[O-01] Incidence of hypersensitivity reactions associated with nevirapine-containing HAART in patients with prior treatment experience may differ from that in treatment-naïve patients: the ATHENA cohort study

9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV

19-21 July 2007, Sydney, Australia

INCIDENCE OF HYPERSENSITIVITY REACTIONS ASSOCIATED WITH NEVIRAPINE-CONTAINING HAART IN PATIENTS WITH PRIOR TREATMENT EXPERIENCE MAY DIFFER FROM THAT IN TREATMENT-NAÏVE PATIENTS: THE ATHENA COHORT STUDY

Antiviral Therapy 2007; 12(Suppl. 2):L4 (abstract no. O-01)

F Wit¹, A Kesselring², L Gras², C Richter³, M van der Ende⁴, K Brinkman⁵, J Lange¹, F de Wolf² and P Reiss¹
¹Center for Poverty-Related Communicable Diseases and Academic Medical Center, Department of Infectious Diseases, Tropical Medicine and AIDS, Amsterdam, Netherlands; ²HIV Monitoring Foundation, Amsterdam, Netherlands; ³Rijnstate ziekenhuis, Department of Internal Medicine, Arnhem, Netherlands; ⁴Erasmus Medical Center, Department of Internal Medicine, Rotterdam, Netherlands; ⁵Onze Lieve Vrouwe Gasthuis, Department of Internal Medicine, Amsterdam, Netherlands

BACKGROUND: Current recommendations that nevirapine (NVP) should not be initiated in females with CD4 counts greater than 250/µl or in males with CD4 counts greater than 400/µl are based on findings in treatment-naïve patients. The incidence rate is unknown for treatment- experienced patients with low pre-ART CD4 counts and current CD4 counts above the mentioned threshold, who switch to NVP-containing regimens. Whether current guidelines are applicable in such patients is unclear.

METHODS: All patients in the ATHENA cohort who ever used NVP were included. We identified patients who discontinued NVP because of NVP-induced HSR within 18 weeks after first starting NVP. We grouped patients according to CD4 counts at the start of NVP-based HAART, being either high (>250/µl for females and >400/µl for males) or low. Treatment-experienced patients were also subdivided according to the last available pre-ART CD4 count using the same criteria: treatment-naïve, low current CD4 (NL), treatment-naïve, high current CD4 (NH); pretreated, low pre-ART CD4 and low current CD4 (PLL); pretreated, low pre-ART CD4 and high current CD4 (PLH); pretreated, high pre-ART CD4 and low current CD4 (PHL); and high pre-ART CD4 and high current CD4 (PHH). Risk factors for developing HSR were assessed using multivariate logistic regression.

RESULTS: In patients that ever used NVP (n=3,752), HSR occurred in 231 (6.2%). We found no difference in HSR rate between the NL and PLL groups (5.2% versus 4.4%, P=0.44). Similarly, NH patients had a HSR rate comparable to the HSR rate in PHH patients (8.4% versus 10.8%, P=0.33). The HSR rate in the PLH group (6.2%) was higher than in the PLL group (4.4%, P=0.057), but lower when compared with the rate in the PHH group (10.8%, P=0.003). Using PLH as the reference group, the multivariate adjusted odds ratios (OR) for developing HSR were significantly lower for NL (OR 0.54; 95%CI 0.35–0.82) and PLL (OR 0.55; 95%CI 0.38–0.78). Other independent risk factors include female gender and Asian race. Having an undetectable viral load at the start of NVP use was also associated with reduced risk for developing HSR (OR 0.52; 95%CI 0.38–0.71). Using NL as the reference group, PLH patients with a detectable viral load at the start of NVP use had a significantly higher risk for HSR (OR 1.87; 95%CI 1.11–3.12), whereas PLH patients with undetectable viral load did not (OR 1.03; 95%CI 0.66–1.61).

CONCLUSIONS: Treatment-experienced patients with low pre-ART CD4 counts, high current CD4 counts and undetectable viral load have a similar risk for developing HSR when they switch to NVP compared with treatment-naïve patients with low CD4 counts. This suggests that NVP may be safely initiated in such patients. However, in similar patients with a detectable viral load, it is prudent to continue adhering to current guidelines.

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2007-07-24
O-01

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