The LOPSAQ study: 48 week analysis of a boosted double protease inhibitor regimen containing lopinavir/ritonavir plus saquinavir without additional antiretroviral therapy

Second line antiretroviral therapy for treatment of HIV in Asia

Limited access to virological monitoring has led to a high prevalence of resistance to nucleoside reverse transcriptase inhibitors (NRTIs) at the time of first line failure in most studies from low- and middle-income countries (LMIC). Nevertheless, the current standard of care is to include NRTIs in second line regimens. The activity of tenofovir/emtricitabine following failure of stavudine/lamivudine or zidovudine/lamivudine is dependent on the sensitivity of the monitoring strategy used during first line therapy and the threshold for switching, whereas these factors are less important if the opposite sequencing strategy is used. Boosted protease inhibitors (PIs) are the foundation of effective second-line therapy with demonstrated efficacy in early salvage regimens and high barrier to resistance. Lopinavir/ritonavir and ritonavir-boosted atazanavir have recently been described by the World Health Organization as preferred boosted PIs for use in LMIC. Alternative approaches currently under investigation include boosted PI monotherapy, dual boosted PIs, and the combination of raltegravir (an HIV integrase inhibitor) and a boosted PI.

HIV-1 replication in central nervous system increases over time on only protease inhibitor therapy

There are concerns about central nervous system (CNS)-replication of HIV-1 in patients on boosted protease inhibitors. Purpose of this study was to compare HIV-1 viral loads (VLs) from patients treated with only boosted dual protease inhibitor (bdPI), versus combination antiretroviral therapy (cART group), containing two nucleoside analogue reverse transcriptase inhibitors (NRTI) and a third partner. All patients from a large German HIV-treatment cohort with available medication, clinical and demographic data, including results from simultaneous HIV-1 viral load (VL) assessments in cerebrospinal fluid (CSF) and blood plasma, were retrospectively evaluated as controlled cross-sectional study. CSF had been obtained from patients with variable neurological symptoms during 2005-2014. Statistical analysis comprised nonparametric tests, regression and correlation techniques accounting for undetectable quantifications. Statistical analysis comprised nonparametric tests, regression and correlation techniques accounting for undetectable quantifications. Overall, 155 patients were evaluable (bdPI: 24; cART: 131). At time of CSF-collection, both groups were comparable in age, gender, CD4-cell counts, or primary HIV-transmission risks, though bdPI patients were clinically more advanced. The proportion of patients with undetectable HIV-1 (<50 copies/ml) in CSF was lower for bdPI group (25 vs 49.6 %; p = 0.026), but similar in plasma (46 vs 41 %). Median CSF-VL was higher in bdPI group (600 vs 50 copies/ml; p = 0.027) and similar in plasma. Mean VL CSF/plasma ratio was 342.91 for bdPI- and 54.48 for cART patients (p < 0.001). Pearson's regression analysis revealed a trend for an elevated VL-ratio over time within bdPI group. HIV-1 replication was higher and more frequently detectable in CSF from bdPI patients, indicating a worse CNS penetration effectiveness of used boosted PI. Within bdPI group, measured CNS-viral replication was increasing over time, suggesting an over time impaired HIV-1 suppression in CSF.

Impact of HIV-1 replication on immunological evolution during long-term dual-boosted protease inhibitor therapy

To explore CD4-cell and viral evolution in relation to different levels of HIV-1 replication, as observed during protease inhibitor (PI)-based antiretroviral therapy. Adult HIV-1 infected cohort patients, receiving historical salvage therapy with daily doses of saquinavir (2,000 mg), ritonavir (200 mg) and either lopinavir (800 mg) or atazanavir (300 mg) for >36 weeks were retrospectively analysed for highest detectable viral load up to week 96 and assigned to groups according to the viral load level: always <50 copies/ml (1), 50-199 copies/ml (2), 200-499 copies/ml (3) and ≥500 copies/ml (4). A total of 126 patients were evaluated; at baseline, median CD4-cell count was 204/mm(3), HIV-1 RNA was 5.13 Log10-copies/ml and duration of prior HIV-1 infection was 11.7 years. Patients were assigned by 43, 30, 7 and 20 % to groups 1-4. Median observation time was 136 weeks (range: 38-304); at weeks 48/96, the CD4-cell gains for groups 1-4 were +88/+209, +209/+349, +67/+300 and +114.5/+ 128, respectively. After fitting data in a linear fixed effect model, ascending CD4 slopes were continuously increasing for group 1, similarly for 2 and clearly decreasing for 3-4 (p = 0.0006). Of 25 individuals from group 4, patient number with major IAS-USA protease mutations increased from 5 to 10 before and after failing PI therapy, whereas minor mutations remained stable (n = 18). On double-boosted PI therapy, CD4-cell increases through week 96 were similar for patients at always undetectable or with detection of low viral load. Viral detection >200 copies/ml was associated with decreasing CD4-cell slopes and emergence of major mutations, supporting this as benchmark for virological failure definition on PI therapy.

