Antiretroviral Genotypic Resistance Mutations in HIV-1 Infected Korean Patients with Virologic Failure

Resistance assays are useful in guiding decisions for patients experiencing virologic failure (VF) during highly-active antiretroviral therapy (HAART). We investigated antiretroviral resistance mutations in 41 Korean human immunodeficiency virus type 1 (HIV-1) infected patients with VF and observed immunologic/virologic response 6 months after HAART regimen change. Mean HAART duration prior to resistance assay was 45.3±27.5 months and commonly prescribed HAART regimens were zidovudine/lamivudine/nelfinavir (22.0%) and zidovudine/lamivudine/efavirenz (19.5%). Forty patients (97.6%) revealed intermediate to high-level resistance to equal or more than 2 antiretroviral drugs among prescribed HAART regimen. M184V/I mutation was observed in 36 patients (87.7%) followed by T215Y/F (41.5%) and M46I/L (34%). Six months after resistance assay and HAART regimen change, median CD4+ T cell count increased from 168 cells/µL (interquartile range [IQR], 62-253) to 276 cells/µL (IQR, 153-381) and log viral load decreased from 4.65 copies/mL (IQR, 4.18-5.00) to 1.91 copies/mL (IQR, 1.10-3.60) (P<0.001 for both values). The number of patients who accomplished viral load <400 copies/mL was 26 (63.4%) at 6 months follow-up. In conclusion, many Korean HIV-1 infected patients with VF are harboring strains with multiple resistance mutations and immunologic/virologic parameters are improved significantly after genotypic resistance assay and HAART regimen change.     

Prediction of early and confirmed virological response by genotypic inhibitory quotients for lopinavir in patients na?ve for lopinavir with limited exposure to previous protease inhibitors.

OBJECTIVE: To determine the impact of genotypic inhibitory quotient (GIQ) for lopinavir (LPV) in patients failing HAART with limited antiretroviral exposure. DESIGN: Retrospective analysis of a prospective trial. METHODS: Lopinavir GIQ was calculated as the ratio between the mean trough concentration (C(trough)) and the number of protease mutations using eight different HIV drug resistance mutation lists or algorithms. Early (by week 12) and confirmed (up to week 24) virological response (HIV-RNA< 400 copies/mL, ECVR) was used as dependent variable in logistic regression model. RESULTS: Seventy-one of 109 (65%) patients achieved ECVR. At multivariable logistic regression analysis, each mug/mL increase of GIQ was correlated with increasing probability of ECVR as far as the following mutations were computed: multi-protease inhibitor (PI) associated mutations listed by IAS (OR=1.17; 95% CI=0.99-1.39; P=0.058), mutations associated with LPV resistance by ANRS algorithm (OR=1.21; 95% CI=1.02-1.44; P=0.03), major mutations associated with LPV resistance by Stanford database (OR=1.16; 95% CI=1-1.35; P=0.05), and the whole set of mutations associated with LPV resistance in the same database (OR=1.22; 95% CI=1.02-1.46; P=0.03). Using ROC curve method, a specific threshold GIQ was assessed, above which this parameter could predict ECVR with the highest sensitivity (74.6% with GIQ obtained through Stanford LPV mutations) or specificity (89.5% with GIQ obtained through ANRS LPV mutations). CONCLUSIONS: Our results suggest that increasing GIQ can improve virological outcome even in patients with limited exposure to PIs. Further studies are necessary to understand what HIV protease mutations should be considered and whether such mutations should be weighted differently to improve LPV GIQ predictive value.     

Response of HIV positive patients to the long-term salvage therapy by lopinavir/ritonavir.

