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 HIV and Coverage of the
th IAS Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2009)
 July 19 - 22, 2009, Cape Town, South Africa
 The material posted on HIV and about IAS 2009 is not approved by nor is it a part of IAS 2009.
Potent Next-generation Experimental Integrase Inhibitor S/GSK1349572 Debuts at IAS 2009

S/GSK1349572 is a novel new integrase inhibitor (INI) that has demonstrated potent antiviral activity in laboratory studies, human pharmacokinetics (PK) that support once daily dosing, and a favorable safety profile. Results of 5 studies of the drug were presented at IAS 2009 conference in Cape Town. This review summarizes the outcomes of the one clinical study presented, a short monotherapy study in HIV patients that demonstrates the "unprecedented antiviral activity" of the drug and its "superior resistance profile," according to the study authors.

By Ronald Baker, PhD

Shionogi of Japan and GlaxoSmithKline have partnered in a joint venture to develop next-generation integrase inhibitors, which led to their selection of S/GSK1349572 as their lead candidate for development. The drug is the only once daily, unboosted integrase inhibitor currently in development.

Study Methods

This was a Phase 2 dose ranging, placebo-controlled study of S/GSK1349572 in 35 INI-naïve HIV-1 infected adults who were not currently receiving antiretroviral therapy.
Participants had HIV RNA of greater than or equal to 5000 copies/ml and CD4 greater than or equal to 100 cells/mm3.
They were randomized to doses of 2mg, 10mg, 50mg or placebo once daily.
HIV-1 RNA, genotypes/phenotypes, safety labs, vital signs, ECGs and PK sampling were performed.


Thirty-five people completed all study visits.
Demographics were similar across treatment groups.
There were no deaths or severe adverse events (SAEs).
No patients withdrew from the study due to an adverse event (AE).
Diarrhea, fatigue and headache were the most commonly reported AEs (except for headache, which was more common in the placebo group).
Similar AE rates were observed in S/GSK1349572 and placebo groups
Most AEs were mild to moderate.
No clinically significant trends were noted in laboratory abnormalities, vital signs or ECG values.
A mean decrease from baseline on Day 11 in plasma HIV-1 RNA of 1.51 to 2.46 log10 copies/mL was observed across the S/GSK1349572 doses tested (2mg - 50mg) compared with placebo.
At the 50mg dose, 70% of participants achieved undetectable plasma HIV-1 RNA levels (< 50 copies/mL).
No S/GSK1349572 phenotypic resistance was noted.
No signature substitutions associated with in vivo raltegravir or elvitegravir clinical resistance or with S/GSK1349572 in vitro passage were detected.

Authors' Conclusions

S/GSK1349572 is a potent inhibitor of HIV integrase.
S/GSK1349572 had limited cross-resistance to raltegravir and elvitegravir resistant virus.
S/GSK1349572 was generally well-tolerated and demonstrated unprecedented anti-HIV activity following short-term, once-daily, unboosted dosing in INI-naïve patients.
These data support progression into phase 2b clinical trials.

ING111521 Investigators, Research Triangle Park, United States, GlaxoSmithKline, Research Triangle Park, United States, Shionogi & Co., Ltd., Osaka, Japan, GlaxoSmithKline, Infectious Diseases Medicine Development Center, Research Triangle Park, United States.

To view posters and or slides from the five studies on S/GSK1349572 presented at IAS 2009, visit the IAS 2009 Library of Slides and Posters on the IAS 2009 Conference Main Page on HIV and

Editor's Note: In a teleconference following the study presentation, GSK said that two phase 2b studies of S/GSK1349572 will start in late July 2009, one in treatment-naïve patients and the other in treatment-experienced patients. Further, the company expects phase 3 studies to start by the end of 2009.


J Lalezari, L Sloan, E Dejesus, and others . Potent antiviral activity of S/GSK1349572, a next generation integrase inhibitor (INI), in INI-naïve HIV-1-infected patients. 5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2009). July 19-22, 2009. Cape Town, South Africa. Abstract TUAB105.















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