Santaris Pharma A/S Advances miravirsen, the First microRNA-Targeted Drug to Enter Clinical Trials, Into Phase 2 to Treat Patients Infected With Hepatitis C Virus

Santaris Pharma A/S initiates Phase 2a clinical trial with miravirsen (SPC3649) to assess safety and tolerability in treatment-naive patients with chronic Hepatitis C

HOERSHOLM, Denmark and SAN DIEGO, September 22, 2010 - Santaris Pharma A/S, a clinical-stage biopharmaceutical company focused
on the discovery and development of RNA-targeted therapies, today announced
that it has advanced miravirsen (SPC3649), the first microRNA-targeted drug
to enter clinical trials, into Phase 2 studies to assess the safety and
tolerability of the drug in treatment-naive patients infected with the
Hepatitis C virus (HCV).

Paving the way to conduct the first clinical trials of a
microRNA-targeted drug in the United States, Santaris Pharma A/S also
received acceptance of its Investigational New Drug (IND) application from
the U.S. Food and Drug Administration (FDA). In addition to the United
States, the Phase 2a clinical trials will be conducted in the Netherlands,
Germany, Poland, Romania, and Slovakia.

The World Health Organization estimates about 3% of the world's
population has been infected with HCV and that some 170 million are chronic
carriers at risk of developing liver cirrhosis and/or liver cancer(2).
Approximately 3-4 million Americans are chronically infected with an
estimated 40,000 new infections per year(1). In Europe, there are about 4
million carriers(2). The current standard of care, pegylated interferon in
combination with ribavirin, is effective in only about 50% of those
treated(1).

Developed using Santaris Pharma A/S proprietary Locked Nucleic Acid (LNA)
Drug Platform, miravirsen is a specific inhibitor of miR-122, a liver
specific microRNA that the Hepatitis C virus requires for replication.
Miravirsen is designed to recognize and sequester miR-122, making it
unavailable to the Hepatitis C virus. As a result, the replication of the
virus is effectively inhibited and the level of Hepatitis C virus is reduced.

"Advancing miravirsen, the first microRNA-targeted drug to enter clinical
trials, into Phase 2 studies in patients with Hepatitis C demonstrates
Santaris Pharma A/S leadership in developing RNA-targeted medicines," said
Arthur A. Levin, Ph.D., Vice President, Chief Development Officer and
President, US Operations. "Receiving IND acceptance from the FDA to conduct
the first clinical trials with a microRNA-targeted drug in the United States
brings Santaris Pharma A/S one step closer to potentially providing a growing
number of patients chronically infected with HCV with a more effective and
better tolerated treatment option."

The LNA Drug Platform is the only technology with both mRNA and microRNA
targeted drugs in clinical trials, reinforcing the broad utility of the
platform. The unique combination of small size and very high affinity, which
is only achievable with LNA-based drugs, allows this new class of drugs to
potently and specifically inhibit RNA targets in many different tissues
without the need for complex delivery vehicles. LNA-based drugs are a
promising new type of therapy that enables scientists to develop drugs to
attack previously inaccessible pathways.

"Using our LNA Drug Platform to advance the first microRNA-targeted
therapy into human clinical trials was certainly a scientific breakthrough,"
said Henrik Oerum, Ph.D., Vice President and Chief Scientific Officer of
Santaris Pharma A/S. "We are extremely pleased with the results of the Phase
I trials and excited to progress miravirsen into Phase 2 clinical trials.
Because of its unique mechanism of action and tolerability profile,
miravirsen has the potential to be an effective treatment option for patients
with HCV."

The randomized, double-blind, placebo-controlled, ascending multiple-dose
Phase 2a study will assess the safety and tolerability of miravirsen and is
designed to enroll up to 55 treatment-naïve patients with chronic Hepatitis C
virus genotype 1 infection. Secondary endpoints include pharmacokinetics of
miravirsen and its effect on viral load. Miravirsen will be given as
subcutaneous injections weekly or every other week for four weeks.