BACKGROUND: The cohort of 19 patients on LPV/r salvage regimen was followed for the period of up to 37.5 months. Patient's virologic response was evaluated with regard to the various baseline characteristics. RESULTS: A 73.7% of patients (14 out of 19) achieved viral suppression during the first three months of treatment, either complete (47.4%) or partial (26.3%). This effect was only transient in five cases (virologic rebound emerged after 9 months of treatment on average) and in nine cases the treatment was successful in the long-term analysis (HIV RNA plasma level still undetectable at 31st month of the therapy on average with maximum of 36 months). We analyzed the link between the virologic response and possible predictive factors of treatment efficiency, such as lopinavir mutation score, various individual mutations, previous PI exposure, etc. We also describe changes in the PR sequence associated with poor response to the salvage therapy to LPV/r. CONCLUSIONS:The results of LPV/r salvage therapy were encouraging. About 47% of patients from our study achieved stable suppression of viral replication for 31 months on average. LPV/r proved to be potent inhibitor despite unfavourable prognosis.     

Effect of zidovudine resistance mutations on virologic response to treatment with zidovudine or stavudine,each in combination with lamivudine and indinavir

The authors studied the effect of zidovudine (ZDV) resistance mutation on virologic response to treatment with ZDV or stavudine (d4T) each in combination with lamivudine and indinavir. Viral genotyping was performed on plasma HIV-1 RNA at study entry and concerned 155 patients previously treated with ZDV, didanosine, or zalcitabine and enrolled in the NOVAVIR (Agence National de Recherche sur le SIDA [ANRS] 073) trial. Three virologic responses were investigated: early response (<50 copies/mL at week 24), late response (<500 copies/mL at week 80), and virologic failure (two HIV-1 RNA >5000 copies/mL). Patients were classified as resistant or susceptible to ZDV according to the ANRS algorithm. Plasma viral RNA from 123 of 155 patients had two or more ZDV resistance mutations. The number of ZDV resistance mutations was positively correlated with the duration of prior antiviral therapy (p <.001). At week 24, 74% and 77% of patients with virus classified as resistant were responders in the d4T and ZDV arm, respectively. Similar results were found at week 80. Virologic failure was reached in 7 of 24 patients with virus classified as susceptible and in 26 of 131 patients with resistant virus (p =.29). In the ZDV arm, patients classified as resistant had longer times to virologic failure than those classified as susceptible (p =.003). In conclusion, sustained virologic response despite presence of ZDV resistance mutations implies that these mutations do not preclude an early and durable response to treatment with a potent three-drug regimen in these patients. Patients susceptible to ZDV had lower median mean corpuscular volumes and lower random indinavir levels, suggesting that adherence was the main reason for failure.     

A Pilot,Prospective, Open-Label Simplification Study to Evaluate the Safety,Efficacy, and Pharmacokinetics of Once-Daily Lopinavir-Ritonavir Monotherapy in HIV-HCV Coinfected Patients: The MONOCO Study

Abstract

Background: A safe, effective, easy-to-dose antiretroviral therapy that minimizes hepatic complication risk is essential in optimizing HIV-HCV treatment. Nucleoside-sparing boosted protease inhibitor monotherapy may achieve this goal. Methods: A prospective, open-label pilot simplification study of once-daily lopina-vir/ritonavir (LPV/r) monotherapy in HIV-HCV coinfected patients was conducted in patients on HAART with undetectable HIV RNA for ≥6 months. The primary outcome was maintenance of HIV RNA <50 copies/mL through week 48. HIV RNA, immune measures, metabolic markers, and pharmacokinetics were assessed. Results: Twenty participants received once-daily LPV/r monotherapy. Mean baseline age was 46.9 years and CD4 467 cells/L. By per protocol analysis, 71.4% (95% CI, 45.4-88.3) remained on once-daily LPV/r monotherapy with virologic suppression at week 48. Virologic breakthrough (HIV RNA >50 copies/mL on 2 consecutive measures) occurred in 7 patients (mean standard error [SE] time to breakthrough, 38.3 [4.8] weeks). Resuppression occurred with improved adherence in 2 partici-pants and improved adherence plus addition of nucleosides in 2 others. LPV C ^min was <1 mg/L in 8 patients and was associated with virologic breakthrough in 2 cases but with no development of resistance. No clinically significant changes in CD4, lipids, or glucose were noted. Three participants developed transient ≥5-fold liver enzyme elevations. None of 9 severe adverse events were LPV/r- or liver-related. Six discontinued participation for withdrawal of consent (n=1), poor adherence (n=3), or drug intolerance (n=2). Conclusions: Once-daily LPV/r monotherapy in HIV-HCV coinfected individuals offers a safe and effective approach to the management of the HIV infection, with a predictable pharmacokinetic profile.     

