Genmab — Earnings Release 2013

May 1, 2013

Company Announcement

-- 95% overall response rate and 43% complete response rate in patients with
previously untreated chronic lymphocytic leukemia
-- 74% overall response rate and 11% complete response rate in relapsed
chronic lymphocytic leukemia
-- Treatment was well tolerated with 87% of patients completing the full
treatment course

Copenhagen, Denmark; May 1, 2013 – Genmab A/S (OMX: GEN) announced today
top-line results from a Phase II study of ofatumumab in combination with
bendamustine in patients with untreated or relapsed chronic lymphocytic
leukemia (CLL).

A total of 97 patients were treated in the study and 87% of patients completed
the full course of six cycles of therapy. The study population comprised 44
patients with untreated CLL and 53 patients with relapsed CLL. In patients
with untreated CLL the overall response rate (ORR) was 95%, with a complete
response (CR) rate of 43%. The ORR in patients with relapsed CLL was 74%, with
a CR rate of 11%. Treatment with ofatumumab and bendamustine was well
tolerated by patients in the study . The most common adverse reactions (>20% of
patients) were neutropenia, nausea, rash, pyrexia and thrombocytopenia.

“These data show encouraging clinical responses in patients treated with
ofatumumab plus bendamustine, a commonly used chemotherapeutic agent, in both
untreated and relapsed CLL. This is only the first set of key data we expect
to report for ofatumumab over the next 15 months. Data from five pivotal
studies are due during this time period, including results from a Phase III
study of ofatumumab in front line CLL during the first half of 2013,” said Jan
van de Winkel, Ph.D., Chief Executive Officer of Genmab.

About the study
This Phase II study included patients who had untreated and relapsed CLL.
Patients in the study were treated with a maximum of 6 cycles of study
treatment. All subjects received 3 cycles of ofatumumab plus bendamustine and
were eligible for additional treatment cycles dependent upon response to
treatment. The primary objective of the study was to evaluate the
investigator-assessed overall response rate according to the International
Workshop for Chronic Lymphocytic Leukaemia (IWCLL) updated National Cancer
Institute-sponsored Working Group (NCIWG) guidelines, in two populations:
subjects with untreated CLL and subjects with relapsed CLL treated with
ofatumumab plus bendamustine.

About chronic lymphocytic leukemia
CLL is the most common form of leukemia in adults. Based on estimates by the
American Cancer Society, CLL will account for more than 15,680 new cases and
more than 4,580 deaths in the United States of America alone in 2013. At
present, no cure is available.

About ofatumumab
Ofatumumab is a human monoclonal antibody which targets an epitope on the CD20
molecule encompassing parts of the small and large extracellular loops (Teeling
et al 2006). Ofatumumab is being developed under a co-development and
commercialization agreement between Genmab and GlaxoSmithKline. Ofatumumab is
marketed under the trade name ARZERRA® and is approved to treat chronic
lymphocytic leukemia (CLL) in patients who are refractory to fludarabine and
alemtuzumab in the US and EU as well as other territories. The approval was
based on results from a pivotal study in this refractory patient population
where 42% of patients responded to treatment with ARZERRA. These patients had a
median duration of response of 6.5 months.

In the pivotal trial on which approval was based (total population n=154), the
most common adverse reactions (?10%, all grades) to ofatumumab were
neutropenia, pneumonia, pyrexia, cough, diarrhea, anemia, fatigue, dyspnoea,
rash, nausea, bronchitis, and upper respiratory tract infections. The most
common serious adverse reactions were infections (including pneumonia and
sepsis), neutropenia, and pyrexia. A total of 108 patients (70%) experienced
bacterial, viral, or fungal infections. A total of 45 patients (29%)
experienced ?Grade 3 infections, of which 19 (12%) were fatal. The proportion
of fatal infections in the fludarabine- and alemtuzumab-refractory group was
17%.

ARZERRA is not approved for the treatment of untreated CLL anywhere in the
world.

About Genmab A/S
Genmab is a publicly traded, international biotechnology company specializing
in the creation and development of differentiated human antibody therapeutics
for the treatment of cancer. Founded in 1999, the company’s first marketed
antibody, ofatumumab (ARZERRA®), was approved to treat chronic lymphocytic
leukemia in patients who are refractory to fludarabine and alemtuzumab after
less than eight years in development. Genmab’s validated and next generation
antibody technologies are expected to provide a steady stream of future product
candidates. Partnering of innovative product candidates and technologies is a
key focus of Genmab’s strategy and the company has alliances with top tier
pharmaceutical and biotechnology companies. For more information visit
www.genmab.com.

Contact:
Rachel Curtis Gravesen, Senior Vice President, Investor Relations &
Communications
T: +45 33 44 77 20; M: +45 25 12 62 60; E: r.gravesen@genmab.com

This Company Announcement 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
pre-clinical and clinical development of products, 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
risk management sections in Genmab’s most recent financial reports, which are
available on www.genmab.com. Genmab does not undertake any obligation to update
or revise forward looking statements in this Company Announcement nor to
confirm such statements in relation to actual results, unless required by law.

Genmab A/S and its subsidiaries own the following trademarks: Genmab®; the
Y-shaped Genmab logo®; HuMax®; HuMax-CD20®; DuoBody®, HexaBody(TM) and
UniBody®. Arzerra® is a trademark of GlaxoSmithKline.

Company Announcement no. 19
CVR no. 2102 3884

Genmab A/S
Bredgade 34E
1260 Copenhagen K
Denmark