We are testing a new investigational drug that may help patients with cancer gain and/or maintain their weight. "Investigational" means the "treatment has not been approved for sale by the United States Food and Drug Administration (FDA). The purpose of this study is to evaluate safety and the effects of different doses of an investigational drug called B07 on a patient's weight to see if their weight can be maintained, or increased slightly while they are receiving chemotherapy for their advanced colorectal cancer. In addition to their weight, the study will also look at the effects of B07 on their BMI (a measure of weight divided by height that is useful for determining who is underweight, normal, overweight, or obese), appetite, food intake, physical and psychological well-being, and quality of life as they undergo your cancer treatment.