Phase 2 Study for SAR443820 in Participants With Amyotrophic Lateral Sclerosis (ALS)

This was a parallel treatment, Phase 2, randomized, double-blind study to assess the efficacy, safety, tolerability, PK, and PD of twice daily (BID) oral SAR443820 compared with placebo in male and female participants, 18 to 80 years of age with ALS followed by an open-label, long-term extension period. Study ACT16970 consisted of 2 parts (A and B) as follows: Part A was a 24-week, double blind, placebo-controlled part, preceded by a screening period of up to 4 weeks before Day 1. On Day 1 of Part A, participants were randomized in a 2:1 ratio to the SAR443820 treatment arm or matching placebo arm as listed below: * Treatment arm: SAR443820, BID * Placebo arm: Placebo, BID Randomization was stratified by the geographic region of the study site, region of ALS onset (bulbar vs other areas), use of riluzole (yes vs no), use of edaravone (yes vs no) and use of the combination of sodium phenylbutyrate and taurursodiol (named Relyvrio in the United States of America \[USA\] and Albrioza in Canada) (yes vs no). Participants attended in-clinic study assessments at baseline (Day 1), Week 2, Week 4, Week 6, Week 8, Week 10, Week 12, Week 16, Week 20, Week 21, Week 22, Week 23, and Week 24. All ongoing participants at Week 24 rolled to open-label extension Part B. The Week 24 Visit was the end of Part A and the beginning of Part B. Part B was an open-label, long-term extension period that starts from Week 24 and continues up to Week 106. The objectives of Part B were to provide extended access to SAR443820 participants in Part A and to further evaluate the safety and efficacy of long-term SAR443820 treatment. The treatment assignment of participants at randomization in Part A remained blinded to Investigators, participants, and site personnel until the end of Part B. Every participant, except those who discontinued Investigational Medicinal Product (IMP) treatment permanently in Part A, received BID oral tablets of SAR443820 in Part B.