This past month, a new study was published in the New England Journal of Medicine that reported interesting results on a potential asthma treatment. Researchers from Brigham and Women’s Hospital, Harvard Medical School, and Novartis Institutes for Biomedical Research, all in Boston, Massachusetts, investigated the effect a well-known cancer therapy has on severe asthma. The cancer treatment, imatinib (also known as Gleevac), is used primarily to treat chronic myeloid leukemia along with other cancers. It is a chemotherapy that has the potential to inhibit the growth of mast cells.1 This inhibition of growth was proven using mice models, and has since moved on to further investigation in humans.
Mast cells are white blood cells that are connected to many allergic reactions. They cause the airways to be hyper-reactive, or twitchy, in response to pollutants and other allergens. Mast cells also increase the secretion of mucus. Both of these responses contribute to the familiar respiratory symptoms asthmatics endure. Although mast cells are involved in the allergic response, it is believed that they are vestigial and don’t benefit the immune system. This means at one point there may have been a use for these cells in our body, however, in our current world, we may not need them. Of this property, lead investigator and researcher at Brigham and Women’s Hospital, Dr. Elliot Israel said, “When we lived in a different environment, where there were lots of parasites, mast cells potentially might have been more useful. But right now, they just contribute to hives, allergy, and asthma.”2
Even with glucocorticoid treatment, mast cells can still be present and contribute to inflammation and airway hyper-reactivity. Imatinib can target stem cell factor, and its receptor KIT, both involved in mast cell production, to prevent these cells’ growth. According to research from the study, this could relieve asthma symptoms while having relatively little effect on an individual’s immune system and response.
Within the study, 62 individuals participated and were randomly assigned to a placebo or treatment group. Those taking the imatinib experienced reduced hyper-reactivity and an opening of the airways when compared to their control counterparts. The main side effects of the drug were low white blood cell counts that rebounded once the medication was stopped, and muscle cramps. The researchers hope to expand and elongate the study, as 62 individuals is a low number of participants, and of those who did receive the treatment, several dropped out due to intolerance of the medication or its side effects. However, the improvement found in those who were able to tolerate the drug was significant enough to warrant future studies and investigate this treatment further.
The results of this study help shed light on the biology behind asthma and its causes, as well as identify mast cells as a potential target for future drug development. Currently, imatinib can retail for incredibly high prices, however, these findings could lead to the investigation and creation of new treatments that could be less expensive, or could increase the amount of options on the market. Additionally, the improvements from this study were the most significant for individuals without allergic asthma. Many drugs in development are geared towards allergic asthma, making this breakthrough unique and applicable to a different subset of individuals than others being reported at this time.
Cahill KN, et al. “KIT inhibition by imatinib in patients with severe refractory asthma.” New England Journal of Medicine. May 2017. 376(2): 1911-1920. Available from: http://www.nejm.org/doi/full/10.1056/NEJMoa1613125?query=featured_homet=abstract
Keshavan, Meghana. “Blockbuster cancer drug shows surprising promise in treating severe asthma.” StatNews. 17 May 2017. Available from: https://www.statnews.com/2017/05/17/gleevec-for-asthma/