icon- folder.gif   Conference Reports for NATAP  
  16th CROI
Conference on Retroviruses and Opportunistic Infections Montreal, Canada
February 8-11, 2009
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Efficacy and Safety of Abacavir/Lamivudine Compared to Tenofovir/Emtricitabine in Combination with Once-Daily Lopinavir/Ritonavir through 48 Weeks in the HEAT Study
  Reported by Jules Levin
CROI 2009 Feb 8-12 Montreal
Kimberly Y. Smith1, Derek Fine2, Parul Patel3, NicholaosC. Bellos4, Louis Sloan5, Phillip Lackey6, Denise H. Sutherland-Phillips3, Cindy Vavro3, QimingLiao3, and Mark S. Shaefer3 1Rush University Medical Center, Chicago, IL, US; 2Johns Hopkins University School of Medicine, Baltimore, MD, US; 3GlaxoSmithKline, RTP, NC, US; 4Southwest Infectious Disease Associates, Dallas, TX, US; 5North Texas Infectious Disease Consultants, Dallas, TX, US; 6ID Consultants, Charlotte, NC,
ABC/3TC is comparable to TDF/FTC in virologic efficacy when combined with LPV/r through 48 weeks.
Both treatment regimens were well tolerated with few discontinuations due to adverse events in either arm.
ABC/3TC was virologically non-inferior to TDF/FTC through 48 weeks when each was combined with LPV/r.
-- 68% vs. 67% of subjects (ABC/3TC vs. TDF/FTC) achieved an HIV-1 RNA <50 c/mL at Week 48 (ITT-E, M=F, switch included).
-- 75% vs. 71% of subjects (ABC/3TC vs. TDF/FTC) achieved an HIV-1 RNA <400 c/mL at Week 48 (ITT-E, M=F, switch included).
Efficacy results were consistent and robust to multiple analyses including when switches were counted as failures.
Median CD4+ cell responses differed between arms at Week 48 (429 cells/mm3 for ABC/3TC and 370 cells/mm3 for TDF/FTC).
A conservative definition of virologic failure resulted in a somewhat elevated failure rate in both arms. Twice as many subjects receiving TDF/FTC failed therapy with an M184V or mixture which was a finding not previously reported.
No new safety findings were observed for either NRTI backbone.
-- Rate of ABC HSR was 4% with ABC/3TC and 1% with TDF/FTC.
(HLA-B*5701 screening was not performed in this study)
-- PRTD occurred in 0% with ABC/3TC and 1% with TDF/FTC.
-- Lipids elevations were observed in both arms, however
TC:HDL ratio remained below 5 for each.
A blinded analysis of the data was performed at Week 48 to protect the integrity of this 96 week study.
Limited direct comparative data exist between the recommended dual NRTI fixed dose combinations, ABC/3TC and TDF/FTC.
The HEAT study is the first head-to-head trial to evaluate the efficacy and safety of these dual NRTI backbones with a boosted PI as part of recommended first-line treatments in HIV-1 infected subjects.
To establish that ABC/3TC is virologically noninferior to TDF/FTC when administered in combination with LPV/r over 48 weeks.
To compare the safety and tolerability of ABC/3TC versus TDF/FTC over 96 weeks.