Groundbreaking research at the Swim Across America Lab at Memorial Sloan Kettering Cancer Center helps advance a treatment that could allow patients to avoid chemotherapy, radiation and surgery while preserving their quality of life
CHARLOTTE, N.C., Oct. 21, 2026 — A groundbreaking immunotherapy treatment for rectal cancer, developed through pioneering research at Memorial Sloan Kettering Cancer Center (MSK) with critical early-stage funding from Swim Across America, has received accelerated approval from the U.S. Food and Drug Administration (FDA). The historic approval of Jemperli (dostarlimab) on Oct. 19, 2026, marks a major advancement in cancer care, offering certain patients with locally advanced rectal cancer the possibility of eliminating their cancer without chemotherapy, radiation or surgery.
The FDA approval builds on research conducted by Luis Diaz Jr., MD, and Andrea Cercek, MD, gastrointestinal oncologists at Memorial Sloan Kettering Cancer Center, whose pioneering clinical trials demonstrated that immunotherapy alone could eliminate tumors in patients with a specific genetic mutation, as reported in the April 27, 2025, issue of The New England Journal of Medicine and a previous June 5, 2022, report in The New England Journal of Medicine. Swim Across America provided critical grant funding for the early research and subsequent clinical trials through its longstanding support of immunotherapy research at MSK, including the Swim Across America Lab, funded by Swim Across America – Long Island Sound and Swim Across America – Nassau-Suffolk.
The FDA granted accelerated approval to Jemperli, developed by pharmaceutical company GSK, for adults with stage II or III locally advanced rectal cancer whose tumors are microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR). These tumors have genetic characteristics that make them particularly responsive to certain immunotherapies, which help the body’s immune system recognize and attack cancer cells.
For patients facing rectal cancer, standard treatment has often involved chemotherapy, radiation and major surgery, which can result in permanent colostomies, infertility, incontinence and other lifelong complications. This new immunotherapy approach offers eligible patients the possibility of avoiding these treatments while preserving their organs, independence and quality of life.
“This is an extraordinary milestone for cancer research – and for the thousands of swimmers, volunteers and donors who have supported critical cancer research through Swim Across America throughout the years,” said Rob Butcher, CEO of Swim Across America. “Our mission is to fund innovative cancer research that gives patients hope, and this FDA approval demonstrates how early investments in promising science can lead to treatments that transform lives. We are incredibly proud of the groundbreaking research at Memorial Sloan Kettering and grateful to our Swim Across America communities whose fundraising has helped make this progress possible.”
This work has had years of research that has supported this incredible progress and years of clinical trials that demonstrated that all 12 rectal cancer patients in an initial clinical trial treated with the immunotherapy dostarlimab, experienced a complete clinical response, meaning there was no detectable evidence of cancer following treatment. None of the patients required chemotherapy, radiation or surgery during the initial study follow-up.
The unprecedented 100% clinical response rate attracted worldwide attention and opened the door to expanded studies examining whether immunotherapy could replace traditional cancer treatments for patients with mismatch repair-deficient tumors.
In April 2025, additional findings published in The New England Journal of Medicine and presented at the American Association for Cancer Research Annual Meeting demonstrated the potential of immunotherapy to treat a broader range of solid tumors. The expanded study included 103 patients with stage I-III cancers, including 49 patients with rectal cancer and 54 with other cancers, such as gastroesophageal, hepatobiliary, colon, genitourinary and gynecologic cancers. Approximately 80% of patients in the study avoided surgery following immunotherapy treatment.
“Grants provided by Swim Across America were critical to our initial study and advancing this trial to phase 2,” said Dr. Diaz, gastrointestinal oncologist and head of the Division of Solid Tumor Oncology at Memorial Sloan Kettering Cancer Center, in a statement about the earlier clinical trial.
The FDA’s October 2026 accelerated approval was supported primarily by results from AZUR-1, a larger international clinical trial evaluating dostarlimab in 154 patients with previously untreated stage II or III MSI-H/dMMR locally advanced rectal cancer.
According to the FDA, 110 patients, or 71%, received dostarlimab alone without additional cancer treatment or disease progression during the study assessment period. The trial also demonstrated sustained complete clinical responses in a substantial proportion of patients, reinforcing the potential of immunotherapy as an alternative to traditional treatment.
The approval is the first for an immunotherapy specifically indicated for this group of patients with locally advanced rectal cancer. Continued clinical follow-up and confirmatory research will help establish its long-term benefits.
Beyond the potential to eliminate cancer, the treatment represents a major advancement in preserving patients’ quality of life.
Traditional rectal cancer treatments can permanently affect bowel, bladder and sexual function, fertility and a patient’s ability to maintain normal daily activities. For patients who achieve a complete response to immunotherapy, avoiding these treatments can have a profound impact on their physical and emotional well-being.
“This study shows that immunotherapy can replace surgery, radiation and chemotherapy for mismatch repair-deficient solid tumors, which could help patients preserve their organs and avoid the harsh side effects of chemo and radiation,” said Dr. Cercek, gastrointestinal oncologist and co-director of the Center for Young Onset Colorectal and Gastrointestinal Cancer at Memorial Sloan Kettering Cancer Center.
“Preserving a patient’s quality of life, while also successfully achieving positive results in eliminating their cancer, is the best possible outcome. They can return to their daily routines and maintain their independence,” Dr. Cercek added.
Dr. Cercek also got emotional when she shared that several of the patients have gone on to get pregnant and have babies – after treatment – something that was unheard of with previous types of treatment for these types of cancers.
For decades, Swim Across America has supported innovative immunotherapy research at Memorial Sloan Kettering Cancer Center through grants generated by its charity swims, including Swim Across America – Long Island Sound, Swim Across America – Nassau-Suffolk and Swim Across America – Fairfield County, its three New York City area open water swims.
The named Swim Across America Lab at MSK focuses on advancing innovative immunotherapy clinical trials and research that can lead to more effective treatments for cancer patients. Swim Across America-supported research has played an important role in advancing four previously FDA-approved immunotherapy medicines: ipilimumab (Yervoy), nivolumab (Opdivo), pembrolizumab (Keytruda) and atezolizumab (Tecentriq). Swim Across America is thrilled to now add the fifth FDA approved treatment of Jemperli (dostarlimab) to that list.
The accelerated approval of Jemperli for locally advanced rectal cancer represents another major milestone in this longstanding investment in immunotherapy research and underscores how philanthropic funding can help researchers investigate innovative approaches before they become established treatment options.
Since its founding in 1987, Swim Across America has raised more than $150 million to fight cancer. Each year, thousands of swimmers, volunteers, donors and Olympians participate in charity swims in 27 communities across the United States, with funds supporting cancer research, clinical trials and patient programs at leading cancer institutions. The organization supports more than 60 cancer research projects annually and has 10 named Swim Across America Labs at major research institutions.
Research associated with the dostarlimab clinical trials has also received support from the National Institutes of Health, National Cancer Institute, Stand Up To Cancer and other research partners. GSK provided the immunotherapy medicine used in the trials.
About Swim Across America
Swim Across America, Inc. (SAA) raises money and awareness for cancer research, prevention and treatment through swimming-related events. With the help of volunteers, and Olympians, Swim Across America is an innovator and leader in giving hope to those fighting cancer. To learn more visit swimacrossamerica.org, Facebook @SwimAcrossAmerica, and Instagram @SAASwim.
