Medivir - The Phase 3 Program for TMC435 in Treatment-Naive Patients and Patients who Have Relapsed After Prior Interferon-Based Treatment has Now Started

HUDDINGE, Sweden, February 18, 2011 - Medivir AB (OMX: MVIR), the emerging research-based specialty
pharmaceutical company focused on infectious diseases, notes that its
development partner, Tibotec Pharmaceuticals, announced today that the global
phase 3 studies with TMC435 in treatment-naive patients and patients who have
relapsed after prior SOC treatment have started.

    Phase 3 Program in brief:

    - TMC435-C208 or QUEST-1 includes approximately 375 treatment-naive
      patients
    - TMC435-C216 or QUEST-2 includes approximately 375 treatment-naive
      patients
    - TMC435-C3007 or PROMISE includes approximately 375 who have
      relapsed after prior interferon-based treatment

Medivir's CEO, Ron Long, comments - "This is a momentous and
important step for both the project and for Medivir as a company. It is
impressive to see Tibotec's diligence and enterprise in developing TMC435 in
a time-effective and thorough fashion."

The phase 3 milestone of Euro 5 million flagged in February 2010 will now
be recognized as income in the first quarter 2011.

Tibotec released today the following statement:

Cork, Ireland, February 17, 2011 - Tibotec Pharmaceuticals
announced today that two global, registrational phase 3 trials are recruiting
patients to examine TMC435, its investigational hepatitis C protease
inhibitor, in treatment-naive adults with chronic genotype 1 hepatitis C
virus (HCV). A third global phase 3 trial is being conducted in genotype 1
HCV patients who have experienced a viral relapse after prior
interferon-based treatment.

Approximately 3.2 million people in the U.S. live with chronic
hepatitis C disease and more than 170 million people have the disease
globally.[i],[ii] The response-guided trials will compare the efficacy,
safety and tolerability of TMC435 given as a single 150 mg oral tablet once
daily for 12 weeks versus placebo; each patient also will be treated with a
background regimen of peginterferon and ribavirin for 24 or 48 weeks.

"TMC435 is an important component of our growing HCV pipeline
said Brian Woodfall M.D., Vice President of Global Clinical Development at
Tibotec." "The initiation of the TMC435 phase 3 clinical trial program
reinforces our commitment to develop innovative new treatment options that
may decrease the duration of treatment for patients with chronic hepatitis C
infection."

Three global studies

The first global, phase 3, double-blind, randomized study,
known as TMC435-C208 or QUEST-1 (QD dosing of TMC435 of previoUsly untreated
GEnotype 1 patienTs-1), will evaluate a single TMC435 once-daily oral tablet
(150 mg) versus placebo in treatment-naive HCV patients. Both groups will
also receive peginterferon alfa-2a (Pegasys(R)) and ribavirin (Copegus(R)) as
part of their treatment.

The second global, phase 3, double-blind, randomized study,
known as TMC435-C216 or QUEST-2 (QD dosing of TMC435 of previoUsly untreated
GEnotype 1 patienTs-2), also will evaluate a single TMC435 once-daily oral
tablet (150 mg) versus placebo in treatment-naive HCV patients. However,
patients in this trial will either receive peginterferon alfa-2a (Pegasys(R))
and ribavirin (Copegus(R)) or peginterferon alfa-2b (PegIntron(R)) and
ribavirin (Rebetol(R)) as part of their treatment.

A third global, phase 3, double-blind randomized study, known
as TMC435-C3007 or PROMISE (PROtease inhibitor TMC435 In PatientS who have
previously rElapsed on IFN/RBV), will evaluate a single TMC435 once-daily
oral tablet (150 mg) verses placebo in HCV patients who experienced viral
relapse after previous interferon-based therapy. Both groups will receive
peginterferon alfa-2a (Pegasys(R)) and ribavirin (Copegus(R)). The complete
treatment duration for all three trials will be 24 or 48 weeks, depending on
patient response.

In parallel to these trials phase 3 studies for TMC435 have
also recently been launched in Japan.

Centers and inclusion criteria's

The studies will be conducted at more than 160 sites in 24
countries, including the U.S. and countries throughout Europe, and together
seek to enroll approximately 1,125 HCV genotype 1 infected patients who are
treatment-naive or have experienced a relapse after previous interferon-based
HCV therapy. To be eligible, patients must have chronic hepatitis C
infection, and must have had a liver biopsy within three years of the
screening visit. For those patients who have not had a liver biopsy in the
three years prior to the study, one will be performed before the baseline
visit. In addition, eligible patients need to have completed a recent
ultrasound with no findings suspicious of hepatocellular carcinoma (HCC).
Patients with signs of hepatic decompensation, liver disease of any non-HCV
etiology, co-infection with hepatitis B or HIV-1 and 2 or a history of
malignancy within 5 years of the screening visits are ineligible for the
study.

