Blood Concentrations Of Hydroxychloroquine Research Articles

Effect of hydroxychloroquine blood concentration on the efficacy and ocular toxicity of systemic lupus erythematosus.

In the absence of evidence-based guidance on the impact of hydroxychloroquine (HCQ) blood concentration on efficacy and ocular toxicity in systemic lupus erythematosus (SLE), the clinical monitoring of HCQ blood concentration is not yet widely performed, which raised concerns about the necessity of conducting HCQ blood concentration monitoring. In this retrospective study, we consecutively enrolled 135 patients with SLE who received HCQ treatment for more than 6months from July 2022 to December 2022. Ocular toxicity was evaluated by collecting relevant retinal parameters using optical coherence tomography angiography (OCTA). Therapeutic efficacy was evaluated using the SLE disease activity index (SLEDAI) and relevant clinical parameters. HCQ blood concentration was determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Spearman correlation analysis revealed that the cumulative dose of HCQ was positively correlated with the foveal avascular zone (FAZ) perimeter and FAZ area (r = 0.734, P < 0.001; r = 0.784, P < 0.001). Meanwhile, the treatment duration of HCQ was positively correlated with FAZ perimeter and FAZ area (r = 0.761, P < 0.001; r = 0.882, P < 0.001). The univariate and multivariate logistic regression analyses indicated that HCQ blood concentration was associated with the disease activity of patients with SLE (odds ratio 0.994, 95% CI 0.990-0.999). HCQ blood concentration may be an important factor in assessing the therapeutic effectiveness of SLE patients. The HCQ-related ocular toxicity was a long-term effect related to long term exposure, rather than the blood concentration of HCQ at the time of testing. More importantly, when addressing HCQ-related ocular toxicity, it may be crucial to pay attention to the cumulative dose and treatment duration of HCQ.

Evaluation of early retinal changes in patients on long-term hydroxychloroquine using optical coherence tomography angiography.

Connective tissue diseases (CTD), including systemic lupus erythematosus and rheumatoid arthritis (RA), have long been treated with hydroxychloroquine (HCQ). However, prolonged HCQ use poses a risk of adverse effects, particularly retinopathy. To detect early retinal changes assessed by optical coherence tomography angiography (OCTA) in CTD patients with long-term HCQ treatment and to explore the relationship between OCTA parameters and the concentrations of HCQ and its metabolites. A cross-sectional study conducted from March 2020 to October 2021 at the First Affiliated Hospital of Anhui Medical University. The area and perimeter of the foveal avascular zone (FAZ), the thickness of the fovea and parafovea, and the vascular density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in each area of the macula were measured by OCTA in 43 CTD patients treated with HCQ for over 6 months. Meantime, blood concentrations of HCQ and its metabolites were determined by high-performance liquid chromatography-tandem mass spectrometry, and the clinical documents of all 43 involved patients were collected. There is no significant correlation between OCTA outcomes and the patient's age, disease duration, and weight-dependent dose. HCQ cumulative duration positively correlated with FAZ area and perimeter (r = 0.419, p = 0.005 and r = 0.407, p = 0.007, respectively) and negatively correlated with the foveal vessel density in DCP (r = -0.378, p = 0.012). HCQ cumulative dose had a positive correlation with FAZ area and perimeter (r = 0.445, p = 0.003 and r = 0.434, p = 0.004, respectively) and had a negative correlation with foveal vessel density in SCP and DCP (r = -0.383, p = 0.011 and r = -0.424, p = 0.005, respectively). OCTA outcomes did not correlate with HCQ and its metabolite concentrations. OCTA could be used to detect microvascular changes in the macula of CTD patients with long-term HCQ therapy. It was not found the concentrations of HCQ and its metabolites were associated with retinal vascular changes.

Genotype-guided new approach for dose optimisation of hydroxychloroquine administration in Chinese patients with SLE

ObjectivesThe study aims to investigate the impact of gene polymorphisms on blood hydroxychloroquine (HCQ) concentrations in patients with SLE and provide guidelines for individualised care.Methods489 Chinese patients with SLE taking...

