Eligibility Criteria

Key Inclusion Criteria:

Resectable cutaneous melanoma metastatic to a lymph node and at high risk of recurrence

Complete resection within 13 weeks prior to the first dose of pembrolizumab

Disease free at study entry (after surgery) with no loco-regional relapse or distant metastasis and no clinical evidence of brain metastases

Has an formalin fixed paraffin embedded (FFPE) tumor sample available suitable for sequencing

Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1

Normal organ and marrow function reported at screening

Key Exclusion Criteria:

Prior malignancy, unless no evidence of that disease for at least 5 years prior to study entry

Prior systemic anti-cancer treatment (except surgery and interferon for thick primary melanomas. Radiotherapy after lymph node dissection is permitted)

Live vaccine within 30 days prior to the first dose of pembrolizumab

Transfusion of blood or administration of colony stimulating factors within 2 weeks of the screening blood sample

Active autoimmune disease

Immunodeficiency, systemic steroid therapy, or any other immunosuppressive therapy within 7 days prior to the first dose of pembrolizumab

Solid organ or allogeneic bone marrow transplant

Pneumonitis or a history of (noninfectious) pneumonitis that required steroids

Prior interstitial lung disease

Clinically significant heart failure

Known history of human immunodeficiency virus (HIV)

Known active hepatitis B or C

Active infection requiring treatment

Ages Eligible for Study 18 Years and older (Adult, Older Adult )

Sexes Eligible for Study All

Accepts Healthy Volunteers No