The US FDA has recently unanimously recommended Nucala (Mepolizumab) for add on maintenance treatment in patients 18 years older with severe eosinophilic asthma. The panel recommended against Nucala (mepolizumab) for children aged 12 to 17 years old. Severe eosinophilic asthma is defined as a blood eosinophil count greater than 150 cells/microliters at the start of treatment or greater than 300 anytime the past 12 months.

There are currently no approved treatments for patients with severe asthma with predefined eosinophil levels.

Nucala or Mepolizumab is a humanized monoclonal antibody to human interleukin 5 (IL-5). IL-5 is primarily involved in the regulation of blood and tissue eosinophils. Eosinophils are responsible for airway inflammation in asthma. Thereby by using Nucala (Mepolizumab) which blocks IL-5, this would reduce expression of eosinophils in the blood and tissue.

Nucala (Mepolizumab) is proposed to be administered subcutaneously every 4 weeks. Clinical studies showed a significant reduction in asthma exacerbations in treatment groups receiving Nucala (mepolizumab). The rate of hospitalizations or ER visits was lower in the treatment groups of Nucala (mepolizumab) than the placebo groups.

Side effects seen were local injection site reactions and possibly hypersensitivity reactions with Nucala (mepolizumab). Long term side effects remain to be seen as this drug still hasn’t come out on the market yet.

This would be the second monoclonal antibody drug to come out in the market for severe asthma. Xolair (omalizumab) has been on the market for years and it is used to treat severe persistent asthma. It blocks IgE receptors in the blood and it also has an indication for chronic idiopathic urticaria. It works well in patients who have allergic asthma, but it is very cost prohibitive, in some cases it can be thousands of dollars a month. There is currently no price yet on Nucala (mepolizumab), but most likely it won’t be inexpensive.

But for the patients who have severe persistent eosionophilic asthma, who do not respond to conventional asthma medications, Nucala (mepolizumab) may be a good treatment option in the future. You should speak with your allergist or allergy doctor to see if Nucala (mepolizumab) is right for you.