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

Assessment of hydroxychloroquine blood levels in Sjögren's disease patients: drug adherence and clinical associations

Hydroxychloroquine (HCQ) has been used to treat Sjögren's disease (SjD) patients. However, there are no studies evaluating drug adherence through HCQ blood levels, pharmacy refill (PR) and medication adherence questionnaires. The relationship of HCQ blood levels with glandular/extraglandular disease parameters was also poorly assessed. This cross-sectional observational study included 74 adult SjD patients, who were receiving a stable HCQ dose (4-5.5 mg/kg/day, actual weight) for at least 3 months before study inclusion. HCQ blood levels were quantified by high-performance liquid chromatography coupled to mass spectrometry. Adherence was assessed by PR and Medida de Adesão aos Tratamentos (MAT) questionnaire. The following parameters were evaluated: Xerostomia Inventory, Ocular Surface Disease Index, EULAR (European League Against Rheumatism) Sjögren's Syndrome Disease Activity Index, EULAR Sjögren's Syndrome Patient Reported Index, Schirmer's I test and non-stimulated/stimulated salivary flow rates. HCQ blood levels were 775.3(25.0-2,568.6)ng/mL. Eleven patients (14.9%) had HCQ blood levels < 200ng/mL (non-adherent group); 11(14.9%), 200-499ng/mL (sub-therapeutic levels group); and 52(70.2%), ≥ 500ng/mL (adherent group). PR classified incorrectly all non-adherent/sub-therapeutic patients and 2/52(3.9%) adherent patients. Using MAT, the overall misclassification was 24/52(46.2%) in the adherent group, and were correctly identified 9/11(81.8%) patients in non-adherent and 7/11(63.6%) in sub-therapeutic groups. MAT sensitivity and specificity to identify non-adherent/sub-therapeutic patients were 72.7% and 53.9%, respectively. The three groups were comparable regarding glandular/extraglandular disease parameters (p > 0.05). The assessment of HCQ blood levels is a promising tool for evaluating drug adherence in SjD. This is particularly crucial as one-third of patients exhibited non-adherence/sub-therapeutic levels, and neither PR nor MAT reliably identified these patients.

Hydroxychloroquine Improves Low Complement Levels

OBJECTIVE

Having a low complement level is associated with clinical systemic lupus erythematosus (SLE) disease activity and future organ damage. We studied the association of hydroxychloroquine (HCQ) whole blood levels with changes in complement level.

METHODS

We performed two analyses on data prospectively collected from an SLE cohort. In the first (a "new starts on HCQ" analysis), we compared changes in complement level between those starting HCQ and those not starting it. The second analysis evaluated the association between HCQ whole blood levels and low complement level in all cohort visits using conditional logistic regression.

RESULTS

In the "new starts on HCQ" analysis, a higher percentage of patients starting HCQ (as reflected in HCQ blood levels >50) experienced a normalization of C4 level compared to those not starting HCQ (23 of 57 [40%] vs. 9 of 56 [13%]; P = 0.011), as well as a significantly greater increase in both C3 and C4 level (P = 0.048 and P = 0.017, respectively). In the "all cohort visits" analysis, there was a statistically significant higher probability of having normal C4 levels in visits with higher HCQ whole blood levels (odds ratio 1.8-2.6 depending on the levels). This relationship was most pronounced for whole blood HCQ levels of 200 ng/mL or more.

CONCLUSION

We observed significant improvement in complement levels when HCQ was started and among those with higher whole blood levels of HCQ, particularly with respect to C4. Modulating the pathogenic mechanisms that lead to complement consumption may be one mode by which HCQ prevents poor outcomes in SLE.

