RESCUE-ALS was a Phase 2 randomized, double-blind, placebo-controlled study of CNM-Au8 in early sporadic ALS, with an ongoing open-label extension (OLE) to evaluate the long-term safety and efficacy of CNM-Au8. CNM-Au8 is a suspension of clean-surfaced, catalytically active gold nanocrystals shown to enhance neuronal metabolic energy, reduce oxidative stress, and improve protein homeostasis.
Study participants were randomized 1:1 to receive 30mg CNM-Au8 or placebo daily for 36-weeks during the double-blind portion of the study, followed by an OLE with CNM-Au8 (30mg/day). The trial enrolled 45 participants [n=23 active (CNM-Au8), n= 22 matched placebo)].
During the 36-week double-blind period, 96% of CNM-Au8 treated participants completed, with one mortality event in the active-treatment arm (4%). Amongst placebo-treated participants, 86% completed with two mortality events and one withdrawal due to ALS disease worsening (14% death or withdrawal). Of the participants who completed the double-blind portion, one subject (active) was ineligible for the OLE due to relocation from Australia, and four elected not to continue in the OLE (1 active, 3 placebo) resulting in 90% of eligible participants entering the OLE.
Long-term observed survival across the entire study population from randomization through the latest OLE observation was compared to predicted median survival derived from the published ENCALS model based on each participant’s baseline study characteristics. Data were censored at either last study contact or as of the date of this submission (31-December-2021). Kaplan-Meier analyses showed a significant survival benefit with CNM-Au8 treatment, resulting in 61% decreased risk of death versus predicted, log-rank hazard ratio = 0.39 (95% CI: 0.17 to 0.89, p=0.026). CNM-Au8 treatment was well-tolerated and there were no significant safety findings reported during the OLE.
These results demonstrate improved survival with CNM-Au8 treatment compared to estimated median survival derived from the ENCALS prediction model.