It is looking likely that some patients with a difficult-to-treat form of asthma will get routine access to a novel treatment option on the NHS, after GlaxoSmithKline Nucala's was backed by cost regulators.

The National Institute for Health and Care Excellence has published draft guidelines endorsing use of the drug for a sub-group of adults with severe refractory eosinophilic asthma on the NHS in England and Wales.

In earlier draft guidance, NICE's appraisal committee did not recommend mepolizumab as the evidence presented by GSK suggested that it would be used in less severe cases of asthma and would not therefore be cost effective, but the firm then provided further analyses on its use alongside an additional price reduction.

Now the drug is recommended as an add-on treatment when people have a certain level of eosinophils in their blood despite taking their regular medicines. It is only recommended for eosinophilic asthma if the person has had four or more attacks in the previous 12 months, or if they are taking maintenance oral corticosteroids. 

Nucala is the first biologic therapy that targets interleukin-5 (IL-5) - the main promotor of eosinophil growth, activation and survival - in severe asthma and stops it from binding to its receptor, thereby interrupting the inflammation pathway.

In one study underpinning the drug's regulatory submissions (MEA115588), Nucala cut the frequency of clinically significant exacerbations of asthma by 47 percent versus placebo, while the 100mg dose cut the amount by 53 percent.

This first in class biological medicine targeting this specific type of severe asthma - which affects around 100,000 people in the UK - is now also the first to be granted national access by NICE. It will be made available to patients in specialist centres providing severe asthma services.

"This is great news for eligible adult patients in England and Wales living with severe refractory eosinophilic asthma. It will enable healthcare professionals to offer a targeted treatment to this small but difficult-to-treat group of patients," said Dr Stephen McDonough, GSK's UK and Ireland Medical Director.

"For many patients, despite taking high doses of inhaled medicines, and often oral corticosteroids, their condition remains uncontrolled putting them at high risk of frequent and serious asthma attacks which can sometimes end up with them being hospitalised."

Asthma UK today welcomed the decision, but urged health chiefs to ensure the treatment is made available to those who need it as soon and as widely as possible.

Kay Boycott, the charity's chief executive, said Nucala is one of a new generation of drugs that offers genuine hope to people with severe asthma.

"We are delighted that mepolizumab has finally been recommended for use on the NHS. It has the potential to transform the lives of many people with one of the most debilitating forms of asthma. Not only should it improve some people's symptoms and reduce the risk of life-threatening asthma attacks, but we also hope it will reduce their reliance on high doses of corticosteroids which can have unpleasant and harmful side effects in the long term. We now need to see mepolizumab made available to those who need it as soon as possible."

Nucala is given by injection every four weeks. Its list price is £840 per dose but the what the NHS will actually pay remains confidential.