Pfizer's HIV/AIDS Treatment CELSENTRI(TM) (Maraviroc) Demonstrates Increased Efficacy Rate in Treatment-Naive HIV Patients



    
    Results from MERIT ES Data Reanalysis Using Enhanced Sensitivity Tropism
    Test at 48 weeks
    

    KIRKLAND, QC, Oct. 29 /CNW/ - Patients taking CELSENTRI(TM), in
combination with Combivir(R) (zidovudine/lamivudine) and selected by an
enhanced sensitivity tropism test to screen patients, experienced a 68 percent
rate of virologic suppression to undetectable levels, according to the MERIT
ES (Reanalysis of the MERIT Study with the Enhanced Trofile Assay) reanalysis
presented at the 48th Annual Interscience Conference on Antimicrobial Agents
and Chemotherapy (ICAAC(TM))/ 46th Annual Meeting of the Infectious Diseases
Society of America (IDSA) in Washington D.C., USA.
    MERIT ES is a reanalysis of 48-week efficacy and safety data from the
MERIT (Maraviroc versus Efavirenz Regimens as Initial Therapy) study following
retesting of screening samples using the newly launched enhanced sensitivity
Trofile(TM) assay. This therefore represents a subset of the MERIT 48-week
primary analysis population. The enhanced sensitivity test was not available
at the time of the MERIT study and is the only version of Trofile currently
available.
    In the MERIT ES reanalysis 68 percent of patients in the CELSENTRI(TM)
arm, and 68 percent of patients in the efavirenz arm - a current standard of
care - achieved suppression of the virus to undetectable levels (less than 50
copies/mL). When the criterion of less than 400 copies/mL was used, the
results were 73 percent with CELSENTRI(TM), and 72 percent with efavirenz.
    In the MERIT ES population, 14.2 percent of patients taking efavirenz
discontinued due to adverse events compared to 4.2 percent of patients taking
CELSENTRI(TM). This was largely driven by a greater number of cases of CNS
toxicity (13 vs. 2), rash (9 vs. 0), and tuberculosis (6 vs. 1) in the
efavirenz arm versus the CELSENTRI(TM) arm. In MERIT ES, there were fewer
discontinuations in the CELSENTRI(TM) arm due to lack of efficacy than the
rate seen for the MERIT full study population. In MERIT ES, 9.3 percent of
patients taking CELSENTRI(TM) discontinued due to lack of efficacy, compared
to 4 percent of patients taking efavirenz.
    The enhanced sensitivity Trofile assay is able to detect dual/mixed or
CXCR4-tropic variants of the HIV virus when they are present in patients in
(greater than or equal to)0.3 percent of the total viral population, a 30-fold
improvement in sensitivity.

    About the MERIT Study

    MERIT was a Phase 3 study designed to evaluate the antiretroviral
activity of CELSENTRI(TM) (300 mg twice daily) compared to efavirenz (600 mg
once daily), a current standard of care, in combination with Combivir
(zidovudine/lamivudine) in CCR5-tropic HIV-1 infected patients who had never
received antiretroviral therapy and had no evidence of resistance to any of
the drugs used in the study.
    In MERIT, rates of virologic suppression in patients receiving
CELSENTRI(TM) compared to efavirenz were 70.6 percent vs. 73.1 percent for
(less than)400 copies/ml and 65.3 percent vs. 69.3 percent at (less than)50
copies/ml. Fewer patients experienced grade 3 or 4 adverse events in the
CELSENTRI arm than in the efavirenz arm.
    At 48 weeks, the most common adverse events reported during the study in
both arms were nausea, headaches, diarrhea, dizziness and fatigue. When the
incidence of adverse events was adjusted for exposure to study drug, there was
a higher incidence of nasopharyngitis and bronchitis in the CELSENTRI
treatment group and a higher incidence of dizziness, diarrhea, vomiting, upper
respiratory tract infection, cough, abdominal pain, rash and abnormal dreams
in the efavirenz treatment group.

    About CELSENTRI(TM)

    Discovered by Pfizer scientists in 1997, CELSENTRI(TM) is an oral
medicine that blocks viral entry to human cells. Rather than fighting HIV
inside white blood cells, CELSENTRI(TM) prevents the virus from entering
uninfected cells by blocking its predominant entry route, the CCR5
co-receptor.
    CELSENTRI(TM) has been approved for use in several markets around the
world including Canada, the U.S. and European Union in combination with other
antiretroviral medicinal products, for the treatment of experienced adult
patients with only CCR5-tropic HIV-1 detectable.

    About Pfizer

    Pfizer Canada Inc. is the Canadian operation of Pfizer Inc, the world's
leading pharmaceutical company. Pfizer discovers, develops, manufactures and
markets prescription medicines for humans and animals. Pfizer Inc invests more
than US$7 Billion annually in R&D to discover and develop life-saving and
life-enhancing medicines. Canadian headquarters of Pfizer Global
Pharmaceuticals are in Kirkland, Quebec. For more information, visit
www.pfizer.ca.

    DISCLOSURE NOTICE: The information contained in this release is as of
October 29, 2008. Pfizer assumes no obligation to update any forward-looking
statements contained in this release as the result of new information or
future events or developments.
    This release contains forward-looking information about a potential
additional indication for CELSENTRI(TM), including its potential benefits,
that involves substantial risks and uncertainties. Such risks and
uncertainties include, among other things, the uncertainties inherent in
research and development; decisions by regulatory authorities regarding
whether and when to approve any supplemental drug applications that may be
filed for such additional indication as well as their decisions regarding
labeling and other matters that could affect the availability or commercial
potential of such additional indication; and competitive developments.
    A further list and description of risks and uncertainties can be found in
Pfizer's Annual Report on Form 10-K for the fiscal year ended December 31,
2007 and in its reports on Form 10-Q and Form 8-K.





For further information:

For further information: or to speak with a Canadian physician about the
MERIT ES data reanalysis, please contact: Charles Muggeridge,
Fleishman-Hillard, Phone: (416) 214-0701 ext.239,
Charles.muggeridge@fleishman.ca; Safia Généreux-Khali, Pfizer Canada Inc.,
Phone: (514) 693-4657, Safia.Genereux-Khali@pfizer.com


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