A Study to Evaluate Safety and Therapeutic Activity of RO6874281 in Combination with Pembrolizumab, in Participants with Advanced or Metastatic Melanoma

"Part I Safety Run in:~Cohort 1.1: RO6874281 will be administered by intravenous (IV) infusion; 10 mg (Q3W) every 3 weeks and will be observed over 2 administration cycles (i.e. 6 weeks) in order to confirm the safety of the proposed dose and schedule that will be used in Part II of this study.~Cohort 1.2: RO6874281 will be administered by IV infusion via an induction and maintenance phase; 10 mg (QW) every week for 3 weeks followed by 10 mg (Q3W) every 3 weeks and will be observed over 2 administration cycles (6 weeks) to confirm safety of the proposed dose and schedule to be used in Part III of this study.~Part II Expansion: RO6874281 will be administered by IV infusion; 10 mg (Q3W) every 3 weeks (or lower dose level depending on Part I Cohort 1.1 outcome).~Part III Expansion: RO6874281 will be administered by IV infusion; 10 mg (QW) every week or 10mg (Q3W) every 3 weeks (or lower dose level depending on Part I Cohorts 1.1 and 1.2 outcomes) in either a Q3W or QW/Q3W schedule."

"Part I Safety Run in (Cohorts 1.1 and 1.2): Pembrolizumab will be administered by IV; 200 mg Q3W and will be observed over 2 administration cycles (i.e. 6 weeks).~Part II Expansion: Pembrolizumab will be administered by IV; 200 mg Q3W (or lower dose level depending on Part I Cohort 1.1 outcome)~Part III Expansion: Pembrolizumab will be administered by IV; 200 mg Q3W (or lower dose level depending on Part I Cohorts 1.1 and 1.2 outcomes)"