Routine Hydroxychloroquine Blood Concentration Measurement in Systemic Lupus Erythematosus Reaches Adulthood

Advancements on the impact of hydroxychloroquine in systemic lupus erythematosus

Hydroxychloroquine (HCQ) has gained significant attention as a therapeutic option for systemic lupus erythematosus (SLE) because of its multifaceted mechanism of action. It is a lipophilic, lysosomotropic drug, that easily traverses cell membranes and accumulates in lysosomes. Once accumulated, HCQ alkalizes lysosomes within the cytoplasm, thereby disrupting their function and interfering with processes like antigen presentation. Additionally, HCQ has shown potential in modulating T-cell responses, inhibiting cytokine production, and influencing Toll-like receptor signaling. Its immunomodulatory effects have generated interest in its application for autoimmune disorders. Despite its established efficacy, uncertainties persist regarding the optimal therapeutic concentrations and their correlation with adverse effects such as retinal toxicity. Therefore, standardized dosing and monitoring guidelines are crucial. In this study, we provide a comprehensive review of the mechanisms, efficacy, dosing variations, and retinal toxicity profiles of HCQ, which are essential to optimize SLE treatment protocols and ensure patient safety.

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 6 months 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

Background

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.

Objective

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.

Design

A cross-sectional study conducted from March 2020 to October 2021 at the First Affiliated Hospital of Anhui Medical University.

Methods

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.

Results

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.

Conclusion

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.

Association Between Severe Nonadherence to Hydroxychloroquine and Systemic Lupus Erythematosus Flares, Damage, and Mortality in 660 Patients From the SLICC Inception Cohort

OBJECTIVE

The goals of this study were to assess the associations of severe nonadherence to hydroxychloroquine (HCQ), objectively assessed by HCQ serum levels, and risks of systemic lupus erythematosus (SLE) flares, damage, and mortality rates over five years of follow-up.

METHODS

The Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort is an international multicenter initiative (33 centers throughout 11 countries). The serum of patients prescribed HCQ for at least three months at enrollment were analyzed. Severe nonadherence was defined by a serum HCQ level <106 ng/mL or <53 ng/mL for HCQ doses of 400 or 200 mg/day, respectively. Associations with the risk of a flare (defined as a Systemic Lupus Erythematosus Disease Activity Index 2000 increase ≥4 points, initiation of prednisone or immunosuppressive drugs, or new renal involvement) were studied with logistic regression, and associations with damage (first SLICC/American College of Rheumatology Damage Index [SDI] increase ≥1 point) and mortality with separate Cox proportional hazard models.

RESULTS

Of the 1,849 cohort participants, 660 patients (88% women) were included. Median (interquartile range) serum HCQ was 388 ng/mL (244-566); 48 patients (7.3%) had severe HCQ nonadherence. No covariates were clearly associated with severe nonadherence, which was, however, independently associated with both flare (odds ratio 3.38; 95% confidence interval [CI] 1.80-6.42) and an increase in the SDI within each of the first three years (hazard ratio [HR] 1.92 at three years; 95% CI 1.05-3.50). Eleven patients died within five years, including 3 with severe nonadherence (crude HR 5.41; 95% CI 1.43-20.39).

CONCLUSION

Severe nonadherence was independently associated with the risks of an SLE flare in the following year, early damage, and five-year mortality.

Analysis of Factors Influencing Whole Blood Hydroxychloroquine Concentration in Patients with Systemic Lupus Erythematosus in China

INTRODUCTION

The aim of this study was to determine the factors associated with the concentrations of hydroxychloroquine (HCQ) and its major metabolite, desethylhydroxychloroquine (DHCQ), in patients with systemic lupus erythematosus (SLE).

METHODS

Patients with SLE taking oral HCQ for at least 3 months were recruited from the Department of Rheumatology and Immunology of Nanjing Drum Tower Hospital. Clinical characteristics and laboratory values were examined. The concentrations of HCQ and DHCQ were measured by high-performance liquid chromatography, and the effects of various factors on the concentrations were investigated.

