KOCHI: The name Dostarlimab, unheard till recently, has become a household name over the past few weeks. Such has been the frenzy around this new drug. Here is all you need to know about the drug in question.
The drug
It belongs to a class of drugs called Immune checkpoint inhibitors. It works by recruiting the body’s natural immune mechanisms to fight cancer. It was tried in treating uterine cancer patients and was found to be effective. The recent study by the Memorial Sloan Kettering Cancer Center, New York, is the first clinical investigation that shows its effectiveness against rectal cancer.
The trial
The clinical trial saw the participation of a small group of patients. They were a subgroup of rectal cancer patients who were mismatch repair-deficient (MMR). They all had stage II or III cancer. At the trial, patients were given Dostarlimab every three weeks for six months.
The result
The ongoing clinical trial has shown dramatic responses in rectal cancer patients. There have been no apparent signs of the tumour after at least six months of follow-up. Since the news went viral, many patients in Kerala have been asking about using the drug in their treatment regime.
The cost
The cost of this therapy, as is the case with most new drugs, will be a hurdle. The total treatment cost will be around C50 lakh. It may limit access for a considerable number of patients.
The clarification
Based on available information, this drug cannot be used in all rectal cancers, leave alone all cancers. The current standard of care in most rectal cancers is radiation with chemotherapy followed by surgery and completion of chemotherapy. Only rectal cancer patients who are positive for MMR were part of the study. This genetic variation is seen in only 5-10% of colorectal cancer patients. More than 90% of rectal cancer patients cannot be candidates for this drug. Also, the clinical trial is based on a limited number of patients in a single institution. There should be various studies involving a larger group of patients and ethnicities. Also, we should conduct a survey among our population too. According to the standard modality of treatment, the patients need to be followed up for at least three to five years to see if the disease continues to be under control or whether the drug is safe.
The upside
If the trial is successful in the long run, the patients may not need to undergo surgeries and radiation (sometimes morbid) for rectal malignancies and we can stop at immunotherapy. Though the number of patients was few and the follow-up short, the result is encouraging.
Be cautious
Experts advise ‘cautious optimism’ in this regard. Be cautious as results are preliminary and optimism for the results are encouraging.
The author is senior consultant — medical and hemato oncology, Rajagiri Hospital