A Treatment That Put Every Single Cancer Patient Into Remission

A staggering headline indeed. So what is this ‘miracle new treatment’?A study conducted by the Memorial Sloan Kettering Cancer Centre (MSK), and published  in the New England Journal of Medicine last week reported that an experimental cancer treatment put every single patient into remission without having chemotherapy or radiotherapy. Albeit the small number of patients who were given the new drug - dostarlmab - scientists are still intrigued by the fact that after six months of taking the drug, patients had no trace of cancer. The patients in the study had locally advanced cancer meaning it was stage II or III, and the patients had not been operated upon before this study.

This finding is being considered a breakthrough in the realm of experimental cancer treatments, as Dr. Diaz, one of the authors of the paper said that he believes this to be the first time that this has ever happened in the history of studying cancer treatment, particularly using immunotherapy which is a treatment in which the body’s own immune system is harnessed against the cancer. In fact this is a landmark trial, despite the small size, because immunotherapies are normally trialled only after or with chemo and radiotherapy. This trial used it as a single therapy without any other treatment. And there is a rationale for why this might have worked so well.

All 12 patients had mismatch repair-deficient (MMRd) locally advanced rectal cancer. The drug used in this study, dostralimab, is a checkpoint inhibitor. It is an anti-PD-1 monoclonal antibody which releases the brakes on the immune system, freeing it to recognize and attack cancer cells. Cancer cells with MMRd are not very good at hiding the errors that accumulate inside them. They then present some of those faults to the immune system. Simplified, those cells become more ‘unfamiliar’ and the immune system is designed to attack such cells. The cell can then protect itself with PD-1, the ‘you can ignore me’ marker for cells, and blocking this prompts the immune system to rush into action against these odd looking cells. 

The results are undoubtedly promising, however there were only 12 patients in the study, and all with the same sub group of rectal  cancer. The sample size of the study is simply too small to declare this treatment a miracle cure, or a cure at all. And MMRd cancers are certainly what every cancer patient will have. Although, not a single patient in this study reported an allergic reaction, there is still data that suggests that an average of one in five people who take drugs like dostalimab report an allergic reaction to the drug, and as many 3-5% have severe reactions that include muscle weakness. The long term possibility of autoimmune problems down the line is a known concern after taking immunotherapies that boost the immune system but such matters can be more controlled than metastatic cancer. Several scientists have come forward and expressed their excitement, but not without cautious reservation. Dr. Hanna Sanoff, a gastrointestinal medical oncologist at the University of North Carolina, said, that the results were ‘’small but compelling and very little remains known.’’

Despite the reservations, this study is a huge step forward in recognizing that advances in immunotherapy are proceeding at an unprecedented pace. The findings contribute to the frontier of experimental cancer research as it combines personalised medicine with immunotherapy. If the patients - who will continue to be studied closely - show no signs of cancer in the future, it will confirm that the ambition of of immunotherapy to train the immune system to destroy cancer cells by training the body to recognize and fight off its the specific mutations in the genetic makeup of its own tumour is not misplaced. 

Studies like these remind us that the future of medicine is leaning towards medical care that taps into your own immune system rather than turning first to cytotoxicity and hoping that the fastest growing cells will get more damaged than normal cells, and therefore die selectively. Clearly the very system that scouts for many cancers -  our immune system - being one of the fastest replicating cell types in our bodies, does not do well from cytotoxic approaches. So this study that allows the immune system to do more work before chemotherapy is a refreshing new take. It is an approach that makes a great deal of sense to us. Therapies that hone in on the precise molecular makeup of the cancer to tailor personalised treatment are surely the future of oncology. In cancer research we are increasingly moving from an organ organ-centric guiding treatment choice to a more deep molecular analysis. As a team, we have for long believed that this is the future of modern oncology. If we’re going to have things as small as phone covers, t-shirts, key chains and coffee mugs personalised, it’s about time that we put our weight behind personalising medicine also.