In this study, we aim to validate the exploratory findings of the meta-analysis and confirm the potential of lithium carbonate to prolong the time to death or respiratory insufficiency in patients with ALS homozygous for the C-allele at SNP rs12608932 in UNC13A. We will initiate a group-sequential, placebo-controlled, event-driven design to generate confirmatory evidence and minimize the exposure of patients to potentially ineffective treatment arms. This evidence concerns the gene UNC13A and Respiratory insufficiency.