Data from Phase 1 clinical studies with miravirsen in healthy volunteers
show that the drug is well tolerated. A recent study published in Science
demonstrated that miravirsen successfully inhibited miR-122 and dramatically
reduced Hepatitis C virus in the liver and in the bloodstream in chimpanzees
chronically infected with the Hepatitis C virus(3). Miravirsen provided
continued efficacy in the animals up to several months after the treatment
period with no adverse events and no evidence of viral rebound or resistance.

In addition to miravirsen, Santaris Pharma A/S has a robust product
pipeline targeting mRNAs and microRNAs both internally as well as in
partnerships and collaborations with miRagen Therapeutics (cardiovascular
diseases), Shire plc (rare genetic disorders), Pfizer (undisclosed
therapeutic areas), GlaxoSmithKline (viral disease) and Enzon Pharmaceuticals
(oncology).

About microRNAs

MicroRNAs have emerged as an important class of small RNAs encoded in the
genome. They act to control the expression of sets of genes and entire
pathways and are thus thought of as master regulators of gene expression.
Recent studies have demonstrated that microRNAs are associated with many
disease processes. Because they are single molecular entities that dictate
the expression of fundamental regulatory pathways, microRNAs represent
potential drug targets for controlling many biologic and disease processes.

About Locked Nucleic Acid (LNA) Drug Platform

The LNA Drug Platform and Drug Discovery Engine developed by Santaris
Pharma A/S combines the Company's proprietary LNA chemistry with its highly
specialized and targeted drug development capabilities to rapidly deliver
potent single-stranded LNA-based drug candidates against RNA targets, both
mRNA and microRNA, for a range of diseases including metabolic disorders,
infectious and inflammatory diseases, cancer and rare genetic disorders. The
LNA Drug Platform overcomes the limitations of earlier antisense and siRNA
technologies to deliver potent single-stranded LNA-based drug candidates
across a multitude of disease states. The unique combination of small size
and very high affinity, which is only achievable with LNA-based drugs, allows
this new class of drugs to potently and specifically inhibit RNA targets in
many different tissues without the need for complex delivery vehicles.
LNA-based drugs are a promising new type of therapy that enables scientists
to develop drugs to attack previously inaccessible clinical pathways. The
most important features of LNA-based drugs include excellent specificity,
providing optimal targeting; increased affinity to targets providing improved
potency; and strong pharmacology upon systemic delivery without complicated
delivery vehicles.

About Santaris Pharma A/S

Santaris Pharma A/S is a privately held clinical-stage biopharmaceutical
company focused on the discovery and development of RNA-targeted therapies.
The Locked Nucleic Acid (LNA) Drug Platform and Drug Discovery Engine
developed by Santaris Pharma A/S combine the Company's proprietary LNA
chemistry with its highly specialized and targeted drug development
capabilities to rapidly deliver potent single-stranded LNA-based drug
candidates across a multitude of disease states. The Company's research and
development activities focus on infectious diseases and metabolic disorders,
while partnerships with major pharmaceutical companies include a range of
therapeutic areas including cancer, cardiovascular disease, infectious and
inflammatory diseases, and rare genetic disorders. The Company has strategic
partnerships with miRagen Therapeutics, Shire plc, Pfizer, GlaxoSmithKline,
and Enzon Pharmaceuticals. As part of its broad patent estate, the Company
holds exclusive worldwide rights to all therapeutic uses of LNA. Santaris
Pharma A/S, founded in 2003, is headquartered in Denmark with operations in
the United States. Please visit www.santaris.com for more information.

    (1) American Association for the Study of Liver Diseases -
        www.aasld.org/patients/Pages/LiverFastFactsHepC.aspx

    (2) World Health Organization -
        www.who.int/csr/disease/hepatitis/Hepc.pdf

    (3) Science. 2010 Jan 8; 327(5962):198-201. Epub 2009 Dec 3

Navjot Rai, Director, Global Communications of Santaris Pharma, A/S, Office, +-1-858-764-7064, ext. 206, Cell, +1-619-723-5450, navjot.rai at santaris.com