A Study of TCD601 (Siplizumab) in Newly Diagnosed Adult Amyotrophic Lateral Sclerosis (ALS) Patients

Key Who May Qualify: - Male or female patients ≥ 18 to 80 years of age. - Diagnosis of ALS by revised El Escorial Criteria, at study entry within 24 months of first symptoms. - Patients on existing ALS treatment must have been on a stable dose for 28 days. Key Who Should NOT Join This Trial: - Patient with severe systemic infections, current or within the two weeks prior to randomization. - Subjects who, in the opinion of the investigator, are not capable of giving willing to sign a consent form for the study or who are unable or unwilling to adhere to the study requirements outlined in the protocol. - Use of other investigational products or treatment in another investigational drug study within 30 days of screening - Pregnant or nursing (lactating) women. Always talk to your doctor about whether this trial is right for you.