Long-term efficacy of boosted and unboosted atazanavir-containing regimens: results from the SCOLTA Project

Purpose of the study

In this study we evaluated the efficacy of boosted and unboosted ATV in different regimens in a cohort of HIV-1 infected patients.

Methods

The SCOLTA Project is a prospective, observational, multicenter study involving 24 infectious disease departments created to assess the incidence of adverse events in patients with HAART. In the SCOLTA database there are also data about HAART efficacy and durability.

Summary of results

509 patients starting atazanavir were enrolled between January 2003 and July 2007; 379 (74.5%) patients were treated with boosted ATV and in the others 136 only with ATV. At baseline, differences by sex, VL, CDC stage, pre-treatment with PI, total durability of HAART, use of other antiretroviral therapy, HBV co-infection were not statistically significant in the two groups. Patients with lower CD4+ count received unboosted ATV more frequently. Patients with boosted ATV were older (p = 0.01) and they have less HCV co-infection (p = 0.04) and more lipodistrophy (p = 0.0002) than the others. These patients have also total cholesterol (p = 0.02) and triglycerides (p = 0.002) levels higher than patients without ritonavir. The last therapeutic regime did not influence the choice between use of boosted ATV or not boosted.

Reasons of use for unboosted ATV were ritonavir intolerance in 42.3% of cases, liver dysfunction in 6.2%, simplification of therapy in 9.2%, metabolic alteration in 2.3%, poor compliance in 6.2%, availability of only ATV 200 mg in 12.3%, and other reasons in 16.2%.

The follow-up time was 22.6 months in unboosted patients and 24.3 months in boosted patients. At the end of the follow-up time, 76/130 unboosted patients (58.5%) and 220/379 boosted patients (58.1%) continued therapy. Respectively, 36 (27.7%) and 115 (30.3%) patients withdrew therapy; patients lost to follow-up were 18 (13.9%) and 44 (11.6%), respectively. There are no statistically significant differences between two groups about suspension of therapy (death, virological failure, adverse events, poor compliance and simplification).

At study end, CD4+ count and VL were not significantly different between subjects still in treatment with boosted and unboosted ATV. In unboosted patients lipidic profile was better than in boosted patients but there are no statistically significant differences after adjustment for cholesterol and triglycerides at baseline.

Conclusion

The study data show that, in clinical practice, both ATV-containing regimens have same efficacy and durability.