EULAR: Ofatumumab (HuMax-CD20) for RA Seems Effective in Phase II Trial

June 18, 2007

BARCELONA, Spain -- Ofatumumab (HuMax-CD20), an investigational fully human antibody, appears to be safe and effective for rheumatoid arthritis, researchers said here.

BARCELONA, Spain, June 18 -- Ofatumumab (HuMax-CD20), an investigational fully human antibody, appears to be safe and effective for rheumatoid arthritis, researchers said here.

In a phase II trial, patients getting any of three doses of the drug had a significantly better chance of having a 20% reduction in RA symptoms after 24 weeks, according to Mikkel stergaard, M.D., Ph.D., of Copenhagen University Hospital in Denmark.

"The drug works as expected," Dr. stergaard said during the of the European League Against Rheumatism (EULAR) meeting here, Officials of GlaxoSmithKline and Genmab A/S of Denmark, which are developing the drug, said they plan phase III trials.

The drug -- which targets the CD20 protein on the surface of B-cells -- is also being studied for rituximab (Rituxan)-resistant follicular non-Hodgkin's lymphoma.

The investigational agent targets the same molecule that rituxan does, but rituximab is a chimeric monoclonal antibody, while ofatumumab is a fully human antibody, which might suggest fewer side effects.

But Dr. stergaard said it's not possible to say how the new drug stacks up against rituximab on the basis of the current randomized, placebo-controlled trial involving 225 patients with active RA.

Volunteers in the trial were randomized to placebo or 300, 700, or 1,000 mg of ofatumumab, infused on the first and 14th day of the study. There was no further treatment with the drug.

Patients were allowed to continue concomitant methotrexate and low-dose corticosteroids.

At 24 weeks (halfway through the study), the researchers found:

  • 15% of placebo controls had a 20% reduction in symptoms (the so-called ACR20).
  • In contrast, 41% of those getting 300 mg, 49% of those getting 700 mg, and 46% of those getting 1,000 mg of ofatumumab reported the same level of improvement.
  • The differences from placebo were statistically significant at P=0.002), P