Back to home » Top Stories » IAC 2010
XVIII International AIDS Conference
IAC 2010 XVIII International AIDS Conference
Reed Messe Wien
Vienna, Austria
July 18-23, 2010


New ViiV Integrase Inhibitor Effective Against Some Isentress-Resistant HIV Strains

July 20, 2010

By David Evans

An experimental integrase inhibitor being developed by Shionogi Pharmaceuticals and ViiV Healthcare—currently dubbed S/GSK-572—effectively reduces HIV levels in at least some people with HIV resistant to Isentress (raltegravir). These findings were reported in a presentation Monday, July 19, at the International AIDS Conference (IAC), taking place July 18 to 23 in Vienna.

While very early laboratory experiments suggested that the new Shionogi/ViiV integrase inhibitor would not share similar drug-resistance patterns with Isentress, more recent data have suggested otherwise. People with HIV who have become resistant to most of the available antiretroviral (ARV) medications need new treatment options, however, so the companies believed it was important to explore S/GSK-572’s potential against Isentress-resistant virus.

Joseph Eron, MD, from the University of North Carolina in Chapel Hill, and his colleagues set out to determine the efficacy of S/GSK-572 in people who’d developed resistance to Isentress. They enrolled 27 HIV-positive people who had resistance to Isentress and at least two other ARV classes.

This ongoing study has two phases. In the first phase, people take 50 mg of S/GSK-572, once daily for 11 days, without adding any other ARVs. In the second phase, people add other ARVs, depending on the results of drug resistance testing, to make up a complete optimized regimen. People remain on this optimized regimen, plus S/GSK-572, for up to 48 weeks. The first phase has been completed and was reported at the conference. The second phase is ongoing. The primary end point for phase one is achieving a viral load under 400 by day 11, or a drop in virus of at least 0.7 logs.

All of the participants underwent phenotypic and genotypic drug resistance tests at the beginning of the study. Roughly one third of the participants, in Group 1, had more extensive Isentress resistance, defined as having the Q148H/K/R integrase mutation, plus at least one other related integrase mutation. The other two thirds, in Group 2, had only the Q148 mutation, the N155H or the Y143H mutation.

Eron and his colleagues found that people with only moderate Isentress resistance responded quite well to S/GSK-572. All 18 patients in Group 2 achieved the primary endpoint, and the average drop in virus during 11 days was 1.81 logs. Only three of the nine people in Group 1 achieved the primary endpoint, however, indicating that people with more extensive Isentress resistance might not respond as well to the new integrase inhibitor.

Another finding of the study—which will be useful to clinicians should S/GSK-572 ever be approved—is that phenotypic resistance testing before people started treatment strongly predicted who would respond to S/GSK-572 and who would not.

Side effects to S/GSK-572 during the 11-day study period were mostly mild to moderate, with the most common being diarrhea and insomnia. While there were three more serious side effects—one case each of neurosyphilis, loss of consciousness and significant increases in cholesterol—none were related to S/GSK-572.

Search: Isentress, raltegravir, S/GSK-572, Shionogi, ViiV, resistance, Q148, N155H, Y143H, Joseph Eron

Scroll down to comment on this story.


(will display; 2-50 characters)


(will NOT display)


(will display; optional)

Comment (500 characters left):

(Note: The AIDSmeds team reviews all comments before they are posted. Please do not include ":" "@" "<" ">" in your comment. The opinions expressed by people providing comments are theirs alone. They do not necessarily reflect the opinions of Smart + Strong, which is not responsible for the accuracy of any of the information supplied by people providing comments.)

Comments require captcha.
Please enter this number for verification:

| Posting Rules

Show comments (0 total)

More from AIDS2010

HIV/AIDS Complications

July 28, 2010
Global Survey: Stigma, Isolation and Discrimination Still Pervasive
Universal HIV Treatment Access No Guarantee of Health for Socially Disadvantaged
July 27, 2010
OM-85 BV: A Bacterial Vaccine Against Respiratory Problems in People with HIV and COPD?
Low Vitamin D Levels Not Associated With HIV Drugs
July 23, 2010
Longer Duration of HIV Infection Might Increase the Risk of Brain Disorders
Nearly 75 Percent of People With HIV Might Have Bone Problems
July 22, 2010
Health Care Providers and People With HIV Not Communicating Effectively
July 21, 2010
Non-AIDS Cancers Occurring at Earlier Age Among People With HIV
Hep C Treatment Effective in HIV Patients With Normal Liver Enzymes
Aging Might Have a Smaller Impact on Immune Function Than Suspected
July 20, 2010
Viramune Boosts Hep C Treatment Efficacy in People With HIV
HIV/HCV Coinfection Further Increases Risk of Bone Fractures
Fewer Malignancies Seen in Those Taking Selzentry

Experimental HIV Drugs

July 23, 2010
More Details of TBR-652’s Antiviral and Anti-Inflammatory Potential Reported
July 22, 2010
ViiV HIV Integrase Inhibitor Performing Well in First-Time Treatment Study
Rilpivirine Has Similar Efficacy and Better Tolerability Than Sustiva
Extended-Release Viramune Has Comparable Safety and Efficacy to Standard Viramune
July 20, 2010
New ViiV Integrase Inhibitor Effective Against Some Isentress-Resistant HIV Strains
July 19, 2010
Argos’s Dendritic Cell Therapy Reduces HIV During Treatment Interruption

HIV Transmission and Prevention

July 29, 2010
Prevention Is Failing to Target MSM When They’re Young Enough
July 26, 2010
HPV Cancer Vaccine Effective for Heterosexual, Gay and Bisexual Men
Study Finds PrEP Is Safe in Gay and Bi Men
July 23, 2010
Circumcision Unlikely to Have Major HIV Prevention Benefit Among Gay Men
July 21, 2010
Microbicide Success Story: What It Means and Where We Go Next
MACS: Childhood Sex Abuse and Victimization Linked to Increased HIV Risk
Full-Scale HIV Treatment and Prevention Could Save Millions of Lives
July 20, 2010
Tenofovir Microbicidal Gel Significantly Cuts HIV Infection Rate
HIV Cases in Young People Are Falling Around the World
July 19, 2010
Preliminary Results Suggest Good Safety and Adherence Profile for PrEP

Starting and Switching Treatment

July 22, 2010
Reyataz/Isentress Combo Spares Norvir and Nukes, But Is Integrase Resistance a Concern?
Possibly No Survival Benefit to Starting HIV Treatment at CD4s of 500 or More
Once-Daily Prezista/Norvir Monotherapy Largely Effective Over 96 Weeks
Abacavir/Lamivudine Equivalent to Tenofovir/Emtricitabine in Canadian Cohort Study
July 19, 2010
Strategies for a Cure Reviewed in Vienna
Kaletra/Isentress Shows Promise as HIV Nuceleoside-Sparing Regimen for First-Line Treatment
Switch From Sustiva to Intelence Reduces Central Nervous System Side Effects
Protease Inhibitor-to-Isentress Switch is Effective, Lipid Friendly


July 22, 2010
Health Care Providers and People With HIV Not Communicating Effectively
July 20, 2010
Tenofovir Microbicidal Gel Significantly Cuts HIV Infection Rate
5.2 Million People With HIV in Low- and Middle-Income Countries Now on Treatment
At Least 31 Countries Deporting People Living With HIV
HIV Cases in Young People Are Falling Around the World

[ about AIDSmeds | AIDSmeds advisory board | our staff | advertising policy | advertise/contact us]
© 2014 Smart + Strong. All Rights Reserved. Terms of use and Your privacy.
Smart + Strong® is a registered trademark of CDM Publishing, LLC.