Low estimated glomerular filtration rate is an independent risk factor for higher hydroxychloroquine concentration

BackgroundThe aim of this study was to analyze the relationship of the estimated glomerular filtration rate (eGFR) to hydroxychloroquine (HCQ) blood concentrations in systemic lupus erythematosus (SLE) patients.MethodPatients with SLE who had been taking HCQ for more than 12 months were recruited. All subjects gave written informed consent. Various clinical characteristics and laboratory values were examined. The blood concentration of HCQ was measured by high-performance liquid chromatography, and the relationship of eGFR to HCQ blood concentration was mainly investigated.ResultIn total, 115 patients with SLE receiving long-term HCQ therapy were included in the study. The median concentration of HCQ was 1096 ng/ml (range 116–8240 ng/ml). The eGFR was strongly associated with blood concentration of HCQ (P = 0.011, P < 0.05), when adjusted for age, sex, body mass index (BMI), weight-adjusted dose, prednisone use and immunosuppressive drug use. No statistically significant association were found between age, duration, BMI, weight-adjusted HCQ dose, corticosteroid use, immunosuppressant use and blood concentrations of HCQ.ConclusionWe provided novel evidence that impaired renal function influenced the blood concentration of HCQ. Patients with low eGFR need to adjust the HCQ dosage according to the monitoring results of HCQ blood concentrations.Key points• A higher HCQ blood concentration was associated with low eGFR.• This finding reinforces the importance of routine HCQ measurement to maintain normal blood concentrations.• HCQ blood monitoring will be useful for dose modification in patients with renal dysfunction.

Relationship of cytochrome P450 gene polymorphisms with blood concentrations of hydroxychloroquine and its metabolites and adverse drug reactions

BackgroundHydroxychloroquine (HCQ) is a cornerstone therapy for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This study aimed to investigate the relationship of cytochrome P450 (CYP450) gene polymorphisms with blood concentrations of HCQ and its metabolites and adverse drug reactions (ADRs) in patients with SLE and RA.MethodsA cohort of 146 patients with SLE and RA treated with HCQ was reviewed. The ADRs of the patients were recorded. The blood concentrations of HCQ and its metabolites were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Genotyping of single nucleotide polymorphisms (SNPs) in CYP450, a metabolic enzyme involved in the HCQ metabolic pathway, was performed using a MassARRAY system. The chi-square test, T-test, and one-way analysis of variance were used to analyse data.ResultsAmong 29 candidate SNPs, we found that CYP3A4 (rs3735451) was significantly associated with blood levels of HCQ and its metabolites in both the unadjusted model and adjusted model (patients taking HCQ for > 10 years) (P < 0.05). For CYP3A5 (rs776746), a greater risk of skin and mucous membrane ADRs was associated with the TT genotype than with the CT + CC genotypes (P = 0.033). For CYP2C8 (rs1058932), the AG genotype carried a greater risk of abnormal renal function than the AA + GG genotype (P = 0.017); for rs10882526, the GG genotype carried a greater risk of ophthalmic ADRs than the AA + AG genotypes (P = 0.026).ConclusionsThe CYP2C8 (rs1058932 and rs10882526) and CYP3A5 (rs776746) polymorphisms are likely involved in the ADRs of HCQ. Gene polymorphism analysis of CYP450 and therapeutic drug monitoring of HCQ and its metabolites might be useful to optimise HCQ administration and predict ADRs.

An Integrated Strategy Designed To Explore the Common and Diverging Mechanisms of Potential Drugs against the Novel Coronavirus Pneumonia Based on Network Pharmacology and In Silico Molecular Docking Technology

Drug repositioning may be a promising way to find potential therapies against coronavirus disease 2019. Although chloroquine and hydroxychloroquine showed controversial results against the coronavirus disease 2019 disease, the potential common and diverging mechanisms of action are not reported and need to be dissected for better understanding them. An integrated strategy was proposed to systematically decipher the common and diverging aspects of mechanism of chloroquine and hydroxychloroquine against coronavirus disease 2019-disease network based on network pharmacology and in silico molecular docking. Potential targets of the two drugs and coronavirus disease 2019 related genes were collected from online public databases. Target function enrichment analysis, tissue enrichment maps and molecular docking analysis were carried out to facilitate the systematic understanding of common and diverging mechanisms of the two drugs. Our results showed that 51 chloroquine targets and 47 hydroxychloroquine targets were associated with coronavirus disease 2019. The core targets include tumor necrosis factor, glyceraldehyde 3-phosphate dehydrogenase, lymphocyte-specific protein-tyrosine kinase, beta-2 microglobulin, nuclear receptor coactivator 1, peroxisome proliferator-activated receptor gamma and glutathione disulfide reductase. Both chloroquine and hydroxychloroquine had good binding affinity towards tumor necrosis factor (affinity=-8.6 and -8.4 kcal/mol, respectively) and glyceraldehyde 3-phosphate dehydrogenase (-7.5 and -7.5 kcal/mol). Chloroquine and hydroxychloroquine both had good affinity with angiotensinconverting enzyme 2, 3-chymotrypsin-like protease and transmembrane serine protease 2. However, hydroxychloroquine manifested better binding affinity with the three proteins comparing with that of chloroquine. Chloroquine and hydroxychloroquine could have potential to inhibit over-activated immunity and inflammation. The potential tissue-specific regulation of the two drugs against severe acute respiratory syndrome coronavirus 2 infection may related with the lung, liver, brain, placenta, kidney, blood, eye, et al. In conclusion, our data systematically demonstrated chloroquine and hydroxychloroquine may have potential regulatory effects on coronavirus disease 2019 disease network, which may affect multiple organs, protein targets and pathways. Routine measurements of the chloroquine and hydroxychloroquine blood concentrations and tailored therapy regimen may be essential. But, further rigorous and high quality randomized controlled clinical trials are warranted to validate the antiviral effects of chloroquine and hydroxychloroquine against severe acute respiratory syndrome coronavirus 2. Our proposed strategy could facilitate the drug repurposing efforts for coronavirus disease 2019 treatment.

