Inclusion Criteria: 

• Written or verbal informed consent is obtained.
• Male or female subjects age 18 to 80 years, inclusive.
• Diagnosis of familial or sporadic AL as defined by the El Escorial-Revised (2000) research diagnostic criteria for ALS [clinically definite, clinically probable, probable-laboratory supported].
• If currently using riluzole, subject must be on a stable dose for at least 30 days prior to initiating study drug.
• 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 initiating study drug.
• If currently using edaravone, subject should have completed the first 14 days of their initial treatment cycle prior to initiating study drug.
• Documented ALS history of location of disease onset (i.e., bulbar onset, limb onset).
• A total ALSFRS-R score of at least 35 overall at screening and:
  • No more than one of the 12 ALSFRS-R individual component items have a score of 1 or less at screening;
  • For limb onset subjects, ALSFRS-R score of ≥ 3 on item #1 (speech), #2 (salivation) and #3 (swallowing).
• ALSFRS-R progression rate from onset of the first symptom of weakness to the ALSFRS-R score at Screening of ≥ 0.3 points and ≤ 1 point per month calculated as:
  • ALSFRS-R score at onset of first symptom of weakness (assume 48) minus ALSFRS-R score at Screening divided by number of months since onset of first symptom of weakness.
• Documented pulmonary function test (PFT) result within the last 6 months (i.e., slow vital capacity or forced vital capacity) must be ≥ 70% of predicted. If subject does not have a documented PFT result within the last 6 months, they will be administered a PFT.
• Female subjects of childbearing potential must use one or more effective methods of contraception throughout the entire study period and for 30 days after study drug discontinuation.
• Male subjects agree to practice contraception (e.g., condom use and contraception by female partner) unless partner is post-menopausal or unable to conceive throughout the entire study period and for 30 days after study drug discontinuation.
• Able to swallow study medication capsules.
• Willing and able to comply with the protocol assessments and visits, in the opinion of the Investigator.
• No known allergies to the study drug or its excipients.
• At clinical sites where the pneumococcal vaccine is available and administered as standard of care, has received pneumococcal vaccine within 6 years prior to starting clinical trial.

Exclusion Criteria;

• Confirmed hepatic insufficiency or abnormal liver function (AST and/or ALT > 3 times the upper limit of normal).
• Currently has a clinically significant psychiatric disorder or dementia which would preclude evaluation of symptoms.
• Has a clinically significant medical condition (other than ALS) including the following: neurological, metabolic, hepatic including clinically significant chronic hepatitis, renal, hematological, pulmonary, cardiovascular, gastrointestinal, urological disorder, central nervous system infection or other active infection including a history of HIV (human immunodeficiency virus) that would pose a risk to the subject if they were to participate in the study or that might confound the results of the study.
• Female subject is lactating, pregnant or planning pregnancy at Screening or Baseline.
• History of malignancy < 5 years prior to signing the informed consent, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
• Resting pulse < 50 bpm, SA or AV block, uncontrolled hypertension, or repeated demonstration of a QTc interval of > 450 ms in males and > 470 ms in females.
• Past or current use of ibudilast.
• Current use or treated with parenteral (intravenous or intramuscular) high-dose (> 25 mg/week) vitamin B12 (i.e., methylcobalamin, hydroxylcobalamin, cyanocobalamin, adenosyl cobalamin) within 30 days prior to study drug administration.
• History of stomach or intestinal surgery or any other condition that could interfere with or is judged by the Investigator to interfere with absorption, distribution, metabolism, or excretion of study drug.
• History of alcohol or substance abuse (DSM-5 criteria) ≤ 3 months prior to screening or alcohol or substance dependence (DSM-5 criteria) ≤ 12 months prior to screening.
• 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.
• Unable to cooperate with any study procedures, unlikely to adhere to the study procedures and keep appointments, in the opinion of the Investigator.
• Use of tracheostomy or > 22/24h ventilatory support.

Eligibility last updated 10/13/21. Questions regarding updates should be directed to the study team contact.