Results from the COSMOS study with Simeprevir and Sofosbuvir in cirrhotic and non-cirrhotic HCV genotype 1 patients presented at AASLD

Stockholm, Sweden — Medivir AB (OMX: MVIR) today announced data from the
interferon-free COSMOS study demonstrating safety and efficacy of the
investigational protease inhibitor simeprevir (TMC435) in combination with the
investigational nucleotide inhibitor sofosbuvir (GS-7977), with and without
ribavirin, in genotype 1 chronic hepatitis C adult patients with compensated
liver disease was presented at the Annual Meeting of the American Association
for the Study of Liver Diseases (AASLD) in Washington, D.C. during the late
-breaking oral session on Monday, November 4.

“The high sustained virologic response (SVR) rates seen in genotype 1 patients
with prior null response and in treatment-naïve and prior null response patients
with advanced liver disease, in the COSMOS study, are highly encouraging. These
difficult-to-cure patient groups are in urgent need of efficacious treatment
options which today are lacking” says Charlotte Edenius, EVP Development,
Medivir.

COSMOS - Study Design
COSMOS is a phase IIa, randomized, open-label study investigating the safety and
efficacy of simeprevir in combination with sofosbuvir, with and without
ribavirin, for either 12 or 24 weeks. The study enrolled HCV genotype 1 patients
who were prior null responders to treatment with interferon and ribavirin with
METAVIR F0-F2 scores (cohort 1, n=80), or treatment-naïve patients and prior
null responders with METAVIR F3-F4 scores (cohort 2, n=87).

Final sustained virologic response 12 weeks after the end of treatment (SVR12)
data from cohort 1 in previous null responder patients with METAVIR scores F0-F2
were presented, along with sustained virologic response 4 weeks after the end of
treatment (SVR4) data from the 12 week arms of cohort 2 in treatment-naïve and
previous null-responder patients with METAVIR scores F3-F4. The METAVIR score is
used to quantify the degree of inflammation and fibrosis of the liver. Liver
fibrosis is scored on a four-point scale.

In cohort 1, 77 percent of the patients had genotype 1a (GT1a) subtype with 50
percent of those having baseline Q80K polymorphism. Seventy percent had IL28B CT
genotype, 24 percent had IL28B TT genotype and 59 percent had METAVIR score F2.

In cohort 2, 78 percent of patients had GT1a subtype with 40 percent of those
having baseline Q80K polymorphism. Fifty-six percent had IL28B CT genotype, 23
percent had IL28B TT genotype, 47 percent had METAVIR score F4 (cirrhosis) and
54 percent were prior null responders.

COSMOS – Efficacy Summary
In cohort 1, the SVR12 rate was 93 percent in genotype 1 null-responder patients
with METAVIR scores of F0-F2 treated with simeprevir and sofosbuvir for either
12 or 24 weeks.

In an interim analysis of cohort 2, the SVR4 rate was 100 percent in both
genotype 1 treatment-naive patients and prior null-responder patients with
METAVIR scores of F3-F4 treated with simeprevir and sofosbuvir for 12 weeks.

In a pooled analysis of the 12-week treatment arms in cohorts 1 and 2, SVR4 was
achieved among patients treated with simeprevir and sofosbuvir with or without
ribavirin, in 96 percent of patients with IL28B non-CC genotype, 91 and 100
percent of patients with a METAVIR score of F4, respectively, and 95 percent of
prior null responders.

All patients who completed treatment were HCV RNA undetectable at end of
treatment and there were no viral breakthroughs in either cohort 1 or 2. The
COSMOS study interim results show no benefit from adding ribavirin to simeprevir
and sofosbuvir in this difficult to treat groups of hepatitis C patients and
that 12 week treatment may confer similar clinical benefit to 24 week treatment.

Efficacy results with 150 mg simeprevir (SMV) and 400 mg sofosbuvir (SOF) once
daily with or without ribavirin (RBV). Intent-to-treat (ITT) population.

+-----+-----------------------+----------+-----------------------+----------+
|                                 Cohort 1:                                 |
|        Prior null-responder HCV patients with METAVIR scores F0-F2        |
+-----+-----------------------+----------+-----------------------+----------+
|% (n)|SMV / SOF + RBV 24-week|SMV / SOF |SMV / SOF + RBV 12-week|SMV / SOF |
|     |                       | 24-week  |                       | 12-week  |
+-----+-----------------------+----------+-----------------------+----------+
|SVR12|      79* (19/24)      |93 (14/15)|      96 (26/27)       |93 (13/14)|
+-----+-----------------------+----------+-----------------------+----------+

