GlaxoSmithKline wins US approval for drug to treat severe asthma

The Food and Drug Administration has approved an injectable drug from GlaxoSmithKline PLC to treat severe asthma attacks.

The agency cleared Nucala for patients 12 years and older who cannot control their asthma with more conventional drug options.

The new drug joins four other respiratory medicines Glaxo has launched since 2013 as it tries to re-invigorate its respiratory franchise.

More than 22 million people in the U.S. have asthma, leading to more than 400,000 hospitalizations each year, according to federal figures.

Nucala is injected every four weeks by a health care professional in the arm, thigh or abdomen. The genetically engineered antibody is grown in cells from Chinese hamsters and works by reducing levels of white blood cells that contribute to asthma.

Side effects reported in company testing included headache, injection site reactions, back pain, and fatigue. Hypersensitivity reactions can occur within hours or days of injection with Nucala.

Drugs for asthma and other breathing disorders make up Glaxo's largest drug segment, contributing more than $9 billion in sales during the last fiscal year. But sales have tumbled in recent years as multiple brand-name rivals have forced price cuts and generic competition has slashed sales in several countries.

In the U.S., the patent for the company's best-selling Advair asthma drug expires in August 2016, though generic competition likely won't be immediate because the drug comes inside a special inhaler-like device.

The British drugmaker is headquartered in London.