Featured Research

from universities, journals, and other organizations

Researchers Document Transmission Of Protease-Resistant HIV

Date:
July 2, 1998
Source:
University Of California, San Francisco
Summary:
A team of AIDS researchers has reported a case in which a person has become infected with HIV that is resistant to six of the 11 approved HIV anti-retroviral drugs, including protease inhibitors.

GENEVA, Switzerland -- A team of AIDS researchers has reported a case in which a person has become infected with HIV that is resistant to six of the 11 approved HIV anti-retroviral drugs, including protease inhibitors. The investigators are from the University of California San Francisco AIDS Research Institute, ViroLogic, Inc., and the Centers for Disease Control and Prevention

Protease inhibitors have been approved for two years, and as part of triple combination therapies, have contributed to a dramatic decline in AIDS death rates. Protease inhibitors block construction of proteins the virus needs to build more copies of itself.

Transmission of drug resistant HIV has been reported previously, but only to anti-retrovirals known as reverse transcriptase inhibitors, which work by blocking the replication of the virus. They have been in use for more than 10 years, but are less effective treatments.

The transmission of protease inhibitor resistant strains of HIV to a previously uninfected person could represent an emerging clinical and public health problem because protease inhibitors are a powerful weapon in the arsenal against HIV, said Frederick Hecht, MD, assistant clinical professor of medicine at the UCSF-affiliated San Francisco General Hospital, and lead author of the study. The case study was reported by Hecht here today (July 1) at the 12th World AIDS Conference. Research results also will be published in the New England Journal of Medicine, currently in press.

The multi-drug resistant HIV strain is believed to have been transmitted from one person to another through unprotected anal intercourse. Multiple mutations of HIV are required for the virus to become resistant to protease inhibitors, according to Hecht, and it had been thought that those mutations might make it more difficult for the virus to reproduce and make transmission between people less likely.

"We still don't know how frequently resistant strains are transmitted," he said. "But we now know that people can acquire strains with multi-drug resistance, including resistance to protease inhibitor treatment."

The subject of the case study was a middle-aged homosexual man who reported that his only risk encounter in the six months prior to being infected with HIV was receptive anal intercourse without a condom. He said his partner had withdrawn before ejaculation, a behavior that many in the gay community have considered to be a low-risk practice.

"There may be a tendency to feel complacent because of the success of treatment efforts," Hecht said, "but the fact that this transmission occurred by a practice that many consider to be 'safe' highlights the crucial role of continued prevention efforts needed to control the HIV epidemic."

With the patient's consent, the researchers obtained information from his partner. He was diagnosed with HIV infection in 1990, and since then was sporadically treated with nine anti-retroviral drugs, including reverse transcriptase inhibitors and protease inhibitors.

Hecht said that interruptions in the partner's treatment may have contributed to the development of resistant HIV that was transmitted to the patient.

"This study shows that we can do more harm than good if we don't help patients take their medications correctly," said Margaret Chesney, PhD, professor of medicine at UCSF, a co-investigator of the study, and an expert on adherence issues. "The bottom line is that helping patients stick to these difficult regimens is as important as the drugs themselves."

To examine the sensitivity and resistance of the patient's virus to the 11 approved HIV anti-retrovirals, the researchers used a novel phenotypic drug susceptibility assay developed by ViroLogic, Inc., a biotechnology company located in South San Francisco, Calif. The technique uses a retroviral vector that contains a viral gene segment from the patient's virus and an indicator, to measure the sensitivity of the patient's virus to HIV anti-retrovirals.

Virologic's phenotypic analysis showed the patient's virus was resistant to two reverse transcriptase inhibitors: zidovudine (AZT) and lamivudine (3TC), and four protease inhibitors: saquinavir, ritonavir, indinavir, and nelfinavir. In addition, the researchers evaluated the viral genotype of the patient and the partner to determine whether mutations associated with resistance to anti-retrovirals were present. The patient's virus had four mutations associated with resistance to reverse transciptase inhibitors and seven associated with resistance to protease inhibitors.

Evaluation of the partner's virus showed many of the same mutations, while other genetic tests showed the virus in the patient closely matched that of the partner.

Because this patient's virus is resistant to many anti-retrovirals, typical drug combinations are not working as well as for other patients, Hecht said, but other treatment options still exist.

"This case doesn't mean that combination therapy is not a good thing," said Thomas J. Coates, PhD, director of the UCSF AIDS Research Institute. "A lot of people are living longer and better lives due to combination therapies, but it is clearly not the final answer. We have to help the afflicted communities understand that transmission of resistant strains is possible, even by a practice not considered to be very risky."

The patient was a part of the UCSF Options Project, a study evaluating the usefulness of combination therapy started soon after infection. The project is directed by James O. Kahn, MD, of the UCSF AIDS Program at San Francisco General Hospital.

Co-investigators in this study from the UCSF Gladstone Institute of Virology and Immunology are: Robert Grant, MD, MPH, staff research scientist and director of the UCSF/Gladstone Core Virology Lab; Laura Digilia, MD and Nirmala Bandrapalli, MS.

Other co-investigators are Beth Dillon, MSW, MPH, and Bernard Branson, MD, from the Centers for Disease Control and Prevention, and Christos Petropoulos, PhD; Huan Tian, PhD; and Nicholas Hellmann, MD, from ViroLogic.


Story Source:

The above story is based on materials provided by University Of California, San Francisco. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, San Francisco. "Researchers Document Transmission Of Protease-Resistant HIV." ScienceDaily. ScienceDaily, 2 July 1998. <www.sciencedaily.com/releases/1998/07/980702085949.htm>.
University Of California, San Francisco. (1998, July 2). Researchers Document Transmission Of Protease-Resistant HIV. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/1998/07/980702085949.htm
University Of California, San Francisco. "Researchers Document Transmission Of Protease-Resistant HIV." ScienceDaily. www.sciencedaily.com/releases/1998/07/980702085949.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Google's Next Frontier: The Human Body

Google's Next Frontier: The Human Body

Newsy (July 27, 2014) Google is collecting genetic and molecular information to paint a picture of the perfectly healthy human. Video provided by Newsy
Powered by NewsLook.com
What's To Blame For Worst Ebola Outbreak In History?

What's To Blame For Worst Ebola Outbreak In History?

Newsy (July 27, 2014) A U.S. doctor has tested positive for the deadly Ebola virus, as the worst-ever outbreak continues to grow. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. 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