Drug-Drug Interactions Clinically Manageable With PREZISTA(TM)

Glasgow, Scotland, November 14 (ots/PRNewswire) -

- Data Presented at HIV 8 Conference -

New studies on the use of PREZISTA(TM), an investigational
anti-HIV medication, suggest that it can be co-administered with many
common medications taken by people with HIV, including other
antiretrovirals, proton pump inhibitors, H2 blockers and selective
serotonin reuptake inhibitors. According to current HIV treatment
guidelines, potential drug interactions between HIV antiretrovirals
and other necessary drugs can be dangerous and require special
monitoring(i).

Three studies, including one oral poster, on the co-administration
of PREZISTA, were presented at the Eighth Annual International
Congress on Drug Therapy in HIV Infection (HIV 8) taking place in
Glasgow, Scotland from 12 - 16 November.

PREZISTA (darunavir, also known by the investigational compound
number TMC114), co-administered with 100 mg ritonavir
(darunavir/rtv), is being studied for the treatment of human
immunodeficiency virus (HIV) infection in antiretroviral
treatment-experienced adult patients. It is currently approved in the
United States, Canada and Russia. An application for marketing
authorization was filed with the European Agency for the Evaluation
of Medicinal Products in January 2006.

"With many HIV-infected people taking multiple medications, the
increased potential for drug interactions poses a serious challenge
in finding a safe and effective antiretroviral treatment regimen,"
said David J. Back, Ph.D., Professor, Department of Pharmacology,
University of Liverpool. "These data are important because they
provide information on the interactions between PREZISTA/rtv and
other medications commonly used in patients with HIV."

Use of PREZISTA with common medications (Oral poster PL 5.1)

Location and time: Clyde Auditorium; Tuesday, November 14,
10:30 - 10:45 a.m. GMT

Dr. Back reported results in an oral presentation from clinical
studies evaluating the pharmacokinetic interactions between
darunavir/rtv and a variety of drugs including antiretrovirals such
as atazanavir, indinavir, lopinavir/ritonavir, saquinavir/ritonavir,
efavirenz, nevirapine, tenofovir disoproxil fumarate; antibiotics
such as clarithromycin and ketoconazole; and other medications for
various conditions including atorvastatin, omeprazole, ranitidine,
sildenafil, sertraline, paroxetine and oral contraceptives. Results
showed that darunavir/rtv may be combined with many drugs with no
dose adjustments. Some co-administered drugs, such as indinavir,
sildenafil and atorvastatin may require dose adjustments. In general,
the study found that drug interactions between darunavir/rtv and
drugs commonly used in patients with HIV are manageable.

Pharmacokinetic interaction between PREZISTA with SSRIs assessed
(Poster # P295)

Location and time: Exhibition Hall 4; Monday, November 13 to
Wednesday, November 15, 10:00 a.m. - 7:00 p.m. GMT

The pharmacokinetic interaction between darunavir/rtv and the
selective serotonin reuptake inhibitors (SSRIs), paroxetine and
sertraline, were assessed in a phase I, open-label, two-panel,
randomised, crossover study in 36 HIV-negative, healthy volunteers
presented by Vanitha Sekar, Ph.D. of Tibotec Pharmaceuticals. Safety
and tolerability also were assessed. The study found that the
pharmacokinetics of darunavir/rtv were not significantly affected in
the presence of sertraline or paroxetine, and that darunavir/rtv was
generally well tolerated. Paroxetine and sertraline total
concentrations were decreased in the presence of darunavir/rtv.
Clinical monitoring is recommended when co-administering
darunavir/rtv with SSRIs, although studies have not shown a
correlation between plasma concentration of SSRIs and antidepressant
response.

Co-administration of PREZISTA with methadone (Poster # P294)

Location and time: Exhibition Hall 4; Monday, November 13 to
Wednesday, November 15, 10:00 a.m. - 7:00 p.m. GMT

Dr. Sekar also conducted a trial assessing the effect of multiple
doses of darunavir/rtv on plasma concentrations of methadone since
administration of boosted protease inhibitors has been shown to
decrease methadone plasma concentrations. Results of the open-label,
add-on trial involving 16 patients found co-administration of the
treatment with methadone did not adversely affect the blood plasma
concentrations of methadone, methadone adjustment was not required
when administered with darunavir/rtv, and withdrawal syndrome was
uncommon, occurring in one patient (1/16 patients, 6 percent) during
the co-administration period.

