Use of patch testing for the diagnosis of abacavir-related hypersensitivity reaction in HIV patients.

BACKGROUND: The use of antiretroviral drug abacavir (ABC) has been often associated with cutaneous hypersensitivity reactions, the majority being severe. OBJECTIVE: The present study discusses the issues of patch testing associated with pharmacogenetic screening in light of the development of abacavir hypersensitivity reactions (HSRs). METHODS: The present authors classified 100 patients into three groups: 20 patients (group A) had experienced a hypersensitivity reaction when treated with highly active antiretroviral therapy (HAART) including ABC; 60 HIV-positive patients (group B) were receiving HAART scheme including ABC; 20 HIV-negative patients acted as control group (group C). Patients of group A and B were patch tested with ABC as such, then with an ABC extract diluted to 1 and 10% in petrolatum. Group C patients underwent patches with petrolatum only. A biopsy of the lesion was performed in those patients who showed a positive skin reaction. All patients had been tested for HLA-B5701. RESULTS: A correlation between positive ABC-patch testing and HLA-B5701 was found in 50% of patients enrolled in group A, while in group B and C, all patients tested negative for both genetic marker and ABC-patch testing. Histopathology findings confirmed a vigorous CD4+ and CD8+ cellular response that is compatible with HSR. CONCLUSIONS: Patch testing is a safe and sensitive method that can be used for to confirm or exclude any correlation between abacavir and hypersensitivity skin reactions in patients who have been previously treated with abacavir during HAART. Correlation between patch test, immunohistochimical, and genetic tests results shows that genetic testing increases the possibility to identify patients with a true reaction.

Efficacy and safety of boosted and unboosted atazanavir-containing antiretroviral regimens in real life: results from a multicentre cohort study.

BACKGROUND: Atazanavir (ATV) has demonstrated high efficacy and safety in both treatment-naïve and treatment-experienced patients. Some comparative data are available on the durability of ritonavir-boosted (ATV/r) and unboosted formulations, but there are no data on clinicians' motivations for choosing one or another in everyday practice. The aim of this study was to evaluate the long-term efficacy of boosted and unboosted ATV in a cohort of treatment-experienced patients. METHODS: All patients included in the study were enrolled in an observational cohort within the Surveillance Cohort Long-Term Toxicity Antiretrovirals (SCOLTA) Project. Data on CD4 cell count, HIV viral load, metabolic parameters and adverse events of grade 3-4 are collected through an on-line system every six months. The duration of treatment with ATV was evaluated using the Kaplan-Meier curve and boosted and unboosted regimens were compared using the log-rank test. RESULTS: A total of 509 patients starting ATV as a component of their antiretroviral therapy were enrolled in the SCOLTA Project at the time of the study. Boosted ATV was received by 379 patients (74.5%) while 130 (25.5%) were treated with the unboosted formulation. The last therapeutic regimen did not influence the choice of ATV formulation. The mean observational time was 23.9 months. At the end of follow-up, 58.5% of patients on unboosted ATV and 58.1% of patients on ATV/r continued the treatment and no statistically significant differences were observed for ATV durability between the formulations or among the single causes of therapy interruption. CONCLUSIONS: Our results suggest that, in unselected clinical settings, ATV-containing antiretroviral therapy is durable and safe in both its formulations.