Patients with relapsing multiple sclerosis (MS) treated with intravenous ublituximab had fewer relapses and brain lesions compared with those treated with oral teriflunomide, although both therapies resulted in similar rates of worsening disability, according to results of the two identical phase 3 ULTIMATE I and II trials.
“In these two 96-week trials involving participants with MS, annualized relapse rates were lower with intravenous ublituximab than with oral teriflunomide. Ublituximab was associated with infusion-related reactions. Larger and longer trials are required to determine the efficacy and safety of ublituximab in patients with relapsing MS, including comparison with other disease-modifying treatments such as existing anti-CD20 monoclonal antibodies,” noted lead author Lawrence Steinman, MD, professor of neurology and neurological sciences, pediatrics, and genetics at Stanford (Calif.) University, and colleagues.
Dr. Lawrence Steinman
The results, published in the New England Journal of Medicine, pave the way for ublituximab’s approval as the third high-efficacy anti-CD20 monoclonal antibody to treat relapsing forms of MS, predicted Patricia Coyle, MD, director of the MS Comprehensive Care Center, and professor of neurology, at Stony Brook (N.Y.) Neurosciences Institute, who was not involved in the research. Ublituximab will “widen the anti-CD20 monoclonal choices for MS, and should directly compete with ocrelizumab and ofatumumab,” she said.
Two trials
The double-blind, double-dummy ULTIMATE I and II trials enrolled 549 and 545 participants respectively, with a median follow-up of 95 weeks. Subjects, aged between 18 and 55 years, were randomized to receive either oral placebo and intravenous ublituximab (150 mg on day 1, followed by 450 mg on day 15 and at weeks 24, 48, and 72), or oral teriflunomide (14 mg once daily) and intravenous placebo. The primary endpoint was the annualized relapse rate, defined as the number of confirmed MS relapses per participant-year, with a range of secondary end points including number of lesions on magnetic resonance imaging (MRI) by 96 weeks, and worsening of disability confirmed at 12 weeks.
Prevention and management of infusion-related reactions was with oral antihistamine and dexamethasone, administered 30 to 60 minutes before each intravenous dose of ublituximab or placebo, as well as reductions in infusion flow rates and discretionary acetaminophen.
Results for the primary endpoint in ULTIMATE I showed the adjusted annualized relapse rate over a period of 96 weeks was 0.08 in the ublituximab group and 0.19 in the teriflunomide group (rate ratio, 0.41; P < .001). Corresponding rates for ULTIMATE II were 0.09 and 0.18 (rate ratio, 0.51; P = .002).
The mean number of lesions in both ublituximab arms of the trials was 0.02 and 0.01 compared with 0.49 and 0.25 in the teriflunomide arms (rate ratios 0.03 and 0.04 respectively; P < .001 for both).
Similar disability worsening in both groups
A pooled analysis of the two trials showed worsening disability in 5.2% of the ublituximab group, and 5.9% of the teriflunomide group (hazard ratio, 0.84; P = 0.51). “In both trials, teriflunomide was associated with a numerically lower rate of worsening of disability than that reported in previous studies with this drug, but no conclusions can be drawn from these comparisons,” noted the authors.
Infusion-related reactions occurred in 47.7% of the participants in the ublituximab group, consisting mainly of mild to moderate pyrexia, headache, chills, and influenza-like illness. “The reactions may have been related to cytokine release from immune cells (B and NK cells) on interaction of the Fc antibody domain with Fc gamma receptors on effector cells,” they suggested.
Although no opportunistic infections occurred, a higher frequency of infections, including serious infections, was observed with ublituximab (5.0%) than with teriflunomide (2.9%).
While the ULTIMATE trials showed no difference between ublituximab and teriflunomide in confirmed worsening of disability, only a small percentage of participants in either arm showed deterioration, Dr. Coyle remarked. “In a relatively short trial (96 weeks), in a relapsing population on active treatment, this result was not surprising … If the study was bigger, or longer it would increase the chances of seeing a progressive slow worsening component to affect the EDSS [Expanded Disability Status Scale],” she added.
Equivalent efficacy
Ultimately, “it appears likely” that ublituximab is “equivalent in efficacy” to the earlier anti-CD20 agents ocrelizumab and ofatumumab, Dr. Coyle said. While all three agents target B-cells, “ublituximab targets a novel CD20 binding site, and is bioengineered to have a particularly potent antibody dependent cell cytotoxicity lysis mechanism,” she added. “It has been touted to ultimately allow a short infusion of 1 hour.”
Although the serious infection rate is slightly higher with ublituximab (5.0% vs. 2.5% for ofatumumab, and 1.3% for ocrelizumab), “it is still low,” and infusion-related reactions are also higher with ublituximab, she added (47.7% vs. 20.2% and 34.3%, respectively). She suggested factors that might influence which treatment is chosen for a given patient might include cost, convenience, whether it is more or less likely to cause low IgG, interference with vaccination, or influence on cancer or COVID risk.
The trials were supported by TG Therapeutics.
Dr. Coyle has received consulting fees from Accordant, Biogen, Bristol Myers Squibb, Celgene, Genentech/Roche, GlaxoSmithKline, Horizon, Janssen, Novartis, Sanofi Genzyme, and Viela Bio and grant funding from Actelion, Alkermes, Bristol Myers Squibb, CorEvitas LLD, Genentech/Roche, Sanofi Genzyme, MedDay, NINDS, and Novartis.