Efficacy and safety of a dual boosted protease inhibitor-based regimen, atazanavir and fosamprenavir/ritonavir, against HIV: experience in a pediatric population

Background

Although dual-boosted protease inhibitors regimen is not recommended in children with HIV infection, such a strategy could be useful in subjects with a complex resistance profile. This study was aimed at assessing the long term efficacy and safety of a double-boosted protease inhibitor combination, fosamprenavir (fAVP) and atazanavir/ritonavir (ATV/r) in a cohort of HIV-infected children and adolescents who had failed with nucleoside reverse transcriptase inhibitors.

Methods

Seven vertically infected children and adolescents who had previously failed highly active antiretroviral therapy and were resistant to nucleoside reverse transcriptase inhibitors, received a dual protease inhibitor (PI) regimen including fAVP plus ATV/r for 42 months. The patients were assessed at baseline, every month for the first 24 weeks of therapy and every 3 months until month 32. Physical examination, CD4+ cell count, HIV-RNA viral load, lipid profile and hepatic function were assessed throughout the follow up.

Results

During the study no serious adverse events were reported. CD4 absolute number increased over-time in all subjects. At baseline the median HIV-RNA was 6562 cp/mL (ranging 1048 -102772 cp/mL) and rapidly decreased below the limit of detection (50 cp/mL) after 2 months of the new treatment and remained undetectable in all cases through the entire study period. At the beginning of the study all cases showed a normal lipid profile. During the study period, 4/7 subjects showed total cholesterol, low density lipoprotein and triglyceride levels >97^th cent.le for the males and 94^th cent.le for the females. HDL cholesterol showed protective values. Hepatic enzymes remained stable during the entire observation, whereas total bilirubin showed toxicity II/III grade in 6/7 subjects. No change in fat redistribution and insulin resistance was observed.

Conclusion

Dual-boosted protease inhibitor therapy was virologically and immunologically effective and it could be considered as a possible alternative to a rescue regimen in children and adolescents. However, hypercholesterolemia and hypertriglyceridemia need close follow-up and may limit the use of this therapeutic option.

HIV-GRADE: a publicly available, rules-based drug resistance interpretation algorithm integrating bioinformatic knowledge

BACKGROUND

Genotypic drug resistance testing provides essential information for guiding treatment in HIV-infected patients. It may either be used for identifying patients with transmitted drug resistance or to clarify reasons for treatment failure and to check for remaining treatment options. While different approaches for the interpretation of HIV sequence information are already available, no other available rules-based systems specifically have looked into the effects of combinations of drugs. HIV-GRADE (Genotypischer Resistenz Algorithmus Deutschland) was planned as a countrywide approach to establish standardized drug resistance interpretation in Germany and also to introduce rules for estimating the influence of mutations on drug combinations. The rules for HIV-GRADE are taken from the literature, clinical follow-up data and from a bioinformatics-driven interpretation system (geno2pheno([resistance])). HIV-GRADE presents the option of seeing the rules and results of other drug resistance algorithms for a given sequence simultaneously.

METHODS

The HIV-GRADE rules-based interpretation system was developed by the members of the HIV-GRADE registered society. For continuous updates, this expert committee meets twice a year to analyze data from various sources. Besides data from clinical studies and the centers involved, published correlations for mutations with drug resistance and genotype-phenotype correlation data information from the bioinformatic models of geno2pheno are used to generate the rules for the HIV-GRADE interpretation system. A freely available online tool was developed on the basis of the Stanford HIVdb rules interpretation tool using the algorithm specification interface. Clinical validation of the interpretation system was performed on the data of treatment episodes consisting of sequence information, antiretroviral treatment and viral load, before and 3 months after treatment change. Data were analyzed using multiple linear regression.

