Patients with certain gastrointestinal tumours may be treated with immunotherapy drugs alone, potentially eliminating the need for surgery, chemotherapy, or radiation.
It's based on new research that offers hope it could do away with the need for drastic, life-changing surgeries and other treatments.
Luis Diaz, a gastrointestinal medical oncologist at Memorial Sloan Kettering Cancer Centre in New York and one of the co-leaders of the study, along with Andrea Cercek, who is also a gastrointestinal medical oncologist with MSK, told The Washington Post: ‘For as long as cancer treatment has existed, cutting it out has been the best way to cure it. This is a complete paradigm shift.’
Karen Knudsen, CEO of the Parker Institute for Cancer Immunotherapy, said the approach ‘gives patients more agency in determining how they want to approach their treatment based on chances of survivorship, but also quality of life and side effects’.
The study included data from 103 patients with tumours caused by gastrointestinal cancers affecting organs such as the stomach, bladder, and intestines, which are typically treated with surgery.
They all had tumours with mutations – mismatch repair deficiencies – that prevent cells from repairing DNA damage. These mutations occur in two to three per cent of all cancers.
The trial found that 80% of patients treated with the immunotherapy drug dostarlimab did not require chemotherapy, radiation, or surgery, including organ removal.
This included all 49 patients with rectal cancer, who saw their tumours disappear completely after six months of treatment, with no recurrence at five years. Thirty-five of 54 patients with tumours in locations such as the colon, bladder, oesophagus, and stomach saw their cancer disappear.
Diaz and his team shared the results at the annual meeting of the American Association for Cancer Research and published them in the New England Journal of Medicine. The trial results build on the study’s first phase, which debuted at the same conference in 2022.
During Phase 1, which was conducted in 2020, a tiny sample of 14 patients with early-stage rectal cancer were given dostarlimab. The tumours in all 14 patients vanished after six months of the experimental treatment.
The second phase of the trial included patients with solid, non-rectal tumours. Patients received a 500-milligram dose of dostarlimab intravenously every three weeks for a total of nine treatments. Almost 40 per cent of patients had no side effects at all, Diaz said; some patients experienced mild rashes or itching, while a smaller number experienced more serious lung infections and encephalitis.
Diaz hopes that dostarlimab will become an available option for the small number of cancer patients with mismatch repair mutations.
In December, the Food and Drug Administration designated GSK’s dostarlimab, a drug marketed as Jemperli, as a breakthrough therapy.
