A Study of GDC-0134 to Determine Initial Safety, Tolerability, and Pharmacokinetic Parameters in Participants With Amyotrophic Lateral Sclerosis

Inclusion Criteria:

- Male or female participants with a diagnosis of possible, laboratory-supported
probable, probable, or definite ALS according to modified El Escorial criteria

- Upright forced vital capacity of at least 50 percent (%)

- Ability to fast from food for 8 hours prior to dosing and 2 hours after dosing

Exclusion Criteria:

- Currently taking riluzole unless on a stable dose for the 3 months prior to Day -1 and
without current liver enzyme or liver function abnormalities

- Currently taking edaravone unless after completion of at least the second 14-day
drug-treatment period, as long as Day 1 occurs during a drug-free period at least 24
hours after the last edaravone dose and at least 5 days prior to the first dose of the
next cycle

- Positive for hepatitis C antibody, hepatitis B surface antigen, or human
immunodeficiency virus (HIV) antibody

- Clinically significant thrombocytopenia

- Currently taking nutritional/herbal supplements, except for over-the-counter vitamins
that are within Recommended Dietary Allowance (RDA), unless discontinued at least 7
days prior to Day −1, except upon approval of both the investigator and Sponsor

- For participants participating in a designated drug-drug interaction (DDI) cohort in
the MAD stage of the study, who require midazolam/caffeine administration: known
allergy, religious prohibition, or other condition limiting midazolam or caffeine
administration