RESULTS

As the developed online tool allows easy comparison of different drug resistance interpretation systems, coefficients of determination (R(2)) were compared for the freely available rules-based systems. HIV-GRADE (R(2) = 0.40), Stanford HIVdb (R(2) = 0.40), REGA algorithm (R(2) = 0.36) and ANRS (R(2) = 0.35) had a very similar performance using this multiple linear regression model.

CONCLUSION

The performance of HIV-GRADE is comparable to alternative rules-based interpretation systems. While there is still room for improvement, HIV-GRADE has been made publicly available to allow access to our approach regarding the interpretation of resistance against single drugs and drug combinations.

Single-Boosted Protease Inhibitor versus Double-Boosted Protease Inhibitors for the Salvage Therapy in HIV-Infected Patients

OBJECTIVE

To compare treatment outcomes between the regimens of single-boosted protease inhibitor (PI) and double-boosted PIs for the salvage therapy in patients who failed nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens.

METHODS

A total of 64 patients from 2 cohorts, 40 in twice daily ritonavir-boosted lopinavir (LPV/r) at 400/100 mg plus lamivudine (3TC) and 24 in once daily ritonavir-boosted atazanavir and saquinavir (ATV/SQV/r) at 300/1600/100 mg/d, were studied.

RESULTS

At 48 weeks, 30 (75%) patients in LPV/r group and 20 (83%) patients in ATV/SQV/r group achieved HIV-1 RNA at <400 copies/mL (P = .790). In all, 24 (60%) and 16 (67%) achieved HIV-1 RNA at <50 copies/mL (P = .541). Low-level viral rebound (51-400 copies/mL) was found in 6 (15%) in LPV/r group and 4 (17%) in ATV/SQV/r group (P = 1.000). Medians CD4 counts were 336 cells/mm(3) and 330 cells/mm(3) in the corresponding groups (P = 0.937).

CONCLUSION

No additional benefit is found with double-boosted PIs compared to single-boosted PI in terms of treatment responses in HIV-infected patients failing NNRTI-based regimen.

Gag mutations can impact virological response to dual-boosted protease inhibitor combinations in antiretroviral-naïve HIV-infected patients

ANRS 127 was a randomized pilot trial involving naïve patients receiving two dual-boosted protease inhibitor (PI) combinations. Virological response, defined as a plasma HIV RNA level of <50 copies/ml at week 16, occurred in only 41% patients. Low baseline plasma HIV RNA level was the only significant predictor of virological response. The purpose of this study was to investigate the impact on virological response of pretherapy mutations in cleavage sites of gag, gag-pol, and the gag-pol frameshift region. The whole gag gene and protease-coding region were amplified and sequenced at baseline and at week 16 for 48 patients still on the allocated regimen at week 16. No major PI resistance-associated mutations were detected either at baseline or in the 26 patients who did not achieve virological response at week 16. Baseline cleavage site substitutions in the product of the gag open reading frame at positions 128 (p17/p24) (P = 0.04) and 449 (p1/p6(gag)) (P = 0.01) were significantly more frequent in those patients not achieving virological response. Conversely, baseline cleavage site mutation at position 437 (TFP/p6(pol)) was associated with virological response (P = 0.04). In multivariate analysis adjusted for baseline viral load, these 3 substitutions remained independently associated with virological response. We demonstrated here, in vivo, an impact of baseline polymorphic gag mutations on virological response in naïve patients receiving a combination of two protease inhibitors. However, it was not possible to link the substitutions selected under PI selective pressure with virological failure.

Multidrug resistance: a clinical approach

PURPOSE OF REVIEW

New antiretroviral agents have recently become available within existing and new drug classes, increasing treatment options for patients with multidrug-resistant virus. This review discusses the challenges that these new agents pose for the management of treatment-experienced patients.

