[Ip-health] WSJ: Pfizer Seeks to Prevent HIV

[Matt Price]

Pfizer is licensing maraviroc to the nonprofit International
Partnership for Microbicides for potential microbicidal applications


http://online.wsj.com/article/SB120166682382128005.html
Pfizer Seeks to Prevent HIV
By AVERY JOHNSON
January 30, 2008; Page D5

A new Pfizer Inc. HIV drug will soon be reformulated in an effort to
prevent the transmission of the virus, offering a faint ray of hope in
an arena littered with disappointments.

The New York drug maker is expected to announce today that it will
license its new medicine, Selzentry, to a nonprofit that investigates
ways to turn HIV medicines for infected patients into vaginal
substances to prevent transmission to women during sex. The
partnership offers a low-risk way for Pfizer to find out if the
medicine could become a frequently taken drug, while potentially
offering an empowering concept to women in the developing world.

HIV preventives have proven elusive, with researchers and advocates
still recovering from last year's collapse of Merck & Co.'s
once-promising vaccine trial. And Pfizer's new venture with the
International Partnership for Microbicides is a long shot that relies
on an unproven theory. But with some 33 million people infected with
HIV, the virus that causes AIDS, the enormous health and financial
stakes continue to drive the hunt for treatments.

Pfizer's drug was approved last year for patients who have undergone
other HIV treatment. Pfizer is now giving the IPM a license to try to
turn the medicine into a vaginal gel, ring or film that might prevent
transmission.

The Pfizer drug already has a safety portfolio approved by the Food
and Drug Administration, potentially making it easier to get through
testing in a new form. And the way Selzentry works, by blocking the
virus from infecting healthy cells, could make it more appropriate for
prevention than medicines that prevent already-diseased cells from
replicating.

Jack Watters, Pfizer's vice president for external medical affairs, is
hopeful about Selzentry's prospects as a preventive therapy, but he
says "we're a long way from proving that."

Some drugs are used to both prevent and treat diseases such as malaria
and tuberculosis, and there has been hope that existing HIV medicines
can somehow do the same. The topical use is preferred to daily pills,
because less medicine gets into the bloodstream, potentially making it
safer for long-term use, and it can be concentrated where the disease
enters the body, says Zeda Rosenberg, IPM's chief executive.

Selzentry could be particularly well-suited for HIV prevention.
Because the drug interrupts the virus's ability to penetrate a healthy
cell at an entry point called CCR5, it is only approved for patients
who have one strain of the disease. But that receptor is the primary
one responsible for HIV transmission, says John Mellors, chief of
infectious diseases at the University of Pittsburgh's medical school,
who has done consulting for Merck & Co., Abbott Laboratories, Gilead
Sciences Inc. and the IPM.

But the microbicides' promise is clouded. Last year, one of the most
advanced microbicide trials was halted when early data indicated that
more women became infected with HIV than those using a placebo.

Write to Avery Johnson at avery.johnson@WSJ.com