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Actelion's novel CRTH2 antagonist meets primary endpoint in Phase II study in patients with seasonal allergic rhinitis

ALLSCHWIL/BASEL, SWITZERLAND - 23 May 2011 - Actelion Ltd (SIX: ATLN) today announced that a Phase II study with its novel orally-active CRTH2 antagonist in seasonal allergic rhinitis has met its primary endpoint with statistical significance (p<0.05).

The study assessed the efficacy and tolerability of various doses of this novel CRTH2 antagonist in adult patients with seasonal allergic rhinitis ("hay fever") due to mountain cedar pollen. Treatment in this study was well tolerated across all treatment groups and no serious adverse events were reported.

Jean-Paul Clozel, M.D. and Chief Executive Officer of Actelion commented: "We are very pleased with the results of this study since, for the first time, we now have proof that CRTH2 antagonists can bring clinically relevant benefit to patients suffering from allergic rhinitis. This study complements the positive proof-of-mechanism study in asthma reported in 2009. Together, these studies provide substantial information that will guide us in the further development of this compound and our follow-up molecules in allergic disorders."

Jean-Paul concluded: "We will now fully analyze the data and plan our next steps, taking into account the ongoing development program in asthma. We are very confident that, with these promising results, CRTH2 antagonists can play an important role in expanding Actelion's portfolio beyond specialty products."

Following full analysis of the study, results will be made available through scientific publication.

About the study design

The study was a prospective, multi-center, double-blind, placebo-controlled, active-reference, multiple-dose levels, randomized, parallel-group Phase II study. The study enrolled 579 patients, who were treated for two weeks, with the primary outcome measure to demonstrate efficacy versus placebo being the mean change from baseline in Daytime Nasal Symptom Score over the entire treatment period.

About Actelion's CRTH2 antagonist

Actelion's CRTH2 antagonist blocks some of the effects of prostaglandin D2 (PGD2) on inflammation and, as a consequence, the amplification and maintenance of allergic reactions. It targets allergic inflammation, with the potential of being used as therapy in both asthma and/or allergic rhinitis as well as in many other potential indications that are based on allergic inflammation.

Positive data have previously been obtained in a proof-of-mechanism study with Actelion's orally-active CRTH2 antagonist in mild-to-moderate allergic asthma. In the 18-patient 2-period crossover double-blind placebo-controlled study, the compound was well tolerated and demonstrates efficacy versus placebo on the primary endpoint (FEV1) during the late allergic reaction (3-10 hours) after a bronchial allergen challenge.

A Phase II dose-finding study in asthma is currently enrolling and is expected to report results mid-2012.




Notes to the Editor


About seasonal and perennial allergic rhinitis

Allergic rhinitis is an inflammation of the nasal passages, usually associated with watery nasal discharge, nasal obstruction, sneezing and itching of the nose. Ocular symptoms such as itching, conjunctival swelling and erythema, eyelid swelling, lower eyelid venous stasis are often associated.

Airborne allergens, both perennial and seasonal can cause allergic rhinitis manifestations. Most common among them, dust mites, cockroaches, moulds and animal dander, are examples of year-around allergens. Tree and grass pollens are primarily seasonal outdoor allergens. (Seasonal pollens depend on wind for cross-pollination.)

The impact of allergic rhinitis

Up to 20% of the population can develop allergic rhinitis.

Poorly controlled symptoms of allergic rhinitis may contribute to decreased health-related quality of life, including loss of sleep, secondary daytime fatigue, learning impairment, decreased cognitive functioning, and decreased long-term productivity.

Poorly controlled allergic rhinitis may be associated with the aggravation of, or a predisposal to, asthma.

The American Academy of Allergy, Asthma & Immunology task force on allergic disorders estimated that allergic rhinitis results in 3.5 million lost workdays and 2 million missed school days each year. For more information, visit the AAAI's webpage:

Actelion Ltd.

Actelion Ltd is a biopharmaceutical company with its corporate headquarters in Allschwil/Basel, Switzerland. Actelion's first drug Tracleer®, an orally available dual endothelin receptor antagonist, has been approved as a therapy for pulmonary arterial hypertension. Actelion markets Tracleer® through its own subsidiaries in key markets worldwide, including the United States (based in South San Francisco), the European Union, Japan, Canada, Australia and Switzerland. Actelion, founded in late 1997, is a leading player in innovative science related to the endothelium - the single layer of cells separating every blood vessel from the blood stream. Actelion's over 2,400 employees focus on the discovery, development and marketing of innovative drugs for significant unmet medical needs. Actelion shares are traded on the SIX Swiss Exchange (ticker symbol: ATLN) as part of the Swiss blue-chip index SMI (Swiss Market Index SMI®).


For further information please contact:

Roland Haefeli Vice President, Head of Investor Relations & Public Affairs Actelion Pharmaceuticals Ltd, Gewerbestrasse 16, CH-4123 Allschwil +41 61 565 62 62 +1 650 624 69 36<>


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Posted: May 2011