Recently, the Memorial Sloan Kettering Cancer Centre in New York, USA conducted an experimental therapy trial using Dostarlimab as a result of which all the cancer patients in the trial emerged cancer-free for the first time in history. According to a recent study published in The New England Journal of Medicine, immune checkpoint inhibitors may be particularly helpful in treating persons with a specific type of rectal cancer. Andrea Cercek, MD, Head of the Colorectal Cancer Section and Co-Director of the Center for Young-Onset Colorectal and Gastrointestinal Cancers at Memorial Sloan Kettering Cancer Center presented the findings at the 2022 ASCO Annual Meeting.
Dostarlimab is used to treat adults who have a mismatch repair deficiency (dMMR). "Mismatch repair deficit" refers to cells that contain mutations which prevent them from correcting mistakes when replicating the DNA. Dostarlimab is typically used to treat endometrial cancer. However, this study was focused on using the experimental drug to treat tumors resulting from rectal cancer.
The clinical trial started in December 2019 which featured 18 colorectal cancer patients who took Dostarlimab for about six months. Usually, patients with rectal cancer have to forego surgery and chemotherapy. The patients were given Dostarlimab every three weeks during the trial for six months. Notably, all the patients had cancer at the same stage which had not transgressed to other organs. All the patients in the trial demonstrated a "clinical full response" after six months of follow-up, with no tumors visible via MRI scans, PET scans, endoscopy, and biopsy, among other procedures. Patients have only experienced side effects, such as rash, itching, fatigue, and nausea – however, two years later, every single patients is cancer free, with no trace of cancer whatsoever anywhere in the bodies. The study is scheduled to be completed by November 30, 2025.
According to Indian Oncologists, in the recent times Immunotherapy drugs have become important with respect to cancer care. There exist many drugs similar to Dostarlimab like Pembrolizumab, Nivolumab, Atezolizumab, Ipilimumab etc. in the markets. However, all these drugs are meant for specific indications.
The 12 patient trial was a relatively small trial which included patients with rectum cancer. All the patients were unique as their cancer was deficient for a gene called mismatch repair and this may be the reason for such response to the treatment. The reason why there have been no side effects is because the case numbers were low and the treatment period was relatively short.
However, the greater concerns currently are the costs of the immunotherapy drugs. A paper presented by Tata Memorial Hospital in the very meeting where Dostarlimab data was presented, reported that only 3% of Indian patients are able to even afford these drugs.
This current ebullience in certain areas is "premature," as patients must be observed for another three to five years. Tumours do respond to treatment. Hence the study's final goal should be higher survival rates. The treatment is promising and Dostarlimab may turn out to be an important drug in the oncologists’ arsenal, according to the experts. Still, a larger-scale experiment is needed to evaluate if it will work on a large scale and if the malignancies are actually in remission. Furthermore not just the drugs but also policies which make these drugs affordable and available to common people are required.
