LB-100

This Phase Ib trial studies the side effects and best dose of LB-100 when given with atezolizumab for the treatment of patients with metastatic microsatellite stable colorectal cancer. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of the tumor to grow and spread. LB-100 has been shown to make anticancer drugs work better at killing cancer. LB-100 blocks a protein on the surface of cells called PP2A. Blocking this protein increases the stress signals for the tumor cells that express PP2A. Giving atezolizumab in combination with LB-100 may work better to treat metastatic colorectal cancer patients as the cancer cells that experience increased stress signals are more susceptible for the immunotherapy.