Pembro With Investigational Agents or Pembro Alone in First Line (1L) Advanced Melanoma

Substudy 02B is part of a larger research study that is testing experimental treatments for melanoma, a type of skin cancer. The larger study is the umbrella study.

The goal of substudy 02B is to evaluate the safety and efficacy of investigational treatment arms in participants with 1L advanced melanoma and to identify the investigational agent(s) that, when used in combination, are superior to the current treatment options/pembrolizumab monotherapy.

Arm 1: Pembrolizumab + Vibostolimab was added in the base protocol on 13-Nov-2019, and enrollment into this arm has been completed. Arm 2: Pembrolizumab was added in the base protocol on 13-Nov-2019, and enrollment stopped prematurely on 15-Aug-2022. Arm 3: Coformulation Pembrolizumab/Quavonlimab was added in Amendment 01 on 20-Oct-2020, and enrollment stopped prematurely on 15-Aug-2022. Arm 4: Coformulation Pembrolizumab/Quavonlimab + Lenvatinib was added in Amendment 01 on 20-Oct-2020, and enrollment is ongoing. Arm 5: Coformulation Favezelimab/Pembrolizumab, Arm 6: Coformulation Favezelimab/Pembrolizumab + All-trans Retinoic Acid (ATRA), and Arm 7: Coformulation Favezelimab/Pembrolizumab + Vibostolimab were added in Amendment 04 on 10-May-2023, and enrollment for these arms will be initiated in July 2023.

Inclusion Criteria:

• Has histologically or cytologically confirmed melanoma

• Has unresectable Stage III or Stage IV melanoma, not amenable to local therapy

• Has been untreated for advanced disease.

• Has provided a tumor biopsy

• If capable of producing sperm, male participants agree to the following during the intervention period and for at least the time needed to eliminate each study intervention after the last dose of study intervention (7 days):

  • Abstains from penile-vaginal intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis) and agrees to remain abstinent OR

  • Uses contraception unless confirmed to be azoospermic

• A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies:

  • Is not a WOCBP OR

  • Is a WOCBP and Uses a contraceptive method that is highly effective, with low user dependency, or be abstinent from penile-vaginal intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis) during the intervention period and for at least the time needed to eliminate each study intervention after the last dose of study intervention. The length of time

Required to continue contraception for each study intervention is:

• MK-4280A: 120 days

• MK-1308A: 120 days

• MK-7684: 50 days

• MK-3475: 120 days

• Lenvatinib: 30 days

• ATRA: 30 days

• Has adequate organ function

• Has resolution of toxic effect(s) of the most recent prior therapy to Grade 1 or less (except alopecia and Grade 2 neuropathy)

Exclusion Criteria:

• Has a diagnosis of immunodeficiency or is receiving immunosuppressive therapy within 7 days before the first dose of study intervention

• Has a known additional malignancy that is progressing or requires active treatment within the past 2 years

• Has known central nervous system (CNS) metastases and/or carcinomatous meningitis

• Has ocular or mucosal melanoma

• Has an active autoimmune disease that has required systemic treatment in the past 2 years

• Has an active infection requiring systemic therapy

• Has known history of human immunodeficiency virus (HIV)

• Has history of Hepatitis B or known Hepatitis C virus infection

• Has a history of (noninfectious) pneumonitis

• Has a history of active tuberculosis (TB)

• Has received prior systemic anticancer therapy within 4 weeks prior to randomization

• Has received prior radiotherapy within 2 weeks of first dose of study intervention

• Has had major surgery