Abacavir/lamivudine has shown similar efficacy to other nucleoside conventional combinations in previously HIV-infected patients: results at 48 weeks

Purpose of the study

Controversial data have been recently published with respect to the antiviral response to abacavir(ABC)/lamivudine(3TC) (Kivexa^®). We compared the efficacy and safety of efavirenz(EFV)+abacavir(ABC)/lamivudine(3TC) (Kivexa^®) with other conventional regimens of 2NRTI+efavirenz(EFV).

Methods

A multicenter, prospective and randomized study was performed in 19 centres located in Spain (18) and Italy (1). Patients in treatment with 2NRTI+EFV and viral suppression over ≥6 months were randomized to ABC/3TC (Kivexa^®)+ EFV (Group A) or to continue the same regimen 2NRTI+EFV (Group B) and followed every 3 months until 48 weeks. Mann-Whitney test (non-parametric test) was used to compare between continuous variables.

Summary of results

A total of 100 patients were included in this study: 51 of them in Group A and 49 in Group B. Both groups were comparable for all baseline variables. Only one patient from Group A presented viral rebound at 24 weeks. No statistically significant changes from baseline in CD4+ cell count were seen at week 48 in either group: 528 cell/mm3 (± 252) to 592 (± 266) in Group A and 644 (± 265) to 627 (± 224) in Group B, (p = 0.311 between groups) at week 48. Total cholesterol showed a slight increase only at week 24 in Group A (from 198 mg/dl ± 43 to 214 ± 39, p = 0.014) and in Group B (200 mg/dl ± 50 to 194 ± 53; p = 0.036) without any difference at week 48. Drug discontinuation for toxicity was higher in Group A (seven subjects (7%), five of them for hypersensitivity reaction) than in Group B (only two patients).

Conclusion

ABC/3TC (Kivexa^®), in combination with EFV, was a good alternative as a simplification regimen due to its virological and immunological effectiveness and good tolerability. Nowadays, the availability of a genetic test (HLA B*57) will reduce the incidence of discontinuation due to hypersensitivity reaction.