14th International AIDS Conference Barcelona, Spain — July 7-12, 2002

Int Conf AIDS. 2002 Jul 7-12;14:Abstract No. TuOrB1189

BACKGROUND: Antiretroviral treatment (ART) utilizing dual nucleosides in combination regimens can offer dramatic benefits to individuals with HIV-1 infection. An abacavir/lamivudine combination (ABC/3TC) was studied with EFV, APV/RTV or d4T.

METHODS: ESS40001 is a randomized, open-label trial of ABC 300 mg /3TC 150mg BID combined with either an NNRTI QD, PI QD, or NRTI BID in therapy-naïve HIV-infected subjects with baseline (BL) RNA >5000 c/mL and CD4 >50 c/mm³. 2nd line ART is defined in cases of virologic failure (VF) or toxicity.

Objectives: 1) To assess the 96 week (WK) efficacy and safety of each approach to initial ART; 2) to provide long-term durability data on ABC/3TC combination. Complete WK 48 data will be presented (abstract includes data for 70%). Results from planned interim analysis: 291 subjects completed BL visits. BL demographics were similar between the 3 arms except for disease state (NNRTI: 24%; PI: 37%, NRTI: 21% were CDC Class B or C). 42% had BL RNA >100,000c/mL and 32% entered with CD4 cells <200 cells/mm³. Proportions of subjects with vRNA for 1st line regimens by WK 48 were 90% NNRTI, 80% PI, and 81% NRTI (Kaplan-Meier analysis). At WK 48, proportions with RNA <50c/mL were 93% NNRTI, 73% PI and 73% NRTI (ITT-observed); mean changes from BL in RNA (log₁₀) and CD4 were: NNRTI, -3.12 and 160; PI, -2.98 and 140; and NRTI, –2.87 and 171. 16 of 25 subjects had begun secondary therapy due to VF (8 NRTI and 8 PI). Of 26 subjects (9%) D/Cing the study prematurely, only 5 (2%) were due to study drug-related adverse events (AEs). 20 subjects experienced drug-related Serious AEs. ABC hypersensitivity was reported in 6% of subjects.

Results from planned interim analysis: 291 subjects completed BL visits. BL demographics were similar between the 3 arms except for disease state (NNRTI: 24%; PI: 37%, NRTI: 21% were CDC Class B or C). 42% had BL RNA >100,000c/mL and 32% entered with CD4 cells <200 cells/mm³. Proportions of subjects with vRNA for 1st line regimens by WK 48 were 90% NNRTI, 80% PI, and 81% NRTI (Kaplan-Meier analysis). At WK 48, proportions with RNA <50c/mL were 93% NNRTI, 73% PI and 73% NRTI (ITT-observed); mean changes from BL in RNA (log₁₀) and CD4 were: NNRTI, -3.12 and 160; PI, -2.98 and 140; and NRTI, –2.87 and 171. 16 of 25 subjects had begun secondary therapy due to VF (8 NRTI and 8 PI). Of 26 subjects (9%) D/Cing the study prematurely, only 5 (2%) were due to study drug-related adverse events (AEs). 20 subjects experienced drug-related Serious AEs. ABC hypersensitivity was reported in 6% of subjects.

CONCLUSIONS: All 3 regimens suppressed RNA to <50 in at least 70% of subjects at WK 48, supporting the potency of the ABC/3TC when combined with NNRTI, PI or NRTI. Continuing follow-up of these subjects will provide long-term data on successful approaches to initial ART.

Presenting author: J A Bartlett, Duke University Medical Center, Durham, NC, United States

1 A Bartlett; Duke University Medical Center, Durham, NC, United States

2J Johnson, M S Shaefer; GlaxoSmithKline, Research Triangle Park, NC, United States

3G Herrera; SEMECO, San Jose, Costa Rica

4N Sosa; Consultorio Royal, Panama City, Panama

5A E Rodriguez; University of Miami, Miami, FL, United States

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Copyright © 2002 - International AIDS Society (IAS). Reproduction of this abstract (other than one copy for personal reference) must be cleared through the IAS.