The use of drug resistance algorithms and genotypic inhibitory quotient in prediction of lopinavir-ritonavir treatment response in human immunodeficiency virus type 1 protease inhibitor-experienced patients.

BackgroundDifferent approaches using genotypic, pharmacokinetic parameters or combination of both have been recently developed to monitor antiretroviral treatment in HIV-1-infected individuals. Their uses in clinical practice may improve the benefit of protease inhibitor-based salvage therapy while reducing treatment toxicity and emergence of viral resistance.ObjectivesTo assess the prediction of genotypic inhibitory quotient (GIQ) using different genotypic drug resistance interpretation's algorithms and lopinavir plasma concentration in PI-experienced patients treated by lopinavir/ritonavir (LPV/r). Genotypic susceptibility score (GSS) was also evaluated.Study designForty-seven HIV-1 PI-experienced, but LPV naïve patients were included in a retrospective cohort study. Plasma HIV-1 viral load (VL), CD4 cell count and LPV plasma concentrations were assessed at weeks (W) 12 and 24. Interpretation of baseline resistance genotype was achieved according to four different algorithms and GSS calculated using two expert systems. GIQ was defined as the ratio of LPV concentration to the number of LPV resistance mutations at day 0 (D0) and patients classified by units of GIQ. The end point of the study was the virological response expressed in HIV VL median decrease from D0 to W24.ResultsThe overall median VL decrease from D0 to W24 was −2.42 log₁₀ copies/mL and 60% of patients had VL below 400 copies/mL. The LPV mutation score was predictive of response for all algorithms whereas plasma concentrations of LPV were not. Mean VL decrease was greater for higher GIQ classes and difference reached statistical significance at W24. When considering virological response at W24, GSS calculated with ANRS and Stanford system were good predictor scores as areas under the receiver operating characteristics (ROC) curves were 0.76 for both.ConclusionGIQ was found to be a useful drug-monitoring tool which could be helpful in targeting LPV concentrations in order to achieve long-term undetectable viral load, particularly in genotypic resistant patients.     

Monotherapy with Lopinavir/Ritonavir as Maintenance After HIV-1 Viral Suppression: Results of a 96-Week Randomized,Controlled, Open-Label,Pilot Trial (KalMo Study)

Abstract

Background: Long-term adverse events and expenses associated with HAART have led to an interest in simplified therapy. Lopinavir/ritonavir monotherapy is attractive due to its potency and high genetic barrier. Methods: This is a 96-week, open-label, randomized study to assess the feasibility of using LPV/r monotherapy in patients with undetectable viral load after being on successful HAART for at least 6 months. Subjects were randomized (1:1) to either switch from HAART to LPV/r monotherapy or to maintain their previous regimen. Results: 60 patients were enrolled. Baseline characteristics were similar in both groups. At Week 96, by intention-to-treat analysis, 24/30 (80.0%) subjects in monotherapy group and 26/30(86.6%) in the control group had a plasma viral load of <80 copies/mL. There was one virologic failure (defined as VL > 500 copies/mL) in each arm. Genotyping testing identified no resistance-associated mutations. The patient on the monotherapy arm was successfully resuppressed to <80 copies/mL after intensification with tenofovir and lamivudine. No statistically significant differences were found with regard to changes in CD4 counts. One subject in the monotherapy group discontinued due to diarrhea. Five subjects in the control group underwent regimen changes due to drug-related toxicities. Viral load from semen samples collected at the end of follow-up was undetectable on 14/15 patients randomized to monotherapy. Conclusions: Switching from various HAART regimens to LPV/r monotherapy in patients who were virologically suppressed and without a history of previous virologic failure was effective, safe, and well tolerated through 96 weeks.     

