Xenon Licenses Antisense Drug XEN701 From Isis and Initiates Preclinical Toxicology Studies

   Xenon Licenses Antisense Drug XEN701 From Isis and Initiates Preclinical
                              Toxicology Studies

PR Newswire

CARLSBAD, Calif. and VANCOUVER, British Columbia, June 10, 2013

CARLSBAD, Calif. and VANCOUVER, British Columbia, June 10, 2013 /PRNewswire/
-- Isis Pharmaceuticals, Inc. (NASDAQ: ISIS) and Xenon Pharmaceuticals Inc.
announced today that Xenon has exercised its option to an exclusive worldwide
license to XEN701, an antisense drug discovered in a collaboration between
Isis and Xenon. For the license of XEN701, Isis earns a $2 million payment
from Xenon. XEN701 is a drug candidate designed to inhibit the production of
hepcidin, a target Xenon identified utilizing its extreme genetics platform
for the treatment of anemia of chronic disorders (ACD). XEN701 is currently
being evaluated in studies to support clinical development. Xenon plans to
initially develop XEN701 for patients with chronic kidney disease who are
intolerant of or who are poor responders to erythropoietin (Epo) therapy.
XEN701 is the first drug to enter development from Isis' collaboration with

"We are delighted with the advances we have made with Isis to discover
XEN701," said Simon Pimstone, Xenon's President and CEO. "XEN701 has the
potential to provide significant therapeutic benefit to patients with ACD
through a novel non-Epo receptor based mechanism and we are looking forward to
initiating clinic studies with this compound."

"We are pleased with the success of our collaboration with Xenon and the
opportunity to apply our antisense drug discovery technology to discover
XEN701, a novel antisense drug to treat ACD," said B. Lynne Parshall, chief
operating officer at Isis. "A key component of our business strategy is to
exploit the broad applicability of our antisense technology platform in order
to develop antisense drugs in many different therapeutic areas. By working
with partners like Xenon, who are highly innovative and dedicated to a
therapeutic area, we are able to expand the breadth of our antisense drug
pipeline while staying focused on our internal drug discovery and development

In 2010, Isis entered into collaboration with Xenon to discover and develop
antisense drugs as novel treatments for ACD. Under the terms of the
agreement, Isis received an undisclosed upfront payment in the form of a
convertible promissory note from Xenon to discover and develop antisense drugs
to the targets hepcidin and hemojuvelin. Upon the identification of a
development candidate, Xenon has the option to exclusively license the
development and worldwide commercialization rights for these antisense drugs
from Isis. Xenon paid Isis a $2 million fee to exercise its option to license
XEN701. Xenon is responsible for all future development and commercialization
of XEN701 and Isis is eligible to receive development and commercial milestone
payments and royalties from Xenon on sales of XEN701, as well as a portion of
sublicense revenue.

About ACD
ACD is the second most common form of anemia worldwide and commonly acquired
disorder that is associated with a variety of conditions including kidney
disease, malignancy and other clinical settings of chronic inflammation such
as inflammatory bowel disease. Utilizing its genetics platform, Xenon's
discovery of the genes underlying the rare genetic disorder juvenile
hemochromatosis (JH) led to its selection of hepcidin, a protein produced in
the liver, as a drug target to treat patients with ACD. JH, where hepcidin is
genetically deficient, is a disorder of iron metabolism where white blood
cells are iron-depleted and intestinal iron absorption is enhanced, resulting
in total body iron overload. ACD, on the other hand, is characterized by
iron-rich white blood cells and impaired intestinal iron absorption due to
elevated hepcidin, which can result in restricted iron availability for red
blood cell production and anemia. Inhibition of hepcidin with XEN701 is
predicted to improve the anemia by reversing these iron disturbances
facilitating new red blood cell production.

Xenon is a privately owned, clinical genetics-based drug discovery and
development company engaged in developing novel therapies for rare diseases.
For more information, visit the Company's website at www.xenon-pharma.com. 

Isis is exploiting its leadership position in antisense technology to discover
and develop novel drugs for its product pipeline and for its partners. Isis'
broad pipeline consists of 28 drugs to treat a wide variety of diseases with
an emphasis on cardiovascular, metabolic, severe and rare diseases, and
cancer. Isis' partner, Genzyme, is commercializing Isis' lead product,
KYNAMRO™, in the United States for the treatment of patients with HoFH.
Genzyme is also pursuing marketing approval of KYNAMRO in other markets.
Isis' patents provide strong and extensive protection for its drugs and
technology. Additional information about Isis is available at

This press release includes forward-looking statements regarding Isis'
strategic alliance with Xenon, and the discovery, development, activity,
therapeutic and commercial potential and safety of Isis' antisense drugs,
including XEN701, for the treatment of anemia of chronic disorders. Any
statement describing Isis' goals, expectations, financial or other
projections, intentions or beliefs, including the commercial potential of
KYNAMRO, is a forward-looking statement and should be considered an at-risk
statement. Such statements are subject to certain risks and uncertainties,
particularly those inherent in the process of discovering, developing and
commercializing drugs that are safe and effective for use as human
therapeutics, and in the endeavor of building a business around such drugs.
Isis' forward-looking statements also involve assumptions that, if they never
materialize or prove correct, could cause its results to differ materially
from those expressed or implied by such forward-looking statements. Although
Isis' forward-looking statements reflect the good faith judgment of its
management, these statements are based only on facts and factors currently
known by Isis. As a result, you are cautioned not to rely on these
forward-looking statements. These and other risks concerning Isis' programs
are described in additional detail in Isis' annual report on Form 10-K for the
year ended December 31, 2012 and its most recent quarterly report on Form
10-Q, which are on file with the SEC. Copies of these and other documents are
available from the Company.

Isis Pharmaceuticals® is a registered trademark of Isis Pharmaceuticals, Inc.
KYNAMRO™ is a trademark of Genzyme Corporation.

This release contains forward-looking statements that are not based on
historical fact. These forward-looking statements involve risks, uncertainties
and other factors that may cause the actual results, events or developments to
be materially different from those expressed or implied by such
forward-looking statements. Readers are cautioned not to place undue reliance
on such forward-looking statements.

SOURCE Isis Pharmaceuticals, Inc.

Website: http://www.isispharm.com
Contact: Isis Pharmaceuticals' Contacts: D. Wade Walke, Ph.D., Executive
Director, Corporate Communications and Investor Relations, 760-603-2741, or
Amy Blackley, Ph.D., Associate Director, Corporate Communications,
760-603-2772; or Xenon Pharmaceuticals' Contact: Dr. Robin Sherrington, SVP
Business & Corporate Development, (604) 484-3300, ddunn@xenon-pharma.com
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