Arena Pharmaceuticals and Ildong Pharmaceutical Enter Into Co-Development and License Agreement for Temanogrel, a Novel Agent

Arena Pharmaceuticals and Ildong Pharmaceutical Enter Into Co-Development and
   License Agreement for Temanogrel, a Novel Agent for Thrombotic Diseases

-- Agreement Enables Clinical Development of Temanogrel to Resume with Ildong
Funding --

PR Newswire

SAN DIEGO, Nov. 28, 2012

SAN DIEGO, Nov. 28, 2012 /PRNewswire/ --Arena Pharmaceuticals, Inc. (NASDAQ:
ARNA) today announced that it has entered into a co-development and license
agreement with Ildong Pharmaceutical Co., Ltd., for temanogrel, Arena's
internally discovered inverse agonist of the serotonin 2A receptor. The
agreement grants Ildong exclusive rights to commercialize temanogrel in South
Korea for myocardial infarction, acute coronary syndrome, stroke, peripheral
artery disease, and other cardiovascular diseases, subject to further
development and regulatory approval of temanogrel. Initially, Ildong will be
responsible for funding and conducting, under the direction of a joint
steering committee, the next two planned clinical trials in this program: an
additional Phase 1 trial in healthy volunteers and a Phase 2a proof-of-concept
trial in patients.

"The Phase 1 trials Arena previously conducted support temanogrel's potential
to treat a variety of conditions related to thrombosis through a novel
mechanism that may provide advantages over currently available therapies,"
said Jack Lief, Arena's President and Chief Executive Officer. "A successful
product in this category has the potential to serve as an important treatment
option for many patients, and this collaboration with Ildong enables us to
resume clinical development in a cost-effective manner."

Arena will maintain ownership of temanogrel outside of South Korea, and has
the rights to use data generated by Ildong for the development and potential
commercialization of temanogrel outside of South Korea by Arena or other Arena
licensees. In addition, Ildong has agreed to pay Arena a $2 million
development milestone if the planned additional Phase 1 and Phase 2a clinical
trials conducted by Ildong support continued development and Arena or another
Arena licensee initiates a Phase 2b clinical trial of temanogrel. Arena is
also eligible to receive a royalty on net sales of temanogrel in South Korea,
while Ildong is eligible to receive a share of future payments received by
Arena related to licensing transactions and sales of temanogrel in other

"It is a great pleasure to establish this collaboration with Arena for
temanogrel," said Jung-chi Lee, Ildong's Chairman and Chief Executive Officer.
"We look forward to supporting the global development of this drug candidate
and having the opportunity to bring temanogrel to patients in South Korea as a
treatment for thrombotic diseases."

About Thrombosis

Thrombosis is the formation of a clot, or thrombus, inside a blood vessel.
Thrombus formation that occurs in the blood vessels of the heart or brain can
lead to serious thrombotic diseases including myocardial infarction, acute
coronary syndrome and stroke. One of the initial events in thrombus formation
is the activation of platelets, which then aggregate and adhere to one another
as they release certain factors, including high concentrations of serotonin.
Serotonin promotes further platelet aggregation and also causes constriction,
or narrowing, of the blood vessels. Elevated serotonin levels have been
associated with increased cardiovascular risk. The prothrombotic effects of
serotonin on platelets and blood vessels are mediated by the serotonin 2A
receptor, and inverse agonists of the serotonin 2A receptor have the potential
to inhibit this activity.

About Temanogrel

Temanogrel is an inverse agonist of the serotonin 2A receptor intended for the
treatment of thrombotic diseases, and has completed single- and
multiple-ascending dose Phase 1 trials in healthy volunteers. Temanogrel has
the potential to prevent serotonin-mediated platelet aggregation and reverse
serotonin-mediated vasoconstriction. This dual mechanism of temanogrel may be
therapeutically useful for the treatment or prevention of thrombotic diseases.

