London, UK and Copenhagen, Denmark; July 29, 2009 - GlaxoSmithKline (GSK) and Genmab A/S (OMX: GEN) announced today preliminary top-line results from a Phase III study of ofatumumab administered intravenously for the treatment of rheumatoid arthritis (RA) in patients who had an inadequate response to methotrexate. The study met the primary endpoint, ACR20 at 24 weeks, which indicates a 20 percent or greater improvement in the number of swollen and tender joints, as well as improvements in other disease-activity measures.

In the study, 260 patients were treated and included in the analysis. At week 24, the ACR20 response rate was significantly greater for RA patients on ofatumumab (n=129) than on placebo (n=131) with a 50 percent response rate in the patients receiving ofatumumab, compared to 27 percent for patients on placebo (p-value less than 0.001). All key secondary endpoints were significant (p-value less than or equal to 0.001).

There were no unexpected safety findings. The most common adverse events in the ofatumumab treated patients (greater than 5 percent) were rash, urticaria, nasopharyngitis, pruritus, throat irritation and hypersensitivity. Other than nasopharyngitis, these events generally occurred within 24 hours of the first infusion. One death, judged by the investigator as unrelated to ofatumumab, was reported in the study during the 24-week study period.

"We have always believed in ofatumumab's potential to make a difference in patients' lives. We are pleased with the results of this study, supporting the further investigation of this antibody's promise in the treatment of RA," said Lisa N. Drakeman, Ph.D., Chief Executive Officer of Genmab.

"RA can be a highly debilitating disease. It is encouraging to see the reduction in disease symptoms achieved with intravenous ofatumumab, and we look forward to presenting the full study results," said Carlo Russo, M.D., Senior Vice President, Biopharm Development, GSK.

About the study

In this 24 week double-blind study, patients with active RA were randomized to receive two 700 mg doses of intravenous ofatumumab or placebo two weeks apart in addition to background methotrexate. Disease status was measured every 4 weeks. Patients for this non-IND study were recruited from Europe, South America and Australia.

The primary objective of the study was to determine the efficacy of intravenous ofatumumab in reducing the clinical signs and symptoms in RA patients after two 700 mg doses of ofatumumab compared to placebo. The primary endpoint of the study was ACR20 at 24 weeks. Other key secondary objectives included safety, patient reported outcomes, biomarkers and ACR 50 and ACR 70.

ACR Response

The ACR 20 response is defined as a 20 percent or greater improvement from baseline in tender and swollen joint counts, and 20percent or greater improvement in 3 of the 5 following assessments: patient and physician global assessments, pain, disability, and an acute phase reactant (ESR or CRP).

About ofatumumab

Ofatumumab is a novel, investigational, fully human monoclonal antibody that targets a membrane-proximal (close to the cell surface) small loop epitope (a portion of a molecule to which an antibody binds) on the CD20 molecule of B-cells. This epitope is different from the binding sites targeted by other CD20 antibodies currently available.

Ofatumumab is being developed for other indications under a co-development and commercialization agreement between Genmab and GlaxoSmithKline. It is not yet approved in any country.

Conference Call

Genmab will hold a conference call to discuss the ofatumumab results Thursday, July 30, 2009, at

3:00 pm CEST

2:00 pm BST

9:00 am EDT

The conference call will be held in English.

The dial in numbers are as follows:

+1 877-941-1883 (in the US) and quote conference ID number 4129982

+1 480-629-9702 (outside the US) and quote conference ID number 4129982

To listen to a live webcast of the call please visit