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease characterised by the presence of autoantibodies towards nuclear antigens, immune complex deposition, and chronic inflammation at classic target organs such as skin, joints, and kidneys. Despite substantial advances in the diagnosis and management of SLE, the burden of disease remains high. It is important to appreciate the typical presentations and the diagnostic process to facilitate early referral and diagnosis for patients. In most patients, constitutional, mucocutaneous, and musculoskeletal symptoms represent the earliest complaints; these symptoms can include fatigue, lupus-specific rash, mouth ulcers, alopecia, joint pain, and myalgia. In this Seminar we will discuss a diagnostic approach to symptoms in light of the latest classification criteria, which include a systematic evaluation of clinical manifestations (weighted within each domain) and autoantibody profiles (such as anti-double-stranded DNA, anti-Sm, hypocomplementaemia, or antiphospholipid antibodies). Non-pharmacotherapy management is tailored to the individual, with specific lifestyle interventions and patient education to improve quality of life and medication (such as hydroxychloroquine or immunosuppressant) adherence. In the last decade, there have been a few major breakthroughs in approved treatments for SLE and lupus nephritis, such as belimumab, anifrolumab, and voclosporin. However the disease course remains variable and mortality unacceptably high. Access to these expensive medications has also been restricted across different regions of the world. Nonetheless, understanding of treatment goals and strategies has improved. We recognise that the main goal of treatment is the achievement of remission or low disease activity. Comorbidities due to both disease activity and treatment adverse effects, especially infections, osteoporosis, and cardiovascular disease, necessitate vigilant prevention and management strategies. Tailoring treatment options to achieve remission, while balancing treatment-related comorbidities, are priority areas of SLE management.

Hydroxychloroquine an Antimalarial Drug, Exhibits Potent Antifungal Efficacy Against Candida albicans Through Multitargeting

Candida albicans is the primary etiological agent associated with candidiasis in humans. Unrestricted growth of C. albicans can progress to systemic infections in the worst situation. This study investigates the antifungal activity of Hydroxychloroquine (HCQ) and mode of action against C. albicans. HCQ inhibited the planktonic growth and yeast to hyphal form morphogenesis of C. albicans significantly at 0.5 mg/ml concentration. The minimum inhibitory concentrations (MIC50) of HCQ for C. albicans adhesion and biofilm formation on the polystyrene surface was at 2 mg/ml and 4 mg/ml respectively. Various methods, such as scanning electron microscopy, exploration of the ergosterol biosynthesis pathway, cell cycle analysis, and assessment of S oxygen species (ROS) generation, were employed to investigate HCQ exerting its antifungal effects. HCQ was observed to reduce ergosterol levels in the cell membranes of C. albicans in a dose-dependent manner. Furthermore, HCQ treatment caused a substantial arrest of the C. albicans cell cycle at the G0/G1 phase, which impeded normal cell growth. Gene expression analysis revealed upregulation of SOD2, SOD1, and CAT1 genes after HCQ treatment, while genes like HWP1, RAS1, TEC1, and CDC 35 were downregulated. The study also assessed the in vivo efficacy of HCQ in a mice model, revealing a reduction in the pathogenicity of C. albicans after HCQ treatment. These results indicate that HCQ holds for the development of novel antifungal therapies.

Interpreting hydroxychloroquine blood levels for medication non-adherence: a pharmacokinetic study

OBJECTIVE

Characterise the relationship between hydroxychloroquine (HCQ) blood levels and the number of missed doses, accounting for dosage, dose timing and the large variability in pharmacokinetics (PK) between patients.

METHODS

We externally validated a published PK model and then conducted dosing simulations. We developed a virtual population of 1000 patients for each dosage across a range of body weights and PK variability. Using the model, 10 Monte Carlo simulations for each patient were conducted to derive predicted whole blood concentrations every hour over 24 hours (240 000 HCQ levels at steady state). To determine the impact of missed doses on levels, we randomly deleted a fixed proportion of doses.

RESULTS

For patients receiving HCQ 400 mg daily, simulated random blood levels <200 ng/mL were exceedingly uncommon in fully adherent patients (<0.1%). In comparison, with 80% of doses missed, approximately 60% of concentrations were <200 ng/mL. However, this cut-off was highly insensitive and would miss many instances of severe non-adherence. Average levels quickly dropped to <200 ng/mL after 2-4 days of missed doses. Additionally, mean levels decreased by 29.9% between peak and trough measurements.

