‘Cancer vanishing drug trial exciting but far from a breakthrough’

A phase 2 medical trial in the US has stirred up the medical fraternity as it has shown exciting outcomes and held out hope for a possible cancer cure. Twelve patients with rectal cancer did not show any signs of tumour within six months of taking a drug, indicating a possible remission. While medical oncologs and experts here are excited about these findings, they said the study needs to be validated through a larger cohort of patients before claiming a medical breakthrough.
“This is indeed interesting and exciting. Surgical interventions to treat colon cancer significantly dampen patients’ quality of life. The outcome from this study can obliterate the need for surgical intervention and revolutionise immune checkpoint drugs future in cancer therapy, in general,” Dr Amit Dutt, scient at Tata Memorial Centre-Advanced Centre for Treatment, Research and Education in Cancer-TMC-ACTREC, told The Indian Express.

According to the paper published in the New England Journal of Medicine, all the patients took Dostarlimab, a monoclonal antibody, every three weeks for six months. The cancer disappeared in all of them during follow-ups through MRI, PET scans and other tests. One of the authors of the paper, Dr Luis A Diaz Jr of Memorial Sloan Kettering Centre, has said that he knew of no other study in which a treatment completely obliterated cancer in every patient.
The participants of the trial had a mismatch repair deficient stage II or III rectal adenocarcinoma. After giving the drug every three weeks for six months, the plan was to follow it up with standard chemotherapy and surgery. However, after six months, all 12 patients showed no signs of tumour, according to the study.Best of Express PremiumPremiumPremiumPremiumPremium
Dr Dutt pointed out that these inhibitors — PD-1 inhibitors — are already in use for treating different cancers such as melanoma, ovarian cancer, endometrial cancer and others that have progressed on prior treatment and have a deficiency in the mismatch repair (MMR) mechanism. “However, the response shown in colon cancer in this study is simply unparalleled with a 100 per cent response: too good to be true. If nothing else, this study would surely encourage a broader study across multiple solid cancers with similar MMR- deficiency. The findings from this study need to be validated involving a larger cohort of patients,” Dr Dutt said.

Cancer is a leading cause of death worldwide, accounting for nearly 10 million deaths in 2020, or nearly one in six deaths. According to the World Health Organisation (WHO), the most common cancers are breast (2.26 million cases), lung (2.21 million cases), colon and rectum (1.93 million cases) and prostate (1.41 million). The most common causes of cancer death in 2020 were lung (1.80 million deaths) as well as colon and rectum (916,000 deaths). In India, the annual incidence rates (AARs) for colon and rectal cancer in men are 4.4 and 4.1 per 100,000, according to an Indian Council of Medical Research report (2014).
According to Dr Padmaj Kulkarni, medical oncolog with Deenanath Mangeshkar hospital in Pune and chief editor of the Indian Journal of Medical and Paediatric Oncology, this study has a huge potential to change the paradigm of treatment. “These are extremely thought-provoking findings. However, the trial is a phase II one and conducted in a small set of patients with a short follow-up. Larger phase III studies are required to confirm the results and see whether this is a temporary phenomenon or can the cancer return aggressively. Among rectal cancer patients, this group, which has a mismatch repair deficient gene, comprises about five per cent. Treatment is traumatic and costly for the patients with side effects. Hence for a practice changing applicability, we need larger studies,” Dr Kulkarni said.
At Jehangir Hospital, surgical oncolog Dr Sachin Vaze said that it was too early to predict the benefit of this trial because the malignancy is different in every patient of rectal cancer and the biology of the disease may vary.