CB-839 + Capecitabine in Solid Tumors and Fluoropyrimidine Resistant PIK3CA Mutant Colorectal Cancer

Phase I Primary Objective: To determine the safety, tolerability and recommended phase II dose (RP2D) of combination CB-839 and capecitabine chemotherapy in patients with advanced solid tumors for whom there are no remaining treatment options or for whom single agent capecitabine is an acceptable therapy. Phase II Primary Objective: To determine the disease control rate of combination CB-839 and capecitabine chemotherapy in patients with metastatic PIK3CA mutant colorectal cancers who are refractory to fluoropyrimidine based therapy. Phase I Secondary Objectives: To determine the dose-limiting toxicities and maximum tolerated dose of combination therapy with CB-839 and capecitabine in patients with advanced solid tumors for whom there are no remaining treatment options or for whom single agent capecitabine is an acceptable therapy. To determine the disease control rate as assessed by RECIST criteria of combination therapy with CB-839 and capecitabine in patients with advanced solid tumors for whom there are no remaining treatment options or for whom single agent capecitabine is an acceptable therapy. Phase II Secondary Objectives: To determine the progression free survival following treatment with CB-839 and capecitabine chemotherapy in patients with metastatic PIK3CA mutant colorectal cancer and are refractory to fluoropyrimidine therapy. To determine the overall survival following treatment with CB-839 and capecitabine chemotherapy in patients who have metastatic PIK3CA mutant colorectal cancer and are refractory to fluoropyrimidine therapy.