Background: Axonal degeneration has been recognized as a key early contributor to the clinical presentation and pathogenesis of amyotrophic lateral sclerosis (ALS). Activation of the calcium-dependent cysteine protease calpain-2 is considered a critical effector of axonal degeneration. Based on evidence supporting a potential benefit of calpain-2 modulation in ALS and other neurodegenerative diseases, Amylyx developed AMX0114, an antisense oligonucleotide (ASO) inhibitor of calpain-2. This phase 1 study will assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of AMX0114 in people with ALS. Methods: LUMINA is planned to be conducted at ~15 sites in North America enrolling approximately 48 participants randomized 3:1 to receive AMX0114 or placebo. After study completion, an open-label extension study of AMX0114 will be implemented if data supports a positive benefit-risk profile. Results: The primary endpoints of the study include the incidence of adverse events (AEs), serious AEs, and dose-limiting toxicities. Secondary and tertiary endpoints include PK measurements (plasma and cerebrospinal fluid [CSF] levels of AMX0114), PD biomarkers, and functional measures of ALS progression. Conclusions: LUMINA is a first-in-human study evaluating the safety, tolerability, PK, and PD of AMX0114, the first ASO targeting calpain-2 in adult participants with ALS. Enrollment is planned to begin in Canada in early 2025.