Luis Diaz Jr., MD, was one of the researchers who led a 2022 clinical trial of a specific type of rectal cancer with a 100 percent success rate, Fast Company reported July 6.
In the late 2000s, Dr. Diaz was an oncologist working for Baltimore-based Johns Hopkins on liquid biopsies for early detection of cancer. "I didn't care about immunotherapy," he told Fast Company, until he learned immunotherapy shrunk lung cancer tumors.
Dr. Diaz, now head of the solid tumor oncology division at Memorial Sloan Kettering Cancer Center in New York City, and his colleagues theorized that tumors with a genetic alteration called "mismatch repair" deficiency had more mutations than normal which could make them more sensitive to immune checkpoint inhibitor drugs. He led a clinical trial to test the theory and treated dozens of patients' MMR-deficient tumors with the checkpoint inhibitor pembrolizumab. Three-quarters showed some level of disease control due to the drug and in May 2017, the FDA approved the first "tumor-agnostic" for the drug.
"We were curing patients in hospice and so forth," Dr. Diaz told the publication. "But even in patients who responded, only about 20 percent to 30 percent saw their tumor disappear."
At Memorial Sloan Kettering, Dr. Diaz and Andrea Cercek, MD, ran a clinical trial in 2022 on advanced MMR-deficient rectal cancer that had a 100 percent success rate. After six months of treatment with the immune checkpoint inhibitor Jemperli, all 18 patients saw their tumors disappear with few side effects. Now, Dr. Diaz is running similar trials for gastric, esophageal, prostate and pancreatic cancers.
The first-generation Peruvian American physician is excited about the way this treatment could impact developing countries: "In South America, where my family's from, when the patients get cancer, you don't have radiation or chemotherapy or surgery like we do. Now, if you can diagnose cancer with a liquid biopsy and get treated with pembro, you don't need that medical infrastructure. You can leapfrog all that."