CONCLUSIONS

We propose an algorithm to optimally interpret HCQ blood levels and approximate the number of missed doses, incorporating the impact of dosage, dose timing and pharmacokinetic variability. No single cut-off has adequate combinations of both sensitivity and specificity, and cut-offs are dependent on the degree of targeted non-adherence. Future studies should measure trough concentrations to better identify target HCQ levels for non-adherence and efficacy.

Subtherapeutic hydroxychloroquine concentration is associated with increased disease activity and greater organ damage in lupus

OBJECTIVE

To investigate the effects of the serum HCQ concentration on clinical manifestations, disease activity and organ damage in a longitudinal cohort of SLE patients.

METHODS

The 338 SLE patients were assessed with respect to their demographic data, clinical and laboratory findings, Physician's Global Assessment (PGA), adjusted mean SLEDAI-2000 (AMS) and SLICC Damage Index (SDI) annually for 5 consecutive years. Patients were divided into two groups according to their serum HCQ concentration at baseline: subtherapeutic (<500 ng/ml) and therapeutic (≥500 ng/ml) groups. The impact of the HCQ concentration on the clinical outcomes was evaluated in a longitudinal analysis using a generalized estimating equation (GEE).

RESULTS

Of the 338 patients, 287 (84.9%) were in the subtherapeutic group at baseline. This group had a higher incidence of newly developed LN (P = 0.036) and had been prescribed higher mean and cumulative doses of prednisolone (P = 0.003 and P = 0.013, respectively) than the therapeutic group. In multivariable analyses based on GEE, the subtherapeutic group had a higher AMS score (β = 1.398, 95% CI 0.607, 2.189; P < 0.001), higher PGA score (β = 0.328, 95% CI 0.215, 0.441; P < 0.001) and higher SDI score (β = 0.366, 95% CI 0.061, 0.671; P = 0.019) across all 5 years.

CONCLUSION

The subtherapeutic HCQ concentration was associated with the development of new-onset LN, and had significant associations with disease activity and cumulative organ damage in SLE patients over time.

Balancing risks and benefits in the use of hydroxychloroquine and glucocorticoids in systemic lupus erythematosus

INTRODUCTION

Hydroxychloroquine (HCQ) and glucocorticoids (GCs) constitute the oldest and more used drugs in the treatment of systemic lupus erythematosus (SLE). Despite this long experience, both are still subject to a number of uncertainties, mainly regarding the dose.

AREAS COVERED

We review the main mechanisms of action, the clinical and toxic effects of HCQ and GCs and analyze the recommendations for the use of both in guidelines published since 2018. We offer a set of recommendations based on the pharmacology, mechanisms of action and clinical evidence.

EXPERT OPINION

HCQ is the backbone therapy for SLE, and a judicious use must be accomplished, using doses that allow a good control of lupus without compromising the safety of treatments very much prolonged over the time. Stable doses of 200 mg/day seem to accomplish both conditions. GCs should be used more judiciously, with methyl-prednisolone pulses as the main therapy for inducing rapid remission and doses ≤5-2.5 mg/day be never exceeded in long-term maintenance treatments.

Case series: raw, whole, plant-based nutrition protocol rapidly reverses symptoms in three women with systemic lupus erythematosus and Sjögren's syndrome

Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are chronic autoimmune diseases. Symptoms of SLE can vary widely but often include fatigue, pain, photosensitivity, and, in some cases, nephritis. SS is frequently characterized by extreme dry eye and mouth, resulting from damage to moisture-producing glands, and is often present in combination with SLE. While the health benefits of plant-based diets have been well-established with respect to weight and cardiometabolic outcomes, less research is available to support the role of diet in treatment and management of autoimmune disease. This case series presents three women with SLE and SS who adopted a nutrition protocol to reverse symptoms of autoimmune disease. The protocol emphasizes leafy greens, cruciferous vegetables, omega-3 polyunsaturated fatty acids, and water, and includes predominately raw foods. The three patients reported dramatic improvements in physical symptoms, with nearly all symptoms of SLE and SS resolving after 4 weeks or less of adhering to the protocol. All three patients have remained symptom-free, two of whom have remained symptom-free for 6+ years with no recent medication use. Patients and practitioners should be made aware of the promising possibility of food as medicine in the treatment of SLE and SS. Future research should explore whether dietary changes may be a potential treatment strategy for individuals suffering from severe symptoms and poor quality of life due to SLE and SS.