About Arena Pharmaceuticals

Arena Pharmaceuticals is a biopharmaceutical company focused on discovering,
developing and commercializing novel drugs for weight management,
cardiovascular disease, inflammation and other disorders. BELVIQ^® (lorcaserin
HCl), Arena's internally discovered drug, was approved by the US Food and Drug
Administration in June 2012, and is under review for regulatory approval in
additional territories. Arena's US operations are located in San Diego,
California, and its operations outside of the United States, including its
commercial manufacturing facility, are located in Zofingen, Switzerland. For
more information, visit Arena's website at

Arena Pharmaceuticals^® and Arena^® are registered service marks of Arena
Pharmaceuticals, Inc. BELVIQ^® is a registered trademark of Arena
Pharmaceuticals GmbH.

About Ildong Pharmaceutical Co., Ltd.

Ildong Pharmaceutical Co., Ltd., based in Seoul, Korea, is a leading Korean
company focused on the development, manufacturing and marketing of
pharmaceuticals and OTC products with sales of $294 million in 2011. Ildong,
founded in 1941, is known to have leading expertise in various therapeutic
categories, including antibiotics, gastrointestinal, anti-diabetics,
cardiovascular and oncology. For more information, visit Ildong's website at

Forward-Looking Statements

Certain statements in this press release are forward-looking statements that
involve a number of risks and uncertainties. Such forward-looking statements
include statements about the development, therapeutic indication and use,
safety, efficacy, mechanism of action, regulatory approval and
commercialization of temanogrel; the potential of temanogrel and other
products in the same category, including as compared to other therapies;
rights, obligations, expectations and future activities related to the
co-development and license agreement with Ildong, including funding, the
development and commercialization of temanogrel and milestone and other
payments, the significance of such agreement, and the cost-effectiveness of
development thereunder; Arena's use of data generated under such agreement,
ownership of temanogrel and establishment of other licensing agreements
relating to temanogrel; the regulatory review of BELVIQ; and Arena's focus,
goals, strategy, research and development programs, and ability to discover
and develop compounds and commercialize drugs. For such statements, Arena
claims the protection of the Private Securities Litigation Reform Act of 1995.
Actual events or results may differ materially from Arena's expectations.
Factors that could cause actual results to differ materially from the
forward-looking statements include, but are not limited to, the following:
risks related to the implementation and continuation of the co-development and
license agreement with Ildong and the development of temanogrel; risks related
to commercializing drugs, including regulatory, manufacturing and supply
issues and the pace of market acceptance; cash and revenues generated from
BELVIQ, including the impact of competition; the timing and outcome of
regulatory review is uncertain; government and commercial reimbursement and
pricing decisions; risks related to relying on collaborative arrangements; the
timing and receipt of payments and fees, if any, from collaborators; the entry
into or modification or termination of collaborative arrangements; unexpected
or unfavorable new data; nonclinical and clinical data is voluminous and
detailed, and regulatory agencies may interpret or weigh the importance of
data differently and reach different conclusions than Arena or others, request
additional information, have additional recommendations or change their
guidance or requirements before or after approval; data and other information
related to any of Arena's research and development may not meet safety,
efficacy or other regulatory requirements or otherwise be sufficient for
further research and development, regulatory review or approval or continued
marketing; Arena's ability to obtain and defend patents; the timing, success
and cost of Arena's research and development programs; results of clinical
trials and other studies are subject to different interpretations and may not
be predictive of future results; clinical trials and other studies may not
proceed at the time or in the manner expected or at all; having adequate
funds; and satisfactory resolution of litigation or other disagreements with
others. Additional factors that could cause actual results to differ
materially from those stated or implied by Arena's forward-looking statements
are disclosed in Arena's filings with the Securities and Exchange Commission.
These forward-looking statements represent Arena's judgment as of the time of
this release. Arena disclaims any intent or obligation to update these
forward-looking statements, other than as may be required under applicable

Contact: Arena Pharmaceuticals, Inc.     Media Contact: Russo Partners
Cindy McGee, Vice President              David Schull, President
Investor Relations & Alliance Management                    858.717.2310
858.453.7200, ext. 1479

SOURCE Arena Pharmaceuticals, Inc.

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