Clinical and pharmacokinetic data support once-daily low-dose boosted saquinavir (1,200 milligrams saquinavir with 100 milligrams ritonavir) in treatment-naive or limited protease inhibitor-experienced human immunodeficiency virus-infected patients

Efficacy, safety and pharmacokinetic of once-daily boosted saquinavir (1500/100 mg) together with 2 nucleos(t)ide reverse transcriptase inhibitors in real life: a multicentre prospective study

Background

Ritonavir-boosted saquinavir (SQVr) is nowadays regarded as an alternative antiretroviral drug probably due to several drawbacks, such as its high pill burden, twice daily dosing and the requirement of 200 mg ritonavir when given at the current standard 1000/100 mg bid dosing. Several once-daily SQVr dosing schemes have been studied with the 200 mg SQV old formulations, trying to overcome some of these disadvantages. SQV 500 mg strength tablets became available at the end of 2005, thus facilitating a once-daily regimen with fewer pills, although there is very limited experience with this formulation yet.

Methods

Prospective, multicentre study in which efficacy, safety and pharmacokinetics of a regimen of once-daily SQVr 1500/100 mg plus 2 NRTIs were evaluated under routine clinical care conditions in either antiretroviral-naïve patients or in those with no previous history of antiretroviral treatments and/or genotypic resistance tests suggesting SQV resistance. Plasma SQV trough levels were measured by HPLV-UV.

Results

Five hundred and fourteen caucasian patients were included (47.2% coinfected with hepatitis C and/or B virus; 7.8% with cirrhosis). Efficacy at 52 weeks (plasma RNA-HIV <50 copies/ml) was 67.7% (CI₉₅: 63.6 - 71.7%) by intention-to-treat, and 92.2% (CI₉₅: 89.8 - 94.6%) by on-treatment analysis. The reasons for failure were: dropout or loss to follow-up (18.4%), virological failure (7.8%), adverse events (3.1%), and other reasons (4.6%). The high rate of dropout may be explained by an enrollement and follow-up under routine clinical care condition, and a population with a significant number of drug users. The median SQV Cmin (n = 49) was 295 ng/ml (range, 53-2172). The only variable associated with virological failure in the multivariate analysis was adherence (OR: 3.36; CI95, 1.51-7.46, p = 0.003).

Conclusions

Our results suggests that SQVr (1500/100 mg) once-daily plus 2 NRTIs is an effective regimen, without severe clinical adverse events or hepatotoxicity, scarce lipid changes, and no interactions with methadone. All these factors and its once-daily administration suggest this regimen as an appropriate option in patients with no SQV resistance-associated mutations.

Once-daily treatment with saquinavir mesylate (2000 mg) and ritonavir (100 mg) together with a fixed-dose combination of abacavir/lamivudine (600/300 mg) or tenofovir/emtricitabine (245/200 mg) in HIV-1-infected patients

OBJECTIVES

To investigate the feasibility and pharmacokinetics of a once-daily regimen of 2000 mg saquinavir mesylate boosted with 100 mg ritonavir.

PATIENTS AND METHODS

Patients successfully treated with 1000 mg saquinavir boosted with 100 mg ritonavir twice daily together with two nucleoside or nucleotide reverse transcriptase inhibitors [N(t)RTIs] who were switched to 2000 mg saquinavir with 100 mg ritonavir once daily with unchanged N(t)RTI therapy were analysed. CD4 cells, HIV-RNA PCR and metabolic parameters were compared between baseline and 3, 6, 9 and 12 months after the switch. Saquinavir and ritonavir drug levels were measured before and a median of 3 weeks after switching from twice to once daily at 0, 1, 2, 4, 6, 9, 12 and 24 h after intake of the medication. The area under the serum concentration-time curve from 0 to 24 h (AUC(0-24)) was calculated using the trapezoidal rule.

RESULTS

Eighteen patients (16 males, median age of 41 years) with a median CD4 cell count of 464 cells/mm(3) were analysed. HIV-RNA PCR remained <500 copies/mL for all patients. After switching from 100 mg twice daily to 100 mg once daily, the AUC(0-24) for ritonavir decreased significantly [21 874 to 10 267 ng.h/mL, geometric mean ratio (GMR) = 0.47; P < 0.001], whereas the AUC(0-24) for saquinavir decreased only marginally from 35 000 to 34 490 ng.h/mL (GMR = 0.99; P = 0.426). The CD4 cell count and the fasting metabolic parameters remained unchanged.

CONCLUSIONS

Once-daily treatment with ritonavir-boosted saquinavir was well tolerated and resulted in similar saquinavir drug exposure despite much lower ritonavir concentrations when compared with a twice-daily dosing schedule.

Characterization of virologic failure patients on darunavir/ritonavir in treatment-experienced patients

OBJECTIVE

Characterization of resistance development in virologic failure patients on the protease inhibitor darunavir administered with low-dose ritonavir (DRV/r) in the 48-week analysis of TMC114/r In Treatment-experienced pAtients Naive to lopinavir (TITAN).

DESIGN

TITAN is a randomized, controlled, open-label, phase III, noninferiority trial comparing the efficacy and safety of DRV/r with that of lopinavir/ritonavir (LPV/r) in HIV-1-infected, treatment-experienced, LPV-naive patients. The primary endpoint was the proportion of patients with HIV-1 RNA less than 400 copies/ml at week 48.

METHODS

Patients received DRV/r 600/100 mg twice daily (n = 298) or LPV/r 400/100 mg twice daily (n = 297), and an optimized background regimen. Patients who lost or never achieved HIV-1 RNA less than 400 copies/ml after week 16 were considered virologic failure patients. Genotyping and phenotyping were performed.

RESULTS

The virologic failure rate in the DRV/r arm (10%, n = 31) was lower than in the LPV/r arm (22%, n = 65). Furthermore, fewer virologic failure patients in the DRV/r arm than in the LPV/r arm developed primary protease inhibitor mutations (6 vs. 20) or nucleoside reverse transcriptase inhibitor resistance-associated mutations (4 vs. 15). In addition, fewer virologic failure patients on DRV/r than on LPV/r lost susceptibility to the protease inhibitor (3 vs. 13) or nucleoside reverse transcriptase inhibitor(s) (3 vs. 14) used in the treatment regimen or to other protease inhibitors. Most DRV/r-treated virologic failure patients retained susceptibility to all protease inhibitors.

CONCLUSION

In treatment-experienced, LPV-naive patients, the overall virologic failure rate in the DRV/r arm was low and was associated with limited resistance development. These findings showed that the use of DRV/r in earlier lines of treatment was less likely to lead to cross-resistance to other protease inhibitors compared with LPV/r.