No new safety signals in ofatumumab open-label data

Only a few weeks prior to the MSVirtual 2020, the fully human anti-CD20 monoclonal antibody ofatumumab was approved by the FDA for the treatment of relapsing forms of MS. In the open-label extension study ALITHIOS, ofatumumab's very good safety profile was consistent with data from the core phase 3 ASCLEPIOS I/ASCLEPIOS II trials [1,2].

The indication of ofatumumab is to include clinically isolated syndrome (CIS), relapsing-remitting MS, and active secondary progressive MS in adults. In the ASCLEPIOS trials, ofatumumab demonstrated superior efficacy versus teriflunomide and a favourable safety profile in relapsing-remitting MS patients [2]. Long-term safety data continues to be collected from the open-label phase 3b ALITHIOS extension study.

The overall safety data of all participants in ALITHIOS was reported [1]. This data included 1,230 patients who were randomised to ofatumumab in the core phase 2 APLIOS (12 weeks) or phase 3 ASCLEPIOS I/II (up to 30 months) trials and continued in ALITHIOS, or completed/discontinued the core study and continued the safety follow-up; and 643 patients who were randomised to teriflunomide in ASCLEPIOS I/II and switched to ofatumumab in ALITHIOS.

The overall exposure was 2,118 patient-years.

The most frequently reported adverse events (AEs) were injection-related reactions and upper respiratory tract infections. Most AEs were mild to moderate in severity; the incidence of AEs, serious AEs, or grade 3/4 AEs did not increase in either group. There were no deaths. The overall safety profile was consistent with reports from the core ASCLEPIOS I/II trials. In the newly switched group, injection-related reactions were mild to moderate; none were serious or led to treatment discontinuation. Concerning AEs of special interest: there were no opportunistic infections, hepatitis B reactivation, or progressive multifocal leukoencephalopathy (PML) events. There were no new cases of malignancies in the continuous or newly switched patients either.

1. Cross AH, et al. Safety experience with extended exposure to ofatumumab in patients with relapsing multiple sclerosis from Phase 2 and 3 clinical trials. MSVirtual 2020, P0234.
2. Hauser SL, et al. N Engl J Med. 2020;383:546–57.

Posted on 25 November 202025 March 2024