RESUMEN
BACKGROUND: BRAF inhibitors plus MEK inhibitors (BRAFi/MEKi) and immune checkpoint inhibitors (CPIs) are approved for BRAF V600-mutant advanced melanoma. Combinations of BRAFi/MEKi with CPIs may further improve outcomes and could offer additional treatment strategies. METHODS: STARBOARD (NCT04657991) is a phase III study with an initial safety lead-in (SLI) phase conducted to determine the recommended phase III dose (RP3D) for encorafenib in combination with binimetinib and pembrolizumab. Patients with untreated, unresectable locally advanced or metastatic BRAF V600E/K-mutant cutaneous melanoma received binimetinib 45 mg twice daily and pembrolizumab 200 mg every 3 weeks plus encorafenib 450 mg once daily (COMBO450 plus pembrolizumab) or 300 mg once daily (COMBO300 plus pembrolizumab). The primary endpoint was the incidence of dose-limiting toxicities (DLTs). Secondary endpoints included safety, objective response, time to response, and duration of response. Progression-free survival was assessed post hoc. RESULTS: In the SLI, the median follow-up duration was 19.4 months. Twenty patients received COMBO450 plus pembrolizumab and 17 received COMBO300 plus pembrolizumab. DLTs occurred in 1 of 17 DLT-evaluable patients in the COMBO450 plus pembrolizumab arm and in 2 of 17 DLT-evaluable patients in the COMBO300 plus pembrolizumab arm. No treatment-related deaths occurred in either treatment arm. The overall response rate was 65.0 % in the COMBO450 plus pembrolizumab arm and 47.1 % in the COMBO300 plus pembrolizumab arm. CONCLUSION: The STARBOARD SLI showed that safety across the cohorts was generally comparable to the known safety profile of each agent. The standard dose regimen of COMBO450 plus pembrolizumab was chosen as the RP3D.
RESUMEN
BACKGROUND: Programmed cell death receptor-1 (PD-1)-blocking antibodies are approved to treat metastatic or locally advanced cutaneous squamous cell carcinoma (CSCC) cases ineligible for curative surgery or radiation. Notwithstanding, some patients experience inadequate responses or severe immune-related adverse events (AEs), indicating the need for improved therapies. Cosibelimab is a high-affinity programmed cell death-ligand 1 (PD-L1)-blocking antibody that activates innate and adaptive immunity by blocking PD-L1 interaction with PD-1 and B7-1 receptors. It is an unmodified immunoglobulin G1 subtype with a functional Fc domain capable of inducing antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Here, we present results of the pivotal study of patients with metastatic CSCC from an open-label, multicenter, multiregional, multicohort, phase 1 trial of cosibelimab. METHODS: In this trial, participants with metastatic CSCC received cosibelimab 800 mg intravenously every 2 weeks. Primary endpoint was objective response rate (ORR) by independent central review using Response Evaluation Criteria in Solid Tumors, V.1.1. Secondary endpoints included duration of response (DOR) and safety. RESULTS: Objective response was observed in 37 of 78 participants (47.4% (95% CI: 36.0% to 59.1%)), with median follow-up of 15.4 months (range: 0.4 to 40.5) as of data cut-off. Median DOR was not reached (range: 1.4+ to 34.1+ months), with response ongoing in 73.0% of participants. Common treatment-emergent AEs (≥15%) were fatigue (26.9%), rash (16.7%), and anemia (15.4%). Eighteen participants (23.1%) experienced immune-related AEs (grade 3: n=2 (2.6%); no grade 4/5). No treatment-related deaths were reported. CONCLUSIONS: Cosibelimab demonstrated clinically meaningful ORR and DOR and was associated with a manageable safety profile. TRIAL REGISTRATION NUMBER: NCT03212404.