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FDA rejects mepolizumab on efficacy, but supports safety for COPD



Asthma drug mepolizumab could be added safely to inhaled corticosteroids for maintenance therapy to help reduce exacerbations in chronic obstructive pulmonary disease (COPD) patients who meet criteria for eosinophil counts, but the current data do not support its efficacy strongly enough for approval, according to a majority of members of the Food and Drug Administration’s Pulmonary-Allergy Drugs Advisory Committee.

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The committee voted 16-3 that there was insufficient evidence of efficacy to support mepolizumab’s use as an add-on therapy for COPD patients guided by eosinophil levels; they also voted 16-3 that the risk-benefit profile was not adequate to support approval.

However, on a voting question of safety, the committee voted 17-2 that the safety data on mepolizumab were sufficient to support approval.

Mepolizumab, a humanized monoclonal antibody, is currently approved for the treatment of asthma with eosinophilic phenotype for patients aged 12 years and older and for adults with eosinophilic granulomatosis with polyangiitis. Manufacturer GlaxoSmithKline is seeking approval for its use as an add-on therapy in COPD patients at a subcutaneous dose of 100 mg every 4 weeks. Mepolizumab works by binding to interleukin-5 (IL-5) and reducing eosinophil maturation and survival, which prompted GlaxoSmithKline to pursue an indication for COPD patients in a high-eosinophil stratum.

The application was supported in part by two concurrent randomized trials of 52 weeks’ duration.

Banu A. Karimi-Shah, MD, clinical team leader of the FDA’s Division of Pulmonary, Allergy, and Rheumatology Products, presented data from the two studies, referred to as Study 106 and Study 113.

In Study 106, researchers found statistically significant reductions in exacerbations for patients in the highest eosinophil group. However, challenges of the studies included a lack of consensus over the definition and possible relevance of an eosinophilic COPD phenotype, Dr. Karimi-Shah said in a presentation at the meeting.

In Study 113, mepolizumab had no significant impact on reducing moderate to severe exacerbations at either a 100-mg or 300-mg dose, Dr. Karimi-Shah said. In addition, most secondary endpoints, with the exception of reducing time to the first exacerbation among patients in the highest eosinophil group, did not consistently support the primary endpoint of exacerbation reduction in either study, she said.

Robert Busch, MD, also of the FDA’s Division of Pulmonary, Allergy, and Rheumatology products, served as a clinical reviewer and presented data on safety, efficacy, and risk-benefit profile of mepolizumab.

Dr. Busch noted that the variability in blood eosinophils make it challenging to use as a potential marker to identify patients who would benefit from mepolizumab as an add-on therapy.

Overall, most of the committee agreed on the existence of an eosinophilic COPD phenotype, but expressed concern about the threshold being used.

“The studies were not particularly well controlled regarding the characterization of patients,” said William J. Calhoun, MD, of the University of Texas Medical Branch, Galveston, who cast one of the ‘no’ votes on the question of efficacy.

By contrast, Jeffrey S. Wagener, MD, of the University of Colorado at Denver, Aurora, referenced his background in cystic fibrosis, and voted “yes” on the question of efficacy. “For patients that have no other option, this is a step forward,” he said.

Committee members on both sides of the vote emphasized the need for more research with larger numbers, better patient characterization, and more female patients. The committee members reported no relevant conflicts of interest.

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