Study of Pembrolizumab, Binimetinib, and Bevacizumab in Patients With Refractory Colorectal Cancer

This study will be done in two stages. In stage 1, ten patients will be treated with standard doses of pembrolizumab, binimetinib, and bevacizumab to ensure that the doses are safe and tolerable. In stage 2, patients will be enrolled into either cohort A, where they will be treated with a 7-day run-in of binimetinib, followed by pembrolizumab, bevacizumab, and binimetinib combination treatment in 21 day cycles, or they will be enrolled to cohort B, which does not include the 7-day run-in of binimetinib. Treatment in cohort B will include combination therapy of pembrolizumab, binimetinib, and bevacizumab from first day of treatment.