GlaxoSmithKline's COPD biologic rejected by FDA advisory board

GSK said it would continue to work with the US Food & Drug Administration to address outstanding questions after the regulator's pulmonary allergy drugs advisory committee voted 16-3 against approving the use of mepolizumab as an add-on treatment to inhaled corticosteroid-based maintenance treatment for the reduction of exacerbations in patients with COPD.

The committee voted on the basis of data presented that the risk-benefit profile of mepolizumab was not adequate to support approval and also voted 16-3 that there was not substantial evidence of the efficacy of the treatment.

One positive was that the committee suggested further data to characterise the patient population that would be most likely to benefit from this targeted biologic therapy after voting 17-2 that there was adequate evidence of the safety of the drug.

As FDA advisory committees recommendations are non-binding, GSK is still working towards a 7 September goal date for approval as a prescription drug.

GSK's respiratory research and development chief, Dave Allen, said: "Having participated in today's advisory committee meeting and heard the recommendation we will continue to work with the FDA to address outstanding questions. We remain confident our data supports mepolizumab as a targeted treatment for patients continuing to experience COPD exacerbations guided by blood eosinophil count."

Mepolizumab has been approved under the brand name Nucala in over 20 other markets as an add-on maintenance treatment for patients with severe eosinophilic asthma, and in the US, Canada and Japan as add-on maintenance treatment for patients with eosinophilic granulomatosis with polyangiitis, but is not currently approved for use in COPD anywhere in the world. No biologic therapies have yet been approved for COPD sufferers.

GSK shares fell 2% to 1,510p on Thursday morning.

Analysts at Shore Capital said the submission was based on data from the METREX and METREO trials which produced mixed results: "Namely, in patients with high blood eosinophil count in METREX, there was a statistically significant effect for Nucala, but in Metreo (which enrolled only high blood eosinophil patients), the effect size didn’t reach statistical significance, although the point estimates for a 100mg dose of the drug in both trials was fairly consistent.

"Notably, in METREO, a 300mg dose had a weaker effect size vs. a 100mg dose, which may have warranted further questions from the regulator."