A Study for Patients Who Completed VITALITY-ALS (CY 4031)

Enrolled participants will begin dosing of tirasemtiv 125 mg twice daily (250 mg/day) for a
period of 4 weeks and will titrate to their tolerated dose, the maximum dose being 250 mg
twice daily (500 mg/day). This study will also compare the clinical course of patients who
completed treatment with tirasemtiv in CY 4031 with those who completed treatment with
placebo in CY 4031 during continued treatment of both groups with tirasemtiv during CY 4033,
compare the clinical course of patients who completed treatment with tirasemtiv in CY 4031
during that study with their clinical course during continued treatment with tirasemtiv
during CY 4033, and compare the clinical course of patients who completed treatment with
placebo in CY 4031 during that study with their clinical course during treatment with
tirasemtiv during CY 4033.

Inclusion Criteria:

- Able to comprehend and willing to sign an Informed Consent Form (ICF). If verbal
consent is given, a Legal Designee of the patient must sign the ICF form

- Completed participation on study drug and the Follow-Up Visit in the CY 4031 study

- Male patients, who have not had a vasectomy AND confirmed zero sperm count, must agree
for the duration of their participation in the study to either:

- Use a condom during sexual intercourse with female partners who are of
childbearing potential AND to have female partners use a highly effective means
of contraception OR

- Abstain from sexual intercourse during participation in the study

- Female patients who are not post-menopausal (≥ 1 year) or sterilized, must:

- Not be breastfeeding

- Have a negative pregnancy test

- Have no intention to become pregnant during participation in the study AND

- Practice sexual abstinence, defined as refraining from intercourse during the
duration of the study OR if male partners are not vasectomized with a confirmed
zero sperm count, require use of a condom AND use of a highly effective
contraceptive measure

Exclusion Criteria:

- Has a diaphragm pacing system (DPS) at study entry or anticipate DPS placement during
the course of the study

- Has taken an investigational study drug (other than tirasemtiv) prior to dosing,
within 30 days or five half-lives of the prior agent, whichever is greater

- Use of tizanidine and theophylline-containing medications during study participation

- Participation or planning to participate in any form of stem cell therapy for the
treatment of ALS or another investigational drug