RESULTS

A total of 272 patients were included in this study. The average concentration of HCQ was 690.90 ng/ml and the average concentration of DHCQ was 431.84 ng/ml. Multivariate analysis indicated that gender (P = 0.015), age (year) (P < 0.001), weight (kg) (P = 0.013), duration of HCQ use (month) (P < 0.001), systemic lupus erythematosus disease activity index (SLEDAI) (P < 0.001), platelet count (× 109/l) (P < 0.001), immunoglobulin G levels (g/l) (P = 0.014) were associated with low HCQ concentrations. Gender (P = 0.006), duration of HCQ use (month) (P < 0.001), SLEDAI (P = 0.007), and platelet count (× 109/l) (P < 0.001) were associated with low DHCQ concentrations.

CONCLUSIONS

Patients with SLE require long-term administration of HCQ, but blood levels vary widely between individuals. Studying the factors influencing the blood HCQ and DHCQ concentrations and optimizing the dose according to individual characteristics might help to improve the efficacy of HCQ.

TRIAL REGISTRATION

ChiCTR2300070628.

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

OBJECTIVES

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

METHODS

489 Chinese patients with SLE taking HCQ for more than 3 months were collected in this study. The blood HCQ, desethylhydroxychloroquine (DHCQ) and desethylchloroquine concentrations were measured. The optimal blood concentration of HCQ was determined by receiver operating characteristic curve analysis. Single nucleotide polymorphisms of metabolic enzymes involved in HCQ metabolism were genotyped and the associations with treatment effects were investigated.

RESULTS

The cut-off value of HCQ was 559.67 ng/mL, with sensitivity and specificity values of 0.51 and 0.89, respectively. The TC and CC genotypes of CYP2C8 (rs7910936) were significantly related to the increase in blood HCQ concentrations, and the CYP2C8 (rs10882521) TT genotype was associated with lower blood HCQ concentrations. The DHCQ:HCQ ratio was highest in patients with the GG genotype of the CYP2D6*10 (rs1065852) polymorphism and lowest in those with the AA genotype. Patients with the CYP2C8 (rs7910936) CC genotype were more likely to achieve the optimal blood concentration (p=0.030) in HCQ 200 mg/day group and patients with the CYP2D6*10 (rs1065852) GG genotype were more likely to reach the optimal blood concentration (p=0.049) in 400 mg/day group.

CONCLUSIONS

Our results suggest that the optimal blood concentration of HCQ measured approximately 12-18 hours after the last dosage may be between 500 and 600 ng/mL in Chinese patients with SLE. The observed variations in HCQ concentrations between individuals can potentially be attributed to genetic polymorphisms in CYP2D6*10 (rs1065852) and CYP2C8 (rs7910936 and rs10882521). Genotypical testing of patients and regular monitoring of blood levels are recommended for optimising HCQ dosage management in Chinese patients with SLE.

TRIAL REGISTRATION NUMBER

ChiCTR2300070628.

Pharmacokinetics of hydroxychloroquine in paediatric lupus: data from a novel, direct-to-family clinical trial

Objective

Determine the pharmacokinetics (PK) and exposure–response of hydroxychloroquine (HCQ) and desethylhydroxychloroquine (DHCQ) in paediatric SLE (pSLE).

Methods

We conducted an exploratory phase 2, direct-to-family trial. Children enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry with a diagnosis of pSLE were eligible if they were receiving HCQ as standard of care for ≥3 months. Biological samples were collected at up to four visits over a 6-month period. At each visit, plasma was obtained to measure the concentrations of HCQ and DHCQ, as well as cytokines. HCQ and DHCQ plasma PK data were analysed using a population PK modelling approach.

Results

Twenty-five subjects provided a total of 88 plasma concentrations for PK analysis. There was a poor linear fit between HCQ concentrations and total body weight (R²=0.03). There was a decline in both interferon (IFN)-alpha and IFN-gamma with higher concentrations of HCQ and DHCQ. Volume of distribution for HCQ in plasma was higher in children compared with published values in adults (73 000 L vs 44 000 L), but clearance values in children were similar to adults.