Evaluation of Hydroxychloroquine Blood Concentrations and Effects in Childhood-Onset Systemic Lupus Erythematosus.

Background: Hydroxychloroquine (HCQ) is an antimalarial agent given to patients with systemic lupus erythematosus (SLE) as first-line therapy. It alleviates childhood-onset systemic lupus erythematosus cSLE skin and musculoskeletal disease, decreasing disease activity and flares. HCQ concentration–effect relationships in children remains unknown. This study aimed to investigate the pharmacokinetics of HCQ and possible concentration–effect relationships. Methods: HCQ blood concentrations and effects were obtained during clinical follow-up on different occasions. cSLE flares were defined using the SLE Disease Activity Index (SLEDAI); flare was denoted by a SLEDAI score > 6. Blood concentration was measured using high-performance liquid chromatography with fluorometric detection. Statistical analysis was performed using a nonlinear mixed-effect approach with the Monolix software. Results: A total of 168 blood samples were obtained from 55 pediatric patients. HCQ apparent blood clearance (CL/F) was dependent on patients’ bodyweight and platelet count. Patients with active cSLE had a lower mean blood HCQ concentration compared with inactive cSLE patients (536 ± 294 vs. 758 ± 490 ng/mL, p = 5 × 10−6). Among patients with HCQ blood concentration ≥750 ng/mL, 87.6% had inactive cSLE. Moreover, HCQ blood concentration was a significant predictor of disease status. Conclusion: We developed the first HCQ blood concentration–effect relationship for cSLE associated with active or non-active disease status. A prospective randomized study is necessary to confirm these results.

Efficacy and safety of hydroxychloroquine for treatment of patients with rosacea: A multicenter, randomized, double-blind, double-dummy, pilot study

Efficacy and safety of hydroxychloroquine for treatment of patients with rosacea: A multicenter, randomized, double-blind, double-dummy, pilot study

Adapting a Combination of Intrinsic and Extrinsic Cellular Factors to Generate an Improved Model of Tumor Exposure and Sensitivity to Chloroquine Derivatives

In cancer clinical trials hydroxychloroquine (HCQ) is the only approved autophagy inhibitor for use in treatment. Pharmacokinetic data from clinical trials comparing tumor vs. blood concentrations of HCQ suggest that there is a significant disconnect between drug levels within these compartments [Barnard RA, Wittenburg LA, Amaravadi RK, Gustafson DL, Thorburn A, Thamm DH (2014) “Phase I Clinical Trial and Pharmacodynamic Evaluation of Combination Hydroxychloroquine and Doxorubicin Treatment in Pet Dogs Treated for Spontaneously Occurring Lymphoma Phase I Clinical Trial and Pharmacodynamic Evaluation of Combination Hydroxychloroquine.” Autophagy 10 (8): 1415–25]. Attempts to improve prediction of drug kinetics in these compartments have been made through development of individual patient‐focused physiologically‐based models, but these models fall short in predicting dynamic tumor cell‐specific intrinsic and extrinsic factors that dictate the amount of HCQ that sequesters within its ultimate pharmacodynamic target – the lysosome. Two factors intrinsic to tumor cells suggest that HCQ exposure should be predicted on a tumor‐by‐tumor basis. The first factor being basal levels of HCQ uptake drivers in the context of lysosomal burden, broken up into overall lysosomal volume and pH in a cell population. Different cell lines exhibit different pre‐exposure lysosomal burdens, modifying their overall initial exposure to HCQ both in vitro and in tumor‐bearing mice in vivo. Basal lysosomal burden is coupled to an adaptive response to HCQ exposure as well. This adaptive response is broken up into a short‐term component, driven primarily through lysosomal swelling, and a longer‐term component wherein TFEB‐activation induces biogenesis of functional lysosomes capable of sequestering HCQ. These intrinsic components result in a continual increase in cell uptake of HCQ over a 24‐hour period, split into rapid uptake within the short term (1st hour) and a slower, steadier uptake in the long term (1–24 hours). In addition, the main extrinsic factor that modulates HCQ exposure is extracellular pH. We observed a 5‐fold decrease in total cellular drug uptake and up to 10‐fold decrease in sensitivity to HCQ in media pH 6.8 vs. 7.4 across 4 cell lines. Combining these intrinsic and extrinsic factors we generate a cell‐based pharmacokinetic simulation model capable of predicting HCQ exposure to cell lines, and then translate it to next‐generation chloroquine derivatives through modification of compound‐specific physicochemical parameters. The power of this model is in its ability to account for dynamic systems within the tumor cell, giving a more accurate picture of how the tumor interacts with the drug, accounting for a major form of HCQ resistance through the non‐homogenous acidic tumor microenvironment in vivo, and pushing forward the development of next generation lysosomotropic autophagy inhibitors that may interact with the system similarly.Support or Funding InformationNational Cancer Institute [Grant R01CA190170 Therapeutic Targeting of Autophagy‐Dependent Cancer] and by Department of Defense CDMRP Breast Cancer Research Program [Grant BC130103P1 Identifying and Targeting Autophagy Dependence to Eliminate Metastatic Breast Cancer]