RECENT FINDINGS

Recent studies of the efficacy and safety of new antiretroviral drugs illustrate that drug regimens containing new agents are well tolerated and can suppress viremia in even the most drug-resistant patients. The goal of any new regimen should therefore be suppression of plasma HIV RNA levels to less than 50 copies/ml, even in treatment-experienced patients. Patients should be given a regimen with at least two, or preferably three, fully active drugs after careful consideration of their treatment and adherence history, current and prior genotype tests, comorbidities, and concomitant medications. Newer and more tolerable agents also offer the possibility of regimen simplification among patients with multidrug-resistant HIV who are virologically suppressed.

SUMMARY

Clinicians must optimize the pairing and sequencing of recently available antiretroviral agents. Future studies should continue to investigate the optimal use of new agents in order to further improve long-term treatment efficacy in patients with multidrug-resistant HIV infection.

Effectiveness of boosted protease inhibitor-based regimens in HIV type 1-infected patients who experienced virological failure with NNRTI-based antiretroviral therapy in a resource-limited setting

A number of patients have experienced treatment failure while receiving non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy (ART), particularly in resource-limited countries. The need remains for clinical data on protease inhibitor (PI)-based regimens in these patients. A retrospective cohort study was conducted among HIV-1-infected patients who had failed NNRTI-based regimens, were naive to protease inhibitors (PIs), and subsequently initiated a salvage PI-based regimen between January 2004 and December 2006. The study period ended on 30 December 2007. One hundred and forty patients received a single-boosted PI +/- optimized background regimen (OBR) and 64 received double-boosted PIs. The median (IQR) duration of follow-up was 19 (13-29) months. The overall virological failure rate at 24 months was 15.2%. No statistically significant difference was detected between the two regimen groups (single-boosted PI +/- OBR 16.4% vs. double-boosted PIs 12.5%, log rank p = 0.818). At the end of the study, the median (IQR) change in CD4 cell counts for patients in the double-boosted PI group was higher than for patients in the single-boosted PI +/- OBR group [149 (53-322) vs. 105 (23-199), respectively, p = 0.012]. Patients receiving double-boosted PI regimens displayed a higher frequency of hypertriglyceridemia than those patients who received a single boosted PI +/- OBR (31% vs. 11%, respectively, p = 0.001). Boosted PI-based regimens showed acceptable virological outcomes among patients who had failed NNRTI-based ART. In the subgroup analysis, patients who received double-boosted PIs demonstrated a superior immunological response but not better virological outcomes compared to the single-boosted PI +/- OBR group.

Relationship between plasma protease inhibitor concentrations and lipid elevations in HIV patients on a double-boosted protease inhibitor regimen (saquinavir/lopinavir/ritonavir)

The relationship between plasma protease inhibitor (PI) trough concentrations and hyperlipidemic effects were evaluated retrospectively using data from 2 pilot clinical trials of a double-boosted PI regimen (saquinavir/lopinavir/ritonavir) in 25 HIV patients. The patients' median age was 39 years (range, 25-60). At baseline, PI-naive patients had a median viral load of 53 500 copies/mL and median CD4 of 296 cells/mm(3), while PI-experienced patients had 37 750 copies/mL and 214 cells/mm(3). Plasma PI trough concentrations of saquinavir, lopinavir, and ritonavir at week 12 were 520, 4482, and 153 ng/mL, respectively. At week 12, median fasting lipids increased significantly from baseline: total cholesterol increased from 165 to 189 mg/dL (P = .0005) and the triglyceride increased from 113 to 159 mg/dL (P = .001). There were no associations between PI trough concentrations at week 12 and the percent total cholesterol change at week 12. No associations were found between PI trough concentrations and lipid changes in HIV patients on a double-boosted PI regimen (saquinavir/lopinavir/ritonavir). Factors other than systemic exposure to PIs (such as host or genetic factors) may modulate the hyperlipidemic effect of PIs.

Efficacy and safety of ritonavir-boosted dual protease inhibitor therapy in antiretroviral-naive HIV-1-infected patients: the 2IP ANRS 127 study

OBJECTIVES

We evaluate the efficacy and tolerability of ritonavir-boosted dual protease inhibitor as a nucleoside reverse transcriptase inhibitor-sparing regimen in a prospective open-label randomized pilot trial in antiretroviral-naive patients.

