Medarex Announces Initiation Of Phase I Clinical Trial For The Treatment Of Psoriasis

Medarex, Inc.
(Nasdaq: MEDX) announced today that its partner MedImmune, Inc. has
initiated a Phase I clinical trial of MEDI-545 for the potential treatment
of psoriasis. MEDI-545 is a fully human antibody generated by Medarex's
UltiMAb Human Antibody Development System(R).


The Phase I dose-escalation trial for the treatment of psoriasis is
expected to be conducted at three sites in North America. Patients will be
dosed once and subsequently evaluated for a period of 126 days, including
blood and skin analysis at regular intervals.


MEDI-545 is under evaluation for the treatment of systemic lupus
erythematosus (SLE or lupus) in a Phase I clinical study also being
conducted by MedImmune. The Phase I study in lupus will be the subject of a
poster presentation at the 8th International Lupus Consortium, scheduled
for May 24 - 26 in Shanghai. In addition, MedImmune has filed an
application with the U.S. Food and Drug Administration for orphan drug
status of MEDI-545 for an additional indication, idiopathic inflammatory
myositis, an immunological disease that involves chronic muscle
inflammation, pain and weakness.


"We are pleased with MedImmune's continued commitment to and progress
with this antibody product candidate. We believe that the expansion of
indications could lead to the development of therapeutics for a broad
population of patients afflicted with serious autoimmune diseases," said
Irwin Lerner, Chairman of the Board of Directors and Interim President and
CEO of Medarex.


About MEDI-545


MEDI-545 (previously known as MDX-1103) is a fully human monoclonal
antibody targeting interferon-alpha. Published data indicate that levels of
interferon-alpha are elevated in many patients with active systemic lupus
erythematosus (SLE, or lupus) and other autoimmune disorders, and may be
associated with disease activity. Preclinical data from animal models
suggest that MEDI-545 may suppress the abnormal immune activity associated
with lupus by binding to multiple interferon-alpha subtypes seen in the
serum of lupus patients.



In November 2004, MedImmune entered into a collaboration with Medarex
to focus on two specific antibodies, one of which was MDX-1103 (now known
as MEDI-545). Under the terms of the agreement, MedImmune is responsible
for all ongoing clinical development activities. Prior to the beginning of
pivotal studies, Medarex may elect to co-develop the products in return for
the opportunity to co-promote and to receive a share of the commercial
profits in the United States. In all other cases, Medarex will be entitled
to receive milestone payments and royalties.


About Psoriasis


Psoriasis is an immunological disease affecting as many as 7.5 million
Americans, according to the National Institutes of Health (NIH). Plaque
psoriasis, the most common type of psoriasis, is characterized by the
formation of lesions, or inflamed patches of skin. The severity of
psoriasis can range from a small number of lesions to more severe cases
involving moderate to large areas of skin. Psoriasis occurs nearly equally
in men and women and can develop at any age, commonly appearing between
ages 15 and 35. Approximately 10 to 30 percent of people with psoriasis
will develop psoriatic arthritis, according to the National Psoriasis
Foundation. In psoriatic arthritis, the joints and the soft tissue around
them become inflamed and stiff, affecting the fingers and toes and possibly
involving the neck, lower back, knees and ankles. In severe cases,
psoriatic arthritis can be disabling and cause irreversible damage to
joints.
















About Lupus



Approximately 350,000 individuals in the United States are affected
with lupus, a chronic inflammatory disease that causes the body to attack
its own tissues and organs, including the skin, joints, blood and kidneys.
Treatments for lupus include anti-inflammatory drugs, antimalarials,
corticosteroids and drugs approved for other purposes, such as
immunosuppressive agents given to cancer patients undergoing chemotherapy
or medicines developed to treat arthritis patients. Lupus occurs about 10
times more frequently in adult females than adult males, and is two to
three times more common among African Americans, Hispanics, Asians and
Native Americans.


About Medarex, Inc.



Medarex is a biopharmaceutical company focused on the discovery,
development and potential commercialization of fully human antibody-based
therapeutics to treat life-threatening and debilitating diseases, including
cancer, inflammation, autoimmune disorders and infectious diseases. Medarex
applies its UltiMAb(R) technology and product development and clinical
manufacturing experience to generate, support and potentially commercialize
a broad range of fully human antibody product candidates for itself and its
partners. More than 30 of these therapeutic product candidates derived from
Medarex technology are in human clinical testing or have had INDs submitted
for such trials, with six of the most advanced product candidates currently
in Phase III clinical trials. Medarex is committed to building value by
developing a diverse pipeline of antibody products to address the world's
unmet healthcare needs. For more information about Medarex, visit its
website at medarex/.


Statement on Cautionary Factors



Except for the historical information presented herein, matters
discussed herein may constitute forward-looking statements that are subject
to certain risks and uncertainties that could cause actual results to
differ materially from any future results, performance or achievements
expressed or implied by such statements. Statements that are not historical
facts, including statements preceded by, followed by, or that include the
words "potential"; "believe"; "anticipate"; "intend"; "plan"; "expect";
"estimate"; "could"; "may"; or similar statements are forward-looking
statements. Medarex disclaims, however, any intent or obligation to update
these forward-looking statements. Risks and uncertainties include
uncertainties related to the outcome of clinical trials, slower than
expected rates of patient recruitment, unforeseen safety issues resulting
from the administration of MEDI-545 in patients, risks relating to
MedImmune, Inc. deciding to stop or delay future clinical development with
respect to MEDI-545, to stop or delay the Phase I clinical trial, or to
stop or delay future trials relating to MEDI-545 as well as risks detailed
from time to time in Medarex's public disclosure filings with the U.S.
Securities and Exchange Commission (SEC), including its Annual Report on
Form 10-K for the fiscal year ended December 31, 2006. There can be no
assurance that such development efforts will succeed or that other
developed products will receive required regulatory clearance or that, even
if such regulatory clearance were received, such products would ultimately
achieve commercial success. Copies of Medarex's public disclosure filings
are available from its investor relations department.


Medarex, Inc.

medarex/