Isis Selects Development Candidate, Isis-AATRx, to Treat AATD-Associated Liver Disease

Isis Earns $5 Million Milestone Payment from GSK

CARLSBAD, Calif., Oct. 11, 2011 /PRNewswire/ -- Isis Pharmaceuticals, Inc. (NASDAQ: ISIS) announced today that it has designated the second development candidate, ISIS-AATRx, in its collaboration with GlaxoSmithKline (NYSE: GSK).   Isis earned a $5 million milestone payment from GSK for the selection of ISIS-AATRx.  ISIS-AATRx is an antisense drug designed to treat liver disease caused by alpha-1 antitrypsin deficiency, or AATD, by inhibiting the production of an abnormal protein, which accumulates and causes damage in the liver.  AATD-associated liver disease is a rare disease that can lead to severe and sometimes fatal liver dysfunction.  Isis will develop ISIS-AAT Rx to Phase 2 proof-of-concept, at which time GSK has the option to license the drug.  

"Our collaboration with GSK is off to a very successful start.  Within less than 2 years we have identified two development candidates, with the first, ISIS-TTRRx, expected to finish our Phase 1 study this year and poised to start Phase 2 next year.  This collaboration exemplifies our ability to quickly select targets and discover drugs with promise to treat severe and rare diseases," said Brett P. Monia, Vice President of Drug Discovery and Corporate Development.  "We are pleased to continue to benefit from GSK's expertise as we further expand the breadth of our severe and rare disease franchise and broaden our focus on additional life-threatening diseases for patients who have very limited treatment options."

ISIS-AATRx is an antisense drug designed to inhibit the production of alpha-1 antitrypsin, or AAT, for the treatment of liver disease in patients with AATD.  AATD is a genetic disease that affects 1 out of every 2,500 people in the United States and can lead to severe liver disease, including liver scarring, cirrhosis, and liver cancer. There are currently no available therapies for patients with AATD-associated liver disease, and liver transplantation is the only available option for patients who develop severe liver dysfunction.  Symptoms of AATD-associated liver disease can manifest as early as infancy, and it is the most common genetic disease for which pediatric liver transplantation is performed.  It is estimated that 10-15 percent of all liver transplant candidates have AATD.  

"AATD is an under-diagnosed disease that affects the lungs and, in some patients, can also lead to severe liver damage, end-stage liver disease and liver cancer.  Unfortunately, patients with AATD-associated liver disease currently have no therapeutic options and are only treated to alleviate the symptoms associated with liver damage and scarring.  In cases of severe liver damage, liver transplantation is the only option," said Jeff Teckman, M.D., Professor of Pediatrics and Biochemistry and Director of Pediatric Gastroenterology and Hepatology at Saint Louis University.  "We are encouraged by this therapeutic approach, which could, for the first time, offer an effective and selective treatment for patients with liver disease due to AATD."

In 2010, Isis entered into a strategic alliance with GSK to develop RNA therapeutics for rare and infectious diseases.  With the selection of ISIS-AATRx, Isis has earned $53 million in upfront fees and milestone payments and is eligible to receive license fees and milestone payments, totaling nearly $1.5 billion, in the event all six programs are successfully developed for one or more indications and commercialized through to pre-agreed sales targets.  

ABOUT AATD and ISIS-AATRx

AATD is a genetic disorder in which the patient does not produce normal AAT, a protein primarily produced in the liver that protects lung tissue from damage.  Patients with AATD inherit a mutant gene from one or both parents to produce misfolded AAT protein, which can progressively accumulate in the liver and cause liver disease.  Patients who inherit a mutant gene from both parents are characterized as severe AATD and are at increased risk for developing serious lung conditions, including emphysema, chronic obstructive pulmonary disease, asthma and chronic bronchitis.  Furthermore, approximately 10 percent of infants and 15 percent of adults with severe AATD experience liver damage.  ISIS-AAT Rx is designed to inhibit the production of abnormal AAT in patients with AATD and prevent accumulation of misfolded AAT in the liver, offering a potentially unique approach to treat AATD-associated liver disease.  

ABOUT ISIS PHARMACEUTICALS, INC.

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 24 drugs to treat a wide variety of diseases with an emphasis on cardiovascular, metabolic and severe and rare/neurodegenerative diseases, and cancer.  Isis' partner, Genzyme, plans to commercialize Isis' lead product, mipomersen, following regulatory approval, which is expected in 2012.  Isis' patents provide strong and extensive protection for its drugs and technology.  Additional information about Isis is available at www.isispharm.com.

ISIS PHARMACEUTICALS' FORWARD-LOOKING STATEMENT

This press release includes forward-looking statements regarding Isis' collaboration with GlaxoSmithKline, the discovery, development and potential of drugs for severe and rare diseases, and the development, activity, therapeutic potential and safety of ISIS-AAT Rx.  Any statement describing Isis' goals, expectations, financial or other projections, intentions or beliefs, including the planned commercialization of mipomersen, 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, 2010 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.

In this press release, unless the context requires otherwise, "Isis," "Company," "we," "our," and "us" refers to Isis Pharmaceuticals and its subsidiaries, including Regulus Therapeutics Inc., its jointly owned subsidiary.

Isis Pharmaceuticals® is a registered trademark of Isis Pharmaceuticals, Inc.  Regulus Therapeutics™ is a trademark of Regulus Therapeutics Inc.  

SOURCE Isis Pharmaceuticals, Inc.