METHODS

Thirty patients received fosamprenavir/atazanavir/ritonavir (Group 1) and 31 patients received saquinavir/atazanavir/ritonavir (Group 2). The primary endpoint for efficacy was the rate of early virological success, defined as plasma viral load <50 copies/mL at week 16. The study is registered with ClinicalTrials.gov (NCT00122603).

RESULTS

At baseline, median (range) viral load was 4.8 log(10) copies/mL (4.0-5.7) and the median CD4 cell count was 271/mm(3) (197-740). Viral load was <50 copies/mL in 12/30 patients [40%, 95% confidence interval (CI) 23%-58%] and 13/31 patients (42%, 95% CI 25%-59%) at week 16 in Groups 1 and 2, respectively. Patients with failing regimens (viral load >or=400 copies/mL at week 16 or >or=50 copies/mL at week 24) were switched to a standard antiretroviral regimen. At week 48, by an intention-to-treat analysis, 23/30 patients (77%) and 26/31 patients (84%) had plasma HIV-1 RNA <50 copies/mL in Groups 1 and 2, respectively. Four patients discontinued treatment for adverse events, all before week 4. No major changes in the protease gene were detected at treatment failure relative to baseline. Baseline viral load <50 000 copies/mL was the only predictor of virological success at week 16.

CONCLUSIONS

Ritonavir-boosted dual protease inhibitor regimens targeting only one step of viral replication were insufficient to rapidly suppress plasma HIV RNA to <50 copies/mL in antiretroviral-naive patients with high viral load at baseline.

Safety and efficacy of a double-boosted protease inhibitor combination, saquinavir and lopinavir/ ritonavir, in pretreated children at 96 weeks

Background

This study aimed to assess the long-term efficacy, safety and use of therapeutic drug monitoring (TDM) of a double-boosted protease inhibitor (PI) combination, saquinavir (SQV) and lopinavir/ritonavir (LPV/r), in Thai HIV type-1 (HIV-1)-infected children who had failed on reverse transcriptase inhibitors.

Methods

In total, 50 children from two sites in Thailand were treated with standard dosing of SQV and LPV/r. CD4+ T-cell count and percentage, viral load (VL; HIV-1 RNA), minimum plasma drug concentrations (Cmin) and drug safety laboratory evaluations were monitored. Virological failure was defined as having two consecutive VL measures >400 copies/ml after week 12. An intention-to-treat analysis was performed.

Results

Baseline data were a median age of 9.3 years (interquartile range [IQR] 7.1–11.2), VL 4.8 log10 copies/ ml (IQR 4.5–5.1) and CD4+ T-cell percentage 7% (IQR 3.0– 9.5). CDC classifications were N=4%, A=14%, B=68% and C=14% of participants. Median CD4+ T-cell percentage and CD4+ T-cell count increase were 14% (IQR 7–19) and 558 cells/mm3 (IQR 308–782), respectively (both P<0.001). Overall, 37 (74%) children achieved VL<50 copies/ml with significant differences between sites (90% versus 63%). Over 96 weeks, 10 patients had virological failure. Total cholesterol and high-density lipoprotein increased significantly over time, whereas the triglycerides and low-density lipoprotein did not. Approximately 50% of participants reported no change in body shape, and 33%, 43% and 39% reported fatter arms, face and abdomen, respectively. LPV and SQV Cmin were high and stable over time.

Conclusions

Double-boosted SQV+LPV/r was an effective and safe alternative for a second-line regimen in children. Hypercholesterolaemia needs close follow-up. On the basis of the TDM results, PI dose reduction in this population should be considered.

Two cases of multidrug-resistant human immunodeficiency virus infection treated with atazanavir and lopinavir/ritonavir combination therapy

The combination of atazanavir (ATV) and lopinavir/ritonavir (LPV/RTV) with nucleoside reverse transcriptase inhibitors (NRTI) has been used as a salvage regimen for human immunodeficiency virus (HIV)-positive patients. In this paper, we discuss two cases of HIV-positive patients who had long histories of virological failure following a heavy treatment of antiretroviral drugs, but then achieved virological suppression with double-boosted protease inhibitor (PI) regimens. In patients with multiple genotypic resistance to PIs and NRTIs, virological suppression can be achieved with a combination of ATV plus LPV/RTV with an NRTI backbone. The two cases in this report suggest that a combination of ATV plus LPV/RTV could be a useful salvage regimen for the subset of HIV-positive patients with limited treatment options.