Development and Validation of a Fast Ultra-High Performance Liquid Chromatography-Fluorescent Method for the Quantification of Hydroxychloroquine and Its Metabolites in Patients With Lupus.

Hydroxychloroquine (HCQ) is approved for the treatment of systemic lupus erythematosus (SLE). Therapeutic drug monitoring of HCQ is necessary to detect nonadherence and to improve treatment efficacy in patients with SLE. Liquid chromatographic-tandem mass spectroscopy and high performance liquid chromatography (HPLC)-fluorescent methods are currently used to measure whole blood concentrations of HCQ and its 2 main metabolites desethylhydroxychloroquine and desethylchloroquine in patients with SLE. This study reports the development and validation of an ultra-HPLC (U-HPLC) method with fluorescence detection for the simultaneous quantification of HCQ and its metabolites in whole blood. After adding chloroquine (internal standard) to the samples, a single-step protein precipitation and a subsequent filtration were used for blood sample preparation. Analytes were separated under isocratic elution on a U-HPLC RP18 column with a total run time of 7 minutes. The mobile phase consisted of piperazine buffer (46.4 mM, pH = 9.8) and acetonitrile (68:32, vol/vol), which was delivered at a flow rate of 0.4 mL/min. Fluorescence excitation and emission wavelengths were 335 and 390 nm, respectively. Assay performance parameters were evaluated per FDA bioanalytical guidelines. The calibration curve was linear from 125 to 4000 ng/mL for HCQ. The lower limit of quantification was 10 ng/mL for all analytes. For HCQ, desethylchloroquine, and desethylhydroxychloroquine, accuracies and imprecisions ranged from -7.90% to 7.85% and 1.14% to 8.78%, respectively. A sensitive, accurate, and fast U-HPLC-fluorescent method was validated and successfully applied to quantify whole blood concentrations to perform therapeutic drug monitoring of HCQ in pediatric and adult lupus patients.

Factors Related to Blood Hydroxychloroquine Concentration in Patients With Systemic Lupus Erythematosus.

To identify factors associated with blood concentrations of hydroxychloroquine (HCQ) and its major metabolite, N-desethylhydroxychloroquine (DHCQ), in patients with systemic lupus erythematosus (SLE; lupus) receiving long-term oral HCQ treatment. SLE patients who had been taking HCQ for more than 3 months were recruited. Various clinical characteristics, laboratory values, and SLE Disease Activity Index (SLEDAI) scores were examined. The concentrations of HCQ and DHCQ ([HCQ] and [DHCQ]) were measured by liquid chromatography mass spectrometry, and the relationship between [HCQ], [DHCQ], and [HCQ]:[DHCQ] ratio to various factors was investigated. In total, 189 SLE patients receiving long-term HCQ treatment were included in the analysis. The median (interquartile range [IQR]) [HCQ] was 515 (IQR 353-720) ng/ml, the median [DHCQ] was 417 (IQR 266-591) ng/ml, and the median [HCQ]:[DHCQ] ratio was 1.3 (range 1.0-1.7). [HCQ] was closely associated with [DHCQ] (r = 0.81, P < 0.0001). The weight-adjusted oral HCQ dose was strongly associated with both [HCQ] (P < 0.001) and [DHCQ] (P < 0.001). Time since last dose was associated with [HCQ] (P < 0.001). No statistically significant association was found between renal function or smoking and [HCQ] or [DHCQ]. Use of additional immunosuppressants increased both [HCQ] and [DHCQ] after adjusting for possible confounders (P = 0.04 and P = 0.03, respectively). The lower SLEDAI score was significantly related to higher [HCQ], after adjusting for age, sex, weight-adjusted HCQ dose, time since last dose, number of other immunosuppressants, and smoking status (P = 0.007). Various factors affected blood levels of [HCQ], [DHCQ], or the [HCQ]:[DHCQ] ratio of SLE patients receiving long-term oral HCQ treatment. Notably, higher [HCQ] was associated with a lower SLEDAI score in our typical outpatient clinic population with lupus.

The effect of increasing the dose of hydroxychloroquine (HCQ) in patients with refractory cutaneous lupus erythematosus (CLE): An open-label prospective pilot study

Up to 30% of patients with cutaneous lupus erythematosus (CLE) fail to respond to hydroxychloroquine (HCQ). We sought to evaluate the efficacy of increased daily doses of HCQ on cutaneous response in refractory CLE. We conducted an open-label prospective study between 2010 and 2014. Patients with CLE and HCQ blood level less than or equal to 750 ng/mL were included. The daily dose of HCQ was increased to reach blood concentrations greater than 750 ng/mL. The primary end point was the number of responders defined by an improvement of CLE Disease Area and Severity Index score (4 points or 20% decrease) in patients with HCQ blood concentration greater than 750 ng/mL. We included 34 patients (26 women; median age 45 [range 28-72] years). Two nonadherent patients were excluded. The median CLE Disease Area and Severity Index score before treatment was significantly improved after treatment (8 [range 2-30] vs 1.5 [range 0-30]), P < .001). The primary response criterion was reached in 26 (81%) of the 32 patients analyzed. A decrease in HCQ doses without further CLE flare (median follow-up 15.8 [range 3.06-77.4] months) was achieved in 15 of the 26 responders. The main limitations of the study are its open-label design and the limited number of patients included. Increasing HCQ doses to reach blood concentrations greater than 750 ng/mL should be considered before addition of other treatments in refractory CLE.

Association of Polymorphisms of Cytochrome P450 2D6 With Blood Hydroxychloroquine Levels in Patients With Systemic Lupus Erythematosus

ObjectiveTo evaluate associations of genetic polymorphisms in cytochrome P450 (CYP) isoforms 2D6, 3A5, and 3A4 with blood concentrations of hydroxychloroquine (HCQ) and its metabolite, N‐desethyl HCQ (DHCQ), in patients with systemic lupus erythematosus (SLE).MethodsSLE patients taking HCQ for &gt;3 months were recruited and were genotyped for 4 single‐nucleotide polymorphisms in CYP2D6*10, CYP3A5*3, and CYP3A4*18B. Blood HCQ and DHCQ concentrations ([HCQ] and [DHCQ]) were measured and their association with corresponding genotypes was investigated.ResultsA total of 194 patients were included in the analysis. CYP2D6*10 polymorphisms (rs1065852 and rs1135840) were significantly associated with the [DHCQ]:[HCQ] ratio after adjustment for age, sex, dose per weight per day, and SLE Disease Activity Index score (P = 0.03 and P &lt; 0.01, respectively). In adjusted models, the [DHCQ]:[HCQ] ratio was highest in patients with the G/G genotype of the CYP2D6*10 (rs1065852) polymorphism and lowest in those with the A/A genotype (P = 0.03). Similarly, the [DHCQ]:[HCQ] ratio was highest in patients with the C/C genotype of the CYP2D6*10 (rs1135840) polymorphism and lowest in those with the G/G genotype (P &lt; 0.01). The CYP2D6*10 (rs1065852) polymorphism was significantly related to the [DHCQ] (P = 0.01). However, the polymorphisms of CYP3A5*3 and CYP3A4*18B did not show any significant association with the [HCQ], [DHCQ], or [DHCQ]:[HCQ] ratio.ConclusionOur study showed that the [DHCQ]:[HCQ] ratio was related to CYP2D6 polymorphisms in Korean lupus patients taking oral HCQ. CYP polymorphisms may explain why there is wide variation in blood HCQ concentrations. The role of an individual's CYP polymorphisms should be considered when prescribing oral HCQ.

Determinants of hydroxychloroquine blood concentration variations in systemic lupus erythematosus.

