Dose reduction effective in alleviating symptoms of saquinavir toxicity.

Gastrointestinal intolerance is a limitation of boosted saquinavir antiretroviral treatment. We present three HIV-infected individuals whose severe toxicity symptoms started directly after initiation of a standard dose saquinavir hard-gel capsule-containing regimen (saquinavir/ritonavir 1000/100 mg). All patients underwent immediate 12 h pharmacokinetic (PK) assessment and showed extraordinarily high saquinavir plasma exposure. All three patients did not recover until the saquinavir exposure was decreased. This pilot case study anticipates a new concept of 'direct PK'-guided individual dose interventions under close viral load monitoring. Two major reasons for symptomatic saquinavir overexposure were defined: impaired liver function in a chronic hepatitis C virus co-infected individual at normal liver performance parameters and a delayed cytochrome p450 enzyme autoinduction. Overexposure seems to be an independent intolerance factor. Although delayed autoinduction is not well established as a reason for adverse events in saquinavir therapy, this observation may be confirmed in the near future by increased use.

The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load.

OBJECTIVES: The aim of the study was to evaluate the safety and efficacy of abacavir (ABC) and efavirenz (EFV) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (< 50 HIV -1 RNA copies/mL). To be eligible for inclusion, patients had to have a history of viral load < 400 copies/mL for at least 3 months and had to be naive to treatment with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed. DESIGN: An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV. At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured. Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide. Additionally, an oral glucose tolerance test (OGTT) was performed. A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition. RESULTS: Thirty patients were included in the study. Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by nonadherence. At week 48, all remaining patients had viral loads < 50 copies/mL with stable CD4 counts. The fasting metabolic parameters and abdominal fat distribution remained unchanged. CONCLUSIONS: In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.

CD4 lymphocyte count as a predictor of the duration of highly active antiretroviral therapy-induced suppression of human immunodeficiency virus load.

The association between CD4 cell count and duration of virus load suppression was investigated in 558 patients in the Frankfurt HIV Clinic Cohort who had begun highly active antiretroviral therapy and who had virus load declines to 500 copies/mL; P=.0001). Baseline virus load was not associated with virus load rebound. Lower baseline CD4 cell counts were associated with increased risk of viral rebound; however, this risk was significantly reduced in persons with low baseline CD4 cell counts who experienced substantial increases in CD4 cell counts during follow-up.

Virological response to protease inhibitor therapy in an HIV clinic cohort.

OBJECTIVE: New antiretroviral strategies aim to reduce plasma HIV RNA (viral load) to below the limits of detectability of assays with the objective of reducing viral replication in order to stop or reverse the pathogenic process and prevent development of drug resistance. First use of a protease inhibitor might offer the most realistic chance of achieving this aim. Our objective was to study the virological response to protease inhibitors in patients taking them for the first time. METHODS: A total of 901 patients from a large outpatient clinic were followed a mean of 15 months from the time of starting a protease inhibitor until 1 May 1998. Viral load and CD4 cell count measurements were made on average every 34 days. RESULTS: Overall there was a 79% [95% confidence interval (CI), 76-82] probability of the patients achieving a viral load < 500 copies/ml by 24 weeks after starting the protease inhibitor. In a multiple Cox regression model, those with lower initial viral load [relative hazard (RH), 0.72; P < 0.0001], higher CD4 cell count (RH, 1.07; P = 0.002), those starting other new drugs at same time as the protease inhibitor (RH, 1.46 for two versus none; P = 0.003), those who were antiretroviral-naive, and those using indinavir or nelfinavir were more likely to achieve such levels. In those 651 patients achieving viral load < 500 copies/ml within 24 weeks, there was an estimated 53% (95% CI, 51-55) probability of rebound of viral load to > 500 copies/ml by 52 weeks from the first undetectable value. Again, those who had started other new drugs at the same time as the protease inhibitor (RH, 0.57; P = 0.003 for starting two versus none) tended to experience a lower probability of viral load rebound, as did those with higher initial CD4 cell count (RH, 0.87 per 100 x 10(6)/l higher; P = 0.0007). Those who took saquinavir achieved less durable virological responses than those who took other protease inhibitors. CONCLUSIONS: Starting protease inhibitor therapy with two other new antiretroviral drugs simultaneously with protease inhibitor therapy offers a better best chance of achieving sustained viral load < 500 copies/ml than starting fewer new drugs.

Nevirapine/didanosine/lamivudine once daily in HIV-1-infected intravenous drug users.

Human immunodeficiency virus (HIV)-infected, active intravenous drug users received once-daily therapy consisting of a combination of didanosine (2',3'-dideoxyinosine or DDI), lamivudine [(-)-beta-L-2',3'-dideoxy-3'-thiacytidine or 3TC] and nevirapine. Preliminary results for the first 24 weeks show that the regimen provides potent immunological and antiviral effects.