Pharmacokinetics of high-dose lopinavir-ritonavir with and without saquinavir or nonnucleoside reverse transcriptase inhibitors in human immunodeficiency virus-infected pediatric and adolescent patients previously treated with protease inhibitors

Human immunodeficiency virus (HIV)-infected children and adolescents who are failing antiretrovirals may have a better virologic response when drug exposures are increased, using higher protease inhibitor doses or ritonavir boosting. We studied the pharmacokinetics and safety of high-dose lopinavir-ritonavir (LPV/r) in treatment-experienced patients, using an LPV/r dose of 400/100 mg/m(2) orally every 12 h (p.o. q12h) (without nonnucleoside reverse transcriptase inhibitor [NNRTI]), or 480/120 mg/m(2) p.o. q12h (with NNRTI). We calculated the LPV inhibitory quotient (IQ), and when the IQ was <15, saquinavir (SQV) 750 mg/m(2) p.o. q12h was added to the regimen. We studied 26 HIV-infected patients. The median age was 15 years (range, 7 to 17), with 11.5 prior antiretroviral medications, 197 CD4 cells/ml, viral load of 75,577 copies/ml, and a 133-fold change in LPV resistance. By treatment week 2, 14 patients had a viral-load decrease of >0.75 log(10), with a median maximal decrease in viral load of -1.57 log(10) copies/ml at week 8. At week 2, 19 subjects showed a median LPV area under the concentration-time curve (AUC) of 157.2 (range, 62.8 to 305.5) microg x h/ml and median LPV trough concentration (C(trough)) of 10.8 (range, 4.1 to 25.3) microg/ml. In 16 subjects with SQV added, the SQV median AUC was 33.7 (range, 4.4 to 76.5) microg x h/ml and the median SQV C(trough) was 2.1 (range, 0.2 to 4.1) microg/ml. At week 24, 18 of 26 (69%) subjects remained in the study. Between weeks 24 and 48, one subject withdrew for nonadherence and nine withdrew for persistently high virus load. In antiretroviral-experienced children and adolescents with HIV, high doses of LPV/r with or without SQV offer safe options for salvage therapy, but the modest virologic response and the challenge of adherence to a regimen with a high pill burden may limit the usefulness of this approach.

Pharmacokinetics of an indinavir-ritonavir-fosamprenavir regimen in patients with human immunodeficiency virus

STUDY OBJECTIVE

To evaluate the pharmacokinetic compatibility of a ritonavir-boosted indinavir-fosamprenavir combination among patients with human immunodeficiency virus (HIV).

DESIGN

Single-center, nonrandomized, prospective, multiple-dose, two-phase pharmacokinetic study.

SETTING

University research center.

PATIENTS

Eight adult patients with HIV infection who had been receiving and tolerating indinavir 800 mg-ritonavir 100 mg twice/day for at least 2 weeks. Intervention. After 12-hour pharmacokinetic sampling was performed on all patients (period A), fosamprenavir (a prodrug of amprenavir) 700 mg twice/day was coadministered for 5 days, with a repeat 12-hour pharmacokinetic sampling performed on the fifth day (period B).

MEASUREMENTS AND MAIN RESULTS

Pharmacokinetic parameters were determined for indinavir, ritonavir, and amprenavir: area under the concentration-time curve from time 0 to 12 hours after dosing (AUC(0-12)), maximum plasma concentration (C(max)), and 12-hour plasma concentration (C(12)). For each parameter, the geometric mean, as well as the geometric mean ratio (GMR) comparing period B with period A, were calculated. Indinavir C(max) was lowered by 20% (GMR 0.80, 95% confidence interval [CI] 0.67-0.96), AUC(0-12) was lowered by 6% (GMR 0.94, 95% CI 0.74-1.21), and C(12) was increased by 28% (GMR 1.28, 95% CI 0.78-2.10). Ritonavir AUC(0-12) was 20% lower (GMR 0.80, 95% CI 0.54-1.19), C(max) was 15% lower (GMR 0.85, 95% CI 0.55-1.32), and C(12) was 7% lower (GMR 0.93, 95% CI 0.49-1.76). With the exception of indinavir C(max), the changes in indinavir and ritonavir pharmacokinetic parameters observed after fosamprenavir coadministration were not statistically significant. The geometric means of amprenavir AUC(0-12), C(max), and C(12) were 41,517 ng*hour/ml (95% CI 30,317-56,854 ng*hr/ml), 5572 ng/ml (95% CI 4330-7170 ng/ml), and 2421 ng/ml (95% CI 1578-3712 ng/ml), respectively.

