PI Perspective #48

March 2009     View PDF     En español

Prezista fares better than Kaletra in first line therapy

Two year (96-week) results from the ARTEMIS study show Prezista (darunavir + ritonavir) superior to Kaletra (lopinavir/ritonavir) at suppressing HIV levels in people taking therapy for the first time. Both drugs are potent protease inhibitors, but these results continue to show Prezista's excellent ability at suppressing HIV over time.

ARTEMIS studied people who had never taken therapy and randomly assigned them to take either once-daily Prezista or once-daily Kaletra along with Truvada (tenofovir + emtricitabine). A self-rated M-MASRI questionnaire was given to the volunteers to rate their level of adherence to their regimens. A person's ability to maintain adherence impacted results on suppressing HIV levels.

A total of 689 people with viral loads above 5,000 enrolled. The study included 70% men, 58% people of color and the average age was 35. At study start, volunteers, on average, had been HIV-positive for about two years, had CD4 counts about 220, and viral levels were 4.86 logs. Treatment failure was defined as:

• stopping therapy for any reason,
• not achieving undetectable viral loads on at least two consecutive visits, or
• showing detectable viral levels on two consecutive visits.

Results at 96 weeks show that 79% of those taking Prezista achieved undetectable viral loads compared to 71% of those on Kaletra. Of those taking Prezista, 82% who were optimally adherent (took their meds as prescribed more than 95% of the time) had undetectable viral loads compared to 78% of those on Kaletra. As for those who were not optimally adherent (below 95% of the time), 76% of those on Prezista were undetectable while only 53% of those on Kaletra were. People on Prezista had more pronounced HIV suppression even when they were less adherent to their regimens.

Diarrhea was the most common side effect, occurring in 4% of those on Prezista and 11% on Kaletra. As for changes in levels of blood fats (lipid levels), Prezista also performed better than Kaletra on triglyceride (18% vs 28%) and cholesterol (4% vs 13%) levels.

Factors that affected a better response to therapy included lower viral levels at study entry, older age, race and level of adherence to the regimens. Those who were more adherent to their regimens, who started the study at lower baseline viral loads, and who were not black had better suppression of their HIV. CD4 count at study entry did not significantly affect anti-HIV response rates.

Prezista is the latest protease inhibitor approved by the FDA. Its development focused on overcoming the resistance found in other protease inhibitors in efforts to give treatment experienced individuals a potent option should they need to find a new regimen. Given these encouraging results, it appears that Prezista is also becoming a potent option for those starting on their first HIV regimens.