Conclusions

We report the first population PK model for HCQ and DHCQ in children using data from a novel direct-to-family clinical trial. We observed high interindividual variability in HCQ PK and found that weight-based dosing for HCQ is poorly correlated with drug concentrations, suggesting the need to use therapeutic drug monitoring to individualise dosing. Furthermore, our results suggest that the current weight-based dosing paradigm for HCQ may result in suboptimal drug exposures, particularly for children with obesity. Accordingly, additional studies of HCQ are needed in pSLE to determine the optimal drug concentration and dosing to reduce disease activity and improve outcomes.

Trial registration number

NCT04358302.

Patient and healthcare team recommended medication adherence strategies for hydroxychloroquine: results of a qualitative study informing intervention development

OBJECTIVE

Patients identified as black and from disadvantaged backgrounds have a twofold higher hydroxychloroquine (HCQ) non-adherence, which contributes to worse lupus outcomes and disparities. Yet, most adherence interventions lack tailored strategies for racially and socioeconomically diverse patients who face unique challenges with HCQ. We aimed to examine a broadly representative group of patients with SLE and physician perspectives on HCQ adherence and adherence strategies to redesign an adherence intervention.

METHODS

We conducted four virtual focus groups (90 min each) with 11 racially and socioeconomically diverse patients with SLE recruited from two health systems. Additionally, we hosted two focus group meetings with nine healthcare advisors. In focus groups, patients: (1) shared their perspectives on using HCQ; (2) shared concerns leading to non-adherence; (3) discussed strategies to overcome concerns; (4) prioritised strategies from the most to least valuable to inform an adherence intervention. In two separate focus groups, healthcare advisors gave feedback to optimise an adherence intervention. Using content analysis, we analysed transcripts to redesign our adherence intervention.

RESULTS

Worry about side effects was the most common barrier phrase mentioned by patients. Key themes among patients' concerns about HCQ included: information gaps, logistical barriers, misbeliefs and medication burden. Finally, patients suggested adherence strategies and ranked those most valuable including co-pay assistance, personal reminders, etc. Patient and healthcare advisors informed designing a laminate version of an adherence intervention to link each barrier category with four to six patient-recommended adherence strategies.

CONCLUSION

We developed a patient stakeholder-informed and healthcare stakeholder-informed tailored intervention that will target non-adherence at the individual patient level.

Clinical Significance of Monitoring Hydroxychloroquine Levels in Patients With Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis

OBJECTIVE

Despite the pivotal role that hydroxychloroquine (HCQ) plays in treating systemic lupus erythematosus (SLE), less than 50% of patients take HCQ as prescribed. Measurement of HCQ blood levels can help clinicians distinguish nonadherence versus lack of efficacy of HCQ. Our objective was to systematically review publications and perform a meta-analysis to examine the correlation between HCQ levels and 1) nonadherence and 2) Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, in SLE.

METHODS

A comprehensive search was performed. We included observational and interventional studies that measured HCQ levels and assessed adherence or SLEDAI scores in adults with SLE. Forest plots compared pooled estimates of correlations between HCQ levels and reported nonadherence or SLEDAI scores.

RESULTS

Among 604 studies screened, 17 were reviewed. We found 3-times higher odds of reported nonadherence in patients with low HCQ levels (odds ratio 2.95 [95% confidence interval (95% CI) 1.63, 5.35], P < 0.001). The mean SLEDAI score was 3.14 points higher in groups with below-threshold HCQ levels on a priori analysis (δ = 3.14 [95% CI -0.05, 6.23], P = 0.053), and 1.4 points higher in groups with HCQ levels of <500 ng/ml (δ = 1.42 [95% CI 0.07, 2.76], P = 0.039). Among 1,223 patients, those with HCQ levels ≥750 ng/ml had a 58% lower risk of active disease, and their SLEDAI score was 3.2 points lower.

CONCLUSION

We found a strong association between low HCQ levels and reported nonadherence. Our results suggest that HCQ levels of ≥750 ng/ml might be a potential therapeutic target.

