A Master Protocol (OLMP): A Study of LY4256984 in Participants With Amyotrophic Lateral Sclerosis (ALS)

Participants must meet eligibility criteria below. Additional criteria are specified in the substudy to which the participant will enroll. Inclusion Criteria: * Have completed an eligible parent study, as determined by the investigator. Eligible parent studies will be defined by the sponsor but will be clinical studies designed to evaluate a study intervention for the treatment of ALS. * Note 1: To be considered a "completer" of a parent study, the participant must finish the main treatment period/phase of the parent study as well as any off-treatment period/phase as described in the parent study's protocol. * Note 2: Visits missed in a parent study will have no impact on the completer status of a potential participant. Exclusion Criteria: * During the parent study, the participant permanently or temporarily discontinued the investigational medicinal product (IMP), such that restarting the IMP would pose an unacceptable risk to the participant's safety, in the opinion of the investigator. * During the parent study, the participant experienced extreme ALS disease progression (for example, permanent mechanical ventilation) that poses an unacceptable risk to the participant's safety in the opinion of the investigator. * During the parent study, the participant developed an unresolved SAE or a medical illness (other than ALS) that, in the opinion of the investigator, precludes either continued exposure to an IMP or participation in study procedures due to an unacceptable risk to the participant's safety.