Featured Research

from universities, journals, and other organizations

Drug Tested For HIV Prevention In Baltimore

Date:
February 27, 2003
Source:
Johns Hopkins Medical Institutions
Summary:
As effective vaccines against HIV remain elusive, Johns Hopkins researchers have completed the first tests to see if a drug already used to treat HIV infection might one day be used to prevent sexual and blood-borne transmission of the virus that causes AIDS.

As effective vaccines against HIV remain elusive, Johns Hopkins researchers have completed the first tests to see if a drug already used to treat HIV infection might one day be used to prevent sexual and blood-borne transmission of the virus that causes AIDS.

Reported in the March 7 issue of the journal AIDS (available online now), the 12-week study of nevirapine in Baltimore is believed to be the first in the United States to evaluate a pre-exposure, drug-based prevention strategy for adults at high risk, say the researchers. Previous strategies have focused on behavioral changes such as condom use and clean needles.

"This is a new concept for prevention of HIV infection," says J. Brooks Jackson, M.D., M.B.A., director of pathology and leader of the study. "A combination of drugs is used to treat HIV infection, but we want to see if long-term, low doses of one of these drugs can prevent new HIV infections in people at high risk. HIV infection rates are fairly steady in the United States, but skyrocketing elsewhere. We can't afford to wait for a vaccine."

When taken twice a day, nevirapine is one part of routine anti-retroviral therapy to keep HIV infection from resulting in AIDS. In small, one-time-only doses, the Johns Hopkins researchers already have proven -- overseas -- that nevirapine cuts in half the risk an HIV-infected mother will pass the virus to her baby during childbirth.

The new study tested the safety of three different doses of nevirapine -- all just a fraction of the treatment dose -- in 33 people at high risk of contracting HIV because of sexual practices or injection drug use. No serious adverse side effects related to nevirapine were seen in any participants, and none contracted HIV during the study period, the scientists report.

"This study wasn't designed to test whether nevirapine could in fact prevent HIV transmission, but it would have been bad for the future of this effort if we'd detected significant side effects or new infection," notes Jackson. "The important thing is that the treatment doses were well tolerated, and now we feel comfortable moving forward."

While it can take as long as six months after exposure for HIV to appear, today's HIV tests (which detect antibodies created to battle the virus) can reliably catch a new infection within four to six weeks of exposure, notes Jackson.

At treatment-level doses of 200 milligrams twice a day, the risk of liver damage is serious enough when used with other anti-retroviral drugs that nevirapine is not used to prevent HIV infection after suspected exposure (such as in health care workers or rape victims). The three much-lower doses tested were chosen to spare the liver, yet keep blood levels of the drug high enough to potentially provide a benefit.

Participants were divided into three groups: the first 12 received one tablet (200 milligrams) of nevirapine once a week for 12 weeks, the second group of 12 received one tablet twice a week, and the third group of nine took one tablet every other day. The scientists tested for HIV and hepatitis B and C infection and measured participants' liver function throughout the study period.

No clinically severe or life-threatening side effects were seen at any dose, says Jackson. However, participants susceptible to liver damage for reasons other than nevirapine (hepatitis C infection, excessive alcohol consumption, or exposure to toxic chemicals) were more likely to have slightly elevated liver enzymes (a measure of liver function) while taking the drug, regardless of dose.

Importantly, the researchers discovered that at all doses, blood levels of the drug seemed high enough to potentially prevent HIV infection. While the necessary blood level of nevirapine to prevent HIV infection in people is unknown, in the lab 10 nanograms of the drug per milliliter is enough to inhibit the virus.

"We decided on a blood level of drug 10 times that as the lowest desirable level in our study, but we don't know yet whether that will prevent infection," notes Jackson. That determination will begin with a large clinical trial, currently in the planning stages.

Tested just before getting their next dose of nevirapine, almost all participants had at least the desired level of nevirapine in their blood. While no new infections were noted, one participant with longstanding hepatitis B infection no longer tested positive after two weekly doses of nevirapine, a finding worth pursuing, says Jackson.

A few participants had blood levels of nevirapine as high as those typically seen with treatment-size doses, which could possibly contribute to liver damage over time. Another concern is that chronic use of nevirapine or another medicine might make the drug less useful if HIV infection does occur, notes Jackson. However, if the drug is well tolerated and prevents infection, that may be a risk worth taking, he adds.

The study was funded by the Johns Hopkins School of Medicine Department of Pathology. Authors on the report are Jackson, Scott Barnett, Estelle Piwowar-Manning, Linda Apuzzo, Charles Raines, Craig Hendrix, Fayez Hamzeh and Joel Gallant, all of Johns Hopkins.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Drug Tested For HIV Prevention In Baltimore." ScienceDaily. ScienceDaily, 27 February 2003. <www.sciencedaily.com/releases/2003/02/030227074827.htm>.
Johns Hopkins Medical Institutions. (2003, February 27). Drug Tested For HIV Prevention In Baltimore. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2003/02/030227074827.htm
Johns Hopkins Medical Institutions. "Drug Tested For HIV Prevention In Baltimore." ScienceDaily. www.sciencedaily.com/releases/2003/02/030227074827.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Snack Attack: Study Says Action Movies Make You Snack More

Snack Attack: Study Says Action Movies Make You Snack More

Newsy (Sep. 2, 2014) You're more likely to gain weight while watching action flicks than you are watching other types of programming, says a new study published in JAMA. Video provided by Newsy
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins