Comparing the efficacy of Truvada^® and Kivexa^® combination therapy in HAART-naive individuals with different viral loads

Purpose of the study

Truvada (emtricitabine + tenofovir) and Kivexa (abacavir + lamivudine) are combination therapies used as the nucleos(t)ide backbone in combination antiretroviral therapy. Recent reports have suggested Kivexa may be inferior to Truvada at high viral load (>100,000 copies/ml).

Methods

Retrospective case note review. All patients underwent HLA B5701 testing.

Summary of results

Between April 2006 and April 2008, 87 HAART-naive patients were commenced on either Truvada or Kivexa in combination with; efavirenz (53), nevirapine (3), Kaletra (6), atazanavir/ritonavir (9), other protease inhibitors (13). In the Truvada group (53), overall mean baseline viral load (VL) was 122,106 copies/ml. In the Kivexa group (33), overall mean baseline VL was 99,883 copies/ml. In order to assess the effect of different initial viral loads on the response to combination therapy, the patients were divided into three groups: those with High (>100,000 copies/ml), Intermediate (10,000 – 100,000 copies/ml) and Low (<10,000 copies/ml) viral loads prior to commencing HAART. (Table 1.)

Table 1

Failure to achieve a viral load of less than 1,000 copies/ml by 4 weeks of therapy is strongly associated with failure to achieve long-term viral suppression. In the Truvada group, 67% of all patients achieved this level by 4 weeks of therapy. In the Kivexa group, 70% of all patients achieved a viral load of <1,000 copies/ml after 4 weeks of therapy.

Conclusion

There is no significant difference in clinical practice when comparing the use of Truvada and Kivexa in patients with different viral loads at commencement.