Reference Range of Hydroxychloroquine Blood Levels That Can Reduce Odds of Active Lupus and Prevent Flares

OBJECTIVE

Recent data show that lower hydroxychloroquine (HCQ) doses are associated with a two- to six-fold higher risk of lupus flares. Thus, establishing an effective reference range of HCQ blood levels with upper and lower bounds for efficacy may support individualizing HCQ dosing to prevent flares.

METHODS

HCQ levels in whole blood and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were measured during the baseline visit and again during a standard of care routine follow-up visit. Active cross-sectional lupus at baseline was defined as SLEDAI ≥6; a within subject flare was defined as a subsequent three-point increase in SLEDAI with clinical symptoms requiring therapy change. We examined associations between active lupus and HCQ blood levels at baseline and flares and HCQ levels during 6 to 12-month routine lupus follow-up visits using mixed regression analysis.

RESULTS

Among 158 baseline patient visits, 19% had active lupus. Odds of active lupus were 71% lower in patients with levels within a 750 to 1,200 ng/mL range (adjusted odds ratio 0.29, 95% confidence interval 0.08-0.96). Using convenience sampling strategy during a pandemic, we longitudinally followed 42 patients. Among those patients, 17% flared during their follow-up visit. Maintaining HCQ levels within 750 to 1,200 ng/mL reduced the odds of a flare by 26% over a nine-month median follow-up.

CONCLUSION

An effective reference range of HCQ blood levels, 750 to 1,200 ng/mL, was associated with 71% lower odds of active lupus, and maintaining levels within this range reduced odds of flares by 26%. These findings could guide clinicians to individualize HCQ doses to maintain HCQ levels within this range to maximize efficacy.

Therapeutic Drug Monitoring in Patients with Systemic Lupus Erythematosus: Utility and Gaps

Despite advances in the treatment of patients with systemic lupus erythematous (SLE), outcomes have remained suboptimal. Persistent disease activity, patient comorbidities and drug toxicities contribute to the accrual of progressive irreversible damage and high rates of morbidity and mortality. Currently, similar drug doses and regimens are promulgated in the treatment guidelines for all SLE patients, despite the vast differences in patient and environmental factors that affect the drugs' metabolism and blood concentrations. This causes a disconnect between drug dosing and drug blood concentrations, which can then result in unpredictability in drug toxicities and therapeutic effects. In this review, we discuss commonly used oral immunosuppressive medications in SLE, their pharmacogenomics, and factors affecting their metabolism and blood concentrations. Further, we highlight the role of therapeutic drug monitoring in SLE, which is the first accessible step to individualising therapy.

The presumable effects of hydroxychloroquine and its metabolites in the treatment of systemic lupus erythematosus

OBJECTIVE

Hydroxychloroquine (HCQ) is an essential drug in the treatment of systemic lupus erythematosus (SLE). This study aimed to detect the concentrations of HCQ and its metabolites from peripheral blood of SLE patients and to investigate the relationship between those concentrations and SLE disease activity.

METHODS

176 SLE patients treated with HCQ were enrolled in this study. The concentrations of HCQ and its metabolites in their peripheral blood were measured by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Patients' disease activity was evaluated with the systemic lupus erythematosus disease activity index (SLEDAI). The variables between different concentrations or treatments were statistically analyzed. Linear regression was employed to explore relationships between the concentrations of HCQ and its metabolites with the disease activity.

RESULTS

The SLEDAI was lower in patients with higher concentrations of HCQ, desethylhydroxychloroquine (DHCQ), and desethylchloroquine (DCQ) (P = 0.024, P = 0.018, and P = 0.003, respectively). There were no significant differences in SLEDAI and the concentrations of HCQ and its metabolites among groups with different treatments (P > 0.05). After adjusting age, gender, disease duration, HCQ dose adjusted to actual body weight, and glucocorticoid (GC) dose, the SLEDAI was negatively correlated with the concentrations of HCQ, DHCQ, DCQ and bisdesethylchloroquine (BDCQ) (P = 0.007, P = 0.011, P = 0.029, and P = 0.008, respectively). After grouping analysis, in patients treated with HCQ and GC, the SLEDAI was negatively correlated with concentrations of HCQ, DHCQ and BDCQ (P = 0.011, P = 0.035, and P = 0.036, respectively).

