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Differences in virologic response among African-Americans and females regardless of therapy in the HEAT study
K.Y. Smith1, P.N. Kumar2, P. Patel3, N.C. Bellos4, L. Sloan5, P. Lackey6, D.H. Sutherland-Phillips3, C. Vavro3, L. Yau3, M.S. Shaefer3
1Rush University Medical Center, Chicago, United States, 2Georgetown University, Washington, United States, 3GlaxoSmithKline, Research Triangle Park, United States, 4Southwest Infectious Disease Associates, Dallas, United States, 5NorthTexas Infectious Disease Consultants, Dallas, United States, 6ID Consultants, Charlotte, United States
Background: Differences in virologic and immunologic response have been observed with different antiretroviral combinations. We evaluated week 96 responses by sex and by race in the HEAT study which previously demonstrated the non-inferiority of abacavir sulfate/lamivudine (ABC/3TC) versus tenofovir/emtricitabine (TDF/FTC), when each was combined with lopinavir/ritonavir (LPV/r), at 48 weeks and subsequently confirmed at 96 weeks in ART-naïve subjects.
Methods: Virologic response at week 96 was determined by the proportion with HIV-1 RNA (VL) < 50 c/mL by missing=failure (M=F) and observed analyses. Race and ethnicity were self-identified.
Results:
| | ABC/3TC + LPV/r
N=343 | TDF/FTC + LPV/r
N=345 | | Week 96 | Median CD4+ Count cells/cmm
BL(Δ96) | VL<50 c/mL,
Observed
%(n/N) | VL<50 c/mL,
M=F
%(n/N) | Median CD4+ Count cells/cmm
BL(Δ96) | VL<50 c/mL,
Observed
%(n/N) | VL<50 c/mL,
M=F
%(n/N) | | All Subjects | 214
(+250) | 87%
(205/236) | 60%
(205/343) | 193
(+247) | 91%
(200/219) | 58%
(200/345) | | Female | 213
(+307) | 84%
(26/31) | 46%
(26/56) | 168
(+262) | 90%
(36/40) | 52%
(36/69) | | Male | 214
(+245) | 87%
(179/205) | 62%
(179/287) | 200
(+245) | 92%
(164/179) | 59%
(164/276) | | African-American* | 182
(+245) | 80%
(60/75) | 50%
(60/119) | 137
(+245) | 86%
(59/69) | 48%
(59/124) | | Caucasian | 209
(+225) | 89%
(97/109) | 68%
(97/143) | 237
(+255) | 95%
(99/104) | 67%
(99/147) | | Hispanic | 247
(+323) | 93%
(42/45) | 58%
(42/73) | 179
(+236) | 92%
(36/39) | 58%
(36/62) | | Other | 184
(+249) | 86%
(6/7) | 75%
(6/8) | 232
(+151) | 86%
(6/7) | 50%
(6/12) | | * African-American race, but not female sex, was a significant predictor of virologic failure in a multivariate logistic regression model studied. |
Conclusions: Differences in CD4+ and virologic responses by sex and race at week 96 were observed. Notably, fewer African-Americans and females achieved VL< 50 c/mL in both arms and in both analyses suggesting these differences may be multifactorial. Slightly greater CD4+ increases were observed in females and although African-Americans had lower initial CD4 counts, immunologic recovery was similar across other racial groups and between groups over 96 weeks. Further investigation into the underlying differences in response is required.
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