Inclusion Criteria:

1. Male and female patients ≥18 years of age with Sporadic or familial ALS. In Part 1, patients must have a risk of ALS progression characterized by a European Network for the Cure of ALS (ENCALS) risk profile score ≥ -6 and ≤ -3. In Part 2 patients must have a risk of ALS progression characterized by an ENCALS risk profile score ≥ -7 and ≤ -3.
2. If taking riluzole, edaravone, and/or sodium phenylbutyrate and taurursodiol, must be on a stable dose prior to Screening. Sodium phenylbutyrate and taurursodiol are not permitted for patients enrolled in Part 2 of the study.
3. Part 2 only: Patients with a pathogenic mutation in superoxide dismutase 1 gene (SOD1) must not be receiving treatment with tofersen or eligible for treatment with tofersen if available. Patients who have received prior treatment with tofersen and discontinued due to safety and/or efficacy reasons prior to Screening are eligible.
4. Part 2 only: Use of ultra high-dose methylcobalamin for the treatment of ALS is permitted provided the patient has been on a stable dose for ≥11 weeks prior to the Day 1 visit.

Exclusion Criteria:

1. History of a clinically significant non-ALS neurologic disorder
2. Inability to swallow capsules.
3. Blood platelet count <150,000/mm^3.
4. Renal impairment indicated by Estimated Glomerular Filtration Rate (eGFR) ≤30 mL/min/1.73 m^2. Part 2 only: Patients with a recent history of acute kidney injury should have returned to their baseline renal function prior to enrollment.
5. Human immunodeficiency virus (HIV) or current chronic/active infection with hepatitis C virus or hepatitis B virus. Part 2 only: Known history of HIV or chronic/active infection with hepatitis C or hepatitis B virus; testing does not need to be performed if infection status is unknown.
6. Women who are pregnant, planning to become pregnant, or are breastfeeding.
7. Use of non-invasive ventilation (NIV) or mechanical ventilation via tracheostomy, or on any form of oxygen supplementation.
8. Current or anticipated need of a diaphragm pacing system (DPS).
9. Currently using glucocorticoids or have a history of regular systemic glucocorticoid use within the last 12 months.
10. Previous exposure or treatment with glucocorticoid receptor modulators or antagonists.