The treatment of metastatic colon cancer had until recently hit a wall. A few chemo drugs, two antibodies and one growth factor inhibitor were all there had been for a decade. The discovery of immune checkpoint inhibition has ushered in a whole new way to treat cancer. Normally the immune system recognizes cancer and attacks it, but shuts down before it can finish the job — the immune checkpoint. Researchers have found a way to modify this so that the immune system keeps working: immune checkpoint inhibition. Now colon cancer has fallen to this approach.
Colon cancers with microsatellite instability — the kind seen in inherited forms of the disease — are very sensitive to immune checkpoint inhibition. Why those and not the other 90% of colon cancers remains a mystery. However, for patients with this form of colon cancer, two drugs, ipilimumab (Yervoy) and nivolumab (Opdivo), when given together, provide very long-term remissions to patients who have already exhausted their options with chemotherapy and growth factor inhibitors. In a recently study published in the Journal of Clinical Oncology doctors at MD Anderson Cancer Center found that over 70% patients given this combination were still in remission at a year after treatment began. Click here for the abstract. Dr. Stark can provide the entire article if you submit a request on the form to the right of this page.
Dr. Stark comments: This treatment is a sea change. Immune checkpoint inhibition has meant so much to patients with the much rarer metastatic melanoma — think Jimmy Carter — and now it can be used to offer major help to the multitude of patients with metastatic colon cancer whose tumors exhibit microsatellite instability. The MD Anderson group will now give this treatment to patients just diagnosed with metastasis. The hope is that they will enter long-term remission.