Real versus virtual phenotype to guide treatment in heavily pretreated patients: 48-week follow-up of the Genotipo-Fenotipo di Resistenza (GenPheRex) trial

We compared viroimmunologic response after real phenotype (r-PHT) versus virtual phenotype (v-PHT) in patients failing highly active antiretroviral therapy (HAART). A total of 201 patients with >2 years of exposure, more than six experienced drugs, >1000 HIV RNA copies/mL, and on stable HAART for >6 months were randomized to the r-PHT or v-PHT arm. The primary end point was the proportion of HIV plasma viral load (pVL) <400 copies/mL. Secondary end points were absolute pVL change, proportion of pVL reduction >0.5 log(10) copies/mL, and absolute CD4 cell change. In the intention-to-treat-last observation carried forward analysis, study outcomes were not significantly different between arms over 48 weeks of follow-up: 20% and 24% pVL <400 copies/mL; 58% and 61% pVL reduction >0.5 log(10) copies/mL; -0.92 and -0.94(10) log copies/mL mean pVL decrease; and +41.6 and +94.4 cells/mm(3) mean absolute CD4 increase in the r-PHT and v-PHT arms, respectively. On-treatment analyses gave similar results. In the multivariate analysis of pVL <400 copies/mL, the following covariates were independent predictors at week 48: adherence (OR p= 0.25; p=.002), baseline CD4 (OR = 4.39; p=.007), intravenous drug use as risk factor for HIV acquisition (OR = 0.33; p=.024), and sensitivity score of the new regimens by biologic cut-offs (OR = 1.84; p=.029). Prescribed drugs for which patients were naive resulted in marginal prediction (OR = 1.93; p=.054). In conclusion, virologic and immunologic outcomes did not differ when r-PHT or v-PHT was used in this cohort of heavily pretreated patients. Several factors should be considered to take better advantage of resistance testing, including treatment history, clinical status, and patients' ability to adhere to treatment.     

Different outcomes in patients achieving complete or partial viral load suppression on antiretroviral therapy

BACKGROUND: Potent combination antiretroviral therapy can reduce HIV plasma viral load (VL) to levels below the detection limit for as long as 2 years or more. A VL <500 HIV RNA copies/mL was until recently considered a reasonable therapeutic goal. However, lower levels seem necessary if VL rebounds and development of drug resistance are to be avoided. PATIENTS AND METHODS: The clinical and virologic outcome at 1 year were prospectively examined in a group of 100 patients who began a triple combination antiretroviral therapy regimen consisting of stavudine (d4T), lamivudine (3TC), and indinavir (IDV). A modified ultrasensitive VL test with a detection limit of 40 copies/mL and a point mutation nested polymerase chain reaction (PCR) assay for detecting the codon 184 mutation conferring 3TC resistance were used for testing samples collected longitudinally from these individuals. RESULTS: Overall, VL values <40 copies/mL were reached in 45% and 32% of patients at nadir and at 12 months, respectively. More than half (24 of 45 persons) who achieved a level <40 copies/mL at nadir remained with undetectable VL at 1 year, whereas this occurred in only one fourth (7 of 28 persons) of those having levels of 40 to 500 copies/mL (P < .05). However, rebounds in VL to >500 copies/mL at 1 year were seen at similar rates (26.6% and 25%, respectively) in persons achieving either complete (<40 copies/mL) or partial (40-500 copies/mL) VL suppression at nadir. In contrast, the codon 184 mutation emerged more frequently at 1 year in patients whose VL remained between 40 and 500 copies/mL at nadir than in those who reached a level <40 copies/mL (30.7% versus 0%; P < .05). CONCLUSION: Plasma VL at nadir after beginning highly active antiretroviral therapy (HAART) predicts the 1-year outcome. The achievement of levels of viremia <40 copies/mL are desirable during antiretroviral therapy if prolonged benefit is to be obtained. Because more than two thirds of persons with residual viremia do not show drug resistance, intensification strategies should be investigated for those patients with a good virologic response but without complete suppression during the first 6 months on HAART.     

