1
|
Maitre T, Muret P, Blot M, Waldner A, Duong M, Si-Mohammed A, Chavanet P, Aho S, Piroth L. Benefits and Limits of Antiretroviral Drug Monitoring in Routine Practice. Curr HIV Res 2020; 17:190-197. [PMID: 31490758 DOI: 10.2174/1570162x17666190903232053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/26/2019] [Accepted: 08/20/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND HIV infection is a chronic disease for which therapeutic adherence and tolerance require particular attention. OBJECTIVE This study aimed to assess whether and when therapeutic drug monitoring (TDM) could be associated with a benefit in routine practice. METHODS All HIV-infected patients who underwent at least one TDM at the University Hospital of Dijon (France) between 1st January 2009 and 31st December 2012 were retrospectively included. Compliance with the recommendations, the results (antiretroviral concentrations), any subsequent therapeutic modifications, and the virological results at 4-8 months were analysed each time TDM was performed. TDM was defined as "practically relevant" when low or high antiretroviral concentrations led to a change in therapy. RESULTS Of the 571 patients who followed-up, 43.4% underwent TDM. TDM complying with recommendations (120 patients) was associated with a higher proportion of antiretroviral concentrations outside the therapeutic range (p=0.03). Antiretroviral treatment was modified after TDM in 22.6% of patients. Protease inhibitors, non-nucleoside reverse transcriptase inhibitors and raltegravir were more significantly modified when the measured concentration was outside the therapeutic range (p=0.008, p=0.05 and p=0.02, respectively). Overall, 11.7% of TDM was considered "practically relevant", though there was no significant correlation between subsequent changes in antiretroviral treatment and undetectable final HIV viral load. CONCLUSION TDM may be a useful tool in the management of HIV infection in specific situations, but the overall benefit seems moderate in routine practice. TDM cannot be systematic and/or a decision tool per se, but should be included in a comprehensive approach in certain clinical situations.
Collapse
Affiliation(s)
- Thomas Maitre
- Department of Infectious Diseases, University Hospital, Dijon, France
| | - Patrice Muret
- Laboratory of Clinical Pharmacology, University Hospital, Besancon, France.,UMR1098, University of Franche-Comte, Besançon, France
| | - Mathieu Blot
- Department of Infectious Diseases, University Hospital, Dijon, France
| | - Anne Waldner
- Department of Infectious Diseases, University Hospital, Dijon, France
| | - Michel Duong
- Department of Infectious Diseases, University Hospital, Dijon, France
| | | | - Pascal Chavanet
- Department of Infectious Diseases, University Hospital, Dijon, France.,UMR1347, University of Burgundy, Dijon, France
| | - Serge Aho
- Department of Hospital Hygiene, University Hospital, Dijon, France
| | - Lionel Piroth
- Department of Infectious Diseases, University Hospital, Dijon, France.,UMR1347, University of Burgundy, Dijon, France
| |
Collapse
|
2
|
Punyawudho B, Singkham N, Thammajaruk N, Dalodom T, Kerr SJ, Burger DM, Ruxrungtham K. Therapeutic drug monitoring of antiretroviral drugs in HIV-infected patients. Expert Rev Clin Pharmacol 2016; 9:1583-1595. [PMID: 27626677 DOI: 10.1080/17512433.2016.1235972] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Therapeutic drug monitoring (TDM) may be beneficial when applied to antiretroviral (ARV). Even though TDM can be a valuable strategy in HIV management, its role remains controversial. Areas covered: This review provides a comprehensive update on important issues relating to TDM of ARV drugs in HIV-infected patients. Articles from PubMed with keywords relevant to each topic section were reviewed. Search strategies limited to articles published in English. Expert commentary: There is evidence supporting the use of TDM in HIV treatment. However, some limitations need to be considered. The evidence supporting the use of routine TDM for all patients is limited, as it is not clear that this strategy offers any advantages over TDM for selected indications. Selected groups of patients including patients with physiological changes, patients with drug-drug interactions or toxicity, and the elderly could potentially benefit from TDM, as optimized dosing is challenging in these populations.
