The primary purpose of this study is to compare pembrolizumab/vibostolimab to pembrolizumab with respect to recurrence-free survival (RFS). The primary hypothesis is that pembrolizumab/vibostolimab is superior to pembrolizumab with respect to RFS as assessed by the investigator in participants with high-risk resected Stage IIB, IIC, III and IV melanoma.

With Amendment 4, participants will discontinue treatment with pembrolizumab/vibostolimab.

The protocol-specified futility analysis of the primary outcome measure was completed with a data cut-off of 06-Mar-2024 (Primary Completion Date) and served as the final analysis of the primary outcome measure. Per protocol, 192 participants enrolled after the primary completion date and will be analyzed in the End of Trial analysis.

Inclusion Criteria:

• Has surgically resected and histologically or pathologically confirmed diagnosis of Stage IIB and IIC (pathological or clinical), III, or IV cutaneous melanoma per the American Joint Committee on Cancer (AJCC) eighth edition guidelines
• Has not received any prior systemic therapy for melanoma beyond surgical resection
• Has had no more than 12 weeks between final surgical resection and randomization
• Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on anti-retroviral therapy (ART)
• Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV viral load before randomization
• Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable at screening

Exclusion Criteria:

• Has ocular, mucosal, or conjunctival melanoma
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior the first dose of study medication
• Has not adequately recovered from major surgical procedure or has ongoing surgical complications
• Has received prior radiotherapy within 2 weeks of start of study intervention or has had a history of radiation pneumonitis
• Received a live or live attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines is allowed
• Has received an investigational agent or has used an investigational device within 4 weeks before study intervention administration
• Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
• Has a known additional malignancy that is progressing or has required active treatment within the past 3 years
• Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
• Has an active autoimmune disease that has required systemic treatment in past 2 years
• Has an active infection requiring systemic therapy
• Has had an allogenic tissue/solid organ transplant

https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf