FDA Gives Permission to Initiate Pivotal Study

Copenhagen, DENMARK; December 12, 2001 - Genmab A/S (CSE: GEN and Neuer Markt: GE9D) announced today that it has received permission from the US Food and Drug Administration to begin a Phase III study with HuMax™-CD4 to treat patients with active rheumatoid arthritis (RA) who have failed to respond to treatment with methotrexate and TNF-a blocking agents. These patients represent a major unmet medical need, as they do not have an effective treatment option.

The objective of the Phase III trial is to confirm the safety and efficacy of HuMax-CD4 in the treatment of RA. It will enroll 400 patients who will be treated with either 80 or 160 milligrams of HuMax-CD4 or placebo for a total of 26 weeks. The patients will be given two doses, two weeks apart, followed by one dose each month. The Phase III trial will be initiated in the US and Europe in December 2001, and is planned to take place at over 50 sites.

To date, over 200 patients have been treated with HuMax-CD4, with the vast majority receiving multiple doses of the product. In previously reported studies, HuMax-CD4 has been safe and well tolerated and shown favorable responses in a Phase I/II RA study, where half the patients in the highest four dose groups achieved responses ranging from ACR 20 to ACR 70.

Genmab will manage this study with its substantial in-house product development team that includes clinical, regulatory and biometric groups in the US and Europe. In addition to addressing the refractory RA market, the Company plans additional Phase III studies in the broader indication of moderately to severely diseased patients. HuMax-CD4 is also being tested in psoriasis in Phase II studies.

“Genmab is now a member of the biotech elite in Europe as one of just a handful of companies with products in every stage of clinical development,” said Lisa N. Drakeman, Ph.D., Chief Executive Officer. “The rapid progression to Phase III is a sign of the expertise of the Genmab team and shows that we are effectively implementing our business strategy to be a product development company.”


Background

HuMax-CD4 and Previous Clinical Experience

HuMax-CD4 is a high affinity fully human antibody that targets the CD4 receptor on T-lymphocytes. These cells are involved in promoting autoimmune disease and an antibody that targets them can be used for the treatment of several inflammatory diseases including rheumatoid arthritis and psoriasis.

HuMax-CD4 has been studied by Genmab in both Rheumatoid Arthritis (RA) and Psoriasis clinical trials. Genmab presented Phase I/II clinical trial results in patients with rheumatoid arthritis in November 2000 at the American College of Rheumatology meeting. In this study, severely diseased patients who had failed to respond to conventional therapy received a single dose of the antibody. HuMax-CD4 was safe and well tolerated. Furthermore, in the four highest dose cohorts, fifty percent of the treated patients achieved favorable responses to the antibody as measured by objective criteria defined by the American College of Rheumatology, achieving responses ranging from ACR 20 to ACR 70.

HuMax-CD4 is the subject of an ongoing Phase II study in a broad RA indication, patients with active moderate to severe arthritis despite treatment with methotrexate. Results of this study are expected to be available next year.

The dose response observed in the Phase I/II RA study correlates with the initial results of the HuMax-CD4 Phase II dose finding study in psoriasis patients, where the antibody has shown a statistically significant dose response. In addition, mean Psoriasis Area Severity Index (PASI) score was reduced in all treatment groups with a 30% difference between the placebo and 160mg dose groups. HuMax-CD4 was also safe and well tolerated. These initial results are based on data at the seven-week time point from 79 of 85 patients in the Phase II study and were presented at the American College of Rheumatology Annual Meeting in San Francisco in November 2001.

This psoriasis trial was a small placebo controlled Phase II study designed to establish the safety and lowest effective dose of HuMax-CD4 in patients with moderate to severe psoriasis. Patients received either one of four dose levels or placebo weekly for four weeks. Eighty-five patients were followed for a total of 16 weeks and final results of the study will be presented early next year.

Market Potential

Around 1% of the world’s population has RA indicating more than two million people in the US have this debilitating disease. Current medical practice is to treat patients earlier in the disease stage compared to the practice in the past, thus increasing the size of the potential market.

In actual clinical practice approximately half the patients respond to TNF alpha inhibitors. As TNF inhibitors on the market have combined sales of approximately USD 1 billion these figures suggest there is a potentially large market for other treatments.