First patient dosed in new phase III study targeted towards a future clinical indication expansion for Zubsolv

Uppsala, Sweden – June 17, 2013 - Orexo AB announces today that the first
patient has been dosed with Zubsolv in a phase III study for a new clinical
indication for Zubsolv.

Currently all buprenorphine/naloxone combination products licensed in the US are
indicated for maintenance treatment only. Following review by the United States
Food and Drug Administration (FDA), Orexo has initiated a phase III study, which
once completed successfully, will be the basis for an application to expand the
Zubsolv label with a clinical indication that encompass induction of treatment.
Zubsolv is a novel sublingual formulation of buprenorphine and naloxone, with
projected approval for use in maintenance treatment of opioid dependence by the
FDA by July 2013.

Approximately 300 patients will be included in this US trial, and the study is
expected to be completed in early 2014.

Induction of opioid dependence treatment is currently limited to buprenorphine
products not containing naloxone. With a successful study result and subsequent
regulatory approval, physicians will be able to prescribe Zubsolv on-label for
induction of opioid addiction treatment, and thereby facilitate an easier
transition onto such treatment regimen for patients addicted to opioids.

”Orexo is working with the FDA to secure an on-time approval of Zubsolv for use
in maintenance treatment. Once approved Zubsolv will be directed to the more
than five million US citizens suffering from opioid dependence. Our new clinical
research program will ensure that Zubsolv gains an important clinical practice
differentiation and will ensure that patients can be offered Zubsolv from when
they commence treatment for their opioid addiction”, states Nikolaj Sørensen,
President and Chief Executive Officer of Orexo.

He continued by adding “Orexo is committed to take a leading role in optimizing
treatment of opioid dependence in the US. We have previously conducted
acceptance trials for Zubsolv, in which 89% of trial participants favored
Zubsolv over the conventional buprenorphine treatment modalities for opioid
addiction, to understand how our formulation technology could aid in improving
acceptability of buprenorphine treatment. The current clinical research
initiative to expand the future labeled indication for use of Zubsolv is a
logical next step, and we look forward to report on the data in the first half
of 2014”

For further information, please contact:
Nikolaj Sørensen, President and CEO
Tel: + 46-703 50 78 88, Email: nikolaj.sorensen@orexo.com

About the Induction Study
The study is conducted with approximately 300 patients in the US. It is a
randomized, multi-center, blinded, parallel group, active-controlled non
-inferiority study comparing Zubsolv with buprenorphine. It is expected to run
until early 2014.

About Zubsolv
Zubsolv is a novel sublingual formulation of buprenorphine and naloxone using
Orexo’s extensive knowledge in sublingual technologies. Zubsolv is intended for
maintenance treatment of people suffering from opioid dependence. Through
application of its proprietary technologies Orexo has increased the
bioavailability of the active ingredient, accelerated dissolve time, reduced
tablet size and improved taste. In a comparative acceptability study 9 out of 10
participants choose Zubsolv over the market leader Suboxone Film for a daily
treatment. Zubsolv has the potential to be the first new entrant into a growing
USD 1.5 billion market, with more than five million patients suffering from
opioid dependence and where a majority of patients are not adequately treated
today. Market potential for Zubsolv is at peak estimated at above USD 500
million in sales annually.

About Orexo
Orexo AB is an emerging specialty pharma company developing improved treatments
using proprietary drug delivery technology. Orexo’s expertise is within the area
of reformulation technologies and especially sublingual formulations. The
company has a portfolio of revenue generating EU and US approved products
currently marketed under licence and a pipeline of several reformulations of
approved compounds for areas of unmet medical need. Orexo also has collaboration
projects with several international pharma companies. Orexo AB, with its
headquarters in Sweden, is listed on NASDAQ-OMX. The largest shareholders are
Novo A/S and HealthCap.

For information about Orexo AB, please visit www.orexo.com

Orexo is required under the Financial Instruments Trading Act to make the
information in this press release public. The information was submitted for
publication at 08:45am CET on June 17th, 2013.