Rectal cancer, a rare neoplasm related to colon cancer, is usually diagnosed at an advanced stage, when it is more difficult to treat. The standard treatment for locally advanced rectal cancer is neoadjuvant (preoperative) chemotherapy and radiation therapy to shrink tumors, followed by surgery to remove all or part of the rectum, which may require a colostomy.
At the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, Andrea Cercek announced the results so far from her Phase II clinical trial: patients with a genetic variation known as mismatch repair deficiency (dMMR) (present in approximately 10% of these tumors) achieved a complete response when treated first-line with Jemperli (dostarlimab). This drug is an immunotherapy monoclonal antibody targeting PD-1, a T-cell receptor that regulates immune function. Jemperli was first approved in April 2021 for advanced dMMR endometrial cancer; the indication was subsequently expanded to all dMMR tumors regardless of location.