A clinical trial at Memorial Sloan Kettering Cancer Center (MSK) has led to the FDA granting a Breakthrough Therapy Designation to Jemperli (dostarlimab), an immunotherapy drug from GSK, for treating a specific subset of rectal cancer patients. The trial focuses on patients with mismatch repair-deficient (MMRd) or microsatellite instability-high (MSI) tumors. By using immunotherapy alone—without surgery, chemotherapy, or radiation—researchers achieved a 100% remission rate in all 42 participants, with no evidence of disease persisting for up to four years and counting.
This approach spares patients from the life-altering side effects of standard treatments, such as infertility and incontinence, greatly improving their quality of life. The dramatic success has prompted changes in national treatment guidelines, enabling broader insurance coverage and inspiring adoption by clinicians worldwide.