Collapse
Affiliation(s)
- Baralee Punyawudho
- a Department of Pharmaceutical Care, Faculty of Pharmacy , Chiang Mai University , Chiang Mai , Thailand
| | - Noppaket Singkham
- a Department of Pharmaceutical Care, Faculty of Pharmacy , Chiang Mai University , Chiang Mai , Thailand
| | | | - Theera Dalodom
- b HIV-NAT , Thai Red Cross AIDS Research Centre , Bangkok , Thailand
| | - Stephen J Kerr
- b HIV-NAT , Thai Red Cross AIDS Research Centre , Bangkok , Thailand.,c The Kirby Institute, University of New South Wales , Sydney , Australia.,d Department of Global Health, Academic Medical Center , University of Amsterdam, Amsterdam Institute for Global Health and Development , Amsterdam , The Netherlands
| | - David M Burger
- e Radbound University Medical Center , Nijmegen , The Netherlands
| | - Kiat Ruxrungtham
- b HIV-NAT , Thai Red Cross AIDS Research Centre , Bangkok , Thailand.,f Faculty of Medicine , Chulalongkorn University , Bangkok , Thailand
| |
Collapse
|
3
|
Zhang X, Tierney C, Albrecht M, Demeter LM, Morse G, DiFrancesco R, Dykes C, Jiang H, Haas DW. Discordant associations between SLCO1B1 521T→C and plasma levels of ritonavir-boosted protease inhibitors in AIDS clinical trials group study A5146. Ther Drug Monit 2013; 35:209-16. [PMID: 23503447 DOI: 10.1097/ftd.0b013e318280d0ad] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Among HIV-positive patients prescribed ritonavir-boosted lopinavir, SLCO1B1 521T→C (rs4149056) is associated with increased plasma lopinavir exposure. Protease inhibitors (PIs) are also substrates for cytochrome P450 (CYP) 3A and ABCB1, which are induced by NR1I2. We characterized relationships between ABCB1, CYP3A4, CYP3A5, NR1I2, and SLCO1B1 polymorphisms and trough PI concentrations among AIDS Clinical Trials Group study A5146 participants. METHODS At study entry, subjects with virologic failure on PI-containing regimens initiated new ritonavir-boosted PI regimens. We studied associations between week 2 PI plasma trough concentrations and 143 polymorphisms in these genes, including 4 targeted polymorphisms. RESULTS Among 275 subjects with both drug concentrations and genetic data, allelic frequencies of SLCO1B1 521T→C were 15%, 1%, and 8% in whites, blacks, and Hispanics, respectively. Further analyses were limited to 268 white, black, or Hispanic subjects who initiated ritonavir-boosted lopinavir (n = 98), fosamprenavir (n = 69), or saquinavir (n = 99). Of targeted polymorphisms, SLCO1B1 521T→C tended to be associated with higher lopinavir concentrations, with a 1.38-fold increase in the mean per C allele (95% confidence interval, 0.97-1.96; n = 98; P = 0.07). With fosamprenavir, SLCO1B1 521T→C was associated with lower amprenavir concentrations, with a 35% decrease in the mean per C allele (geometric mean ratio 0.65; 95% confidence interval, 0.44-0.94; n = 69; adjusted P = 0.02). There was no significant association with saquinavir concentrations, and none of the remaining 139 exploratory polymorphisms were statistically significant after correcting for multiple comparisons. CONCLUSIONS With ritonavir-boosted PIs, a SLCO1B1 polymorphism that predicts higher lopinavir trough concentrations seems to predict lower amprenavir trough concentrations. The mechanism underlying this discordant association is uncertain.
