Cytokinetics Inc. announced the presentation of exploratory analyses of data from EMPOWER, a Phase 3 clinical trial of dexpramipexole in patients with ALS, which demonstrated the rate of decline of slow vital capacity (SVC) predicts the risk of meaningful clinical events, including a decline in the three respiratory questions of the ALSFRS-R, as well as the time to the first occurrence of respiratory insufficiency, tracheostomy or death. Data from placebo-treated patients in EMPOWER were provided to Cytokinetics by Knopp Biosciences. The analyses were presented recently at the 6th Annual California ALS Research Summit in La Jolla, California.

To better understand the relationship of decline in SVC to the decline in other measures of respiratory function in ALS, investigators analyzed data from placebo-treated patients in EMPOWER. The objective of the study was to investigate the natural history of SVC decline to determine what demographic variables impact decline in SVC and how changes in SVC predict other clinically meaningful events in ALS. Key findings from the analyses of data from EMPOWER include: The overall slope of decline in percent predicted SVC from baseline through the follow-up period of 1.5 years was -0.090 percentage points per day (2.73 percentage points per month).

Older subjects (greater than 65) had a steeper slope of decline in SVC (-0.12 percentage points per day), as did subjects with baseline ALSFRS-R less than 39 (-0.10 percentage points per day). A slowing in the decline in SVC by 0.05 percentage points per day from baseline to the month 6 visit predicted reduction in risk by 19% of any decline in the respiratory subdomain of ALSFRS-R or death; by 22% for the first onset of respiratory insufficiency or death; by 23% for first occurrence of tracheostomy or death; and by 23% for death at any time after the month 6 visit (p < 0.0001 for all).