Three anti-IL-5 pathway directed therapies are approved for use in patients with severe eosinophilic asthma, however no head to head comparison data are available. Nucala (mepolizumab) and Cinqair (reslizumab) target IL-5 and Fasenra (benralizumab) binds to the IL-5 receptor. All 3 therapies have demonstrated statistically significant reductions in exacerbation rates. Additionally, Nucala and Fasenra reduced dependency on oral steroid use, Nucala improved health related quality of life, and Cinqair and Fasenra significantly improve pulmonary function.
A recent study published in the January 2019 issue of The Journal of Allergy and Clinical Immunology titled “Anti-IL-5 treatments in patients with severe asthma by blood eosinophil thresholds: Indirect treatment comparison” sought to compare Nucala, Cinqair and Fasenra. They looked at clinical outcomes, exacerbations, lung function and symptoms were compared in relation to different blood eosinophil cut off points. The higher baseline blood eosinophil counts have been associated with more beneficial responses for all 3 treatments (mepolizumab, reslizumab and benralizumab).
*Before we discuss the data, it has to be disclosed that GSK (the maker of Nucala, funded this indirect treatment study).
11 studies were included in this indirect comparison. All treatments significantly reduced the rate of clinically significant exacerbations and improved asthma control versus placebo in all blood eosinophil count subgroups. Nucala reduced clinically significant exacerbations by 34% to 45% versus Fasenra across some subgroups and by 45% versus Cinqair in the eosinophil subgroup of >400 eosinophils. Asthma control was significantly improved with Nucala versus Fasenra and versus Cinqair in the high eosinophil count group. Fasenra significantly improved lung function versus Cinqair in the high eosinophil count group.
The authors conclusion was that mepolizumab was associated with significantly greater improvements in clinically significant exacerbations and asthma compared with reslizumab or benralizumab in patients with similar blood eosinophil counts.
Studies being funded by pharmaceutical companies which favor their own medications have to be taken into consideration. More studies will be needed that are self funded to help identify which IL-5 treatment works best for a particular asthma patient. However the authors conclusion was that mepolizumab induced significantly greater asthma exacerbations reductions and asthma control improvements versus reslizumab and benralizumab at all baseline blood eosinophil count thresholds, informing treatment decisions for patients with severe eosinophilic asthma.