Evaluation of MN-166 (Ibudilast) for 12 Months Followed by an Open-label Extension for 6 Months in Patients With ALS

Major Inclusion Criteria: * Male or female subjects age 18 - 80 years, inclusive; * Diagnosis of familial or sporadic ALS as defined by the El Escorial-Revised (2000) research diagnostic criteria for ALS \[clinically definite, clinically probable, probable-laboratory-supported\]; * ALS onset of ≤18 months from first clinical signs of weakness prior to screening; * If currently using riluzole, subject must be on a stable dose for at least 30 days prior to initiation of study drug; * If currently using edaravone, subject should have completed at least 14 days of their initial treatment cycle prior to initiation of study drug; * Last documented pulmonary function test result (i.e., slow vital capacity or forced vital capacity) must be greater than or equal to 70% predicted; * Able to swallow study medication capsules; * No known allergies to the study drug or its excipients; * Received pneumococcal vaccine within 6 years prior to starting clinical trial. Major Exclusion Criteria: * Confirmed hepatic insufficiency or abnormal liver function (AST and/or ALT \>3 times upper limit of normal); * Currently diagnosed with a clinically significant psychiatric disorder or dementia that would preclude evaluation of symptoms; * Currently use or treated with parenteral (intramuscular or intravenous) high dose (\>25 mg/week) Vitamin B12 within 30 days prior to study drug administration; * Poor peripheral venous access that will limit the ability to draw blood as judged by the Investigator; * Currently participating, or has participated in a study with an investigational or marketed compound or device within 30 days or 5 half-lives, whichever is shorter, prior to signing the informed consent; * Use of tracheostomy or \>22/24-hour ventilatory support.