VMALS-002-2b was a safety extension study following VMALS-002-2, which was a Phase 2a, double-blind, randomized, placebo-controlled, multicenter study designed to assess the safety of intramuscular administration of Engensis in subjects with Amyotrophic Lateral Sclerosis.Following completion of the Day 180 visit in VMALS-002-2 and signing of written informed consent, subjects were enrolled in this approximately 180-day extension study, with subjects completing combined participation with a Day 365 visit. Assessments to be conducted during this extension study were as follows: vital signs, weight and height, complete physical examination, 12-lead electrocardiogram, a record of all concomitant medications and procedures, clinical laboratory assessments, Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, handheld dynamometry, slow vital capacity, Amyotrophic Lateral Sclerosis Assessment Questionnaire, 40 questions, Patient Global Impression of Change, and Clinical Global Impression of Change. Assessments of treatment-emergent adverse events, treatment-emergent serious adverse events, adverse events of special interest, and clinically significant laboratory values continued from the Day 180 visit of Study VMALS-002-2 through the VMALS-002-2b extension study to Day 365.