A Phase 2/3, Randomized, Open-Label Study of Maintenance GRT-C901/GRT-R902, A NeoantigenVaccine, in Combination with Immune Checkpoint Blockade for Patients with Metastatic ColorectalCancer

The purpose of this research study is to learn more about an experimental personalized vaccine that has two components called GRT-C901 and GRT-R902. GRT-C901 works by increasing your immune system’s response to decrease levels of neoantigens (proteins that help your tumor grow) in your body. GRT-R902 works by using proteins in your body called messenger ribonucleic acid (mRNA) to decrease the levels of neoantigens. Study participants will be randomized, like flipping a coin, into two groups--treatment group and control group. We will learn more about the effects of this vaccine on advanced colorectal cancer when used together with United Stated Food and Drug Administration (FDA) approved medications, such as ipilimumab and atezolizumab in combination with the standard therapy you would normally receive (specifically fluoropyrimidine and bevacizumab, that activate the immune system to help your vaccine work. GRT-C901 and GRT-R902 are not FDA approved for the treatment of the subject’s colorectal cancer.

Are you Eligible? (Inclusion Criteria)

• You are ≥18 years of age. - You are not pregnant, planning to become pregnant, or nursing. - You do not have a history of a bleeding disorder. GO-010