Rectal cancer disappeared in all patients involved in a small clinical trial of a new immunotherapy treatment, according to updated results released this month.
The study was a collaboration between the US-based Memorial Sloan Kettering Cancer Center (MSK) and the pharmaceutical company GSK.
It looked at a new drug called dostarlimab-gxly to treat patients with a specific type of rectal cancer caused by a genetic mutation.
“As a clinician, I’ve seen firsthand the debilitating impact of standard treatment of dMMR rectal cancer and am thrilled about the potential of dostarlimab-gxly in these patients,” Dr Andrea Cercek, section head of colorectal cancer from MSK and the study’s principal investigator, said in the statement.
MMRd stands for mismatch repair deficient meaning that the cells have a dysfunctional DNA repair system. These represent around five per cent of rectal cancers.
The current treatment for such cancer is radiotherapy, chemotherapy, surgery, or a combination of them.
The treatments often have a heavy impact on the patient's quality of life with for example intestinal disorders, bowel incontinence or sexual dysfunctions, according to Dr Clélia Coutzac, a medical oncologist who was not involved in the study.
How does dostarlimab work?
“Because dMMR are hypermutated tumours, they're super visible to the immune system, at first the immune system will see the cancer cells as foreign and will go and kill them. After a while, the cancer evolves and eventually the immune system stops working,” Coutzac told Euronews Health.
“What works very well in these tumours is that we reactivate the system with immunotherapy, and in this case, GSK's dostarlimab, a drug that will guide the lymphocytes to recognise the cancer cells again as harmful and kill them,” she added.
The patients who followed the six month treatments showed a complete clinical response with “no evidence of tumours” found by MRI, endoscopy or digital exam during the follow-up, according to GSK’s statement.
Coutzac described the results as “amazing”.
Further research ongoing
Before dostarlimab - also known under its brand name Jemperli - potentially arrives on the market to treat MMRd rectal cancer, further research is needed.
A global study called Azur-1 is designed to further test the efficiency of dostarlimab-gxly when used alone, instead of chemotherapy, radiation, or surgery, and to confirm the MSK findings.
