Will a new drug change the rules of treatment for some cases of rectal cancer?

Rectal cancer is a common type of cancer, and treatment usually depends on surgery, chemotherapy, or radiation. However, rapid developments in the field of immunotherapy have opened new horizons, with increasing indications of the possibility of improving treatment outcomes in specific categories of patients. .

The American magazine TIME highlighted a promising medical development in the treatment of some cases of locally advanced rectal cancer, after the US Food and Drug Administration (FDA) approved the drug dostarlimab, known commercially as “Gimberly”, to treat adults with a specific type of rectal cancer characterized by a defect in the DNA repair mechanism, which raises hopes for providing more accurate treatment options for this category of patients.

This type represents between 5 and 10% of rectal cancer cases, and produces genetic mutations that impair the cells' ability to repair DNA damage. As these mutations accumulate, the abnormal cells continue to grow and divide, contributing to the development and spread of cancer cells.

The results of a study that included 154 patients showed that 68% of participants achieved a complete clinical response after a year of treatment with dostarlimab, which means that doctors were not able to detect any evidence of the tumor through imaging examinations or approved follow-up methods. Patients received nine doses of the drug, one dose every three weeks over a period of six months, as part of a study submitted by the manufacturer, GlaxoSmithKline, to the US Food and Drug Administration.

Treatment without surgery?

“Patients not only achieved a complete clinical response, they maintained it for an entire year,” said Dr. Andrea Sircic, chief of colorectal cancer at Memorial Sloan Kettering Cancer Center and the study's lead investigator, noting that some of the early participants remained tumor-free for longer periods. She added that these results enhance the possibility that the treatment will continue to be effective in the long term.

Dostarlimab is an immunotherapy drug that helps the immune system recognize and attack cancer cells by removing some of the mechanisms that tumors use to hide from the body's natural defenses, allowing immune cells to target and eliminate cancer.