Blood concentrations of hydroxychloroquine (HCQ) vary widely among patients with systemic lupus erythematosus (SLE). A pharmacokinetic/pharmacodynamic relationship has been found in different situations, and a very low blood concentration of HCQ is a simple marker of nonadherence to treatment. Therefore, interest in blood HCQ concentration measurement has increased, but little is known about factors that influence blood HCQ concentration variability. This study was undertaken to analyze determinants of blood HCQ concentrations. We conducted a retrospective analysis of patient data, including data from the Plaquenil Lupus Systemic (PLUS) study, to determine the association of epidemiologic, clinical, and biologic factors with blood HCQ concentrations. Data for nonadherent patients (blood HCQ concentration <200 ng/ml) were excluded. To examine homogeneous pharmacologic data, we restricted the analyses of the PLUS data to the 509 SLE patients receiving 400 mg/day. We found no association of ethnicity or smoking with blood HCQ concentrations and no pharmacokinetic drug-drug interaction with antacids or with inhibitors or inducers of cytochrome P450 enzymes. On multivariate analysis, high body mass index (P = 0.008), no treatment with corticosteroids (P = 0.04), increased time between the last tablet intake and measurement of blood HCQ concentrations (P = 0.017), low platelet count (P < 0.001), low neutrophil count (P < 0.001), and high estimated creatinine clearance (P < 0.001) were associated with low blood HCQ concentrations. In 22 SLE patients with chronic renal insufficiency (median serum creatinine clearance 52 ml/minute [range 23-58 ml/minute]) who received 400 mg/day HCQ, the median blood HCQ concentration was significantly higher than that in the 509 patients from the PLUS study (1,338 ng/ml [range 504-2,229 ng/ml] versus 917 ng/ml [range 208-3316 ng/ml]) (P < 0.001). We provide a comprehensive analysis of determinants of blood HCQ concentrations. Because this measurement is increasingly being used, these data might be useful for clinicians.

Development, validation and clinical application of a LC-MS/MS method for the simultaneous quantification of hydroxychloroquine and its active metabolites in human whole blood

A rapid, sensitive and specific method using liquid chromatography coupled to tandem mass spectrometry was developed for the simultaneous quantification of hydroxychloroquine (HCQ) and its three major metabolites in human whole blood. The assay, using a sample volume of 100μL, was linear in a dynamic 25–2000ng/mL range (R2>0.99) for all four compounds and suitable for the determination of elevated HCQ concentrations up to 20,000ng/mL, after appropriate sample dilution. Inter- and intra-assay precisions were <18.2% and accuracies were between 84% and 113% for any analyte. No matrix effects were observed. The assay was successfully applied to a blood sample obtained from one poisoned patient following a massive HCQ self-ingestion resulting in an estimated concentration of 19,500ng/mL on hospital admission. In this patient, HCQ metabolites were identified and quantified at 1123, 465 and 91ng/mL for monodesethylhydroxychloroquine, desethylchloroquine and bisdesethylchloroquine, respectively. Further investigations are still required to assess the usefulness of the simultaneous measurement of blood concentrations of HCQ and its three active metabolites for monitoring HCQ treatment and managing HCQ poisoning.

A cross‐sectional study of hydroxychloroquine concentrations and effects in people with systemic lupus erythematosus

To investigate the pharmacokinetics of hydroxychloroquine (HCQ) and relationships of HCQ concentration with disease activity variables (concentration-effect relationships) in patients with systemic lupus erythematosus (SLE). HCQ concentration and disease activity were measured at a single time point in 60 patients with SLE receiving HCQ for at least 6 months. Some retrospective objective data on disease activity prior to HCQ commencement were available. Correlations were sought between HCQ blood concentrations and disease variables (Systemic Lupus Activity Measure (SLAM) scores, joint scores, morning stiffness, pain, well-being, general improvement, other medication use (including corticosteroids), and physician and patient assessments). Blood HCQ concentrations were also dichotomised into 'more' and 'less/no' disease activity, and mean blood concentrations in the two groups for each disease activity measure were compared. The pharmacokinetics (dose-concentration relationships) of HCQ were highly variable in people with SLE. Apparent total clearance of HCQ from blood was 316 (± 319) mL/min (mean (± standard deviation). There was no correlation between SLAM score, patient global assessment or physician global assessment, and blood HCQ concentrations (r(2) = 0.2, 0.04 and 0.13, respectively; P > 0.05). However, during HCQ therapy, 64% (14 of 22 patients) had a reduction in prednisolone dose of 50% or more compared with pre-HCQ therapy. No significant concentration-effect relationship for HCQ in the treatment of SLE was observed perhaps because consistently high enough blood HCQ concentrations were not achieved. Pharmacokinetic variability led to a wide range of blood HCQ concentrations. A concentration-targeting study for HCQ in SLE would be timely.

A Parallel Design Study to Assess the Bioequivalence of Generic and Branded Hydroxychloroquine Sulfate Tablets in Healthy Volunteers

