An Open-Label Immunogenicity and Pharmacokinetics Study of Daclizumab High Yield Process Prefilled Syringe in Relapsing Remitting Multiple Sclerosis

Following a screening period, participants will receive DAC HYP over a 24-week treatment period (6 monthly injections) and then enter a 20-week washout period for assessment of immunogenicity, PK, pharmacodynamics, safety, and tolerability. The 20-week washout is necessary to ensure measurement of anti-DAC HYP binding antibodies (ADAbs) and neutralizing antibodies (NAbs) in the absence of drug interference. After washout, the participants may resume monthly treatment with DAC HYP 150 mg for an additional 3 years. All participants will be followed for 6 months after their last dose for safety monitoring. Additionally, two sub-studies will be performed: (1) an intensive serial PK sampling performed over the first and last dosing interval following DAC HYP doses administered at week 0 and at week 20, and (2) a therapeutic protein-drug interaction (TP-DI) sub-study, during which a probe drug cocktail will be administered at weeks 43 and 53 followed by serial probe-drug PK sampling up to 96 hours after probe-drug administration. A maximum of 20 participants will be enrolled in the TP-DI sub-study.