Collapse
Affiliation(s)
- Xinyan Zhang
- Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Peripheral neuropathy in ART-experienced patients: prevalence and risk factors. J Neurovirol 2013; 19:557-64. [PMID: 24297499 DOI: 10.1007/s13365-013-0216-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/11/2013] [Accepted: 10/17/2013] [Indexed: 01/13/2023]
Abstract
Peripheral neuropathy (PN) is a common neurological complication of HIV infection that has debilitating effects on quality of life. While there has been a comprehensive evaluation of the prevalence of neuropathic signs/symptoms and risk factors (RFs) for PN or symptomatic PN (SPN) with initiation of combination antiretroviral therapy (cART) in ART-naïve patients, similar evaluation in ART-experienced patients is limited. This study investigated the prevalence and RFs for PN/SPN in ART-experienced patients enrolled in clinical salvage therapy studies. Between February 2000 and June 2007, 522 ART-experienced participants who experienced virologic failure with a prior regimen and started new regimens were followed longitudinally and annually screened for signs and symptoms of PN. Rates of PN/SPN at 3 years since parent study entry were 52.8 and 24.0 %, respectively. Aging, taller height, protease inhibitor use, and female sex were significant RFs for PN/SPN. The use of statin drugs was significantly associated with lower odds of SPN, and it may prevent progression from no SPN to SPN.
Collapse
|
5
|
Novel method to assess antiretroviral target trough concentrations using in vitro susceptibility data. Antimicrob Agents Chemother 2012; 56:5938-45. [PMID: 22964257 DOI: 10.1128/aac.00691-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Durable suppression of HIV-1 replication requires the establishment of antiretroviral drug concentrations that exceed the susceptibility of the virus strain(s) infecting the patient. Minimum plasma drug concentrations (C(trough)) are correlated with response, but determination of target C(trough) values is hindered by a paucity of in vivo concentration-response data. In the absence of these data, in vitro susceptibility measurements, adjusted for serum protein binding, can provide estimations of suppressive in vivo drug concentrations. We derived serum protein binding correction factors (PBCF) for protease inhibitors, nonnucleoside reverse transcriptase inhibitors, and an integrase inhibitor by measuring the effect of a range of human serum concentrations on in vitro drug susceptibility measured with the PhenoSense HIV assay. PBCFs corresponding to 100% HS were extrapolated using linear regression and ranged from 1.4 for nevirapine to 77 for nelfinavir. Using the mean 95% inhibitory concentration (IC(95)) for ≥1,200 drug-susceptible viruses, we calculated protein-bound IC(95) (PBIC(95)) values. PBIC(95) values were concordant with the minimum effective C(trough) values that were established in well-designed pharmacodynamic studies (e.g., indinavir, saquinavir, and amprenavir). In other cases, the PBIC(95) values were notably lower (e.g., darunavir, efavirenz, and nevirapine) or higher (nelfinavir and etravirine) than existing target recommendations. The establishment of PBIC(95) values as described here provides a convenient and standardized approach for estimation of the minimum drug exposure that is required to maintain viral suppression and prevent the emergence of drug-resistant variants, particularly when in vivo concentration-response relationships are lacking.
Collapse
|
6
|
López Aspiroz E, Cabrera Figueroa SE, Domínguez-Gil Hurlé A, García Sánchez MJ. [New strategies in the optimisation of lopinavir/ritonavir doses in human immunodeficiency virus-infected patients]. Enferm Infecc Microbiol Clin 2012; 31:36-43. [PMID: 22280562 DOI: 10.1016/j.eimc.2011.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 11/21/2011] [Accepted: 11/28/2011] [Indexed: 01/11/2023]
Abstract
Lopinavir/ritonavir (LPV/r) has demonstrated virological and immunological efficacy in the combined antiretroviral treatment (cART), in both naïve and experienced patients. Furthermore, LPV/r showed a high barrier to the development of resistance. Although generally well tolerated, adverse gastrointestinal side effects and metabolic disorders are frequent. The different tools used to optimise the cART with this drug combination in the daily clinical practice, emphasising the therapeutic drug monitoring (TDM) of LPV/r and the genetic analysis of the main enzymes responsible for the metabolism and transport, are reviewed. The relationship between phenotype and genotype, established through TDM, could be useful for the physician to improve the clinical management of the HIV infection, due to the possibility of individualising the dose with this drug. Monotherapy is also reviewed as a new strategy used in the simplification of the treatment with this drug, which could increase safety and reduce costs.
