Orexo announces successful completion of the first clinical trial in OX51

Uppsala, Sweden, March 31, 2011 - Orexo AB (STO: ORX) announces the positive outcome following completion of the initial pharmacokinetic trial in the OX51 project. The project is aimed at developing a sublingual dosage form tailored to treat acute intensive pain episodes in relation to care-related diagnostic or therapeutic procedures for patients whom are not receiving sufficient pain relief.

Orexo plans to enter the next stage of development during the second half of 2011 following discussions with regulatory authorities.

Orexo currently has 3 fully owned programs (including OX51) in early stage clinical development, all directed towards hospital and specialist commercial segments. Initial data from OX219 was communicated in Q4 2010, and initial results from OX27 will be communicated during Q2 2011.

Anders Lundström, Orexo’s President and CEO, said:
“The successful outcome of this trial shows important progress for Orexo in building its proprietary pipeline. This is yet another important step towards our defined goal of becoming a specialty pharmaceutical company”.

For further information please contact:
Anders Lundström, President & CEO
Tel: +46 (0)70-667 22 66
Email: anders.lundstrom@orexo.com

Robin Wright, EVP and CFO
Tel: +44 7720 300025
Email: robin.wright@orexo.com

About OX51 and acute intensive pain episodes
OX51 is a novel sublingual tablet formulation with a currently undisclosed substance for the potential treatment of intensive pain episodes. Today, healthy people as well as severely ill patients often do not receive appropriate pain relief in relation to care-related diagnostic or therapeutic procedures. Orexo is striving to alleviate the unnecessary stress of such investigations, by improving the way improved pain management may be practiced in a simple way. The total number of such intensive pain episodes experienced in hospital or specialists clinics is estimated at more than 100 million annually in Europe and United States.

About Orexo
Orexo is a pharmaceutical company focusing on developing treatments for pain and inflammation. Orexo is developing proprietary products based on its proven reformulation technologies, targeted at the Specialty Pharmaceutical market. Orexo intends to commercialize some of these products itself in one or more major markets. Its development activity builds on Orexo’s core competences in R&D, which have previously resulted in several successful products, currently out-licensed through worldwide partnership agreements to larger pharmaceutical companies. Today, Orexo has four products on the market of which Abstral is a leading product for the treatment of breakthrough pain in cancer patients. Orexo also has three significant partnerships with major pharmaceutical companies for research and development programs: discovery stage collaborations with Ortho-McNeil Janssen and Janssen Pharmaceutica in respiratory inflammation and with Boehringer Ingelheim for inflammation and pain, both within the arachidonic acid cascade and a clinical stage development agreement with Novartis for the treatment of gastrointestinal disorders. Orexo’s head office is located in Uppsala, Sweden. More information can be found at www.orexo.com.

This is information that Orexo AB (publ.) is required to disclose pursuant to the Swedish Securities Markets Act. The information was provided for public release on March 31, 2011 at 4:00 a.m. CET.