CONCLUSION

The combination of indinavir 800 mg-ritonavir 100 mg-fosamprenavir 700 mg twice/day appears to be devoid of a clinically significant drug-drug interaction and should be evaluated as an alternative regimen in salvage HIV treatment. This combination may be suitable as part of a background regimen to optimize the therapeutic benefit of newer classes of antiretroviral agents such as the integrase and coreceptor inhibitors in the treatment of multidrug-resistant viruses.

Decrease of atazanavir and lopinavir plasma concentrations in a boosted double human immunodeficiency virus protease inhibitor salvage regimen

The human immunodeficiency virus protease inhibitor combination of atazanavir (ATV)-lopinavir-ritonavir was reported to exhibit a mutual pharmacoenhancement of plasma lopinavir and ATV concentrations which may be beneficial for salvage patients. We identified 17 patients in our pharmacokinetic database taking this combination and found conflicting results. Plasma concentrations of both ATV and lopinavir were modestly, although not significantly, decreased when the drugs were coadministered. Therefore, patients should be selected carefully for this regimen and frequent clinical and therapeutic drug monitoring is strongly advised.

Predictive Factors for Response to a Boosted Dual HIV-Protease Inhibitor Therapy with Saquinavir and Lopinavir in Extensively Pre-Treated Patients

Objective

To evaluate predictive factors for therapy outcome of a boosted double-protease inhibitor (PI) regimen in 58 extensively pre-treated patients with HIV.

Methods

Patients received lopinavir/ritonavir 400/100 mg and saquinavir 1,000 mg twice daily without reverse transcriptase inhibitors (RTI). The primary outcome parameter was HIV RNA <400 copies/ml at week 48, secondary parameters were HIV-1 RNA and CD4+ T-cell count changes from baseline to week 48. Pharmacokinetics, genotypic resistance and clinical and individual parameters were correlated with the clinical outcome in regression analyses. Covariates for the analyses were minimum plasma concentration (Cmin), maximum plasma concentration, area under the concentration versus time curve, half-life and clearance of lopinavir and saquinavir, the genotypic inhibitory quotients (GIQ) of archived (GIQarch) and baseline PI resistance mutations, previously taken antiretrovirals, archived and baseline viral resistance mutations, baseline HIV-1 RNA and CD4+ T-cell count.

Results

The analyses detected correlations between the primary outcome parameter and several factors: baseline CD4+ T-cell count ( P=0.001); absence of mutations at V82T/A/F/I/S plus I54M/V/L ( P=0.002) or K20M/R ( P=0.010); and lopinavir CminGIQarch ( P=0.046). This regression model had a predictability of 97.0% for response to therapy. Covariates for the decrease of HIV-1 RNA from baseline to week 48 were baseline HIV-1 RNA ( P<0.001), lopinavir CminGIQarch ( P=0.013), presence/absence of mutations at V82T/A/F/I/S or I84A/V plus L10I/R/V/F, I54M/V/L or L63P ( P=0.018), and previously taken antiretrovirals ( P=0.034).

Conclusions

Baseline HIV-1 RNA <5.0 log10 and CD4+ T-cell count >200 cells/μl, lopinavir CminGIQarch >2,000 ng/ml and the absence of viral resistance mutations at V82T/A/F/I/S and I54M/V/L are highly predictive for therapeutic success of a regimen of saquinavir/lopinavir/ ritonavir without RTI in a heterogenic cohort of patients with an extensive pre-treatment history and highly variable pharmacokinetics.

