Background: Checkpoint inhibitors and targeted therapies have improved outcomes in pts with BRAF V600–mutant advanced melanoma; however, many pts progress and new treatment (tx) strategies are needed. BRAF inhibition increases T-cell infiltration, melanoma antigen expression, and PD-1/PD-L1 expression, which may lead to synergistic activity with anti–PD-1 therapy. Methods: COMBI-i is investigating first-line S 400 mg Q4W + D 150 mg BID + T 2 mg QD in pts with unresectable or metastatic BRAF V600–mutant melanoma (NCT02967692). Here we report pooled efficacy and safety data from parts 1 (run-in cohort) and 2 (biomarker cohort). Response was assessed per RECIST v1.1. Results: 36 pts were enrolled (part 1: n = 9; part 2: n = 27); 18 (50%) had stage IV M1c and 15 (42%) had elevated LDH levels. At the data cutoff (median follow-up, 15.2 mo), tx was ongoing in 17 pts (47%). The confirmed objective response rate (ORR) by investigator assessment was 75% (n = 27), with 33% complete responses (CRs; n = 12). Medians for duration of response (DOR; 7/27 pts with events), progression-free survival (PFS; 13/36 pts with events), and overall survival (OS; 7/36 pts with events) were not reached. 12-mo DOR rate was 71.4% (95% CI, 49%-85%). 12-mo PFS and OS rates were 65.3% (95% CI, 47%-79%) and 85.9% (95% CI, 69%-94%), respectively. In pts with high baseline LDH: ORR was 67%, with 3 CRs (20%), median PFS was 10.7 mo (events in 10/15 pts [67%]), and median OS was not reached, with events in 6/15 pts (40%). All pts had ≥ 1 AE; 27 (75%) had grade ≥ 3 AEs. 6 pts (17%) had AEs leading to discontinuation of all 3 study drugs. Any-grade AEs in ≥ 40% of pts included pyrexia, chills, fatigue, cough, and arthralgia. Grade ≥ 3 AEs in > 3 pts were neutropenia, pyrexia, and increased lipase. One pt died of cardiac arrest that was not considered related to study tx. Conclusions: S+D+T showed promising and durable ORR (75%) with CR in 33% of pts. With > 15 mo of follow-up, median PFS was not reached. The safety profile was manageable reflecting individual toxicities of D, T, and S. The global, placebo-controlled, randomized phase 3 (part 3) of COMBI-i is ongoing. Clinical trial information: NCT02967692