A prospective phase 2 study in which the drug Dostarlimab was administered as a single agent to a total of 18 patients with colorectal cancer resulted in a big surprise for medical scientists in the field of oncology.
After all of those patients had at least 6 months of follow-up with the monoclonal drug that blocks the protein in immune cells, all had a complete clinical response, with no evidence of tumor by physical exam, endoscopy, PET scans and MRIs.
The drug was given every 3 weeks for 6 months to patients with stage II or III rectal adenocarcinoma with cells that have mutations ‒ or changes ‒ in certain genes.
"I think this is the first time this has happened in the history of cancer," said Dr. Luis A. Diaz Jr., one of the authors of the study published in the scientific journal New England Journal of Medicine and led by a team at Memorial Sloan Kettering Cancer Center in New York, who said they were not aware of any other study in which a treatment had completely eliminated cancer in all patients.
While the small study, funded by drugmaker GlaxoSmithKline and the Simon and Eve Colin Foundation, among others, showed good response to the single-agent treatment, it will need extended follow-up and repetition to assess the duration of response and whether it amounts to a cure.
This treatment was to be followed by standard chemotherapy and radiotherapy procedures, as well as surgery. However, none of this was necessary, as the tumors disappeared completely, without presenting significant clinical complications.
According to Andrea Cercek, an oncologist at Memorial Sloan Kettering Cancer Center and co-author of the paper, “there were a lot of tears of joy” upon seeing the results.
It is worth noting that, on average, one in five patients has some adverse reaction to drugs such as the one taken by the patients, dostarlimab, known as immune checkpoint inhibitors.
The drug was administered every three weeks for six months and cost about $11,000 per dose, The New York Times reported.
How does the colorectal cancer drug work?
Dostarlimab is an anti-PD-1 monoclonal antibody that exposes cancer cells, allowing the immune system to identify and destroy them.
The inspiration for the rectal cancer study came from a clinical trial Diaz conducted in 2017, funded by the pharmaceutical company Merck, in which 86 people with metastatic cancer in various parts of the body participated.
But all the cancers had a genetic mutation in common that prevented cells from repairing DNA damage - mismatch repair deficiency - which occurs in four percent of cancer patients.
As if that weren't enough, Diaz is working to develop a "molecular Pap test" that can diagnose ovarian cancer and endometrial cancer at an early stage. A crucial advance that would mean being able to detect more cases of these cancers and begin treating them as quickly as possible.
The test is currently in clinical trials.
With information from The New York Times.
You may be interested in: New center for gastric disease care and research at Stanford Children's Hospital
