An innovative clinical trial at Memorial Sloan Kettering Cancer Center (MSKCC) demonstrated that immunotherapy alone can effectively eliminate tumors, and eliminating the necessity of invasive surgery, radiation, or chemotherapy in a selected group of cancer patients. This finding indicates a major change in how specific solid tumors, specifically those that have a mutation in the mismatch repair (MMR) gene, can be treated in the future.Â
Patients who have a solid tumor in an organ like the stomach, esophagus, rectum, liver, or urinary tract go for aggressive treatment. This includes surgery to remove the affected organs, which leads to a permanent change in the function of the body, infertility because of radiation, and toxicity from chemotherapy. In search of an alternative, MSKCC researchers led by Dr. Andrea Cercek and Dr. Luis A. Diaz Jr. collaborated with the GSK pharmaceutical company to study the effects of dostarlimab on patients with tumors harboring an MMR mutation. Dostarlimab is an immunotherapy drug. Â
Of the 103 participants, 49 had rectal cancer. These patients received dostarlimab as an independent treatment without chemotherapy or surgery. All 49 patients reported elimination of the tumor and no recurrence in 5 years of follow-up. Among the 54 patients who had other types of cancer, such as liver, urinary tract, stomach, endometrial, esophageal, and prostate, 35 patients received full recovery. Five patients reported the recurrence, 4 of them responded effectively to immunotherapy or minor surgery and are now disease-free. The tumor of the 5th patient reduced after more treatment. Â
Dr. Bert Vogelstein, a senior oncologist at Johns Hopkins, described this research as groundbreaking and highlighted that it represents the results of decades of foundational scientific research. He explained that this remarkable success of immunotherapy in this context is closely linked to the biological nature of tumors with MMR mutations. These tumors can accumulate a high number of genetic mutations, which lead to the production of abnormal proteins that serve as red flags to the immune system. He observed that such tumors develop an advanced method to prevent immune detection. The immunotherapy drugs, like dostarlimab, step in to target and disable those evasive mechanisms and allow the immune system to effectively recognize and attack the cancer.Â
Dostarlimab is expensive and difficult to obtain. Each dose costs approximately $11,000. A typical treatment includes 9 infusions spread over 6 months. Although it is approved by the Food and Drug Administration (FDA) to treat uterine cancer with MMR mutations and for use in clinical guidelines for rectal cancer, it is not fully covered by insurance for other cancer types. Patients who are qualified for the ongoing clinical trial at MSKCC can get this drug at no cost, with the given eligibility criteria.Â
Side effects of this drug are fatigue, itching, and rash, which are manageable. A few patients had more severe adverse effects, such as encephalitis and lung inflammation.Â
Maureen Sideris, a 71-year-old New Yorker, experienced a life-changing treatment for a stomach and esophagus tumor. Initially facing surgery and radiation, she qualified for a trial because of her tumor’s MMR mutation. After starting dostarlimab, her tumor disappeared in months. Although she needs hormone support for adrenal function now, she avoided surgery. This trial suggests that immunotherapy alone may offer a safe, effective, and less debilitating path to remission for a small but significant subset of cancer patients. Further studies and regulatory support are needed to expand access to this promising treatment.Â
Reference: Kolata G. Medicine Spares Cancer Patients from Grisly Surgeries and Harsh Therapies. The New York times. Published April 27, 2025. Accessed April 29, 2025. Immunotherapy Drug Spares Cancer Patients From Grisly Surgeries and Harsh Therapies – The New York Times