Collapse
Affiliation(s)
- Elena López Aspiroz
- Servicio de Farmacia, Hospital Universitario de Salamanca, Salamanca, España
| | | | | | | |
Collapse
|
7
|
Population pharmacokinetics of lopinavir/ritonavir (Kaletra) in HIV-infected patients. Ther Drug Monit 2012; 33:573-82. [PMID: 21912331 DOI: 10.1097/ftd.0b013e31822d578b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND A relationship between plasma concentrations and viral suppression in patients receiving lopinavir (LPV)/ritonavir (RTV) has been observed. Therefore, it is important to increase our knowledge about factors that determine interpatient variability in LPV pharmacokinetics (PK). METHODS The study, designed to develop and validate population PK models for LPV and RTV, involved 263 ambulatory patients treated with 400/100 mg of LPV/RTV twice daily. A database of 1110 concentrations of LPV and RTV (647 from a single time-point and 463 from 73 full PK profiles) was available. Concentrations were determined at steady state using high-performance liquid chromatography with ultraviolet detection. PK analysis was performed with NONMEM software. Age, gender, height, total body weight, body mass index, RTV trough concentration (RTC), hepatitis C virus coinfection, total bilirubin, hospital of origin, formulation and concomitant administration of efavirenz (EFV), saquinavir (SQV), atazanavir (ATV), and tenofovir were analyzed as possible covariates influencing LPV/RTV kinetic behavior. RESULTS Population models were developed with 954 drug plasma concentrations from 201 patients, and the validation was conducted in the remaining 62 patients (156 concentrations). A 1-compartment model with first-order absorption (including lag-time) and elimination best described the PK. Proportional error models for interindividual and residual variability were used. The final models for the drugs oral clearance (CL/F) were as follows: CL/F(LPV)(L/h)=0.216·BMI·0.81(RTC)·1.25(EFV)·0.84(ATV); CL/F(RTV)(L/h) = 8.00·1.34(SQV)·1.77(EFV)·1.35(ATV). The predictive performance of the final population PK models was tested using standardized mean prediction errors, showing values of 0.03 ± 0.74 and 0.05 ± 0.91 for LPV and RTV, and normalized prediction distribution error, confirming the suitability of both models. CONCLUSIONS These validated models could be implemented in clinical PK software and applied to dose individualization using a Bayesian approach for both drugs.
Collapse
|
8
|
Rakhmanina NY, la Porte CJ. Therapeutic Drug Monitoring of Antiretroviral Drugs in the Management of Human Immunodeficiency Virus Infection. Ther Drug Monit 2012. [DOI: 10.1016/b978-0-12-385467-4.00017-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
9
|
Albrecht M, Mukherjee AL, Tierney C, Morse GD, Dykes C, Klingman KL, Demeter LM. A randomized clinical trial evaluating therapeutic drug monitoring (TDM) for protease inhibitor-based regimens in antiretroviral-experienced HIV-infected individuals: week 48 results of the A5146 study. HIV CLINICAL TRIALS 2011; 12:201-14. [PMID: 22044856 DOI: 10.1310/hct1204-201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND We devised an open-label, randomized trial to evaluate whether therapeutic drug monitoring (TDM) of protease inhibitors (PIs) and dose escalation based upon a normalized inhibitory quotient (NIQ), which integrates PI trough concentration and drug resistance, could improve virologic outcome in PI-experienced patients with treatment failure. Secondary analyses through 48 weeks are presented. METHODS Eligible HIV-infected subjects with a screening viral load of ≥ 1000 copies/mL initiated a new PI-based regimen at entry and had NIQ performed at week 2. Subjects with an NIQ ≤1 were randomized at week 4 to a standard-of-care (SOC) arm or TDM arm featuring PI dose escalation. RESULTS One hundred and eighty-three subjects were randomized. There was no significant treatment difference in change from randomization to week 48 in HIV-1 RNA [ P = .13, median (25th, 75th percentile log10 copies/mL change): -0.03 (-0.74, 0.62) with TDM and 0.11 (-2.3, 0.82) with SOC]. In subgroup analysis, patients with ≥ 0.69 active PIs benefited from TDM compared to those with <0.69 active PIs ( P = .05). CONCLUSIONS While the TDM strategy of PI dose escalation did not improve virologic response at week 48 overall, in subgroup analysis, TDM favorably impacted virologic outcome in subjects taking PI-based regimens with moderate antiviral activity.
