Subcutaneous ocrelizumab in multiple sclerosis: Results of the Phase 1b OCARINA I study.

Objective: Subcutaneous ocrelizumab is being developed to provide treatment flexibility and additional choice to patients with multiple sclerosis. OCARINA I (NCT03972306) is an open-label, multicenter, Phase 1b, dose-finding study to investigate the pharmacokinetics, safety, tolerability, and immunogenicity of subcutaneous ocrelizumab and to select a dose for the Phase 3 OCARINA II study (NCT05232825).

Methods: Patients with relapsing or primary progressive multiple sclerosis (aged 18-65 years; Expanded Disability Status Scale score 0.0-6.5) were enrolled into two groups: previously treated with intravenous ocrelizumab (Group A) or naïve to ocrelizumab (Group B). Patients received single ascending doses of subcutaneous ocrelizumab up to 1200 mg. Following dose escalation, new patients in Group A were randomized (1:1) to receive a single 600 mg intravenous ocrelizumab dose or the candidate subcutaneous dose, which was predicted to result in similar exposure as the 600 mg intravenous dose while being safe and well tolerated. The area under the concentration-time curve for both formulations was used to select the subcutaneous ocrelizumab dose. Patients in all cohorts could enter a dose-continuation phase.

Results: Eighty-eight and 47 patients were enrolled into Group A and B, respectively; most patients were female (72.7%/63.0%), and mean age at baseline was 45.7 and 39.7 years, respectively. Subcutaneous ocrelizumab was well tolerated across all doses tested. The 920 mg subcutaneous ocrelizumab dose was selected for the OCARINA II study based on pharmacokinetic and safety data.

Interpretation: Subcutaneous ocrelizumab may provide patients with multiple sclerosis with an additional treatment option.