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Boosted Saquinavir Matches Lopinavir After 24 Weeks
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8th International Congress on Drug Therapy in HIV Infection
November 12-16, 2006
Glasgow, Scotland
Mark Mascolini
Interim analysis of a trial comparing lopinavir/ritonavir with the 500-mg saquinavir tablet plus 100 mg of ritonavir twice daily showed equivalent viral load and CD4 responses after 24 weeks [1]. Some who saw these results detailed at the "Glasgow meeting" questioned early unveiling of the findings in this 48-week trial.
Jihad Slim from St. Michael's Medical Center in Newark and colleagues in Bangkok and Toronto randomized 150 treatment-naive people to saquinavir/ritonavir or lopinavir/ritonavir, both plus fixed-dose once-daily tenofovir/emtricitabine. Median viral loads stood above 100,000 copies in both groups, and average CD4 counts were low--134 in the saquinavir arm and 121 in the lopinavir arm. About one third overall had a pretreatment CD4 count under 50, and 11% in both groups had hepatitis C virus coinfection.
Intent-to-treat and on-treatment analyses showed statistically equivalent 24-week virologic responses with saquinavir and lopinavir (Table). CD4 gains through 24 weeks were also similar in the two treatment groups.
Five people taking saquinavir/ritonavir had a virologic failure by week 24 (including 2 with poor adherence), as did 2 taking lopinavir/ritonavir (1 with poor adherence). As in earlier studies of ritonavir-boosted protease inhibitors (PIs), new PI-related mutations did not emerge during any of these virologic failures.
Gastrointestinal side effects proved almost twice as common with lopinavir/ritonavir (23%) as with saquinavir/ritonavir (14%). Two serious treatment-related problems in the saquinavir group--hypokalemia and an acute psychotic episode--resolved without further developments. One Thai woman without known liver problems stopped lopinavir/ritonavir and tenofovir/emtricitabine because of liver failure and died several weeks later.
Lipid upswings appeared to favor the saquinavir group. Whereas 17% starting saquinavir had a total cholesterol above 200 mg/dL, 21% had a reading that high at week 24. Respective percentages in the lopinavir group were 13% and 38% (P = 0.036 for 38% vs 21%). While no one had triglycerides above 400 mg/dL when starting saquinavir, 1% did after 24 weeks. Respective percentages in the lopinavir arm were 4% and 13% (P = 0.009 for 13% vs 1%).
Brian Gazzard of London's Chelsea and Westminster Hospital criticized presentation of these interim results ahead of the primary endpoint analysis, a 48-week intent-to-treat reckoning of proportions with a viral load under 50 copies. Researchers sometimes fear that preliminary results will sway study participants' decision about staying in a. trial.
Reference
1. Slim J, Avihingsanon A, Ruxrungtham K, et al. Saquinavir BID vs lopinavir plus emtricitabine/tenofovir QD in ARV-naïve HIV-1 infected patients: GEMINI study. 8th International Congress on Drug Therapy in HIV Infection, November 12-16, 2006, Glasgow. Abstract 2.5.
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