An experimental drug appeared to rid people of rectal cancer in an unprecedented study, according to The New York Times.

A group comprising 18 patients took a drug called Dostarlimab for around six months, and in the end, every one of them saw their tumours disappear.

In conversation with the New York Times, Dr Luis Diaz, an author of a paper, said he could not remember any other study wherein cancer was obliterated in patients.

“I believe this is the first time this has happened in the history of cancer,” Diaz added.

According to the NY Times, the patients — who were a part of the study — had previously faced gruelling treatments including chemotherapy, radiation and, most likely, life-altering surgery that could result in bowel, urinary and sexual dysfunction.

Dr. Alan Venook, a colorectal cancer specialist at the University of California, told the daily that a complete remission in every single patient was "unheard-of".

Venook commended the research as a world-first, noting that the absence of significant side effects meant that “either they [patients] did not treat enough patients or, somehow, these cancers are just plain different.”

However, in an editorial accompanying the paper, Dr. Hanna K. Sanoff of the University of North Carolina’s Lineberger Comprehensive Cancer Center, who was not affiliated with the study, termed it “small but compelling" but said it was not clear if the patients were cured.

“Very little is known about the duration of time needed to find out whether a clinical complete response to dostarlimab equates to cure,” Sanoff said.