Shorter infusion time of ocrelizumab: Results from the randomized, double-blind ENSEMBLE PLUS substudy in patients...

Ocrelizumab is an approved intravenously administered anti-CD20 antibody for multiple sclerosis (MS). Shortening the 600 mg infusion to 2 hours reduces the total site stay from 5.5-6 hours (approved infusion duration including mandatory pre-medication and post-infusion observation) to 4 hours. The safety profile of shorter-duration ocrelizumab infusions was investigated using results from ENSEMBLE PLUS.

ENSEMBLE PLUS is a randomized, double-blind substudy to the single-arm ENSEMBLE study (NCT03085810). In ENSEMBLE, patients with early-stage relapsing-remitting MS received ocrelizumab 600 mg infusions every 24 weeks for 192 weeks. In ENSEMBLE PLUS, ocrelizumab 600 mg administered over the approved 3.5-hour infusion time (conventional duration) is compared with a 2-hour infusion (shorter duration); the durations of the initial infusions (2×300 mg, 14 days apart) were unaffected. The primary endpoint was the proportion of patients with infusion-related reactions (IRRs) following the first Randomized Dose.

From November 1, 2018, to December 13, 2019, 745 patients were randomized 1:1 to the conventional or shorter infusion group. At the first Randomized Dose, 99/373 patients (26.5%) in the conventional and 107/372 patients (28.8%) in the shorter infusion group experienced IRRs. The majority of IRRs were mild or moderate; >99% of all IRRs resolved without sequelae in both groups (conventional infusion group, 99/99; shorter infusion group, 106/107). No IRRs were serious, life-threatening, or fatal. No IRR-related discontinuations occurred. During the first Randomized Dose, 22/373 (5.9%) and 39/372 (10.5%) patients in the conventional and shorter infusion groups, respectively, had IRRs leading to infusion slowing/interruption. Adverse events were consistent with the known safety profile of ocrelizumab.

The rates and severity of IRRs were similar between conventional and shorter infusions. No new safety signals were detected. Shortening the infusion time to 2 hours reduces the total site stay time (including mandatory pre-medication/infusion/observation) from 5.5-6 hours to 4 hours, and may reduce patient and site staff burden. A short video summarizing the key results is provided in supplemental material.