Hydroxychloroquine (HCQ) is a racemic 4-aminoquinoline derivative that was first introduced as an antimalarial, and subsequently applied to the treatment of autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Information on the pharmacokinetics of HCQ in healthy volunteers, especially in a Chinese population is limited, and this study was conducted to provide support for a generic product to obtain marketing authorization in China.The aim of the present study was to compare the pharmacokinetics and assess bioequivalence of a new generic test and the branded reference hydroxychloroquine sulfate tablets in healthy volunteers.This was a parallel, open-label, randomized, single-dose, 1-period fasting study. 54 healthy subjects were randomly assigned (1:1) to receive 200 mg hydroxychloroquine sulfate tablets of the test or the reference formulation. 15 blood samples were collected and whole blood concentrations of HCQ were determined by a validated liquid chromatography-isotopic dilution mass spectrometry method. Log-transformed Cmax and AUC0-24 values were used to test for bioequivalence. The 2 formulations were considered bioequivalent if 90% confidence intervals (CIs) for the log-transformed ratios of Cmax and AUC0-24 were within the predetermined bioequivalence range of 80-125%. Tolerability was evaluated throughout the study by vital signs, physical examinations, clinical laboratory tests, 12-lead electrocardiograms, and interviews with the subjects about adverse events.54 healthy subjects were enrolled and completed the study (mean [SD] age, height, body weight, and BMI were 23.9 [2.4] years, 168.9 [5.0] cm, 61.3 [5.4] kg, and 21.5 [1.7] kg/m2), 27 subjects per group. No formulation or sequence effects were observed. The mean values of Cmax and AUC0-24 for the test and reference formulations of HCQ (197.6 and 199.0 ng/mL, 2460.1 and 2468.3 ng/mL/h) were not significantly different. The 90% CIs of the ratios of Cmax and AUC0-24 were 99.3% (98.1-102.1%), 99.7% (98.9-101.4%), respectively. 4 subjects (7.41%) experienced a total of 4 mild AEs (headache and microscopic hematuria, 1 each; and increase in plasma triglycerides, 2).The results of this study suggest that the test and reference hydroxychloroquine sulfate tablets are bioequivalent. Both formulations were generally well tolerated.

Low Blood Concentration of Hydroxychloroquine in Patients With Refractory Cutaneous Lupus Erythematosus

To study the relation between blood concentration of hydroxychloroquine and the clinical efficacy of hydroxychloroquine sulfate in a series of patients with cutaneous lupus erythematosus (CLE). Prospective multicenter study. A staff dermatologist blinded to blood hydroxychloroquine concentrations performed a standardized review of medical records and assessment of hydroxychloroquine efficacy in the following 3 categories: complete remission, partial remission (clearing of >50% of skin lesions), or treatment failure. Whole-blood samples were collected for measurement of blood hydroxychloroquine concentration. Fourteen French university hospitals. Three hundred consecutive patients with subacute or chronic CLE who had been treated with hydroxychloroquine for at least 3 months. The statistical significance of correlation between blood hydroxychloroquine concentration and efficacy of hydroxychloroquine and the statistical associations in univariate and multivariate analyses of complete remission with several variables. The study included 300 patients with discoid lupus erythematosus (n = 160), subacute CLE (n = 86), lupus erythematosus tumidus (n = 52), chilblain lupus (n = 26), and lupus panniculitis (n = 16); 38 of these patients had 2 or more associated forms. Median blood hydroxychloroquine concentration was significantly higher in patients with complete remission (910 [range, <50 to 3057] ng/mL) compared with partial remission (692 [<50 to 2843] ng/mL) and treatment failure (569 [<50 to 2242] ng/mL) (P = .007). In the multivariate analysis, complete remission was associated with higher blood hydroxychloroquine concentrations (P = .005) and the absence of discoid lesions (P = .004). Thirty patients (10.0%) had very low blood hydroxychloroquine concentrations (<200 ng/mL) and may be considered nonadherent to the treatment regimen. Monitoring hydroxychloroquine blood concentrations might improve the management of refractory CLE.

Efficacy and Safety of Hydroxychloroquine Sulphate In Chronic Lymphocytic Leukemia: Clinical Trial Experience In Untreated Patients

