Dr. Wohl, in your practice what would you recommend for treatment experienced patients who are resistant to Sustiva and need a PI - boosted reyataz or kaletra? I know the reyataz would have less cholesterol issues, but I'm worried that it might not be as effective as kaletra in controlling the virus. Thanks for all of your help! Dave

Treatment options for the multi-drug experienced patient are increasing. While Kaletra has been included in salvage regimens since it came on the market, recent data suggests that ritonavir boosted atazanavir may be comparable in this situation. In a study of over 350 people with extensive antiretroviral experience, a median CD4 of 300 and a median viral load of 30,000 were randomized to once a day atazanavir 300 mg + ritonavir 100 mg vs twice a day Kaletra (lopinavir + ritonavor) vs once daily atazanavir 400 mg + saquinavir 1200 mg. Bottom line was the atazanavir/ritonavir and the Kaletra arms did better in suppressing viral loads below 50 copies over 6 months (~40%)compared to the other arm (~23%). There may have been a trend favoring Kaletra but lipids were unsurprisingly better in the boosted atazanavir arm. These were 24 week data so longer term follow-up will be important. More on this study can be found at: http://www.thebodypro.com/confs/ias2003/cohen2.html

Another advance for salvage will be tipranavir, a new protease inhibitor that also needs ritonavir boosting and is in expanded access now.

At this point, there are more data and experience supporting Kaletra but I think boosted atazanavir remains an option in this situation especially because the leading cause of treatment failure is probably suboptimal adherence. A regimen with fewer pills and less frequent dosing may lead to more adherence and maybe better results for those who tend to miss doses. Note, the temptation to use tenofovir with azatanavir, even when boosted with ritonavir, has to be tempered by the reduction in atazanavir levels seen when these once a day drugs are combined. DW