Comparison of twice-daily stavudine plus once- or twice-daily didanosine and nevirapine in early stages of HIV infection: the Scan Study

Objectives: To evaluate the safety and effectiveness of once-daily didanosi ne and nevirapine plus twice-daily stavudine versus twice-daily administrat ion of all three drugs. Methods: This open-label, randomized, multicentre study enrolled 94 antiret roviral-naive patients with chronic HIV infection, CD4+ cell counts > 500 x 10(6) cells/l, and viral loads > 5000 copies/ml. Patients were treated wit h either 40 mg stavudine (twice daily) plus 400 mg didanosine (once daily) and 400 mg nevirapine (once daily) or 40 mg stavudine (twice daily) plus 20 0 mg didanosine (twice daily) and 200 mg nevirapine (twice daily). Results: After 12 months, 68% of patients who received twice-daily didanosi ne and nevirapine had viral loads < 200 copies/ml in the intention-to-treat and 79% in the on-treatment analysis, respectively. The corresponding valu es for patients treated with didanosine and nevirapine, taken once-daily, w ere 73 and 85%. The percentages of patients in each group with viral loads < 5 copies/ml at 12 months were 40% (once daily) and 45% (twice daily) for the intention-to-treat analysis. Five of 11 patients (45%) with plasma vira l loads < 5 copies/ml at 12 months had detectable virus in tonsillar tissue . Genotypic resistance to nevirapine was noted in seven of the 14 patients with detectable viral load at month 12. Mean changes in CD4+ cell counts fo r patients treated with stavudine plus once- or twice-daily didanosine and nevirapine were 154 and 132 x 10(6) cells/l, respectively. Treatment was in terrupted due to adverse events in seven patients (8%) (four who received o nce-daily didanosine and nevirapine and three treated with twice-daily dose s). Conclusions: The combination of twice-daily stavudine plus once-daily didan osine and nevirapine was as safe and well tolerated as twice-daily administ ration of all three agents. Both regimens were equally effective in reducin g viral loads and in increasing CD4+ cell counts. (C) 2000 Lippincott Willi ams & Wilkins.