GlaxoSmithKline plc  has submitted a regulatory application to the Japanese Ministry of Health, Labour and Welfare (MHLW) for mepolizumab as an add-on maintenance treatment for patients with severe eosinophilic asthma who experience exacerbations on standard treatment.

Mepolizumab is an anti IL-5 monoclonal antibody delivered in a 100mg fixed dose via a subcutaneous injection every four weeks.

The New Drug Application for mepolizumab has been submitted to the MHLW for adults and adolescents aged 12 years or older with severe eosinophilic asthma identified by a blood eosinophil count of at least 150 cells per microlitre at the start of treatment, or 300 cells per microlitre in the past 12 months, and who are treated with high dose ICS and other maintenance treatment(s).

Mepolizumab is not currently approved for use anywhere in the world. Regulatory filings in a number of other countries, including the US and EU, are underway. Further submissions are planned during the course of 2015.

Currently the World Health Organization estimates that as many as 235 million people live with asthma worldwide. For many of these patients existing therapies can provide adequate control of their symptoms if used appropriately. However approximately 5% of patients with severe asthma cannot achieve symptom control with existing therapies.

Severe eosinophilic asthma is a sub-type of severe asthma in which the over-production of eosinophils (a type of white blood cell) cause inflammation in the lungs that can affect the airways, limiting breathing and increasing the frequency of exacerbations. Interleukin-5 (IL-5) is the main promoter of eosinophil growth, activation and survival and provides an essential signal for the movement of eosinophils from the bone marrow into the lung.

Mepolizumab is an investigational monoclonal antibody, which stops IL-5 from binding to its receptor on the surface of eosinophils. Inhibiting IL-5 binding in this way reduces blood, tissue and sputum eosinophil levels. Mepolizumab is also being investigated in eosinophilic COPD and Eosinophilic Granulomatosis with Polyangiitis (EGPA).