Major Shareholder Announcement

Summary: Major shareholder announcement for Genmab A/S.                         

Copenhagen, Denmark; September 13, 2010 - Genmab A/S (OMX: GEN) announces under 
reference to Section 29 of the Danish Securities Trading Act that Credit Suisse 
Securities (Europe) Ltd. has informed us that ownership in Genmab A/S as of     
September 2, 2010 consists of 2,556,874 shares, which is 5.69% of the total     
shares in the Company.                                                          

About Genmab A/S                                                                
Genmab is a leading international biotechnology company focused on developing   
fully human antibody therapeutics for the potential treatment of cancer.        
Genmab's world class discovery and development teams are using cutting-edge     
technology to create and develop products to address unmet medical needs.  Our  
primary goal is to improve the lives of patients who are in urgent need of new  
treatment options.  For more information on Genmab's products and technology,   
visit www.genmab.com.                                                           

This Stock Exchange 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. For a further discussion of these risks, please refer to the section   
“Risk Management” in Genmab's Annual Report, which is available on              
www.genmab.com.  Genmab does not undertake any obligation to update or revise   
forward looking statements in this Stock Exchange Release nor to confirm such   
statements in relation to actual results, unless required by law.               

Genmab(R); the Y-shaped Genmab logo(R); HuMax(R); HuMax-CD20(R); HuMax-EGFr(TM);
HuMax-IL8(TM); HuMax-TAC(TM); HuMax-HepC(TM); HuMax-CD38(TM); HuMax-CD32b(TM);  
HuMax-TF(TM); HuMax-Her2(TM); HuMax-VEGF(TM); HuMax-Wnt; HuMax-cMet(TM) and     
UniBody(R) are all trademarks of Genmab A/S. Arzerra(R) is a trademark of       
GlaxoSmithKline.                                                                

Contact: Helle Husted, Vice President, Investor Relations, T: +45 33 44 77 30,  
M: +45 25 27 47 13, E: h.husted@genmab.com                                      
                                                                                
Stock Exchange Release no. 33/2010                                              

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