The first patient to try the drug was Washington DC's Sascha Roth, who got the good news on a Friday evening just four weeks before she was scheduled to undergo weeks of radiation therapy.
More than a dozen others would soon receive the good news.
The MSK clinical trial was investigating if immunotherapy alone could beat rectal cancer that had not spread to other tissues, in a subset of patients whose tumor contained a specific genetic mutation, the hospital said in a release.
In every case, the rectal cancer disappeared after immunotherapy — without the need for the standard treatments of radiation, surgery, or chemotherapy — and the cancer has not returned in any of the patients, who have been cancer-free for up to two years, MSK said.
The results are so impressive they were published in The New England Journal of Medicine and featured at the nation’s largest gathering of clinical oncologists in June 2022.
The trial was spearheaded by MSK oncologists Dr. Andrea Cercek and Dr. Luis Diaz, Jr.
Diaz has seen success in treating cancer with immunotherapy, which found that checkpoint inhibitors could “help people with MMRd colorectal tumors that have spread,” he said. “We thought, ‘Let’s try it before cancer metastasizes as a first line of treatment.'"
In addition to avoiding toxicity often associated with treating rectal cancer, the doctors sought to learn who would benefit most from immunotherapy treatment.
All patients in the trial must have stage 2 or 3 rectal tumors that are MMRd — which makes their cancer particularly sensitive to immunotherapy, according to the MSK release.
They were given the checkpoint inhibitor dostarlimab (Jemperli) intravenously every three weeks, for six months.
The results left Cercek and Diaz pleasantly surprised.
“The immunotherapy shrank the tumors much faster than I expected,” Cercek said, noting patients stopped bleeding and pain subsided after just one treatment.
After two or three treatments, patients told Cercek they felt "normal" again.
Diaz said the trial is just the beginning, and hopes to use immunotherapy to replace surgery, chemotherapy, and radiation to remove cancer.
"That might sound futuristic — but in this trial, we have a clinical example where that happened."
Click here for the full release from MSK on the trial.
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