Dostarlimab for cancer cure: Hope or hype?
Treatment with the immunotherapy dostarlimab showed promising results in a small trial of more than a dozen rectal cancer patients, according to new research, but further study is needed and it is too early to call it a cure.
Dostarlimab, an immunotherapy drug from GlaxoSmithKline, is dominating headlines internationally for making rectal cancer ‘vanish’ in a small group of patients in New York and is being touted as a ‘miracle therapy’ for cancer. The drug was given to 12 patients with rectal cancer, all of whom went into remission, in a small study at the Memorial Sloan Kettering Cancer Center in New York, as part of a phase 2 clinical trial.
Reports say that after the course of treatment, cancer was undetectable on physical examination, endoscopy, positron-emission-tomography (PET) and MRI scans of every patient and the participants did not need any other treatment for up to a year, on average. Also, there were no side effects severe enough to curtail day-to-day activities, according to the researchers, some of whom claimed that such results had not been seen in the history of cancer treatment ever.
The drug was manufactured by a small biotechnology company called Tesaro, which was later acquired by GlaxoSmithKline. The medicine, sold under the brand name Jemperli, was first approved for the treatment of a specific type of endometrial cancer in the US and the European Union in 2021.
It's worth noting that the positive results have only been seen in 12 patients so far (the trial is ongoing), all of whom had tumors with genetic mutations called mismatch repair deficiency (MMRd), seen in a subset of approximately 5–10 percent of rectal cancer patients.
Patients with such tumors tend to be less responsive to chemotherapy and radiation treatments, which increases the need for surgical removal of their tumors.
If immunotherapy can be a curative treatment for rectal cancer, eligible patients may no longer have to accept functional compromise in order to be cured.