Thursday, February 6, 1997
HIV:
Study shows protease inhibitors hold great promise for attacking
virus in pediatric casesBy Kathryn Combs
Daily Bruin Contributor
Parents of the ’90s have to keep a close eye on various aspects
of their children’s health: immunizations, teaching healthy eating
habits, pollution, and increasingly, HIV education and
treatment.
According to the Morbidity and Mortality Weekly Report (MMWR),
HIV infection is something that parents are having to face more
often than ever before. The number of pediatric cases of HIV
infection increased last year by 216.
What many Americans don’t realize is that of the approximately
200,000 HIV infected individuals in the United States alone,
roughly 20 percent, or 10,000 of these, are children.
According to researchers with the UCLA division of pediatric
immunology and infectious diseases, such as Paul Krogstad, it is
precisely this increase and a seeming neglect in bringing updated
treatments to pediatric patients that prompted them to attack this
problem.
The Nelfinavir Pediatric Study, initiated in September of 1996,
is an ongoing pediatric clinical trial designed to evaluate the
safety, tolerance levels and long term efficacy of the protease
inhibitor called Nelfinavir, also known as Viracept.
Phase one of the trial, headed by Krogstad and staffed by a
group of UCLA doctors and nurses, found that Viracept can be
administered to children who are infected with HIV with little or
no side effects however in doses 2 1/2 times more than that needed
to treat adults.
"There’s tended to be a lag in bringing new medications to HIV
infected children," said Krogstad.
"Only one of the nine licensed anti-HIV drugs was studied in
children at the same time as adults. (This is) preventing children
from having access to the benefits of this whole class of protease
agents," he added.
Protease inhibitors seem to be the most effective in suppressing
the virus in adults with HIV.
According to Krogstad, the HIV virus has three enzymes that it
needs to complete its life cycle. One of these enzymes is protease.
Protease is responsible for the complete maturation of the viral
particles within the cells. If the production of protease is
blocked, the virus will reproduce and release more of the virus but
those particles released will not be infectious. Protease
inhibitors were first licensed for prescriptive use by the FDA in
fall 1995.
Krogstad said that this study is the first of its kind.
"No one had ever attempted to see how these drugs might be
useful in children," he said.
In the past there has been a problem with trying to use the same
drugs used to treat adult cases of HIV and applying them to
pediatric cases because of the form that they come in.
Many of the medications used to treat cases of HIV infection
come in pill form and are unable to be used for HIV patients under
5 years of age, because it is often difficult to administer pills
to children.
As a result, Agouron Pharmaceuticals Inc., in San Diego, has
been working closely with UCLA researchers to solve this problem.
Agouron has been able to produce Viracept in both a pill and oral
powder form, making it easier to prescribe this therapy to children
under 5.
UCLA researchers have found that triple drug therapy including
the use of Viracept is effective in reducing levels of HIV found in
the blood. Now that the drug can be administered to children,
researchers say they are optimistic about treatment possibilities
for their youngest HIV patients.
"What we’re seeing is a tremendous decline of virus levels (in
the blood) to almost undetectable levels in most children," said
Karin Nielson, with the division of pediatric immunology and
infectious diseases.
"(However) we are not using this drug alone. It has been shown
that triple therapy is more effective than mono-therapy," he
said.
Although the study was largely focused on evaluating the
effectiveness of Viracept itself, researchers said the resulting
outcomes are the result of the combination of the protease
inhibitor and Viracept.
"It’s like hitting them hard," said Deena Jung, pediatric nurse
practitioner and study coordinator for this clinical trial.
"When we add the protease inhibitor, we are changing two parts
of the therapy, creating two places where the drugs can attack the
virus," she explained.
Krogstad stressed the importance of maintaining high enough
levels of therapeutic drugs in the blood stream so that the
HIV/AIDS virus can not immediately mutate to become resistant to
the treatment.
Findings from phase one were presented by Krogstad at the Fourth
Conference on Retroviruses and Opportunistic Infections in
Washington D.C. Jan. 22-26.
AARON TOUT
Paul Krogstad headed phase one of the Nelfinavir Pediatric
Study.