Pharmacokinetics of saquinavir, atazanavir, and ritonavir in a twice-daily boosted double-protease inhibitor regimen

The objective of this study was to evaluate the pharmacokinetics of atazanavir (ATV), saquinavir (SQV), and ritonavir (RTV) in a boosted double-protease inhibitor (PI) therapy regimen without reverse transcriptase inhibitors (RTIs). The study design was as follows. Patients with limited RTI options received a PI combination of 300/100 mg ATV/RTV once daily and 1,000 mg SQV twice daily (group 1; n=49) without RTI comedication. The results were compared to the plasma concentrations of PIs of patients taking either 300 mg ATV/100 mg RTV once daily plus RTIs (group 2; n=72) or patients taking 1,000 mg SQV/100 mg RTV plus RTIs (group 3; n=90). The study methods were as follows. Patients were given a 12/24-h pharmacokinetic assessment at steady state. Drug concentrations were measured by liquid chromatography-tandem mass spectrometry. The minimum and maximum concentrations (Cmin and Cmax), area under the concentration-time curve under steady-state conditions (AUCss), elimination half-life, time of maximum concentration and lag time were subject to statistical analysis. The results show that patients treated with ATV/SQV/RTV exhibited significantly high SQV concentrations and moderate enhancement of the AUCss of ATV in comparison to those of patients of the control groups: for SQV in groups 1 and 3, the geometric mean (GM) of the AUCss was 22,794 versus 15,759 ng.h/ml (GM ratio [GMR]=1.45; P<0.05), the GM of the Cmax was 3,257 versus 2,331 ng/ml (GMR=1.40; P<0.05), and the GM of the Cmin was 438 versus 437 ng/ml (GMR=1.00); for ATV in groups 1 and 2, the GM of the AUCss was 39,154 versus 33,626 ng.h/ml (GMR=1.16), the GM of the Cmax was 3,488 versus 2,924 ng/ml (GMR=1.20), and the GM of the Cmin was 515 versus 428 ng/ml (GMR=1.21). RTV levels were comparable for all groups. A subgroup analysis detected only marginal differences in ATV plasma exposure if combined with tenofovir-disoproxilfumarate and without it. We conclude that our pharmacokinetic results support the use of a boosted double-PI regimen of ATV/SQV/RTV as a treatment option for patients who need antiretroviral therapy without RTIs.

Pharmacokinetics of Darunavir (TMC114) and Atazanavir during Coadministration in HIV-Negative, Healthy Volunteers

BACKGROUND AND OBJECTIVE

To investigate the potential for pharmacokinetic interactions between the protease inhibitors darunavir (DRV, TMC114) coadministered with low-dose ritonavir (darunavir/r), and atazanavir in HIV-negative, healthy volunteers.

METHODS

This was an open-label, randomised, three-period, crossover study. Darunavir/r (400/100mg twice daily), atazanavir/r (300/100mg once daily) or darunavir/r (400/100mg twice daily) plus atazanavir (300mg once daily) were administered in three separate sessions, with a washout period of at least 7 days between regimens. The follow-up lasted 30 days. Twenty-three healthy volunteers participated. Pharmacokinetic assessments were performed at steady-state on day 7. Plasma drug concentrations were determined by liquid chromatography-tandem mass spectrometry and pharmacokinetic parameters were compared between treatments. The safety and tolerability of the study medications were monitored throughout.

RESULTS

Darunavir pharmacokinetics were unaffected by atazanavir. No change in overall exposure to atazanavir was observed during coadministration with darunavir/r. However, there was a 52% increase in minimum atazanavir plasma concentration (least squares mean ratio [90% CI 0.99, 2.34]). Mean systemic exposure to ritonavir was increased by 65% and 106%, respectively, with the combination treatment compared with darunavir/r alone or atazanavir/r alone. There were no apparent differences in mean changes in lipids between the darunavir/r, atazanavir/r or darunavir/r plus atazanavir regimens. Hyperbilirubinaemia and ocular icterus were reported with atazanavir-containing regimens.

CONCLUSION

Atazanavir at a dose of 300mg once daily can be coadministered with a darunavir/r twice-daily regimen without any dose adjustment if there is a clinical need to combine darunavir/r and atazanavir in HIV-1-infected patients.