13th Annual Conference of the British HIV Association 29 March–1 April 2007, Brighton, UK

HIV CO-RECEPTOR TROPISM IN TREATMENT-NAÏVE PATIENTS: IMPACT ON CD4 DECLINE AND SUBSEQUENT RESPONSE TO HAART

HIV Med 2007; 8(Suppl. 1):4 (abstract no. O15)

L Waters, S Mandalia, A Wildfire, P Randell, B Gazzard and G Moyle
St Stephen’s AIDS Trust, Chelsea and Westminster Hospital, London, UK

OBJECTIVES: In early HIV infection CCR5 (R5)-tropic virus predominates. The proportion of CXCR4 (X4) utilizing strains increases with advancing disease; X4 virus is associated with lower CD4 cell counts and higher viral loads. We aimed to study the impact of X4-tropic virus on CD4 decline prior to starting HAART and subsequent response to therapy.

METHODS: We identified subjects who had undergone tropism testing as part of a previous study and divided them into R5 and X4 (X4 included mixed/dual tropic virus). We used our prospectively collected database to record demographics, treatment history, CD4 count and viral load (VL). Rate of CD4 decline prior to HAART was analysed by DAVG mixed model (adjusted for VL) and CD4 response to HAART by linear mixed model (adjusted for VL and HAART regimen). We compared rates of viral suppression with chi-squared test and regression analysis was used to assess time to viral suppression (both adjusted for HAART regimen).

RESULTS: Of 402 subjects, 326 carried R5-tropic virus and 76 X4 (three pure X4). 340 commenced HAART: 229 R5, 60 X4, 51 excluded (insufficient follow-up); 62 remained off therapy. 12 month CD4 decline prior to HAART was significantly greater in the X4-tropic group (P=0.026) but on commencing HAART CD4 rise was the same (R5 + 185 and X4 + 182 cells/mm³, P=0.81). Viral suppression (<50 c/mL) was achieved in 73.4% and 78.3% of R5 and X4 subjects at 12 months (P=0.51); respective 24 month suppression rates were 72.5% and 68.3% (P=0.67). Time to viral suppression was similar.

CONCLUSION: X4-tropic virus is associated with more rapid CD4 decline prior to HAART; CD4 rise and viral suppression on therapy are similar for R5-and X4-tropic virus. X4-tropism does not appear to impair response to therapy.

2007-03-29
O15

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