Ofatumumab (also known as Arzerra®)

Experimental Medications: Monoclonal Antibody Medications

Company: Novartis

  • Administered via intravenous infusion and will also be studied via subcutaneous injection
  • Ofatumumab is being studied in RRMS

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Like Rituxan and ocrelizumab, this drug is an anti-CD20 monoclonal antibody. It has the potential advantage of being a human monoclonal antibody (versus antibodies from non-human species that have been modified).

Ofatumumab has a unique target on the CD20 molecule and is approved for certain forms of leukemia. Genmab, the pharmaceutical company developing this medication prior to Novartis, announced positive interim results for a Phase II safety and pharmacokinetics (how the body processes the drug) study of ofatumumab in 2010. This study had 38 patients with RRMS who were randomized to ofatumumab or placebo in a cross-over design. Statistically, the number of gadolinium-enhancing lesions and new or enlarging T2 lesions was significantly less in patients treated with ofatumumab compared to placebo.

Results from MIRROR, a 12-week Phase II study comparing several doses of ofatumumab in RRMS, were reported in 2014.14 In the MIRROR study, 231 patients with RRMS were assigned to one of four doses of ofatumumab or placebo. This “dose-ranging study” included doses of 3 mg every 12 weeks, 30 mg every 12 weeks, 60 mg every 12 weeks, and 60 mg every four weeks. After 12 weeks, the placebo group received 3 mg of ofatumumab. The study treatments were given for 24 weeks. The primary endpoint was suppression of MRI-lesion activity during the first 12 weeks. Results suggested a 90-percent or greater reduction in the active, enhancing lesions for all cumulative doses of ofatumumab 30 mg or greater.

Five serious adverse events were reported, all in the highest-dose treatment group. This study design allows for an “optimal dose” to be utilized in future studies of ofatumumab. The aim is to achieve suppression of MS-disease activity without completely eliminating B cells, with the intent of minimizing adverse events.

The MIRROR trial extension data presented in fall 201515 demonstrated continued suppression of new MRI lesions at week 48 and a dose-responsive effect on B cells. These data will guide future clinical trials of this agent, expected to be initiated in 2016.

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