Multiple Doses of AT-1501-A201 in Adults With ALS

A Phase 2a Open-Label, Multi-Center Study to Evaluate the Safety and Tolerability of Multiple Doses of AT-1501 in Adults With ALS

This is a Phase 2a, multi-center, open label, multiple dose study of AT-1501, a humanized monoclonal antibody antagonist to CD40 ligand (CD40L). Approximately 54 adults with Amyotrophic Lateral Sclerosis (ALS) will be enrolled into the study in the United States and Canada at approximately 13 ALS treatment sites.

Participants will be enrolled into one of four ascending doses.

This is a Phase 2a, multi-center, open label, multiple dose study of AT-1501, a humanized monoclonal antibody antagonist to CD40L. Approximately 54 adults with ALS will be enrolled into the study in the United States and Canada at approximately 13 ALS treatment sites.

Four ascending doses of AT-1501 will be administered as an IV infusion to sequentially enrolling cohorts. Each participant will receive 6 bi-weekly (every other week) infusions of AT-1501 over an 11-week period.

The study is estimated to take 19 weeks for participants.

Inclusion Criteria:

1. ALS diagnosed as possible, laboratory supported probable, probable, or definite as defined by revised El Escorial criteria
2. ALS Functional Rating Scale - Revised (ALSFRS-R) Aggregate score of 37 or greater
3. No more than 24 months from diagnosis

Exclusion Criteria:

1. Any other central or peripheral nervous system disease that may interfere with the evaluation of ALS or its progression

2. Presence of a tracheostomy, or use of permanent assistive ventilation (ventilatory support for 23 hours per day or more)

3. History of malignancy within the previous 5 years, except for localized non-melanoma skin cancers

4. Abnormal function of the immune system resulting from:

   • Clinical conditions affecting the immune system (e.g. HIV infection, agammaglobulinemia),
   • Systemic administration of corticosteroids (PO/IV/IM) at a dose equivalent to 20 mg/day of prednisone for more than 14 consecutive days within 90 days prior to screening,
   • Administration of anti-neoplastic and/or immunomodulating agents (e.g. Tumor necrosis factor alpha (TNF α) antagonists or anti-B cell antibodies) or radiotherapy within 1 year prior to screening.

5. Recipient of Stem Cell or Gene Therapy

6. Positive test for Hepatitis B surface antigen, Hepatitis C antibody, or HIV.

7. History of deep venous thrombosis or pulmonary embolism

8. History of active substance abuse within the past 2 years

9. History of stroke, poorly controlled or significant cardiovascular disease, diabetes