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The rabbit study: ritonavir and saquinavir in combination in saquinavir-experienced and previously untreated patients.


AIDS Res Hum Retroviruses. 1999 Sep 1;15(13):1181-9. Unique Identifier :

Thirteen protease inhibitor-naive patients with HIV-1 infection, and 12 patients with a median of 58 months prior treatment with saquinavir (SQV) monotherapy, were treated with SQV (400 mg twice daily) and ritonavir (RIT, 500 mg twice daily) in a study designed to assess the effect of prior treatment with SQV monotherapy on the antiretroviral activity of RIT-SQV combination therapy. Median baseline viral load and CD4+ cell counts were 155,000 and 262,000 copies/ml and 333 and 225 cells/mm3 in the naive and experienced groups, respectively. Mean viral load changes at 24 weeks were -1.63 and -0.27 log copies/ml in the naive and SQV-experienced groups, respectively (intent-to-treat analysis). Baseline genotype by point mutation assay and sequencing in the SQV-experienced group was highly predictive of virological response. Eight of 11 SQV-experienced patients had evidence of phenotypic resistance to RIT at baseline, despite previous treatment with SQV only. There was strong correlation between phenotypic resistance to RIT and the presence of the L90M mutation. We conclude that prolonged prior treatment with saquinavir monotherapy may produce cross-resistance to ritonavir and reduce the subsequent response to ritonavir-saquinavir in combination. In this study, both phenotypic resistance to ritonavir and presence of the L90M mutation predicted the viral load response to ritonavir-saquinavir.

CLINICAL TRIAL CLINICAL TRIAL, PHASE I CLINICAL TRIAL, PHASE II JOURNAL ARTICLE Adult Anti-HIV Agents/*THERAPEUTIC USE Cohort Studies CD4 Lymphocyte Count Drug Interactions Drug Resistance, Microbial/GENETICS Drug Therapy, Combination Female Gene Products, pol/GENETICS Human HIV Infections/*DRUG THERAPY/VIROLOGY HIV Protease Inhibitors/*THERAPEUTIC USE HIV-1/*DRUG EFFECTS/GENETICS Male Middle Age Mutation Ritonavir/ADVERSE EFFECTS/PHARMACOKINETICS/*THERAPEUTIC USE Saquinavir/ADVERSE EFFECTS/PHARMACOKINETICS/*THERAPEUTIC USE Sequence Analysis, DNA Support, Non-U.S. Gov't Viral Load


Information in this article was accurate in December 30, 1999. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.