The US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have provided a clear path forward for Mereo BioPharma’s investigational oral neutrophil elastase inhibitor, alvelestat (MPH-966).

The regulatory feedback followed end-of-phase 2 meetings regarding the alvelestat program for the treatment of alpha-1 antitrypsin deficiency (AATD)-associated lung disease (AATD-LD).

“We are very pleased with the feedback from our meetings with both the FDA and EMA, and grateful for the thorough guidance each agency provided and the clear path forward that the Agencies have each outlined for alvelestat,” said Denise Scots-Knight, PhD, chief executive officer of Mereo, in a press release.

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Based on clear recommendations from both agencies, Mereo is designing a single, global, phase 3 study evaluating alvelestat (240 mg) versus placebo at 12 to 18 months in patients with AATD-LD.

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The proposed phase 3 study will have 2 primary endpoints that have been shown to be associated with reductions in AATD biomarkers: a patient-reported outcome (PRO) and lung density measured by computerized tomography (CT) scan, as guided by the FDA and EMA, respectively.

“We believe this is the first time a proposed registrational study in AATD-LD will use both a patient-reported outcome approach, and an objective clinical outcome measure of lung density measured by CT scan as independent primary endpoints, allowing for a clinical trial with a reasonable number of patients conducted over a manageable timeframe. We believe this represents a significant step forward in the development of new therapies for AATD-LD, and we look forward to further collaboration with both agencies as we refine the phase 3 study design to support alvelestat’s continued efficient clinical development and its timely availability for patients,” said Dr. Denise.

The results of the proposed phase 3 study aim to support applications for full approval of alvelestat in both the US and EU.


Mereo BioPharma provides regulatory updates on alvelestat for the treatment of alpha-1-antitrypsin deficiency-associated lung disease. News release. Mereo BioPharma Group; March 21, 2023.