Press Release: Actelion's Chief Scientific -2-

Actelion Pharmaceuticals Ltd / Actelion's Chief Scientific Officer Martine Clozel awarded the Tomoh Masaki award by the 14th International Conferences on Endothelin . Processed and transmitted by Nasdaq OMX Corporate Solutions. The issuer is solely responsible for the content of this announcement.

SAVANNAH, UNITED STATES OF AMERICA AND ALLSCHWIL, SWITZERLAND - 05 September 2015 - Actelion Ltd (SIX: ATLN) today announced that its Chief Scientific Officer and Member of the Actelion Founding team, Martine Clozel, has been awarded the Tomoh Masaki Award by the International Conferences on Endothelin, the bi-annual scientific event, currently taking place for the 14th time in Savannah, Georgia/USA.

In its tribute, the award committee highlighted Dr. Clozel's contribution to successfully discovering multiple endothelin receptor antagonists, especially Tracleer(R) (bosentan) and Opsumit(R) (macitentan), two molecules that each made history in the field of pulmonary arterial hypertension.

Accepting the award, Dr. Clozel highlighted her long-term commitment to turn groundbreaking scientific achievements, such as the discovery of the endothelin system by Professor Tomoh Masaki and his team, into innovative medicines that change the lives of patients. She also highlighted the key contribution of Professor Masashi Yanagisawa, who was the lead author on the study in the discovery of endothelin and was the first recipient of the award, as well as Professor Kastutoshi Goto, the second recipient, for his role in understanding the pathophysiology of endothelin.

Dr. Clozel said: "It is my privilege to be part of such a vibrant research community as the one that covers endothelin science. I have been actively participating to every international conference on endothelin since the very first one in 1988 in London. At every meeting, new information has been presented that showed the path forward for new endothelin-based medical therapies."

Dr. Clozel specifically highlighted the ongoing further research and development efforts at Actelion in the field of endothelin receptor antagonists, with multiple clinical studies either ongoing or in the process of being initiated, to identify further applications where counteracting the deleterious effects of an endothelin overproduction could result in significant changes in clinical outcome and patient well-being.

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NOTES TO EDITOR:

ABOUT THE AWARD

Professor Tomoh Masaki, a Japanese physician-scientist born in 1934, is particularly known for the discovery of endothelium-derived peptide endothelin and its receptors, among many other scientific achievements. The Tomoh Masaki Award was established in 2011 by the Endothelin International Advisory Board of The International Conferences on Endothelin as a biannual scientific prize with the purpose of "recognizing individuals for their outstanding scientific achievements to advance science and medicine, the ability to motivate and mentor others, and for continuous scientific excellence in the endothelin field".

The International Advisory Board on Endothelin Conferences is a group of leading academic scientists from around the world who preside over the organization of these conferences and is responsible for selecting Tomoh Masaki award recipients. These bi-annual conferences that first began nearly 25 years ago rotate between Europe, North America and Japan and represent a unique partnership of a diverse range of scientists from both industry and academia. These meetings are typically hosted by one of the host country's scientific societies, which this year is the American Physiological Society, founded in 1887 and is the oldest biomedical research organization in the North America.

ABOUT MARTINE CLOZEL

Martine Clozel, a pediatrician specialized in neonatal intensive care, has an MD degree from Nancy University, France, and received further training in physiology and pharmacology from McGill University, Montreal, and the University of California, San Francisco.

During her 11 years at F. Hoffmann-La Roche Ltd, she initiated the research project on endothelin and endothelin receptor antagonists which led to the discovery and clinical development of bosentan (Tracleer(R) ), tezosentan, clazosentan and other molecules. In 1997 she was awarded the Hoffmann-La Roche Research Prize for her achievements in the field of endothelin research.

In 1997 Martine co-founded Actelion Pharmaceuticals Ltd, where she is Senior Vice President, Head of Drug Discovery, Pharmacology & Preclinical Development. Under her leadership, Actelion applied a tailored drug discovery effort that resulted in Opsumit (macitentan), a novel endothelin receptor antagonist currently available in more than 30 markets worldwide.

Dr. Clozel is the author on more than 90 scientific publications in the field of endothelin science, in particular the seminal publication published in Nature (21 October 1993) titled "The pathophysiological role of endothelin revealed by the first orally active endothelin receptor antagonist".

Martine also serves as the Chief Scientific Officer and a member of the Extended Actelion Executive Committee.

ABOUT THE ENDOTHELIUM AND THE ENDOTHELIN SYSTEM

The endothelium is an organ consisting of a single layer of cells between the blood stream and the blood vessel wall. The main functions of the endothelium include:

-- maintenance of blood vessel tone, which is critical for regulating blood pressure levels

-- prevention of blood clots forming on the vessel wall by providing a non-adhesive surface

Endothelial cells produce several vasoactive chemical factors, among them endothelin and nitric oxide, which work in opposition. Nitric oxide dilates blood vessels, prevents platelet adhesion, and inhibits cell proliferation.