*17% (4/24) non-virologic failure

+-----+--------------------+---------+---------------------+--------------------
-+
|                                  Cohort 2**:
|
|Prior null-responder and treatment-naïve HCV patients with METAVIR scores F3-F4
|
+-----+--------------------+---------+---------------------+--------------------
-+
|% (n)|SMV / SOF+ RBV Naive|SMV / SOF|   SMV / SOF + RBV   |      SMV / SOF
|
|     |      12-week       |  Naive  |Null response 12-week|Null response 12
-week|
|     |                    | 12-week |                     |
|
+-----+--------------------+---------+---------------------+--------------------
-+
|SVR4 |    100 (12/12)     |100 (7/7)|     93 (14/15)      |      100 (7/7)
|
+-----+--------------------+---------+---------------------+--------------------
-+

**SVR4 data was only available for 12-week arms at time of interim analysis cut
-off

COSMOS - Summary Safety
The most common adverse events in both treatment arms were fatigue, headache,
nausea and insomnia. Rash, itching, anemia and bilirubin increases occurred
mainly in the ribavirin-containing arms of treatment. Four percent of patients
(2/54) treated with simeprevir and sofosbuvir with ribavirin and 7 percent of
patients (2/31) treated with simeprevir and sofosbuvir without ribavirin,
respectively, discontinued treatment due to an adverse event in the 24 week
arms, while no patients (0/82) in the 12 week arms discontinued treatment due to
an adverse event at the time of this analysis.

For more information please contact:
Rein Piir, EVP Corporate Affairs & IR
Mobile: +46 708 537 292.

Medivir is required under the Securities Markets Act to make the information in
this press release public. The information was submitted for publication at 4.30
p.m. EST on 4 November 2013.

About Hepatitis C
Hepatitis C, a blood-borne infectious disease of the liver and a leading cause
of chronic liver disease, is the focus of a rapidly evolving treatment
landscape. Approximately 150 million people are infected with hepatitis C
worldwide – including approximately 3.2 million people in the United States –
and 350,000 people per year die from the disease globally. When left untreated,
hepatitis C can cause significant damage to the liver including cirrhosis.
Additionally, hepatitis C may increase the risk of developing complications from
cirrhosis, which may include liver failure.

About Simeprevir
Simeprevir (TMC435) is an investigational NS3/4A protease inhibitor jointly
developed by Janssen R&D Ireland and its affiliated companies and Medivir AB for
the treatment of genotype 1 chronic hepatitis C in adult patients with
compensated liver disease, including all stages of liver fibrosis. Simeprevir
works by blocking the viral protease enzyme that enables the hepatitis C virus
to replicate in host cells.

Janssen is responsible for the global clinical development of simeprevir and has
acquired exclusive, worldwide marketing rights, except for the Nordic countries.
Medivir AB will retain marketing rights for simeprevir in these Nordic countries
under the marketing authorization held by Janssen-Cilag International NV.

On October 24, the U.S. Antiviral Drugs Advisory Committee of the FDA voted
unanimously (19-0) to recommend approval of the new drug application filed by
Janssen Research & Development, LLC for simeprevir administered once daily with
pegylated interferon and ribavirin for the treatment of genotype 1 chronic
hepatitis C virus (HCV) in adult patients with compensated liver disease.
Simeprevir was approved on September 27, 2013 in Japan for the treatment of
genotype 1 hepatitis C. A Marketing Authorisation Application was submitted in
April to the European Medicines Agency (EMA) by Janssen-Cilag International NV
seeking approval of simeprevir for the treatment of genotype 1 or genotype 4
chronic hepatitis C.

Simeprevir is also being studied in several interferon-free regimens using
selected combinations of direct-acting antiviral agents with different
mechanisms of action. To date, more than 43,700 patients have been treated with
simeprevir in clinical trials.

In October, Janssen Pharmaceuticals, Inc. acquired the investigational compound
GSK2336805, an NS5a replication complex inhibitor in phase II development for
the treatment of chronic HCV, from an affiliate of GlaxoSmithKline plc. Since
being acquired, the compound has been renamed JNJ-56914845. Janssen
Pharmaceuticals plans to initiate phase II studies to evaluate the use of JNJ
-56914845 in interferon-free combinations with simeprevir and TMC647055, the
company’s non-nucleoside polymerase inhibitor, for the treatment of chronic HCV
in adult patients with compensated liver disease.

About Sofosbuvir
Sofosbuvir (formerly referred to as GS-7977) is a once-daily nucleotide analog
polymerase inhibitor for the treatment of HCV infection being developed by
Gilead Sciences, Inc. Sofosbuvir is being evaluated as part of multiple
therapeutic regimens, including programs with RBV alone and in combination with
peg-IFN and RBV.

About Medivir
Medivir is an emerging research-based pharmaceutical company focused on
infectious diseases. Medivir has world class expertise in polymerase and
protease drug targets and drug development which has resulted in a strong
infectious disease R&D portfolio. The Company’s key pipeline asset is
simeprevir, a novel protease inhibitor for the treatment of hepatitis C that is
being developed in collaboration with Janssen R&D Ireland. The company is also
working with research and development in other areas, such as bone disorders and
neuropathic pain. Medivir has also a broad product portfolio with prescription
pharmaceuticals in the Nordics.

For more information about Medivir AB, please visit the Company’s website:
www.medivir.com