Task Order 7: Regimen B: Verdiperstat Home Spirometry and Open-Label Extension (OLE) Period

Task Oder 7: Regimen B: Verdiperstat OLE - Platform Trial for the Treatment of Amyotrophic Lateral Sclerosis Regimen-Specific Appendix [B] For verdiperstat (also known as BHV-3241). Rationale and RSA Design The proposed study is based on cumulative preclinical and clinical studies that implicate myeloperoxidase (MPO) activity in the onset and progression of neurodegenerative diseases and suggest treatment with verdiperstat at a dosage of 600 mg twice daily (BID) has the potential to slow neurodegeneration in Amyotrophic Lateral Sclerosis (ALS). Allocation to Treatment Regimens Participants must first be screened under the Master Protocol before they are randomized to an RSA. As soon as pre-defined criteria for futility for the RSA are met, or the target number of randomized participants for the RSA has been reached, enrollment will stop in the RSA. Number of Planned Participants and Treatment Groups The number of planned participants for this regimen is 160. There are 2 treatment groups for this regimen, active and placebo. Participants will be randomized in a 3:1 ratio to active treatment or placebo (i.e., 120 active: 40 placebo). Planned Number of Sites Research participants will be enrolled from approximately 60 centers in the US. Treatment Duration The maximum duration of the placebo-controlled portion is 24 weeks. Follow-up Duration At the conclusion of the 24-week placebo-controlled period of the study, all participants will either schedule a 28-day follow up phone call and end their participation in the regimen or have the option to receive verdiperstat in the open-label extension (OLE) phase of the study. The duration of the OLE phase is planned for 52 weeks. At the completion of the OLE, a Follow-up Safety Call should be conducted approximately 28 days after the last dose of study drug. For participants who withdraw early from the placebo-controlled phase, an in-person Early Termination Visit and a Follow-up Safety Call should be conducted. At the Early Termination Visit the same procedures as described for the Week 24 visit should be conducted. At the Follow-up Safety Call, information on clinical status should be collected. For participants who withdraw early from the OLE, an in-person Early Termination Visit and a Follow-up Safety Call should be conducted. At the Early Termination Visit the same procedures as described for the Week 52 visit should be conducted. At the Follow-up Safety Call, information on clinical status should be collected.