Phase 2 Data from “ASTRAEUS” Trial of Mereo BioPharma’s Alvelestat in Alpha-1 Antitrypsin Deficiency-associated Lung Disease Presented at the 2023 American Thoracic Society International Conference

LONDON, May 23, 2023 (GLOBE NEWSWIRE) -- Mereo BioPharma Group plc (NASDAQ: MREO), (“Mereo” or “the Company”), a clinical-stage biopharmaceutical company focused on rare diseases today announced that data from the Phase 2 “ASTRAEUS” trial of alvelestat for the treatment of Alpha-1 Antitrypsin Deficiency-associated Lung Disease (AATD-LD), as well as post-hoc analyses demonstrating the association between biomarker reductions with alvelestat and improvements in SGRQ, a key Patient-Reported Outcome (PRO) measure, were presented for the first time to the scientific community at the 2023 American Thoracic Society International Conference. The ASTRAEUS data were presented during an oral abstract session on novel treatments and targets by Prof. Robert Stockley, Lung Investigation Unit, University of Birmingham (United Kingdom) and Chief Investigator of the ASTRAEUS trial, while the post-hoc analyses were presented in a poster session by Dr. Jackie Parkin, Senior Vice President and Therapeutic Head at Mereo.

Consistent with previously reported biomarker analyses, alvelestat demonstrated significant and consistent reductions in all three biomarkers related to AATD-LD disease activity: blood neutrophil elastase (NE), Aα-val³⁶⁰ and the elastin breakdown product, desmosine. Low - and high-dose alvelestat significantly suppressed NE activity compared to baseline (-83.5% and -93.3%, p=0.023 and p<0.001 respectively) and versus placebo (p=0.001 and p<0.001). In the high dose arm, Aα-val³⁶⁰ and desmosine progressively decreased from baseline, -22.7% (p=0.004) and -13.2% (p=0.045) respectively, with significant reductions compared to placebo as well (p=0.001 and p=0.041). The low dose did not generate consistent changes in Aα-val³⁶⁰ or desmosine.

Based on these data, Mereo is completing preparatory work for a single pivotal Phase 3 study evaluating the high dose of alvelestat (240mg), which, if successful, is expected to support submissions for full regulatory approvals in both the U.S. and EU. The planned study will have two independent primary endpoints, based on the recommendations of the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA): i) a Patient-Reported Outcome (PRO) expected to be change from baseline in the SGRQ-Activity Domain score, as guided by the FDA, and ii) lung density measured by CT scan, as guided by the EMA. In line with previous guidance, Mereo is continuing to explore potential partnerships to fund the Phase 3 development of alvelestat.