Abacavir and Efavirenz in Combination as a Substitute for a Protease Inhibitor in Heavily Pretreated HIV Patients with Undetectable Viral Load

The aim of the study was to evaluate the safety and efficacy of abacavir/ABC (Ziagen) and efavirenz/ EFV (Sustiva) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (<50 HIV-1 RNA copies/mL).

To be eligible for inclusion, patients had to have a history of viral load <400 copies/mL for at least 3 months and had to be naive to treatment with non nucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed.

An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV.

At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured.

Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide.

Additionally, an oral glucose tolerance test (OGTT) was performed.

A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition.

Results

·         Thirty patients were included in the study.

·         Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by non adherence.

·         At week 48, all remaining patients had viral loads <50 copies/mL with stable CD4 counts.

·         The fasting metabolic parameters and abdominal fat distribution remained unchanged.

In conclusion, the authors write, “In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.”

Department of Infectious Disease, HIV Treatment and Research Unit, JW Goethe University, Frankfurt, Germany.

05/23/05

Reference
M Bickel and others. The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load. HIV Medicine 6(3):179-184. May 2005.

Link to Index of All HIV and AIDS Articles by Topic