The study plans to treat patients with pembrolizumab and thus blocking the PD-1/PD-L1 axis would render tumor-infiltrating lymphocytes (TILs) in the tumor parenchyma more functional as a consequence of BRAF inhibition, such that T cell activation by BRAFi would not be dampened by the PD-1/PD-L1 interaction. This combination would reverse dysfunction among T cells in the tumor parenchyma, maximizing T cell mediated immune anti-tumor efficacy. Progression free survival (PFS) with pembrolizumab in KEYNOTE-001 was 57% at 6 months, and 46.4% in the more recently reported phase III trial. PFS with vemurafenib treatment in BRIM-3 was ~50% at 6 months. Combined treatment with pembrolizumab, cobimetinib and vemurafenib for BRAF mutant melanoma is hypothesized to be safe and to improve the PFS compared to these recent historical controls. Because this combination has not yet been tested, and because the primary objective is to assess safety, the investigators are staging accrual in the first phase of the trial. The study aims to accrue up to 30 patients to the mTPI design of this study with the expectation that there will be at least 30 patients treated at RP2D. In case there are less than 30 patients on the RP2D, additional patients will be accrued. Patients will continue to receive treatment with pembrolizumab, vemurafenib and cobimetinib until disease progression or dose limiting toxicity. Patients with treatment response and no dose limiting toxicity may receive treatment with pembrolizumab for up to 24 months.
Name: Pembrolizumab
Description: Pembrolizumab will be given at a dose of 200 mg q3 weeks (this is the standard dosage, ). Treatment with pembrolizumab and vemurafenib will commence on the same day. One cycle of treatment will be defined as one dose of pembrolizumab and 3 weeks of vemurafenib.Type: DrugPembrolizumab plus vemurafenib and Cobimetinib
Name: Vemurafenib
Description: Vemurafenib will be given at 480 mg twice daily, 720 mg twice daily, or 960 mg twice daily. Treatment with pembrolizumab and vemurafenib will commence on the same day. One cycle of treatment will be defined as one dose of pembrolizumab and 3 weeks of vemurafenib.Type: DrugPembrolizumab plus vemurafenib and Cobimetinib
Name: Cobimetinib
Description: Cobimetinib will be given at 20 mg once daily, 40 mg once daily, or 60 mg once daily. Treatment with cobimetinib will commence on the same day. Cobimetinib will be given daily for 21 days, then held for 7 days.Type: DrugPembrolizumab plus vemurafenib and Cobimetinib
Description: determine the safety and maximum tolerated dose of vemurafenib and cobimetinib with pembrolizumab
Measure: Percentage of participants that experience a dose-limiting toxicity Time: Up to 2 yearsSingle Group Assignment
There are 2 SNPs
Only patients with BRAF V600E or V600K mutated tumors will be enrolled. --- V600E ---
Only patients with BRAF V600E or V600K mutated tumors will be enrolled. --- V600E --- --- V600K ---