Times Live Blog: Promising results in blocking HIV during first days of infection: M2010
Indevus pharmaceuticals announces PRO 2000 found to show promise in large HIV prevention study
By PR NEwswire (LEXINGTON, Mass, U.S.A) 9 February 2009: Indevus Pharmaceuticals, Inc. (Nasdaq: IDEV) announced today that a National Institutes of Health (NIH)-sponsored clinical study found that participating women who received PRO 2000, the Company's candidate vaginal microbicide for HIV prevention, had an approximately 30% lower risk of acquiring HIV infection than women who received a placebo or no vaginal product.
All women participating in the study were offered free condoms and
safer-sex counseling. This is the first trial to suggest any
microbicide may prevent male-to-female sexual transmission of HIV
although the beneficial effect did not reach statistical significance.
The results will be presented today at the 16th Conference on
Retroviruses and Opportunistic Infections in Montreal.
"We are extremely excited with the results of this trial," stated Glenn
L. Cooper, M.D., chairman and chief executive officer of Indevus.
"Though not conclusive, these results provide encouragement that PRO
2000 may offer a female-controlled method that can be used to protect
against the sexual transmission of HIV.
"In addition to the HPTN 035 trial, we are awaiting results from the
MRC-sponsored trial which will provide data on nearly 10,000 women,"
continued Dr. Cooper. "These results should be available by the end of
2009."
The HIV Prevention Trials Network (HPTN) 035 trial was a
multi-national, randomized, placebo-controlled trial to assess the
safety and effectiveness of PRO 2000 and another investigational
vaginal microbicide (BufferGel(R), ReProtect, Inc.) in preventing HIV
infection in women. The trial was sponsored by the National Institute
of Allergy and Infectious Diseases (NIAID), a component of the NIH, and
conducted by the NIH-funded Microbicide Trials Network (MTN) at seven
clinical centers in Malawi, Zimbabwe, South Africa, Zambia, and the
United States.
The trial was initiated in February 2005 and enrolled approximately
3,100 eligible, HIV-uninfected women, all of whom provided written
informed consent. Enrolled participants were randomly assigned to one
of four arms: PRO 2000 gel (0.5% strength), BufferGel, a placebo gel,
or no gel. Women enrolled in the three gel arms were asked to apply the
assigned study product vaginally up to one hour before each act of
sexual intercourse. The gel arms were double-blinded so that neither
the participant nor the study staff knew the identity of the assigned
study product. Women in all four arms received a standard-of-care HIV
prevention package, which included free male condoms, risk-reduction
counseling, and treatment of sexually transmitted infections.
Participants were followed for 12-30 months (20 months on average),
depending on when they entered the study.
A total of 194 new HIV infections occurred among study participants
over the course of the trial. Of these, 36 occurred in the PRO 2000
arm, 54 in the BufferGel arm, 51 in the placebo arm, and 53 in the
no-gel arm. Based on these data, PRO 2000 was 30 percent effective
(approximately 33 percent effectiveness would have been considered
statistically significant). The adverse event profile was similar in
all four arms, indicating that 0.5% PRO 2000 is safe for vaginal use. A
full analysis of the trial data is underway.
The study was conducted in communities where the background rate of HIV
infection is high. Participants who became infected with HIV during the
trial were referred to local HIV care and support services. Where
possible, infected participants were invited to participate in
Microbicide Trials Network (MTN) 015, a clinical study examining the
nature of HIV progression and treatment response in HIV-positive women
who had been using a topical microbicide or oral antiretrovirals as an
HIV preventive measure when they acquired HIV infection.
A second large trial testing the safety and effectiveness of the 0.5%
dose of PRO 2000 is currently underway. This trial is being sponsored
by the United Kingdom's Medical Research Council (MRC) and conducted by
the Microbicides Development Programme (MDP), an international
partnership of researchers established to develop microbicides for the
prevention of HIV transmission. Study MDP 301 is a multi-national,
randomized, double-blind, placebo-controlled Phase III trial designed
to examine the safety and effectiveness of PRO 2000 in preventing HIV
infection in women. As in the HPTN 035 trial, all participants receive
free condoms, risk-reduction counseling, and treatment for sexually
transmitted infections. Approximately 9,400 women have been enrolled at
study sites in South Africa, Tanzania, Uganda, and Zambia. The trial is
expected to be completed during the summer of 2009.
Should PRO 2000 be shown conclusively to be safe and effective, Indevus
intends to seek worldwide marketing approvals, and plans to work with
government agencies and other organizations to help ensure affordable
access to the product in resource-limited settings where the need is
greatest.
According to statistics from UNAIDS and the U.S. Centers for Disease
Control and Prevention, nearly half of the 33 million people living
with HIV/AIDS worldwide are women. Most HIV infections in women are due
to heterosexual intercourse. Moreover, women are twice as likely as
their male partners to acquire HIV during sex, due in part to
biological factors that make women more vulnerable. Although correct
and consistent use of male condoms has been shown to prevent HIV
infection, women often cannot negotiate condom use with their male
partners. A safe and effective vaginal microbicide could offer a
readily available approach for many women who cannot simply rely on
condoms or abstinence as methods for protecting themselves from HIV.
Even a partially effective microbicide could have a profound impact on
the dynamics of HIV transmission. According to mathematical modeling
conducted by the London School of Hygiene and Tropical Medicine, 2.5
million HIV infections could be averted over three years if a
microbicide with 60 percent effectiveness were used in 73 low-income
countries.
About Indevus
Indevus Pharmaceuticals, Inc. is a specialty pharmaceutical company
engaged in the acquisition, development, and commercialization of
products to treat conditions in urology and endocrinology. The
Company's approved products include SANCTURA(R) and SANCTURA XR(TM) for
overactive bladder, VANTAS(R) for advanced prostate cancer,
SUPPRELIN(R) LA for central precocious puberty, and DELATESTRYL(R) to
treat male hypogonadism. The Indevus development pipeline contains
multiple compounds within the Company's core therapeutic areas in
addition to several partnered or partnerable programs. The most
advanced compounds in development include, VALSTAR(TM) for bladder
cancer, NEBIDO(R) for hypogonadism, PRO 2000 for the prevention of
infection by HIV and other sexually-transmitted pathogens, the
octreotide implant for acromegaly and carcinoid syndrome, and pagoclone
for stuttering.
PRO 2000
PRO 2000 (a naphthalene sulfonate polymer) is under development as a
topical vaginal microbicide to prevent the sexual transmission of HIV
and other sexually transmitted diseases. Laboratory studies have shown
that PRO 2000 is active against HIV, herpes simplex virus, chlamydia
and the bacterium that causes gonorrhea. Vaginally applied PRO 2000 has
been found to afford protection in mouse models for genital herpes
infection and gonorrhea, and in a simian model for vaginal HIV
infection. Prior to initiation of the HPTN 035 trial, PRO 2000 had
undergone extensive safety testing in several clinical trials involving
women and men in the United States, Europe, Africa and India.