516 Analysis of Treatment-associated Viral Load Change During Primary HIV Infection P. Grey1, M. Johnston2, K. Petoumenos1, T. Ramacciotti1, P. Cunningham3, E. Rosenberg2, D. Smith*1, G. Robbins2, R. Finlayson4, D. Cooper1, B. Walker2, J. Kaldor1, C. Corcoran2, A. Carr3 1Univ of New South Wales, Sydney, Australia; 2Massachusetts Gen Hosp and Harvard Med Sch, Boston; 3St Vincent's Hosp, Sydney, Australia; and 4Taylor Square Private Clin, Sydney, Australia
Background: Primary HIV Infection (PHI) is often associated with high viral loads and transient CD4 decline, which may influence time to achieving an undetectable viral load on therapy. Therefore, we looked at what may be the determinants of viral suppression with treatment of PHI.
Methods: Both acute and early PHI patients (pts) consenting to antiretroviral treatment between 1997-2002 in Sydney, Australia, and Boston, Massachusetts, were prospectively studied. Acute PHI was defined as a negative or incomplete antibody pattern with positive plasma viremia, and early PHI was defined as HIV seroconversion within a 6-month period. Viral loads were assessed by either Roche version 1.5 RT-PCR range (400-750,000) RNA copies/ml or the Roche ultra sensitive PCR range (50-100,000) RNA copies/ml, depending on the preceding viral load. Patients had viral load and CD4 counts measured immediately prior to therapy and at 12 or more visits over the 1st yr. Determinates of viral suppression to below 50 copies/ml within one year were assessed on an intention to treat basis, using the Kaplan-Meier method. Baseline variables: age, number of Western Blot bands, acute or early PHI classification, acute retroviral syndrome (ARS) severity, number of antiretrovirals, protease inhibitor (PI) containing regimen or not, were covariates in a Cox proportional hazards model.
Results: We studied 222 pts (136 in Sydney and 86 Boston), with a mean age of 35 years, 97% male. Mean baseline CD4 count was 517 (SD 234) median viral load was 5.4 log10 (IQR 5.00-5.9), 60% were acute and 40% early PHI, 74% had an ARS illness, with 57% having 4 or more symptoms. Therapy with a PI was used in 85% of cases. Within 1 yr, 70% of pts achieved < 50 copies/ml. The median time to achievement of a viral load below 50 copies/mL was 20 wks (IQR 12-30). None of the above factors were significantly associated in achieving viral suppression, although a trend (HR = 0.73 (95% CI: 0.53-1.00), p = 0.057) to be less likely to achieve suppression was noted in the early group.