In Part A, approximately 24 patients will be randomized to one of four different treatment groups. After a 7-day washout of riluzole, patients in each treatment group will receive daily oral doses of placebo, 125 mg, 250 mg, or 375 mg of CK-2017357 for 14 days. Patients will take daily doses of CK-2017357 or placebo (Day 1 through Day 14) and will return to the study site on Day 2, Day 8 and Day 15. All patients will return for a follow-up visit 7 days (± 2 days) after their last dose.~In Part B, approximately additional 24 patients will be randomized to one of four different treatment groups as in Part A. Patients in Part B will be required to decrease their riluzole dose to 50 mg once a day (QD) for 7 days prior to randomization. After this 7 day period, patients will take riluzole at 50 mg QD concurrently with their morning dose of blinded study drug.
The study will generate data on safety, tolerability and pharmacokinetics after multiple daily doses of CK-2017357 in patients with ALS. Patients will be randomized into one of four different treatment groups, receiving daily oral doses of either placebo, 125 mg, 250 mg, or 375 mg of CK-2017357 for 14 days.