New Clinical Data Indicates LEUKINE Maintains Viral Suppression and Extends
(PR Newswire 05/03 14:57:40)
Duration of Antiretroviral Therapy Utility in People With AIDS
Phase III Results of Immune-Based Therapy From Immunex
SEATTLE, and VICTORIA, British Canada, May 3 /PRNewswire/ -- Immunex
Corporation (Nasdaq: IMNX) announced today that LEUKINE(R) (sargramostim;
GM-CSF) maintained viral suppression and extended the duration of
antiretroviral therapy utility in patients with AIDS whose viral loads were
less than 30,000 copies/mL at study entry. In addition, while LEUKINE did not
decrease "AIDS clinical events" including opportunistic infections, bacterial
pneumonia or death, it did reduce the incidence of all infections and death.
The results of the Phase III trial were presented at the Eighth Canadian
Conference on HIV/AIDS Research.
The 309-patient, Phase III, double-blind, randomized, placebo-control
trial evaluated the impact of LEUKINE on the incidence of opportunistic
infections, the rate of survival and changes in viral load, CD4+ T cell counts
and absolute neutrophil counts. Changes in therapeutic regimens also were
monitored in this study. All patients in the trial were diagnosed with
late-stage AIDS (patients entering the study had CD4+ T cell counts of less
than 50, or less than 100 with a prior AIDS-defining opportunistic infection).
Patients were stratified into two groups based on baseline viral loads of
below or above 30,000 copies/mL. Patients received either LEUKINE or a
placebo three times per week for six months as an adjunct to standard
antiretroviral therapy. Physicians were permitted to change antiretroviral
therapy to manage the patient's viral load. Forty-five percent of patients
participated in an optional, blinded study extension up to 20 months of
treatment.
Among 115 patients with viral loads less than 30,000 copies/mL, 81 percent
of the LEUKINE patients were able to remain on the same antiretroviral regimen
and maintain baseline level of viral suppression throughout the duration of
the study as compared to 62 percent of the patients receiving placebo. In the
six-month study, patients with undetectable virus (less than 400 copies/mL)
who received LEUKINE were more likely to maintain undetectable viral loads
than patients receiving placebo. In 57 patients with undetectable virus at
study entry, 83 percent of LEUKINE patients continued to maintain undetectable
viral load at 24 weeks as compared to 54 percent of placebo patients.
"Despite the success of current anti-HIV therapies, there is an increasing
incidence of treatment failure," said Jonathan Angel, M.D., principal
investigator and infectious disease specialist at Ottawa General Hospital in
Ontario, Canada. "Patients are failing existing antiretroviral regimens for
at least two reasons. One is a lack of patient adherence to the strict dosing
regimens of antiretroviral drugs. Another reason is that HIV mutates
-- becoming resistant to a single antiretroviral agent, or whole class of
these therapies. This new data suggests that it is possible to extend the
time patients can maintain viral suppression and their responses to an
antiretroviral regimen."
LEUKINE belongs to a developing class of immune-based therapies being
studied in people with HIV/AIDS. Laboratory research has shown that LEUKINE
protects immune system cells from HIV by blocking the virus from entering
uninfected cells. Previous clinical research has extended this observation
and shown that LEUKINE can reduce viral load in combination with mono or dual
nucleoside analog therapy and can reduce viral resistance to at least one of
these therapies, zidovudine (AZT).
"While antiretroviral therapies attack the virus, immune-based therapies
focus on the immune system cells," said Ann Hayes, M.D., senior vice president
of medical development at Immunex. "Immune-based therapies have the potential
to protect the immune system from HIV infection, ensure that infected cells
remain susceptible to antiretroviral therapies, and ultimately re-establish
the human immune system's ability to fight HIV and infections on its own."
People with AIDS have very low cell counts resulting in a compromised
immune system and very limited defense against infection. Analysis of the
incidence of infections and death (including opportunistic infections used to
define a diagnosis of AIDS and other infections such as bacterial pneumonia,
bacteremia and urinary tract infections) determined that LEUKINE increased the
median time to first event by 41 days in both cohorts. Further, the incidence
of these events was lower in the LEUKINE group (67 percent) as compared to the
placebo group (78 percent).
The Phase III study also found that patients in both cohorts treated with
LEUKINE nearly doubled mean CD4+ T cell counts from 51 at the start of the
study to 94 at six months while patients in the placebo group had an increase
in cell counts from 50 to 71. Also, at six months, LEUKINE increased mean
absolute neutrophil counts by 884 as compared to 266 among patients receiving
placebo.
"We will be reviewing the results of the LEUKINE Phase III trial with the
FDA this spring," said Peggy Phillips, Immunex senior vice president of
pharmaceutical development.
LEUKINE was generally well tolerated. Side effects occurring more
frequently with LEUKINE than placebo included injection site reactions and
weight loss. Injection site reactions were mostly mild and did not require
treatment; weight decreases were typically mild.
The results described herein are based on investigational data analyzed by
Immunex. These data have not been reviewed by the U.S. Food and Drug
Administration (FDA) as part of an application for regulatory approval.
LEUKINE is not indicated for use in HIV, however, the company has been working
aggressively since 1996 to evaluate the product's mechanism of action and role
in HIV treatment. Full prescribing information for LEUKINE can be obtained by
calling 800-IMMUNEX or at www.immunex.com.
The most recent estimate from the Centers for Disease Control indicates
that there are 650,000 to 900,000 Americans currently living with HIV, which
equates to 1:160 men and 1:800 women over age 13.
Immunex is a biopharmaceutical company dedicated to developing immune
system science to protect human health. The company's products offer hope to
patients with cancer, inflammatory and infectious diseases.
American Home Products owns a majority interest in Immunex. AHP is one of
the world's largest research-based pharmaceutical and health care products
companies. It is a leader in the discovery, development, manufacturing, and
marketing of prescription drugs and over-the-counter medications. It is also
a global leader in vaccines, biotechnology, agricultural products and animal
health care.
NOTE: This news release contains forward-looking statements that involve
risks and uncertainties, including risks associated with clinical development,
regulatory approvals, product commercialization and other risks described from
time to time in the SEC reports filed by Immunex, including the most recently
filed Form 10K.
SOURCE Immunex Corporation
-0- 05/03/99
/CONTACT: media, Cathy Keck Anderson, 206-389-4039, or investors, Mark
Leahy, 206-389-4363, both of Immunex Corporation/
/Company News On-Call: prnewswire.com or fax,
800-758-5804, ext. 434644/
/Web site: immunex.com
(IMNX)
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