Collapse
Affiliation(s)
- Mary Albrecht
- Beth Israel Deaconess Medical Center, Boston, MA, USA.
| | | | | | | | | | | | | |
Collapse
|
10
|
Therapeutic drug monitoring of protease inhibitors and efavirenz in HIV-infected individuals with active substance-related disorders. Ther Drug Monit 2011; 33:309-14. [PMID: 21544014 DOI: 10.1097/ftd.0b013e31821d3adb] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Achieving targeted antiretroviral (ARV) plasma concentrations during long-term treatment in human immunodeficiency virus (HIV)-infected patients with substance-related disorders (SRDs) may be challenging due to a number of factors, including medication adherence, coinfection with hepatitis B or C virus, medication intolerance, and drug interactions. One approach to investigate these factors is to conduct therapeutic drug monitoring to measure ARV exposure during treatment. The objective of this study was to utilize therapeutic drug monitoring to compare efavirenz (EFV) and protease inhibitor pharmacokinetics in patients with and without SRDs. METHODS This was a multicenter, cross-sectional open-label study in patients with HIV-1 infection receiving antiretroviral therapy (ART), with active (n=129) or without (n=146) SRD according to National Institute on Drug Abuse criteria. Two hundred seventy-five subjects who were receiving either protease inhibitor-based or EFV-based ART regimens for >6 months were enrolled at 4 HIV treatment centers with an equal distribution of SRD and non-SRD at each site. The patients were instructed during enrollment visits with regard to the importance of adherence before and after study visits. Demographics and routine clinical laboratory tests were recorded. RESULTS Among the 275 patients, 47% had SRD with at least 1 substance. There were no significant differences between SRD and non-SRD groups for race, gender, age, or CD4 count at entry. A significantly higher proportion of patients with SRD had an entry HIV RNA plasma concentration>75 copies per milliliter compared with patients without SRD (40% vs 28%, P=0.044). Logistic regression modeling revealed an association between HIV RNA plasma concentration and African American race (P=0.017). A significantly higher proportion of SRDs also had an EFV or protease inhibitor trough concentration below the desired range (23% vs 9%, P=0.048). Significantly lower trough concentrations were noted in patients with SRDs receiving atazanavir (0.290 vs 0.976 μg/mL) or lopinavir (3.75 vs 5.30 μg/mL). CONCLUSIONS The pharmacokinetic data indicate differences between HIV-infected patients with and without SRDs that may influence viral load suppression during long-term ART. These findings require additional investigation in a randomized design with more intensive pharmacokinetic assessment to identify individual factors that are contributing to suboptimal ARV exposure in patients with SRDs.
Collapse
|
11
|
Abstract
Combination antiretroviral therapy for HIV-1 infection has resulted in profound reductions in viremia and is associated with marked improvements in morbidity and mortality. Therapy is not curative, however, and prolonged therapy is complicated by drug toxicity and the emergence of drug resistance. Management of clinical drug resistance requires in depth evaluation, and includes extensive history, physical examination and laboratory studies. Appropriate use of resistance testing provides valuable information useful in constructing regimens for treatment-experienced individuals with viremia during therapy. This review outlines the emergence of drug resistance in vivo, and describes clinical evaluation and therapeutic options of the individual with rebound viremia during therapy.
