Jazz Pharmaceuticals plc and Concert Pharmaceuticals Announce Worldwide Licensing Agreement to Develop and Commercialize

  Jazz Pharmaceuticals plc and Concert Pharmaceuticals Announce Worldwide
  Licensing Agreement to Develop and Commercialize Deuterium-Modified Sodium
  Oxybate

Business Wire

DUBLIN and LEXINGTON, Mass. -- February 26, 2013

Jazz Pharmaceuticals plc (Nasdaq: JAZZ) and Concert Pharmaceuticals, Inc.
today announced an exclusive license agreement that provides Jazz
Pharmaceuticals worldwide rights to develop and commercialize Concert’s
deuterium-modified sodium oxybate (D-SXB) compounds, including C-10323.

Sodium oxybate is the active ingredient in Xyrem®, a prescription medicine
marketed in the United States by Jazz Pharmaceuticals to treat two of the key
symptoms of narcolepsy, a serious neurological disorder that affects
approximately 157,000 people in the United States.

Under the agreement, Jazz Pharmaceuticals will have worldwide commercial
rights to C-10323, as well as principal responsibility for ongoing development
activities. Concert will receive an upfront payment and is eligible to receive
additional milestone payments as well as tiered royalties based on potential
worldwide sales of any D-SXB products.

“This collaboration reflects our deep commitment to patients with narcolepsy
and to improving their care with safe and effective treatment options,” said
Jeffrey Tobias, MD, executive vice president of research and development and
chief medical officer of Jazz Pharmaceuticals. “Our agreement with Concert on
the D-SXB program provides an excellent opportunity for us to explore the
potential of deuterium technology in this important area. We look forward to
advancing this program into clinical testing in order to further evaluate its
potential to provide benefits for patients with narcolepsy.”

“Preclinical data indicate that selective deuterium incorporation can
stabilize sodium oxybate in vivo and we are eager to see how this improvement
in metabolic properties is reflected in the clinical performance of D-SXB,”
said Roger Tung, Ph.D., president and chief executive officer of Concert
Pharmaceuticals. “This collaboration with Jazz Pharmaceuticals allows us to
progress our deuterium-modified sodium oxybate program with a partner that has
extensive development and commercial experience and is a leader in the
narcolepsy field.”

Through Concert’s DCE Platform® (Deuterated Chemical Entity), Concert has
developed a number of deuterium-containing analogs of sodium oxybate. C-10323
has emerged as the lead compound based on in vivo preclinical testing that
demonstrated prolonged pharmacokinetic profile and reduced variability as a
result of its specific deuterium modification pattern. The companies plan to
submit an investigational new drug (IND) application for C-10323 later this
year.

AboutJazz Pharmaceuticals

Jazz Pharmaceuticals plcis a specialty biopharmaceutical company focused on
improving patients' lives by identifying, developing and commercializing
innovative products that address unmet medical needs. The company has a
diverse portfolio of products in the areas of narcolepsy, oncology, pain and
psychiatry. The company's U.S. marketed products in these areas include:
Xyrem^® (sodium oxybate) oral solution, Erwinaze^® (asparaginaseErwinia
chrysanthemi), Prialt^® (ziconotide) intrathecal infusion, Luvox CR^®
(fluvoxamine maleate), FazaClo^® (clozapine, USP) HD and FazaClo LD. Outside
of the U.S.,Jazz Pharmaceuticalsalso has a number of products marketed by
its EUSA Pharma division. For further information,
seewww.jazzpharmaceuticals.com.

About Concert Pharmaceuticals

Concert Pharmaceuticals is a clinical stage biotechnology company focused on
applying the company’s DCE Platform® (deuterated chemical entity platform) to
create novel and differentiated small molecule drugs. Concert’s approach
leverages decades of pharmaceutical and clinical experience to reduce the
time, risk and expense needed to create important new medicines. The company
has a broad research pipeline addressing renal disease, hematologic disorders,
CNS disorders and other therapeutic areas. Founded in 2006, Concert has raised
more than $110 million of venture and institutional capital. For more
information on Concert Pharmaceuticals, please visit www.concertpharma.com.

About Xyrem

Xyrem® (sodium oxybate) oral solution is indicated for the treatment of
cataplexy and excessive daytime sleepiness (EDS) in patients with narcolepsy
and may be dispensed only to patients enrolled in the Xyrem Success Program®.
Xyrem is the only product approved by the FDA for the treatment of cataplexy
and EDS in narcolepsy, a serious neurological disorder. Xyrem was first
approved in the U.S. in 2002. The Xyrem Success Program is a proprietary
program to ensure the safe use of Xyrem and minimize the risk of abuse,
misuse, and diversion of sodium oxybate. Xyrem is available only by
prescription from physicians enrolled in the Xyrem Success Program and is
distributed through a single central pharmacy directly to patients. The
labeling for Xyrem contains a boxed warning about CNS depression, abuse, and
misuse. In controlled clinical trials, the most common adverse reactions seen
(incidence ≥ 5% and twice the rate seen with placebo) in Xyrem-treated
patients were nausea, dizziness, vomiting, somnolence, enuresis, and tremor.

“Safe Harbor” Statement under the Private Securities Litigation Reform Act of
1995

This press release contains forward-looking statements, including, but not
limited to, statements related to Jazz Pharmaceuticals’ future exploration of
the deuterium-modified sodium oxybate (D-SXB) technology and development of
D-SXB compounds, including C-10323, the future clinical testing of D-SXB to
evaluate the compounds’ therapeutic and commercial potential, and the plan to
submit an investigational new drug application for C-10323. These
forward-looking statements are based on Jazz Pharmaceuticals’ current
expectations and inherently involve significant risks and uncertainties.
Actual results and the timing of events could differ materially from those
anticipated in such forward looking statements as a result of these risks and
uncertainties, which include, without limitation, risks and uncertainties
associated with the timing and results of the exploration of the D-SXB
technology; the companies’ ability to file an IND for C-10323 as currently
contemplated; the uncertainty of clinical success and therapeutic value of
D-SXB compounds, including C-10323; the uncertainty of regulatory approval;
the difficulty in integrating the D-SXB products into the company’s product
portfolio and the possibility that the company may fail to realize the
anticipated benefits (commercial or otherwise) from this license; and those
risks with respect to research and development and clinical trials detailed
from time-to-time under the caption “Risk Factors” and elsewhere in Jazz
Pharmaceuticals’ Securities and Exchange Commissionfilings and reports
(Commission File No. 001-33500), including in the Quarterly Report on Form
10-Q for the quarter endedSeptember 30, 2012and future filings and reports
by the company, including the Annual Report on Form 10-K for the year
endedDecember 31, 2012.Jazz Pharmaceuticalsundertakes no duty or obligation
to update any forward-looking statements contained in this release as a result
of new information, future events or changes in its expectations.

 Concert Pharmaceuticals Inc., the CoNCERT Pharmaceuticals Inc. logo and DCE
     Platform are registered trademarks of Concert Pharmaceuticals, Inc.

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Contact:

Jazz Pharmaceuticals
Kathee Littrell (Investors)
+ 1-650-496-2717 (US)
+ 353 1 634 7887 (Ireland)
or
Ami Knoefler (Media)
+ 1-650-496-2947 (US)
+ 353 1 638 1032 (Ireland)
or
Concert Pharmaceuticals
Justine Koenigsberg (Investors), 781-674-5284
ir@concertpharma.com
or
The Yates Network
Kathryn Morris (Media), 845-635-9828