Issued: 8 September 2010, London, UK and Copehagen, Denmark

GlaxoSmithKline (GSK) and Genmab A/S (OMX: GEN) announced today the start of a Phase III study in patients with indolent B-cell non-Hodgkin’s lymphoma (B-NHL) who did not respond to or progressed during, or within 6 months of a rituximab containing regimen. Under the terms of Genmab’s collaboration with GlaxoSmithKline (GSK), Genmab will receive a milestone payment of approximately DKK 116 million (approximately USD 20 million), triggered by the treatment of the first patient in the study.

About the trial

A total of 338 patients in this open label study will be randomized to receive either ofatumumab in addition to bendamustine or bendamustine alone. The primary endpoint of the study is progression free survival. Patients in the bendamustine monotherapy group will have the opportunity to receive ofatumumab if their lymphoma progresses.

About indolent B-cell non-Hodgkin’s lymphoma

More than one-third of lymphoma patients have indolent B-cell non-Hodgkin’s lymphoma, which includes follicular lymphoma and other typically slow growing lymphomas which initially respond to treatment but relapse with time.¹ Indolent B-NHL is defined by expression of the CD20 molecule, which is the target of monoclonal antibodies such as rituximab and ofatumumab.^2,3

About ofatumumab

Ofatumumab is a human monoclonal antibody which targets CD20. Ofatumumab is not approved in any country for indolent B-cell non-Hodgkin’s lymphoma (B-NHL).

GlaxoSmithKline, one of the world’s leading research-based pharmaceutical and healthcare companies, is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For company information, visit GlaxoSmithKline at http://www.gsk.com.

Genmab A/S - 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.

Enquiries:

UK Media enquiries:

David Mawdsley

(020) 8047 5502

Claire Brough

(020) 8047 5502

Stephen Rea

(020) 8047 5502

Alexandra Harrison

(020) 8047 5502

Jo Revill

(020) 8047 5502

US Media enquiries:

Nancy Pekarek

(919) 483 2839

Mary Anne Rhyne

(919) 483 2839

Kevin Colgan

(919) 483 2839

Sarah Alspach

(919) 483 2839

European Analyst/Investor enquiries:

Sally Ferguson

(020) 8047 5543

Gary Davies

(020) 8047 5503

US Analyst/ Investor enquiries:

Tom Curry

(215) 751 5419

Jen Hill Baxter

(215) 751 7002

Genmab Enquiries

Helle Husted

+45 33 44 77 30

M: +45 25 27 47 13

h.husted@genmab.com

GlaxoSmithKline Cautionary statement regarding forward-looking statements

Under the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Factors that may affect GSK' s operations are described under 'Risk Factors' in the 'Business Review' in the company' s Annual Report on Form 20-F for 2009.

Genmab Forward Looking Statement

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

References

1. Surveillance Epidemiology and End Results (SEER) Cancer Statistics Review 1975-2006 , National Cancer Institute.

2. McLaughlin, Peter. Mayo Clinic Hematology/Oncology Review: Part 1 Progress and Promise in the Treatment of Indolent Lymphomas. The Oncologist, June 2002 Vol. 7, No. 3, 217-225.

3. Cheson, Bruce D. Ofatumumab, a Novel Anti-CD20 Monoclonal Antibody for the Treatment of B-Cell Malignancies. Journal of Clinical Oncology. July 20, 2010 vol.28 no. 21 3525-3530.

Registered in England & Wales:

No. 3888792

Registered Office:

980 Great West Road

Brentford, Middlesex

TW8 9GS