Patients in QUEST-1 and QUEST-2 trials must not have received
any prior treatment for hepatitis C, and patients in the PROMISE trial must
have previously received at least 24 weeks of (peg)interferon-based therapy,
along with documented negative HCV RNA at last on-treatment measurement, and
have relapsed (detectable HCV RNA) within one year of last taking medication.

The primary endpoint of the studies is to assess whether
TMC435 is superior to placebo in achieving sustained virologic reponse (SVR),
defined as HCV RNA <25 IU/ml undetectable, 24 weeks after the planned end of
treatment (SVR 24), with the final analysis being performed after the last
patient reaches week 72 of the study. Secondary endpoints include superiority
of TMC435 versus placebo at 12 weeks (SVR 12), after planned end of treatment
and at week 72 of the study. Evaluations of viral breakthroughs, relapse
rates in treatment groups, safety and tolerability also will be assessed.

*Pegintron(R) and Rebetol(R) are registered trademarks of Schering
Corporation, a subsidiary of Merck & Co., Inc.

*Pegasys(R) and Copegus(R) are registered trademarks of Hoffman-La Roche,
Inc.

[i]Centers for Disease Control and Prevention (CDC). "Hepatitis C FAQs
for the Public." June 9, 2009. Available at
www.cdc.gov/hepatitis/C/cFAQ.htm#. Last accessed February 4, 2011.

[ii] Afdhal, N.H. "The Natural History of Hepatitis C." Seminars in Liver
Disease. 2004. 24 (2): 3-8. Available at
www.ncbi.nlm.nih.gov/pubmed/15346240. Last accessed February 4, 2011.

About TMC435 in other clinical studies

TMC435 is a once-daily (q.d.) protease inhibitor drug jointly
developed by Medivir and Tibotec Pharmaceuticals, to treat chronic hepatitis
C virus infections.

In parallel to the recent start of the global phase 3-studies,
TMC435 is currently in a follow up phase in three phase 2b clinical trials
(TMC435-C205, TMC435-C206 and TMC435-C215) in G1 treatment-naive and in G1
patients that failed previous IFN-based treatment. More safety and efficacy
data from the phase 2b trials will be presented at scientific meetings later
in 2011.

For additional information for these studies, please see
www.clinicaltrials.gov

About Hepatitis C

Hepatitis C is a blood-borne infectious disease of the liver
and is a leading cause of chronic liver disease and liver transplants. The
WHO estimates that nearly 180 million people worldwide, or approximately 3%
of the world's population, are infected with hepatitis C virus (HCV). The CDC
has reported that almost three million people in the United States are
chronically infected with HCV.

About Medivir

Medivir is an emerging research-based specialty pharmaceutical
company focused on the development of high-value treatments for infectious
diseases. Medivir has world class expertise in polymerase and protease drug
targets and drug development. Medivir has a strong R&D portfolio and has
recently launched its first product Xerese(TM)/Xerclear(R). Medivir's key
pipeline asset, TMC435, a protease inhibitor, recently entered global phase 3
development for the treatment of hepatitis C and is partnered with Tibotec
Pharmaceuticals.

Xerese(TM)/Xerclear(R) is an innovative treatment for cold
sores, which has been approved in both the US and Europe. It is partnered
with GlaxoSmithKline to be sold OTC in Europe and Russia and with Meda AB in
North America. Medivir has retained the Rx rights for Xerclear(R) in Sweden
and Finland.

For more information on Medivir, please see the company website:
www.medivir.com

    For additional information, please contact

    Medivir (www.medivir.com)
    Rein Piir, CFO & VP Investor Relations
    Mobile: +46-708-537-292

    M:Communications
    Medivir@mcomgroup.com
    Europe: Mary-Jane Elliott/ Amber Bielecka /Nick Francis
    +44(0)20-7920-2330

    USA: Roland Tomforde
    +1-212-897-5497

For additional information, please contact: Medivir, Rein Piir, CFO & VP Investor Relations, Mobile: +46-708-537-292, M:Communications, Medivir at mcomgroup.com, Europe: Mary-Jane Elliott/ Amber Bielecka /Nick Francis, +44(0)20-7920-2330; USA: Roland Tomforde, +1-212-897-5497