[116] ANALYSIS OF VIROLOGICAL RESPONSE OF ENFUVIRTIDE IN TORO: IMPLICATIONS FOR PATIENT MANAGEMENT

2nd International AIDS Society Conference on HIV Pathogenesis and Treatment

Paris, France - July 13 - 16, 2003

[TITLE:] ANALYSIS OF VIROLOGICAL RESPONSE OF ENFUVIRTIDE IN TORO: IMPLICATIONS FOR PATIENT MANAGEMENT

[AUTHOR(S):] J Montaner¹, R DeMasi², J Delehanty², J Chung³, Z Gafoor² and M Salgo³ on behalf of the TORO ¹ and TORO ² Study Groups
¹University of British Columbia, Vancouver, Canada; ²Trimeris, NC, USA; and ³Roche, NJ, USA

IAS Conf HIV Pathog Treat 2003 Jul 13-16;2nd: Abstract No. 116
Antiviral Therapy 2003; 8(Suppl. 1):S212

[ABSTRACT:] Background: Enfuvirtide (ENF) is an HIV-1 fusion inhibitor, a new class of approved antiretroviral (ARV) that targets HIV-1 gp41 thereby inhibiting HIV fusion to the host cell. The safety and efficacy of ENF plus an optimised background (OB) regimen through 24 weeks of treatment has been established in two pivotal studies, TORO 1 and TORO 2. We evaluated virological response with the objective of providing guidance for clinical practitioners on the effective use of ENF + OB.

Methods: Triple-class experienced patients with plasma HIV-1 RNA >5000 copies/ml selected an OB regimen of 3–5 ARVs based on prior history and baseline (BL) genotypic and phenotypic resistance. The percentages of patients with plasma HIV-1 RNA <50 and <400 copies/ml were summarized by randomized treatment arm. Exploratory multiple logistic regression analyses were used to assess the prognostic value of baseline and treatment factors on virological response, and subgroup analyses were performed to confirm the findings.

Results: 995 patients (ENF + OB: 661; OB: 334) were included in the ITT population (defined as randomized, received at least one dose of study drug and had at least one post-baseline assessment). At 24 weeks, the percentage of patients with plasma HIV-1 RNA <50 and <400 copies/ml were 22.8% and 37.4 % for ENF+OB vs 9.0% and 16.2% for OB, respectively. The likelihood of virological suppression <400 copies/ml was higher for ENF+OB patients that were: healthier [CD4+>100 cells/mm³ vs <100 cells/mm³; OR=3.0, 95% CI=(2.1, 4.2)]; less ARV experience [<10 prior ARVs vs >10 ARVs; OR=1.8, 95% CI=(1.2, 2.7)]; and had more active drugs in their OB (>2 vs <2; OR=2.6, 95% CI=(1.8,3.7)).

Conclusions: While the comparative efficacy of ENF+OB over OB alone has previously been established, these results suggest that the virological response to ENF+OB therapy is directly related to the activity of the background regimen and improved responses were observed in less advanced and less-experienced patients.

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