Benefit of mepolizumab for asthma not proven in trials

WASHINGTON, May 2 (UPI) -- The agency responsible for drug safety in Germany has questioned the efficacy of mepolizumab, a drug for severe asthma, after finding what it called inadequate clinical trials before its approval for use there.

Mepolizumab, sold as Nucala, was not compared fairly against other asthma treatments, raising questions as to whether it has benefits over other drugs already used for the condition, the German Institute for Quality and Efficiency in Health Care said in a press release.

The drug, approved in the United States and Europe in 2015, and just approved in Japan, is a monoclonal antibody intended as a secondary treatment for severe asthma by targeting interleukin-5, an amino acid thought to play a role in inflammation in patients with asthma.

The U.S. Food and Drug Administration approved the drug based on the strength of results in three double-blind, randomized, placebo-controlled trials.

Researchers at the IQWiG, however, say Mepolizumab should have been compared to existing treatments to determine relative benefits, not a placebo.

After conducting the review, published at the IQWiG website, researchers at the agency found a placebo was used for comparison in both studies.

The German approval committee recommended escalation of insufficient treatment -- increased doses of inhaled corticosteroids and bronchodilators, plus oral corticosteroids, tiotropium or omalizumab if appropriate. The researchers found in the review that not all patient treatment was escalated in situations where it should have been, and many patients' previously ineffective treatment was continued unchanged.

The agency's full study has not been published yet, but it will conduct a commenting period after its release and before a final statement on the efficacy of the drug is issued.