Pivotal Data Presented at the 14th Conference on Retroviruses and
                      Opportunistic Infections (CROI)
            Maraviroc Under Accelerated Review in USA and Europe

    LOS ANGELES, March 1 /PRNewswire-FirstCall/ -- At this week's major
HIV/AIDS research meeting, Pfizer presented pivotal data of its
experimental medicine, maraviroc, which tackles HIV in an entirely new way.
A 24 week analysis showed that approximately twice as many patients
receiving maraviroc with an optimized background regimen achieved
undetectable virus in the blood than if an optimized regimen was given
alone.
    The new data, presented at the 14th Conference on Retroviruses and
Opportunistic Infections (CROI), support the accelerated United States and
European regulatory review of maraviroc as a treatment for patients
infected with HIV that is "CCR5 tropic," -- enters immune cells by a
receptor known as CCR5. A test confirms whether a patient is infected with
CCR5-tropic HIV.
    In addition, patients receiving maraviroc and an optimized regimen saw
an increase in CD4 cells nearly twice that seen in those receiving
optimized regimen alone. Adverse events in the group receiving maraviroc
plus an optimized regimen were similar to those receiving an optimized
regimen alone when adjusted for duration of exposure.
    "Data from the two identical studies are remarkably consistent and
demonstrate significant decreases in viral load and increases in CD4 cells
when maraviroc is added to the standard optimized treatment regimen," said
Dr. Howard Mayer, Pfizer's global clinical lead for the maraviroc
development program, who also presented the trial results.
    If approved, maraviroc would be the first new oral class of HIV
medicines in more than a decade, meeting the urgent need of HIV patients
for new drug classes. Discovered by Pfizer scientists in 1997, maraviroc is
an oral medicine that blocks viral entry to human cells. Rather than
fighting HIV inside white blood cells, it prevents the virus from entering
uninfected cells by blocking its predominant entry route, the CCR5
co-receptor.
    Recently, regulatory authorities in the U.S., Europe and Canada granted
accelerated review of maraviroc. Accelerated reviews are granted to
potential medicines that if approved have the potential to fulfill an unmet
medical need. Pfizer is also in the process of submitting marketing
applications around the world to make maraviroc available globally. The
U.S. Food and Drug Administration's Antiviral Drugs Advisory Committee will
discuss maraviroc in April.
    Pfizer is committed to bringing meaningful improvement to the lives of
people living with HIV/AIDS and those at risk around the world. This
commitment is embodied in Pfizer's products, partnerships, pipeline and
philanthropy. Current initiatives include the U.S. Southern States HIV/AIDS
Prevention Initiative; the building of the Infectious Disease Institute in
Kampala, Uganda; the Pfizer Global Health Fellows Program; and the
Diflucan(R) Partnership Program.
    For more information on these and other Pfizer initiatives, go to
http://www.pfizer.com.
    Background on data supporting maraviroc
    The latest results were analyzed at 24 weeks from the ongoing
multicenter, double-blind, placebo-controlled phase 2b/3 MOTIVATE trials
(Maraviroc Plus Optimized Therapy in Viremic Antiretroviral Treatment
Experienced Patients).
    In both studies, approximately twice as many patients treated with
maraviroc plus optimized background therapy (OBT) for either once or twice
daily dosing achieved undetectable viral loads (<50 copies/mL HIV RNA)
compared to those receiving placebo plus OBT (MOTIVATE-1, 42.2% and 48.5%
respectively versus 24.6%; MOTIVATE-2, 40.8% and 45.6% respectively versus
20.9%). Patients receiving maraviroc with OBT for once or twice daily
treatment arms also had significantly higher increases in CD4 cells than
patients receiving placebo plus OBT (MOTIVATE-1, 107 cells/mm3 and 111
cells/mm3 respectively versus 52 cells/mm3; MOTIVATE-2, 112 cells/mm3 and
102 cells/mm3 respectively versus 64 cells/mm3).
    The groups receiving maraviroc plus OBT in both studies had a low rate
of discontinuation due to adverse events regardless of once or twice daily
dosing, similar to the group receiving OBT alone (MOTIVATE-1, 5% and 4%
respectively versus 5%; MOTIVATE-2, 5% and 4% respectively versus 2%).
    In the MOTIVATE 1-2 trials, patients were randomized to receive OBT
combined with either placebo or maraviroc, dosed once or twice daily. OBT
included 3-6 anti-retrovirals, with or without low-dose ritonavir. The
primary endpoint was the mean reduction in HIV-1 RNA from baseline to week
24. MOTIVATE 1 is being conducted at clinical investigational sites in the
U.S. and Canada and MOTIVATE 2 in Europe, Australia, and the U.S.
    In December 2006, Pfizer announced plans to establish a multi-national
Expanded Access Program, a clinical study that provides maraviroc to
patients who have limited or no approved treatment options due to
resistance or intolerance to existing drug classes. The program is open for
enrollment with a target to enroll patients from over 30 countries.
    Pfizer is also studying the utility of maraviroc in treatment naive
patients who have never undergone any HIV medical treatment in an ongoing
study.
    The independent Data Safety Monitoring Board (DSMB) for maraviroc met
on January 15, 2007 to continue to monitor the ongoing clinical programs.
In addition to recommending that the MOTIVATE program continues as
currently designed, the DSMB also recommended that the fully enrolled and
ongoing maraviroc trial in treatment-naïve patients continue.
    DISCLOSURE NOTICE: The information contained in this release is as of
March 1, 2007. 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 that involves
substantial risks and uncertainties regarding a product candidate that is
under review by the United States Food and Drug Administration (FDA), the
European Medicines Evaluation Agency (EMEA) and certain other regulatory
authorities. Such risks and uncertainties include, among other things,
whether and when the FDA, the EMEA and other regulatory authorities will
approve the product candidate, their decisions regarding labeling and other
matters that could affect its availability or commercial potential, as well
as 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, 2006 and in its reports on Form 10-Q and Form 8-K.

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