CONCLUSIONS

The concentrations of HCQ and metabolites were correlated with the SLE disease activity after adjusting possible confounding factors, indicating that HCQ and its metabolites might play certain immunoregulatory roles in SLE treatment. Moreover, GC might have a synergistic effect with HCQ. It is helpful in clinical management and follow-up to monitor the concentrations of HCQ and its metabolites in SLE patients.

EULAR recommendations for the management of systemic lupus erythematosus: 2023 update

OBJECTIVES

To update the EULAR recommendations for the management of systemic lupus erythematosus (SLE) based on emerging new evidence.

METHODS

An international Task Force formed the questions for the systematic literature reviews (January 2018-December 2022), followed by formulation and finalisation of the statements after a series of meetings. A predefined voting process was applied to each overarching principle and recommendation. Levels of evidence and strengths of recommendation were assigned, and participants finally provided their level of agreement with each item.

RESULTS

The Task Force agreed on 5 overarching principles and 13 recommendations, concerning the use of hydroxychloroquine (HCQ), glucocorticoids (GC), immunosuppressive drugs (ISDs) (including methotrexate, mycophenolate, azathioprine, cyclophosphamide (CYC)), calcineurin inhibitors (CNIs, cyclosporine, tacrolimus, voclosporin) and biologics (belimumab, anifrolumab, rituximab). Advice is also provided on treatment strategies and targets of therapy, assessment of response, combination and sequential therapies, and tapering of therapy. HCQ is recommended for all patients with lupus at a target dose 5 mg/kg real body weight/day, considering the individual's risk for flares and retinal toxicity. GC are used as 'bridging therapy' during periods of disease activity; for maintenance treatment, they should be minimised to equal or less than 5 mg/day (prednisone equivalent) and, when possible, withdrawn. Prompt initiation of ISDs (methotrexate, azathioprine, mycophenolate) and/or biological agents (anifrolumab, belimumab) should be considered to control the disease and facilitate GC tapering/discontinuation. CYC and rituximab should be considered in organ-threatening and refractory disease, respectively. For active lupus nephritis, GC, mycophenolate or low-dose intravenous CYC are recommended as anchor drugs, and add-on therapy with belimumab or CNIs (voclosporin or tacrolimus) should be considered. Updated specific recommendations are also provided for cutaneous, neuropsychiatric and haematological disease, SLE-associated antiphospholipid syndrome, kidney protection, as well as preventative measures for infections, osteoporosis, cardiovascular disease.

CONCLUSION

The updated recommendations provide consensus guidance on the management of SLE, combining evidence and expert opinion.

Lupus-Induced Accelerated Heart Failure in a Young African American Female: Cardiovascular and Systemic Complications of Noncompliance to Maintenance Therapy and the Social Determinants of Cardiovascular Disease

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disorder characterized by dysregulations of the immune system with intermittent and remitting symptoms. SLE affects multiple organs and systems, including the cardiovascular system. This condition is associated with an increased risk of cardiovascular disease, particularly in younger patients. Our case report describes a patient who rapidly developed structural, functional, and electrophysiological cardiac abnormalities due to lupus-induced cardiomyopathy. The accelerating cardiac events were the result of medication noncompliance. Myocarditis and other potentially fatal cardiac complications associated with SLE have been the subject of numerous studies. This presentation appears to be the first to emphasize the rarity of lupus-induced cardiomyopathy, the importance of treatment adherence, the adverse cardiac effects of targeted therapeutic interventions, and the influence of social determinants of cardiovascular health on a patient's prognosis.