Endothelin, however, is a powerful blood vessel constrictor that also promotes cell proliferation. In a normal healthy state, the body maintains a balance between nitric oxide and endothelin. In contrast, in certain disease states endothelin is produced in excess. In addition to causing vasoconstriction, the narrowing of blood vessels, excessive endothelin can:

-- stiffen blood vessels and tissues by promoting fibrosis, the accumulation of connective tissue

-- cause vascular remodeling (a change in the vessels' structure), vascular hypertrophy (an increase in the thickness of blood vessel walls), and cardiac hypertrophy

-- predispose the vessels to inflammation

ABOUT PULMONARY ARTERIAL HYPERTENSION

Pulmonary arterial hypertension (PAH) is a chronic, life-threatening disorder characterized by abnormally high blood pressure in the arteries between the heart and lungs of an affected individual. The symptoms of PAH are non-specific and can range from mild breathlessness and fatigue during normal daily activity to symptoms of right heart failure and severe restrictions on exercise capacity and ultimately reduced life expectancy.

PAH is one group within the classification of pulmonary hypertension (PH). This group includes idiopathic PAH, heritable PAH and PAH caused by factors which include connective tissue disease, HIV infection and congenital heart disease.

The last decade has seen significant advances in the understanding of the pathophysiology of PAH, which has been paralleled with developments of treatment guidelines and new therapies. Drugs targeting the three pathways that have been established in the pathogenesis of PAH are endothelin receptor antagonists (ERAs), prostacyclins and phosphodiesterase-5 inhibitors. PAH treatments have transformed the prognosis for PAH patients from symptomatic improvements in exercise tolerance 10 years ago to delayed disease progression today. Improved disease awareness and evidence-based guidelines developed from randomized controlled clinical trial data have highlighted the need for early intervention, goal-oriented treatment and combination therapy.

In PAH, survival rates are unacceptably low and PAH remains incurable.

ACTELION LTD

Actelion Ltd. is a leading biopharmaceutical company focused on the discovery, development and commercialization of innovative drugs for diseases with significant unmet medical needs.

Actelion is a leader in the field of pulmonary arterial hypertension (PAH). Our portfolio of PAH treatments covers the spectrum of disease, from WHO Functional Class (FC) II through to FC IV, with oral, inhaled and intravenous medications. Although not available in all countries, Actelion has treatments approved by health authorities for a number of specialist diseases including Type 1 Gaucher disease, Niemann-Pick type C disease, Digital Ulcers in patients suffering from systemic sclerosis, and mycosis fungoides type cutaneous T-cell lymphoma.

Founded in late 1997, with now over 2,400 dedicated professionals covering all key markets around the world including Europe, the US, Japan, China, Russia and Mexico, Actelion has its corporate headquarters in Allschwil / Basel, Switzerland.

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(R)). All trademarks are legally protected.

For further information please contact:

Andrew C. Weiss

Senior Vice President, Head of Investor Relations & Corporate Communications

Actelion Pharmaceuticals Ltd, Gewerbestrasse 16, CH-4123 Allschwil

+41 61 565 62 62

http://www.actelion.com

The above information contains certain "forward-looking statements", relating to the company's business, which can be identified by the use of forward-looking terminology such as "estimates", "believes", "expects", "may", "are expected to", "will", "will continue", "should", "would be", "seeks", "pending" or "anticipates" or similar expressions, (MORE TO FOLLOW) Dow Jones Newswires

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-2 of 2- 05 Sep 2015 06:00:00 UTC  Press Release: Actelion's Chief Scientific -2-
or by discussions of strategy, plans or intentions. Such statements include descriptions of the company's investment and research and development programs and anticipated expenditures in connection therewith, descriptions of new products expected to be introduced by the company and anticipated customer demand for such products and products in the company's existing portfolio. Such statements reflect the current views of the company with respect to future events and are subject to certain risks, uncertainties and assumptions. Many factors could cause the actual results, performance or achievements of the company to be materially different from any future results, performances or achievements that may be expressed or implied by such forward-looking statements. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described herein as anticipated, believed, estimated or expected.

Press Release PDF: http://hugin.info/131801/R/1950020/708850.pdf

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Source: Actelion Pharmaceuticals Ltd via Globenewswire

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Actelion Pharmaceuticals Ltd

Gewerbestrasse 16 Allschwil Switzerland

ISIN: CH0010532478;

http://www.actelion.com (END) Dow Jones Newswires

   September 05, 2015 02:00 ET (06:00 GMT)- - 02 00 AM EDT 09-05-15