Use of viral load measured after 4 weeks of highly active antiretroviral therapy to predict virologic outcome at 24 weeks for HIV-1-positive individuals

Early prediction of suboptimal viral response to highly active antiretroviral therapy (HAART) is vital to prevent early development of drug resistance. We used logistic regression to predict the odds of achieving virologic suppression (<50 copies/mL) after 24 weeks of HAART in 656 antiretroviral-naive patients starting HAART at the J.W. Goethe University, Chelsea and Westminster, and Royal Free Hospitals according to their week 4 viral load. Therapy changes involving the switch of a single antiretroviral were assumed to have occurred for toxicity reasons and ignored. Because complete regimen changes or additions of new antiretrovirals could be due to virologic failure, patients were counted as virological failures at week 24. Three hundred sixty (84%) of 430 patients with viral loads of <1000 copies/mL, 106 (61%) of 175 with viral loads between 1001 and 10,000 copies/mL, 11 (37%) of 30 with viral loads between 10,001 and 100,000 copies/mL, and 5 (24%) of 21 with viral loads of >100,000 copies/mL at week 4 subsequently attained virologic suppression at 24 weeks. The odds of attaining virologic suppression at 24 weeks was 65% lower for every 1-log higher viral load at week 4 (odds ratio, 0.35; 95% confidence interval, 0.27-0.45). The proportion of patients with an undetectable viral load at 24 weeks among those who have not attained a viral load of <1000 copies/mL by 4 weeks is quite low. We suggest that this group of patients should be particularly closely monitored.     

Pharmacokinetics, safety, and efficacy of tipranavir boosted with ritonavir alone or in combination with other boosted protease inhibitors as part of optimized combination antiretroviral therapy in highly treatment-experienced patients (BI Study 1182.51)

BACKGROUND: Given the limited treatment options for patients with high-level resistance, antiretroviral (ARV) regimens based on concomitant use of 2 ritonavir (RTV)-boosted protease inhibitors (PIs) were considered a therapeutic option. METHODS: Boehringer Ingelheim (BI) study 1182.51 examined the pharmacokinetic profile, safety, and efficacy of RTV-boosted tipranavir (TPV/r), alone and in combination with comparator PIs (CPIs) in 315 triple-class-experienced, HIV-infected patients. RESULTS: Two weeks after single PI therapy, the addition of TPV/r reduced plasma trough levels 52%, 80%, and 56% for lopinavir (LPV), saquinavir (SQV), and amprenavir (APV) recipients, respectively. After 2 weeks, a TPV/r-only regimen reduced HIV viral load (VL) by a median of 1.06 log(10) copies/mL. VL reductions at 2 weeks between single-boosted CPIs were difficult to compare, because the numbers of patients maintaining their previous failing PI after randomization were different. At week 4, patients initiating treatment with TPV-containing regimens sustained VL reduction (median decrease of 1.27 log(10) copies/mL). Patients adding TPV to regimens at week 2 achieved median reductions from a baseline of 1.19 log(10), 0.96 log(10), and 1.12 log(10) copies/mL at week 4 in dual-boosted LPV, SQV, and APV groups, respectively. At 24 weeks, VL reductions (median: -0.24 to -0.47 log(10) copies/mL) were comparable between treatment groups. CONCLUSIONS: The efficacy of a dual PI regimen depended on the presence of TPV, with additional recycled CPIs having limited activity, even in drug-resistant patient populations with plasma trough concentrations regarded as likely to be adequate in this study. No clear guidelines exist about ARV plasma trough concentrations in treatment-experienced patients, however.