Two randomised controlled phase 2 studies of the oral neutrophil elastase inhibitor alvelestat in alpha-1 antitrypsin...

Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder that causes emphysema from lack of the alpha-1 antitrypsin (AAT) serpin antiprotease, leading to protease-antiprotease imbalance. Weekly intravenous AAT therapy (augmentation) is the only specific treatment available. Alvelestat is an oral inhibitor of neutrophil elastase (NE) in development as a novel approach to AATD therapy. Here, we tested the safety and mechanistic efficacy of alvelestat in severe AATD.

We conducted two complementary, double-blind, randomised, placebo-controlled, 12-week trials, incorporating two doses of alvelestat in AATD. ATALANTa investigated 120 mg twice daily, including a subset of participants also receiving augmentation; ASTRAEUS tested 120 and 240 mg twice daily without augmentation. Primary and secondary end-points were the change in blood NE (the putative target) and its activity in AATD (Aα-Val³⁶⁰ and desmosine/isodesmosine) as well as safety and tolerability.

We enrolled 161 participants (63 in ATALANTa and 98 in ASTRAEUS). Blood NE was significantly suppressed in both studies at both doses, with the greatest effect (>90% suppression) at alvelestat 240 mg twice daily. There was no effect of alvelestat 120 mg on disease activity biomarkers, while 240 mg demonstrated significant reduction in Aα-Val³⁶⁰ and desmosine. The most common adverse event was headache, particularly at the 240 mg dose. No safety signals of concern were detected.

Alvelestat effectively suppressed NE and its activity at both doses, but only the 240 mg twice-daily dose demonstrated relevant efficacy compared to placebo on disease activity biomarkers with a favourable safety profile. These findings support progression of the 240 mg twice-daily dose into a clinical end-point study.