Experience with ritonavir/atazanavir in HIV-positive antiretroviral-naïve individuals commencing therapy

Purpose of the study

Ritonavir/atazanavir has recently been registered for use in antiretroviral naïve individuals requiring therapy. We describe our experience of the use of ritonavir/atazanavir in a large urban clinic population.

Methods

Retrospective case note review.

Summary of results

Between March 2004 and April 2008, 133 antiretroviral-naïve individuals were commenced on ritonavir (100 mg)/atazanavir (300 mg) and two nucleos(t)ides. 103 commenced ritonavir/atazanavir with tenofovir and emtricitabine or lamivudine, six with abacavir and lamivudine, and 24 with other nucleoside backbones. Mean baseline viral load was 121,198 copies/ml and mean CD4 count was 221 cells/ml; 73 patients had a CD4 count below 200 and 84 a viral load above 100,000. After 12 months of therapy, 79% had a viral load below 50 copies/ml by ITT (intention to treat) and 89% by OT (on treatment). With a viral load cut-off of less than 500 copies/ml, 89% and 100% achieved this level by ITT and OT, respectively. Mean CD4 count rise at 12 months was 202 cells/ml. There was no impact of baseline CD4 count or viral load. 18 patients stopped therapy within 12 months. Reasons for cessation of therapy were jaundice (eight), simplification of therapy required (three) and not specified (seven). Mean rise in cholesterol at 12 months was 0.4 mmol/l.

Conclusion

Ritonavir/atazanavir is a safe and effective therapy in antiretroviral-naïve individuals requiring a protease inhibitor based therapy.