Inclusion Criteria

Patients who meet all the following criteria may be included in the study:

• Able to comprehend and willing to sign an Informed Consent Form (ICF).
• Males or females between the ages of 18 and 80 years of age, inclusive.
• Diagnosis of familial or sporadic ALS (defined as meeting the possible, laboratory-supported probable, probable, or definite criteria for a diagnosis of ALS according to the World Federation of Neurology El Escorial criteria published in 2000 (Brooks, Miller et al. 2000) ≤ 24 months prior to screening.
• Upright SVC ≥ 60% of predicted for age, height and sex at screening.
• Able to swallow tablets.
• A caregiver (if one is needed).
• Able to perform reproducible pulmonary function tests.
• Pre-study clinical laboratory findings within the normal range or, if outside the normal range, deemed not clinically significant by the Investigator.
• Male patients, who have not had a vasectomy and a confirmed zero sperm count, must agree after receiving the first dose of study drug until 10 weeks after the last dose to do either of the following:
  • use a condom during sexual intercourse with female partners who are of reproductive potential AND to have female partners use an additional effective means of contraception (e.g., diaphragm plus spermicide, or oral contraceptives); or
  • abstain from sexual intercourse.
• Female patients must be post-menopausal (≥ 1 year) OR sterilized, OR if of childbearing potential (i.e., females who have had their first period unless they are anatomically and physiologically incapable to become pregnant), must:
  • not be breastfeeding;
  • have a negative pregnancy test;
  • have no intention of becoming pregnant during the course of the study, AND do either of the following:
    • use contraceptive drugs or devices as detailed in item number 9 from Screening until 10 weeks after the last dose of study drug and require male partners to use a condom during sexual intercourse; or
    • abstain from heterosexual intercourse from Screening until 10 weeks after the last dose of study drug.
• Patients must be either on riluzole for at least 30 days prior to screening or have not taken riluzole for at least 30 days prior to screening and not planning to start riluzole during the course of the study.
• Patients on edaravone must have completed at least 2 cycles of dosing with edaravone at the time of screening or have not taken edaravone for at least 30 days prior to screening and not planning to start edaravone during the course of the study. Two cycles of dosing are defined as having completed Cycle 1 infusion, which is 14 consecutive days of intravenous (IV) edaravone followed by 14 days off edaravone, and Cycle 2, which is 10 out of 14 days of IV edaravone.

Exclusion Criteria

Any of the following will exclude potential patients from the study:

• At the time of screening, any use of non-invasive ventilation, e.g. continuous positive airway pressure, noninvasive bi-level positive airway pressure or noninvasive volume ventilation, for any portion of the day, or mechanical ventilation via tracheostomy, or on any form of oxygen supplementation.
• Neurological impairment due to a condition other than ALS.
• Presence at screening of any medically significant cardiac, pulmonary, gastrointestinal, musculoskeletal, or psychiatric illness that might interfere with the patient’s ability to comply with study procedures or that might confound the interpretation of clinical safety or efficacy data, including, but not limited to:
  • A pulse <40 or >100 bpm; mean systolic blood pressure >180 mm Hg; mean diastolic blood pressure >100 mm Hg (based on measurements taken after rest for 3 minutes) that persist on 3 successive measurements taken at least 2 minutes apart;
  • Clinically significant ECG abnormalities that require medical attention (i.e., persistent atrioventricular conduction block >first degree, or acute myocardial ischemic changes);
  • New York Heart Association Class II or greater congestive heart failure;
  • Chronic obstructive pulmonary disease or asthma requiring daily use of bronchodilator medications;
  • Gastrointestinal disorder that is likely to impair absorption of study drug from the gastrointestinal tract;
  • ALT or aspartate aminotransferase (AST) greater than or equal to 3-times the upper limit of normal (ULN) or has total bilirubin (TBL) greater than or equal to 2-times the ULN at screening. These assessments may be repeated at the Investigator’s discretion (within the screening window);
  • Poorly controlled or brittle diabetes mellitus;
  • Amputation of a limb;
  • Cognitive impairment, related to ALS or otherwise, sufficient to impair the patient’s ability to understand and/or comply with study procedures and provide informed consent;
  • Cancer with metastatic potential (other than basal cell carcinoma, carcinoma in situ of the cervix, or squamous cell carcinoma of the skin excised with clean margins) diagnosed and treated within the last five years;
  • Any other condition, impairment or social circumstance that, in the opinion of the Investigator, would render the patient not suitable to participate in the study;
  • Patient judged to be actively suicidal or a suicide risk by the Investigator;
  • Patient has estimated glomerular filtration rate (eGFR) less than 40 mL/min/1.73 m2 calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin equation based on a cystatin C measurement at baseline. 
• Has taken any investigational study drug within 30 days or five half-lives of the prior agent, whichever is longer, prior to dosing.
• Known to have received CK-2127107 or tirasemtiv in any previous clinical trial.
• Has received or is considering receiving during the course of the study any form of stem cell therapy for the treatment of ALS.
• Has received or is considering receiving during the course of the study any form of gene therapy for the treatment of ALS.
• Has received or is considering obtaining during the course of the study a diaphragmatic pacing system.
• History of substance abuse within the past 2 years.
• Use of a strong cytochrome P450 (CYP) 3A4 inhibitor within 7 days prior to first dose of study drug or a strong CYP3A4 inducer within 14 days prior to first dose of study drug.
• Use of a medication that is an OCT1/OCT2 substrate within 7 days (see Appendix B)