Subcutaneous ocrelizumab in multiple sclerosis: results of the phase Ib dose-finding OCARINA I study

<h3>Objectives</h3> OCARINA I (NCT03972306) is a Phase Ib, dose-finding study exploring a novel subcutaneous formulation for ocrelizumab relapsing and primary progressive multiple sclerosis (RMS/PPMS), every six months. <h3>Methods</h3> Adult patients with RMS/PPMS were enrolled in two groups: prior ocrelizumab treatment (A) or naïve (B) and received ascending subcutaneous doses (40,200,600,1,200mg) for safety. New patients in group A were randomised 1:1 to a single IV dose or selected SC dose and all patients from both groups could enter a subcutaneous continuation phase from week 24 up to 3 years. <h3>Results</h3> Baseline mean age was 45.7 and 39.7 years in Group A (n=53 SC;n=35 IV) and B (n=46), respectively; 72.7%/63.0% were female. Ocrelizumab SC was well-tolerated across all escalation doses. The candidate dose was 1,200mg and 920mg dose was later selected based on safety, tolerability and pharmacokinetic data. Median subcutaneous treatment duration (1,200mg/920mg) was 96 weeks, with 94.7% receiving ≥3 doses. Injection site reactions were the most common adverse events (all mild/moderate). Additional safety, tolerability, immunogenicity and patient satisfaction data will be reported. <h3>Conclusions</h3> Subcutaneous ocrelizumab 920mg was selected to be investigated in the Phase III OCARINA II study. It was well-tolerated and is expected to provide similar exposure to 600mg IV.