Collapse
|
12
|
Neely MN, Rakhmanina NY. Pharmacokinetic Optimization of Antiretroviral Therapy in Children and Adolescents. Clin Pharmacokinet 2011; 50:143-89. [DOI: 10.2165/11539260-000000000-00000] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
13
|
Liu X, Ma Q, Zhang F. Therapeutic drug monitoring in highly active antiretroviral therapy. Expert Opin Drug Saf 2011; 9:743-58. [PMID: 20350281 DOI: 10.1517/14740331003767395] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
IMPORTANCE OF THE FIELD Despite the efficacy of combination antiretroviral therapy (ART), a large proportion of patients living with HIV/AIDS on ART does not achieve or maintain adequate virological suppression. Therapeutic drug monitoring (TDM) has been utilised to improve treatment outcomes of ART. AREAS COVERED IN THE REVIEW The potential incorporation of TDM into the clinical HIV management is supported by the existing relationship between drug exposure and efficacy/toxicity, the high inter-patient variability pharmacokinetics, and the accurate, specific and rapid method for drug level determination. The current status of TDM in ART is reviewed in this article with discussions on its feasibility, potential use and limitations. WHAT THE READER WILL GAIN Mounting evidence from clinical trials has indicated the potential use of TDM in reducing the rates of treatment failure and adverse effect, avoiding the drug interactions, and special populations, such as children, pregnant women and patients with co-infections. TDM may play an important role even in resource-limited settings, to safeguard expanded use of bioequivalent generic antiretroviral drugs and avoid drug interactions with traditional Chinese medicines. TAKE HOME MESSAGE TDM is still in the centre of controversy in that several critical issues need to be addressed, such as limited adherence assessment, inappropriate response predictors, insufficient validation of target concentration windows and lack of the quality control of assay. The utility of TDM will remain experimental until more data are obtained from large clinical trials showing the benefit of TDM.
Collapse
Affiliation(s)
- Xia Liu
- National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nan Wei Road, Beijing 100050, China.
| | | | | |
Collapse
|
14
|
Quality assessment for therapeutic drug monitoring in AIDS Clinical Trials Group (ACTG 5146): a multicenter clinical trial. Ther Drug Monit 2010; 32:458-66. [PMID: 20592644 DOI: 10.1097/ftd.0b013e3181e4427a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In a randomized trial, AIDS Clinical Trials Group (ACTG) protocol 5146 (A5146) investigated the use of therapeutic drug monitoring (TDM) to adjust doses of HIV-1 protease inhibitors (PIs) in patients with prior virologic failure on PI-based therapy who were starting a new PI-based regimen. The overall percentage of "PI trough repeats" such as rescheduled visits or redrawn PI trough specimens increased from 2% to 5% to 10% as the process progressed from the clinical sites, the pharmacology specialty laboratory, and the study team, respectively. Cumulatively, this represents a 17% rate of failure to obtain adequate PI trough sample. While targeting a turnaround of 7 days or less from sample receipt to a drug concentration report, 12% of the received specimens required a longer period to report concentrations. The implementation of dosing changes in the TDM arm were achieved within 7 days or less for 56% of the dose change events and within 14 days or less for 77% of dose change events. This quality assurance analysis provides a valuable summary of the specific points in the TDM process that could be improved during a multicenter clinical trial including: 1) shortening the timeline of sample shipment from clinical site to the laboratory; 2) performing the collection of PI trough specimen within the targeted sampling window by careful monitoring of the last dose times and collection times by the clinicians; 3) increasing patient adherence counseling to reduce the number of samples that are redrawn due to suspecting inconsistent adherence; and 4) decreasing the time to successful TDM-based dose adjustment. The application of some of these findings may also be relevant to single-center studies or clinical TDM programs within a hospital.
Collapse
|