Hydroxychloroquine and COVID-19: a Rheumatologist's Take on the Lessons Learned

PURPOSE OF REVIEW

Told from the viewpoint of rheumatologists, this review tells the story of hydroxychloroquine and its swift ascent to become a household name as a therapeutic strategy against the novel SARS-CoV-2 virus. This review describes the history, mechanisms, pharmacokinetics, therapeutic applications, and safety profile of hydroxychloroquine as an immunomodulatory and antiviral agent. It also summarizes the major studies that launched and assessed the use of hydroxychloroquine against COVID-19 infection.

RECENT FINDINGS

More recent literature calls into question the long-held dogma that endolysosomal alkalinization is the primary mode of action of hydroxychloroquine. Ongoing uncertainty about the multiple potential mechanisms contributing to the therapeutic effect of hydroxychloroquine in rheumatic and viral disease led to a natural avenue for exploration in the treatment of COVID-19. Taken as a whole, the literature does not support utilizing hydroxychloroquine to treat or prevent infection from the SARS-CoV-2 virus. This is, at least in part, due to the wide variability in hydroxychloroquine pharmacokinetics between patients and difficulty achieving adequate target tissue concentrations of hydroxychloroquine without encountering unacceptable toxicities. Hydroxychloroquine continues to be a routinely prescribed, well-tolerated, effective, and low-cost treatment for rheumatic disease. Its therapeutic versatility has led to frequent repurposing for other conditions, most recently as an investigative treatment against the SARS-CoV-2 virus. Despite overall negative findings, the intense study of hydroxychloroquine against COVID-19 infection has enhanced our overall understanding of how hydroxychloroquine operates in autoimmune disease and beyond.

Pharmacokinetics of Hydroxychloroquine in Pregnancies with Rheumatic Diseases

BACKGROUND

Hydroxychloroquine is an oral drug prescribed to pregnant women with rheumatic disease to reduce disease activity and prevent flares. Physiologic changes during pregnancy may substantially alter drug pharmacokinetics. However, the effect of pregnancy on hydroxychloroquine disposition and the potential need for dose adjustment remains virtually unknown.

METHODS

We performed a population-pharmacokinetic analysis using samples from the Duke Autoimmunity in Pregnancy Registry from 2013 to 2016. We measured hydroxychloroquine concentration using high-performance liquid chromatography/tandem mass spectrometry and analyzed data using non-linear mixed-effect modeling. We calculated differences between pregnancy and postpartum empirical Bayesian estimates using paired t tests. We computed steady-state concentration profiles for hydroxychloroquine during pregnancy and postpartum using individual clinical data and empirical Bayesian estimates developed from the final pharmacokinetic model.

RESULTS

We obtained 145 serum samples from 50 patients, 25 of whom had paired pregnancy and postpartum specimens. Five subjects had average concentrations (pregnancy and postpartum) < 100 ng/mL, consistent with medication non-adherence, and were excluded. The population estimated apparent volume of distribution was 1850 L/70 kg and estimated apparent clearance was 51 L/h. Compared with postpartum, median apparent volume of distribution increased significantly during pregnancy (p < 0.001), whereas apparent clearance and 24-h area under the curve did not change.

CONCLUSIONS

We developed a one-compartment population-pharmacokinetic model for hydroxychloroquine in pregnant women with rheumatic disease. Estimates for serum CL were within the expected range for plasma in non-pregnant adults. Because CL and 24-h area under the curve did not change during pregnancy compared with postpartum, our modeling in this small cohort does not support adjusting hydroxychloroquine dose during pregnancy.

Understanding Nonadherence with Hydroxychloroquine Therapy in Systemic Lupus Erythematosus

Objective.

Hydroxychloroquine (HCQ) is a cornerstone to managing systemic lupus erythematosus (SLE), yet adherence to medication is poor. We sought to measure the association of adherence with 5 “dimensions of adherence” as articulated by the World Health Organization for chronic conditions: the patient’s socioeconomic status, and patient-, condition-, therapy-, and healthcare system–related factors. Our longterm goal is to generate evidence to design effective interventions to increase adherence.

