A Study of the Anti-PD1 Antibody PDR001, in Combination With Dabrafenib and Trametinib in Advanced Melanoma

To evaluate the safety and efficacy of the combination of an anti-PD-1 antibody (Spartalizumab (PDR001)), a BRAF inhibitor (dabrafenib) and a MEK inhibitor (trametinib) in unresectable or metastatic BRAF V600 mutant melanoma

This study is designed as a Phase III, multi-center study consisting of three parts:

• Part 1, known as the Safety Run-in, is an open-label part aimed at determining the recommended Phase III regimen (RP3R) of spartalizumab in combination with dabrafenib and trametinib for previously untreated subjects with BRAF V600 mutant unresectable or metastatic melanoma (Stage IIIC/IV per AJCC edition 7). In Part 1, spartalizumab was administered at a starting dose level (DL1) of 400 mg every 4 weeks (Q4W), along with fixed doses of dabrafenib (150 mg twice daily) and trametinib (2 mg once daily). The RP3R for Part 3 was determined using the Bayesian Logistic Regression Model (BLRM) with escalation with overdose control (EWOC) criteria.
• Part 2, referred to as the Biomarker Cohort, is an open-label section focused on characterizing the kinetics of immune biomarkers and potential immune resistance mechanisms. Part 2 started when the fourth subject in dose level 1 (DL1) of Part 1 completed approximately 4 weeks of study treatment, and fewer than 3 dose-limiting toxicities (DLTs) were observed. Participants in Part 2 receive PDR001 (spartalizumab) at a dosage of 400 mg Q4W, in combination with dabrafenib (150 mg BID) and trametinib (2 mg QD).
• Part 3 is a double-blind, randomized, placebo-controlled phase that compares the efficacy and safety of spartalizumab in combination with dabrafenib and trametinib to placebo in combination with dabrafenib and trametinib. Part 3 was initiated after determining the RP3R for the combination of spartalizumab with dabrafenib and trametinib in Part 1. Subjects were randomized in a 1:1 ratio to receive either the RP3R dose of spartalizumab identified in Part 1 or placebo, along with dabrafenib (150 mg BID) and trametinib (2 mg QD).

For all parts of the study, the treatment is continued until the subject experiences any of the following events: disease progression according to RECIST 1.1 as determined by the Investigator, unacceptable toxicity, initiation of a new anti-neoplastic therapy, pregnancy, withdrawal of consent, physician's decision, loss to follow-up, death, or termination of the study by the Sponsor. Safety evaluations are conducted for all subjects for up to 150 days after the last dose of spartalizumab/placebo (safety follow-up period).

Subjects who discontinue study treatment without disease progression as per RECIST 1.1 continue with tumor assessments according to the protocol until documented disease progression, withdrawal of consent, loss to follow-up, or death, regardless of the initiation of new anti-neoplastic therapy (efficacy follow-up period).

Subjects enter the survival follow-up period after completing the safety follow-up period or experiencing disease progression as per RECIST 1.1 or response criteria for immunotherapy, whichever period is longer (survival follow-up period).