The Phoenix Trial: Phase II Trial of Cemiplimab for the Non-operative Management of Localized dMMR Colon Cancer

This study — called the Phoenix Trial — is testing whether cemiplimab (an immunotherapy drug) can treat localized colon cancer that has a genetic feature called mismatch repair deficiency (dMMR) or high microsatellite instability (MSI-H) without requiring surgery. This approach could allow some patients to avoid major colon surgery. **You may be eligible if...** - You are 18 or older with a confirmed colon adenocarcinoma (at least 10 cm from the anal canal) that is dMMR or MSI-H - Your cancer is localized (Stage II or III) or locally recurrent - Your overall health is good (ECOG 0–1) and the tumor is accessible by colonoscopy **You may NOT be eligible if...** - Your cancer has spread to distant organs (metastatic disease) - You have an active autoimmune disease requiring systemic treatment in the past year - You have previously received immunotherapy (checkpoint inhibitor) for your colon cancer - You are currently receiving chemotherapy or other cancer treatment - You are pregnant or breastfeeding - You have a history of severe lung inflammation requiring steroids Talk to your doctor to see if this trial is right for you.