strong efficacy signal for first-line triplet treatment: 33.0 versus 3.4 months for median PFS, 70.0% versus 32.7% for confirmed ORR and improved disease control. It does not yet establish universal triplet use because grade 3–4 toxicity was substantially more frequent and overall survival did not reach statistical significance.

The practical change is a sharper selection discussion. Under Schadendorf’s approach, patients who are easy to treat and PD-L1-positive may still receive PD-1 monotherapy, while others should be considered for the triplet when its added toxicity appears acceptable. Clinical teams must weigh response and PFS gains against severe adverse events rather than treating the combination as uniformly superior.

Mature overall-survival follow-up and official registration decisions will help determine whether the regimen moves from a compelling trial option to a broader first-line standard.