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

FACTORS ASSOCIATED WITH VIRAL REBOUND AMONGST HIGHLY TREATMENT-EXPERIENCED PATIENTS WHO HAVE ACHIEVED VIRAL SUPPRESSION

HIV Med 2007; 8(Suppl. 1):5 (abstract no. O18)

Colette Smith¹, Andrew Phillips¹, Brenda Dauer², Margaret Johnson³, Fiona Lampe¹, Mike Youle³, Mervyn Tyrer³ and Schlomo Staszewski^2
1Royal Free and University College Medical School, London, UK, ²JW Goethe University Hospital, Frankfurt, Germany, ³Royal Free Hospital, London, UK

AIM: As new antiretrovirals (ARVs) have become available, highly treatment- experienced patients are increasingly achieving viral suppression. The durability of virological suppression in this situation remains unclear.

METHODS: Patients who had failed ≥1 antiretroviral in all three main drug classes (virological failure to an antiretroviral occurred on the date they first experienced a viral load >400 copies/mL having received the ARV for >16 weeks), at least three previous antiretroviral regimens (number of unique dates on which an antiretroviral was failed) and subsequently achieved a viral load <50 copies/mL were included. They were followed until stopping combination antiretroviral therapy, end of follow-up or viral rebound (two viral loads >400 copies/mL).

RESULTS: A total of 247 patients contributed 723 person-years and 114 viral rebounds (rate=15.8/100 person-years; 95% CI 12.9–18.7). More recent calendar years of viral suppression [relative risk (RR)=0.89/year later; 0.80– 0.99; P<0.04) and greater number of antiretrovirals in the regimen not previously failed (RR=0.79/1 antiretroviral more; 0.65–0.96; P<0.02) were associated with lower rate of viral rebound. In the first year and 1–2, 2–3 and 3+ years after achieving viral suppression the rates of viral rebound were 30.9, 9.2, 4.3 and 3.5/100 person-years respectively. Compared to the first year, the adjusted RRs (95% CI) of viral rebound 1–2, 2–3 and 3+ years after achieving viral suppression were 0.29 (0.17, 0.51), 0.18 (0.08, 0.51) and 0.11 (0.05, 0.24) respectively (P<0.0001).

CONCLUSIONS: Although viral rebound rates are high, especially in the first 2 years after viral suppression, if treatment-experienced patients can maintain suppression this risk reduces substantially in subsequent years.

2007-03-29
O18

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