VANCOUVER (FRONTLINE MEDICAL NEWS) – Ocrelizumab, a B-cell depleting humanized monoclonal antibody being developed by Hoffman–La Roche, consistently outperformed interferon beta-1a (Rebif) for relapsing multiple sclerosis in two phase III trials reported at the annual meeting of the American Academy of Neurology.

The identical trials , dubbed OPERA I and OPERA II, each had about 800 patients. Subjects were randomized one-to-one to intravenous ocrelizumab 600 mg every 24 weeks or to subcutaneous interferon beta-1a 44 micrograms three times weekly over 96 weeks. Patients had early disease; a significant portion were naive to multiple sclerosis (MS) treatments.

At 96 weeks, 47.9% and 47.5% of ocrelizumab patients versus 29.2% and 25.1% of interferon patients had no evidence of disease activity (NEDA) in the two studies. NEDA is a composite score defined as no relapses, no confirmed disability progression, and no new or enlarging T2 or gadolinium-enhancing T1 lesions.

Across both studies, relapses occurred in about 20% of ocrelizumab patients versus about 35% of interferon patients. About 10% of ocrelizumab, but about 15% of interferon patients, had clinical disease progression. Similarly, about 10% of ocrelizumab patients developed new gadolinium-enhancing lesions, compared with about 35% in the interferon groups. New or enlarging T2 lesions were found in about 40% in the ocrelizumab groups but in more than 60% in the interferon arms.

After week 24, 96% percent of ocrelizumab patients, compared with 60%-70% on interferon, were free of new or enlarging T2 lesions.

In short, ocrelizumab “resulted in greater achievement of NEDA versus [interferon] over 96 weeks, with elimination of new/enlarging T2 lesions in nearly all patients after week 24,” the researchers concluded.

“These are very impressive numbers,” especially because ocrelizumab was compared with a standard treatment. “There was a wonderful constancy of results” across the trials; “a very highly effective treatment is emerging for multiple sclerosis,” said investigator and presenter Dr. Anthony Traboulsee , a neurologist at the University of British Columbia, Vancouver, who also noted that in many cases, patients opted to stay on ocrelizumab at the end of the trials.

Dr. Traboulsee did not present safety data. A previous report of 24-week results found that infusion reactions were significantly more common with ocrelizumab than with interferon beta-1a (34% vs. 9.7%). Otherwise, there were similar rates of serious adverse events, including serious infections, and there were no cases of progressive multifocal leukoencephalopathy (PML). The PML and infection findings are especially important; Roche shelved earlier attempts to develop the biologic for lupus and rheumatoid arthritis due to serious and opportunistic infections, some of which were fatal.

Roche plans to submit its approval package to the Food and Drug Administration in the first half of 2016; the tentative brand name is Ocrevus. FDA granted the biologic breakthrough, fast-track status for primary progressive MS based on the strength of an earlier phase III trial. At present, there are no MS agents indicated for primary progressive disease.

Patients in OPERA were 37 years old, on average, and two-thirds were women. The mean baseline score on the Extended Disability Status Scale was 2.77, and the mean time since diagnosis was about 4 years. Patients had about 1.5 relapses in the first and second year before entering the studies.

The positive results – and the increasing buzz about ocrelizumab in the MS community – raise the question of how it will fit into the MS armamentarium if it’s approved, which seems likely. A review in Therapeutic Advances in Neurological Disorders tackled the issue in January, before the OPERA results were made public ( 2016 Jan; 9[1]:44-52 ).

It’s unclear if ocrelizumab will become the go-to option when patients progress on first-line agents such as interferon and glatiramer acetate. Phase II data suggest ocrelizumab’s “effect on clinical disease activity [seems] to be of the same magnitude compared with that of fingolimod and natalizumab,” and will likely be an alternative to natalizumab and alemtuzumab. “Ocrelizumab seems to have a more favourable risk–benefit profile compared with natalizumab in JC [John Cunningham] virus antibody–positive patients, whereas natalizumab in JC virus antibody–negative patients appears safer. Hence, ocrelizumab could be an attractive option among second-line therapies in patients who are JC virus antibody positive, whereas natalizumab or alternatively oral fingolimod would be the first choice among second-line therapies in JC virus antibody–negative patients,” said authors Dr. Per Soelberg Sorensen and Dr. Morten Blinkenberg , both MS neurologists at the University of Copenhagen.

“It needs to be emphasized that long-term data on the safety of ocrelizumab in the treatment of MS is warranted, and therefore post-marketing safety programs will be needed.” The risk of PML with long-term use is unknown. “Another unsolved question is whether ocrelizumab therapy should be applied at fixed intervals, e.g. every 6 months [as in OPERA], or if re-treatment should be guided by the recovery of CD19-positive B cells,” they said.

In any case, infusion reactions with ocrelizumab should be less than with rituximab (Rituxan), another B-cell depleter used off-label for MS, because ocrelizumab is a more humanized antibody.

OPERA 1 and 2 were funded by Hoffmann–La Roche. Dr. Traboulsee is a paid speaker, consultant, and researcher for the company. Other investigators also reported various ties to Roche; several are employees. The review authors had no disclosures.