Methods.

The retrospective cohort study included Kaiser Permanente Northern California patients ≥ 18 years old during 2006–2014, with SLE and ≥ 2 consecutive prescriptions for HCQ. Adherence was calculated from the medication possession ratio and dichotomized as < 80% versus ≥ 80%. Predictor variables were obtained from the electronic medical record and census data. We used multivariable logistic regression to estimate adjusted OR and 95% CI.

Results.

The study included 1956 patients. Only 58% of patients had adherence ≥ 80%. In adjusted analyses, socioeconomic variables did not predict adherence. Increasing age (65–89 yrs compared with ≤ 39 yrs: OR 1.44, 95% CI 1.07–1.93), white race (p < 0.05), and the number of rheumatology visits in the year before baseline (≥ 3 compared with 0 or 1: OR 1.47, 95% CI 1.18–1.83) were positively associated with adherence. The rheumatologist and medical center providing care were not associated with adherence.

Conclusion.

At our setting, as in other settings, about half of patients with SLE were not adherent to HCQ therapy. Differences in adherence by race/ethnicity suggest the possibility of using tailored interventions to increase adherence. Qualitative research is needed to elucidate patient preferences for adherence support.

Hydroxychloroquine Levels throughout Pregnancies Complicated by Rheumatic Disease: Implications for Maternal and Neonatal Outcomes

OBJECTIVE

Pregnancies in women with active rheumatic disease often result in poor neonatal outcomes. Hydroxychloroquine (HCQ) reduces disease activity and flares; however, pregnancy causes significant physiologic changes that may alter HCQ levels and lead to therapeutic failure. Therefore, our objective was to evaluate HCQ concentrations during pregnancy and relate levels to outcomes.

METHODS

We performed an observational study of pregnant patients with rheumatic disease who were taking HCQ from a single center during 2013-2016. Serum samples were analyzed using high-performance liquid chromatography/mass spectrometry. Primary HCQ exposure was categorized as nontherapeutic (≤ 100 ng/ml) or therapeutic (> 100 ng/ml). Categorical outcomes were analyzed using Fisher's exact test and continuous outcomes using linear regression models, Wilcoxon signed-rank test, Kruskal-Wallis test, t test, and ANOVA.

RESULTS

We analyzed 145 samples from 50 patients with rheumatic disease, 56% of whom had systemic lupus erythematosus (SLE). HCQ concentration varied widely among individuals at each trimester. Mean physician's global assessment scores in patients with SLE were significantly higher in those with average drug levels ≤ 100 ng/ml compared to > 100 ng/ml (0.93 vs 0.32, p = 0.01). Of patients with SLE, 83% with average drug levels ≤ 100 ng/ml delivered prematurely (n = 6), compared to only 21% with average levels > 100 ng/ml (n = 19; p = 0.01). HCQ levels were not associated with prematurity or disease activity in non-SLE patients.

CONCLUSION

With both high and low HCQ levels associated with preterm birth and disease activity in SLE, further study is necessary to understand HCQ disposition throughout pregnancy and to clarify the relationship between drug levels and outcomes.

It hasn't gone away: the problem of glucocorticoid use in lupus remains

The treatment of SLE remains complex, and management is constrained by a lack of safe, effective, targeted therapies. Physicians, also, are constrained by a lack of evidence-based approaches with existing agents, including glucocorticoids, utilized in the majority of patients. While Cushingoid side effects of glucocorticoids are widely recognized, emerging literature now suggests that glucocorticoid use actually contributes to harmful outcomes in SLE, over and above these effects. These studies provide a compelling case for a re-evaluation of the long-term use of glucocorticoids in SLE, focusing on minimizing glucocorticoid exposure as part of the strategy to improve long-term outcomes. In this article, we review the evidence for the harmful effects of glucocorticoids in SLE, and propose therapeutic options that reduce reliance on glucocorticoids. We propose that it is time for the lupus community to have a louder conversation about glucocorticoid use, and for any residual complacency about their risk-benefit ratio to be banished.