AbstractAbstract 1392 Background:Hydroxychloroquine (HCQ) has been used safely for many years for treatment of malaria, systemic lupus erythematosus and rheumatoid arthritis. It is known to have exerted immunomodulatory actions by affecting antigen presentation by macrophages and dendritic cells, DNA/RNA synthesis, and apoptosis in lymphocytes and endothelial cells. All of these actions can be attributed at least partially to the inactivation of endosomal acid proteases.CLL is the abnormal proliferation of a B lymphocyte clone. Based on the unique structural characteristics of the B-cell antigen receptor (BCR), at least some CLL cases probably results from ongoing antigen selection and stimulation. RNA and/or DNA from infection or cell apoptosis are candidate stimulants of this process. Binding of RNA and DNA to toll-like receptors (TLR 7 and 9) in endosomes is dependent on an acidic pH and can be prevented by HCQ due to its de-acidifiying effect. HCQ can also directly induce apoptosis in CLL cells through caspase 3 activation in vitro. We therefore hypothesized that administration of HCQ early in the disease would protect CLL patients from disease progression by eliminating these stimulatory TLR 7 and 9 signals. Methods:22 CLL patients with no urgent need for treatment were enrolled in the clinical trial. Patients took HCQ 400 mg/day for 52 weeks. Clinical response was measured every 4 weeks by history, physical exam, and absolute lymphocyte counts. Additional blood samples were taken every 8 weeks for companion laboratory studies. Statistical analyses used include Fisher's Exact Test, Slopes analysis and Repeated measures analysis of variance on the log-transformed absolute lymphocyte counts (ALCs). Results:In total, 8 IGHV unmutated (U-CLL) and 14 mutated (M-CLL) patients were enrolled; 3 U-CLL and 10 M-CLL completed the full year of HCQ treatment. Five U-CLL patients were dropped from the study due to disease progression requiring CLL therapy. One M-CLL patient left for personal reasons. Three M-CLL patients are still continuing on HCQ therapy.Patient outcomes can be separated into three patterns based on ALC changes: 7 patients (6 M-CLL and 1 U-CLL) had stable counts throughout the trial; 12 patients (8 M-CLL and 4 U-CLL) had a fall in ALCs after treatment; and 3 patients (all U-CLL) developed increased ALCs. The response to HCQ in CLL is associated with Ig V mutation status of patients (P<.03). With some U-CLL patients having a worsening of disease; overall U-CLL patients have worse outcome than M-CLL (P<.045). Nevertheless in most instances, U-CLL patients did respond to HCQ with stabilization or fall in ALC initially, although this was followed at an average of 18–22 weeks with an increase in ALCs and in some instances a need for therapy.Maximum HCQ blood concentrations in healthy individuals receiving 400 mg/day HCQ orally are reported to range from 67–221 ng/ml. In vitro assay using samples collected at trial initiation indicated that direct CLL cytotoxicity occurred at levels ≥10 μg/ml; this value was similar for U- and M-CLL clones. Using a non-cytotoxic concentration of 1 μg/ml of HCQ, in vitro TLR9 ligand ODN2006 enhanced expression of TLR9 was diminished. The proliferation and activation of both U- and M-CLL was blocked completely, although concentrations of 10–100 ng/ml had a superior blocking effect on M-CLL than U-CLL clones.In vivo administration of HCQ blocked CLL cell proliferation initiated by ODN2006. In comparison with samples taken before HCQ administration, patient samples obtained after trial initiation responded to ODN2006 poorly. Interestingly, the type of CLL cell response to ODN2006 closely correlated with patient's ALC change. The least blocking of HCQ on cell proliferation was again observed in U-CLL patients, especially with the samples taken from the timepoint at which elevated ALCs were observed. Conclusion:In this clinical trial, oral administration of HCQ (400 mg/day) stabilized or decreased ALCs in the initial 18–22 weeks (of a 46–52 week regimen) in 91% of patients (14 M-CLL and 6-U-CLL). Subsequently, rising ALCs were observed in most of the U-CLL cases (n=4), and ALCs in M-CLL patients remain stabilized. Our in vitro evaluation suggests that an increased dose of HCQ might target TLR9 signaling better and thus improve outcome especially in U-CLL cases. Another possibility that warrants further study is that HCQ may have several actions on CLL cells leading to worse outcome of the disease. Disclosures:No relevant conflicts of interest to declare.

A dose-ranging study of the pharmacokinetics of hydroxy-chloroquine following intravenous administration to healthy volunteers.

1. The pharmacokinetics of hydroxychloroquine were studied in five healthy volunteers following an intravenous infusion of 155 mg (2.47 +/- 0.25 mg kg-1) racemic hydroxychloroquine. Four of these volunteers also received a further 310 mg (4.92 +/- 0.45 mg kg-1) infusion of hydroxychloroquine and evidence of nonlinearities in the pharmacokinetics of hydroxychloroquine were sought. 2. No nonlinear elimination or distribution processes appeared to be operating at the doses of hydroxychloroquine used in this study, supporting the hypothesis that in the therapeutic dosing range the pharmacokinetics of hydroxychloroquine are linear. 3. Half-life and mean residence time were long (around 40 days) and large volumes of distribution were calculated (5,522 l from blood, 44,257 l from plasma). Sequestration into the tissues is an important feature of the disposition of hydroxychloroquine. The persistence of hydroxychloroquine in the body is due primarily to this extensive tissue distribution, rather than to low clearance (667 ml min-1 based on plasma data, 96 ml min-1 based on blood data). 4. Plasma data were more variable than blood data. Blood to plasma concentration ratios were not constant (mean +/- s.d.: 7.2 +/- 4.2). The data indicate that it is preferable to measure whole blood concentrations of hydroxychloroquine, rather than plasma concentrations, in pharmacokinetic studies. 5. The pharmacokinetics of hydroxychloroquine are similar to those of chloroquine.