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Efficacy and safety of tenofovir, abacavir and efavirenz in treatment-naïve patients: 48-week results (The ABATE Trial)

Abstract number: 1733_1408

Leon A., Pich J., Ferrer E., Murillas J., García I., Segura F., Vidal F., Gutierrez F., Podzamczer D., Miro J.M.

Background: There are few data on the activity of tenofovir (TDF) plus abacavir (ABC) as a nucleotide/nucleoside backbone regimen in combination with efavirenz (EFV). The aim of this study was to evaluate the efficacy and safety of this combination.

Methods: This is a prospective and multicentre cohort study performed in nine Spanish HIV Units. Patients came from a randomised, multicentre, open-label, induction-maintenance clinical trial (the ABATE trial) in naïve HIV-1-infected patients with >100 CD4 cells/mm3 designed in 2002 and started in May 2003. Induction therapy was performed with TDF (300 mg, QD) plus ABC (300 mg, BID) plus EFV (600 mg, QD). Randomisation to maintaining or stopping EFV was planned at 6 months in patients with undetectable plasma RNA HIV-1 viral load (PVL) (<100 copies/mL). However, the DSMB recommended not starting the maintenance phase in September 2003 due to the high rate of early virologic non-response in treatment-naïve patients with the combination of TDF plus ABC plus lamivudine (ESS300009 trial). Endpoints of the study were proportion of patients with PVL of <50 copies/mL, CD4 cell increase and drug-related adverse events (AE) leading to treatment discontinuation at 48 weeks.

Results: The 52 patients included in the study were followed for at least 48 weeks. Mean (IQR) age was 35 (32–43) years, 73% were males. Only 15% of patients were former drug users. At baseline, median (IQR) CD4 and PVL were 287 (238–391) cells/mm3 and 4.9 (4.3–5.3) log10/mL, respectively. None of the patients died or had C events. Three patients were lost to follow-up and 13 patients (26%; 95% CI, 14–39%) discontinued therapy due to AE. Two patients had virological failure. K65R mutation emerged in one patient. The proportion of patients (95% CI) with PVL below 50 copies/mL at week 48 by intention-to-treat (ITT) or per protocol (OT) analysis was 65% (51–78%) and 94% (81–99%), respectively. Median CD4 cell increase (ITT/OT) at 12 months was +201/+232 cells/mm3. AE were due to hypersensitivity reaction (HSR) to ABC in 5 cases, to either CNS disturbances or skin rash associated with EFV in 4 cases, to GI alterations in 2 cases and to skin rash (ABC or EFV) in another 2 cases. 85% of AE appeared within the first month of therapy.

Conclusions: This combination had a high rate of early AE but was highly effective in naïve patients who were able to tolerate it. Genetic screening (HLA-B*5701) to prevent ABC HSR could select in the future those patients who can benefit from this treatment.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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