Genmab's HuMax-HepC Prevents Hepatitis C Virus Infection in Animal Model

Summary: Genmab's HuMax-HepC prevented Hepatitis C virus infection in an animal 
model.                                                                          

Copenhagen, Denmark; May 21, 2007 - Genmab A/S (CSE: GEN) announced today its   
fully human antibody HuMax-HepC(TM) prevented Hepatitis C virus (HCV) infection 
in a novel animal model.  In the pre-clinical study, mice with a compromised    
immune system were transplanted with human liver cells (hepatocytes) and exposed
to a mixture of patient-derived HCV of different genotypes.                     

Replication of HCV was not observed in 5 of 6 mice (83%) treated with           
HuMax-HepC, indicating that HuMax-HepC completely prevented HCV infection.  The 
sixth mouse was infected with HCV, but the virus was subsequently cleared.  In  
comparison, 5 of 6 mice who received a control antibody developed and sustained 
a robust HCV infection.                                                         

“We are pleased to present this pre-clinical data which indicates that          
HuMax-HepC may provide effective protection against HCV infection of human      
hepatocytes in vivo,” said Lisa N. Drakeman, Ph.D., Chief Executive Officer of  
Genmab.                                                                         

This data will be presented today at the American Association for the Study of  
Liver Diseases' (AASLD) Digestive Disease Week(R) in Washington, DC, USA.       

About HuMax-HepC                                                                
HuMax-HepC was originally isolated from a patient who suffered from mild chronic
hepatitis. HuMax-HepC binds to a conformational epitope of envelope protein 2   
(E2), which is expressed on the surface of Hepatitis C virus and plays an       
important role in the entry of hepatitis C virus into target cells.  In         
pre-clinical studies, HuMax-HepC was shown to be broadly cross-reactive with    
several HCV genotypes and potently neutralized binding of HCV-E2 to susceptible 
cells.                                                                          

About Hepatitis C virus (HCV)                                                   
Worldwide more than 170 million people are chronically infected with HCV,       
including approximately 3.9 million in the United States and 8.9 million in     
Europe. Most infected people develop increasing liver fibrosis over time that   
can lead to cirrhosis, liver failure or liver cancer. From population-based     
studies it is estimated that in the United States 8,000-10,000 deaths occur each
year due to HCV-related chronic liver disease. Moreover, Hepatitis C is the main
cause of about half of the estimated 10,000 liver transplants in Europe and the 
United States each year. A major complication of liver transplantation in       
HCV-patients is re-infection of the graft by HCV. Studies conducted in several  
laboratories support the rationale for using antibodies to prevent liver        
infection or re-infection with HCV.                                             

About Genmab A/S                                                                
Genmab A/S is a biotechnology company that creates and develops human antibodies
for the treatment of life-threatening and debilitating diseases. Genmab has     
numerous products in development to treat cancer, infectious disease, rheumatoid
arthritis and other inflammatory conditions, and intends to continue assembling 
a broad portfolio of new therapeutic products. In addition, Genmab has developed
UniBody(TM), a new proprietary technology that creates a stable, smaller        
antibody format.  Genmab has operations in Europe and the US. For more          
information about Genmab, visit www.genmab.com.                                 

This press release contains forward looking statements. The words “believe”,    
“expect”, “anticipate”, “intend” and “plan” and similar expressions identify    
forward looking statements. Actual results or performance may differ materially 
from any future results or performance expressed or implied by such statements. 
The important factors that could cause our actual results or performance to     
differ materially include, among others, risks associated with product discovery
and development, uncertainties related to the outcome and conduct of clinical   
trials including unforeseen safety issues, uncertainties related to product     
manufacturing, the lack of market acceptance of our products, our inability to  
manage growth, the competitive environment in relation to our business area and 
markets, our inability to attract and retain suitably qualified personnel, the  
unenforceability or lack of protection of our patents and proprietary rights,   
our relationships with affiliated entities, changes and developments in         
technology which may render our products obsolete, and other factors. Genmab is 
not under an obligation to up-date statements regarding the future following the
publication of this release; nor to confirm such statements in relation to      
actual results, unless this is required by law.                                 

Genmab(R); the Y-shaped Genmab logo(R); HuMax(R); HuMax-CD4(R); HuMax-EGFr(TM); 
HuMax-Inflam(TM); HuMax-CD20(TM); HuMax-TAC(TM); HuMax-HepC(TM), HuMax-CD38(TM);
HuMax-ZP3(TM); and UniBody(TM) are all trademarks of Genmab A/S.                

Contact: Helle Husted, Sr. Director, Investor Relations, T: +45 33 44 77 30, M: 
+45 25 27 47 13, E: hth@genmab.com                                              
                                                                                
Stock Exchange Release no. 20/2007