About PREZISTA

PREZISTA (darunavir) is an investigational protease inhibitor that
is currently in Phase III comparative clinical trials versus
lopinavir/ritonavir in treatment-naïve (ARTEMIS) and
treatment-experienced patients (TITAN).

PREZISTA does not cure HIV infection or AIDS, and does not prevent
passing HIV to others.

In studies, darunavir/rtv was generally well tolerated. The most
common moderate to severe side effects associated with darunavir
include headache (3.8 percent), diarrhoea (2.3 percent), abdominal
pain (2.3 percent), constipation (2.3 percent), and vomiting (1.5
percent). Mild to moderate rash was seen in 7 percent of patients.
Severe skin rash, including erythema multiforme and Stevens-Johnson
Syndrome, has been reported in subjects receiving PREZISTA during the
clinical development program. Four percent of patients discontinued
treatment due to adverse events. People who are allergic to darunavir
or any of its ingredients or ritonavir (Norvir) should not take
darunavir. It should be used with caution in patients with known
sulfonamide allergy.

There were few relevant drug-drug interactions with other
medications commonly used in HIV patient populations, such as other
antiretroviral medications, proton pump inhibitors, and H2 receptor
antagonists. Patients should talk to their healthcare provider about
all the medicines they are taking or plan to take, including
prescription and nonprescription medicines, vitamins, and herbal
supplements. Due to the need for co-administration of darunavir with
100mg ritonavir, please refer to ritonavir prescribing information
for a description of ritonavir contraindications.

Before taking darunavir, patients should tell their healthcare
provider if they have any medical conditions, including diabetes,
liver problems, haemophilia, or allergy to sulfa medicines and should
tell their doctor if they are pregnant or planning to become
pregnant, or are nursing. Darunavir should be used with caution in
patients with hepatic impairment.

High blood sugar, diabetes or worsening of diabetes, muscle pain,
tenderness or weakness, and increased bleeding in people with
haemophilia have been reported in patients taking protease inhibitor
medicines like darunavir. Changes in body fat have been seen in some
patients taking anti-HIV medicines, including loss of fat from legs,
arms and face, increased fat in the abdomen and other internal
organs, breast enlargement and fatty lumps on the back of the neck.
The cause and long-term health effects of these conditions are not
known at this time.

Clinical laboratory safety observed in the darunavir group was
comparable to the control group.

PREZISTA was developed by Tibotec Pharmaceuticals Ltd. In the
U.S., it is marketed by Tibotec Therapeutics, a division of Ortho
Biotech Products, L.P. In Canada, it is marketed by Tibotec, a
division of Janssen-Ortho Inc. Pending regulatory approval, Tibotec,
a division of Janssen-Cilag, will commercialise PREZISTA in Europe
and other countries.

For further information, please visit www.tibotec.com.

About Tibotec Pharmaceuticals Ltd.

Tibotec Pharmaceuticals Ltd., based in Cork, Ireland, is a
pharmaceutical research and development company. The Company's main
research and development facilities are in Mechelen, Belgium with
offices in Yardley, PA. Tibotec is dedicated to the discovery and
development of innovative HIV/AIDS drugs and anti-infectives for
diseases of high unmet medical need.

Tibotec Pharmaceuticals is developing a Global Access Program to
facilitate access to its antiretrovirals for patients living with
HIV/AIDS in developing countries. The Global Access Program for
PREZISTA includes access pricing, registration, medical education for
appropriate use and voluntary licensing.

About Tibotec

Tibotec, a division of Janssen-Cilag, will bring innovative
products for HIV/AIDS to patients in Europe, the Middle East and
Africa. This new division was created within the Janssen-Cilag
companies in October 2005 to focus on patients' and health care
providers' specific needs in this disease domain. The company will
also commercialise medicine against other viral diseases in the
future.

Janssen-Cilag

Janssen-Cilag is a leader in traditional and biological medicines
for disorders such as in gastroenterology, women's health, mental
health and neurology as well as for pain, oncology, haematology and
nephrology.

(i) "Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected
Adults and Adolescents," DHHS Panel on Antiretroviral Guidelines for
Adults and Adolescents - A Working Group of the Office of AIDS
Research Advisory Council (OARAC); Accessed at:
http://aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf; last
updated October 10, 2006.

Web site: http://www.tibotec.com

ots Originaltext: Tibotec Pharmaceuticals Ltd.
Im Internet recherchierbar: http://www.presseportal.de

Contact:
Kellie McLaughlin, mobile: +1-609-466-3808; or Hans Vanavermaete,
mobile: +32-478-447-278


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