Whole blood hydroxychloroquine: Does genetic polymorphism of cytochrome P450 enzymes have a role?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a wide range of clinical manifestations and multifactorial etiologies ranging from environmental to genetic. SLE is associated with dysregulated immunological reactions, with increased immune complex formation leading to end-organ damages such as lupus nephritis, cutaneous lupus, and musculoskeletal disorders. Lupus treatment aims to reduce disease activity, prevent organ damage, and improve long-term patient survival and quality of life. Antimalarial, hydroxychloroquine (HCQ) is used as a first-line systemic treatment for lupus. It has shown profound efficacy in lupus and its associated conditions. However, wide variation in terms of clinical response to this drug has been observed among this group of patients. This variability has limited the potential of HCQ to achieve absolute clinical benefits. Several factors, including genetic polymorphisms of cytochrome P450 enzymes, have been stipulated as key entities leading to this inter-individual variation. Thus, there is a need for more studies to understand the role of genetic polymorphisms in CYP450 enzymes in the clinical response to HCQ. Focusing on the role of genetic polymorphism on whole blood HCQ in lupus disorder, this review aims to highlight up-to-date pathophysiology of SLE, the mechanism of action of HCQ, and finally the role of genetic polymorphism of CYP450 enzymes on whole blood HCQ level as well as clinical response in lupus.

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.

Hydroxychloroquine in nephrology: current status and future directions

Hydroxychloroquine is one of the oldest disease-modifying anti-rheumatic drugs in clinical use. The drug interferes with lysosomal activity and antigen presentation, inhibits autophagy, and decreases transcription of pro-inflammatory cytokines. Owing to its immunomodulatory, anti-inflammatory, anti-thrombotic effect, hydroxychloroquine has been an integral part of therapy for systemic lupus erythematosus and lupus nephritis for several decades. The therapeutic versatility of hydroxychloroquine has led to repurposing it for other clinical conditions, with recent studies showing reduction in proteinuria in IgA nephropathy. Research is also underway to investigate the efficacy of hydroxychloroquine in primary membranous nephropathy, Alport's syndrome, systemic vasculitis, anti-GBM disease, acute kidney injury and for cardiovascular risk reduction in chronic kidney disease. Hydroxychloroquine is well-tolerated, inexpensive, and widely available and therefore, should its indications expand in the future, it would certainly be welcomed. However, clinicians should be aware of the risk of irreversible and progressive retinal toxicity and rarely, cardiomyopathy. Monitoring hydroxychloroquine levels in blood appears to be a promising tool to evaluate compliance, individualize the dose and reduce the risk of retinal toxicity, although this is not yet standard clinical practice. In this review, we discuss the existing knowledge regarding the mechanism of action of hydroxychloroquine, its utility in lupus nephritis and other kidney diseases, the main adverse effects and the evidence gaps that need to be addressed in future research. Created with Biorender.com. HCQ, hydroxychloroquine; GBM, glomerular basement membrane; mDC, myeloid dendritic cell; MHC, major histocompatibility complex; TLR, toll-like receptor.

Adherence patterns to medications and their association with subsequent hospitalization in adult Egyptian patients with systemic lupus erythematosus

OBJECTIVE

The aim of this study was to evaluate the adherence pattern to medications and the influence of non-adherence on hospitalization rate among Egyptian patients who were diagnosed with systemic lupus erythematosus (SLE).

METHODS

This cross-sectional interview-based study was conducted in an Egyptian rheumatology outpatient clinic. Individuals with SLE who were prescribed oral medications were included in the study. The 19-item Compliance Questionnaire of Rheumatology (CQR) was employed to evaluate drug adherence. Patients were classified as non-adherent and adherent group based on their CQR score Sociodemographic variables, clinical and therapeutic data, and the frequency of outpatient visits and hospitalization were collected and compared between the two groups.

RESULTS

In total, there were 161 SLE patients who participated in the study with mean age 30.70 ± 9.62 years, 129 females and 32 males (F:M 5.4:1). Of them, 93 patients were assigned to the non-adherent group, whereas 68 patients were assigned to the adherent group. There was a statistically significant difference in terms of marital status (p = 0.009), employment (p = 0.032), and the frequency of physical activity (p = 0.045) between the two groups. The adherents had a higher rate of administration of antimalarials (88.2% vs 75.3%, p = 0.039). The frequency of recurrent fever was lower in adherents (23.5% vs 38.7%, p = 0.042), lymphadenopathy (11.8% vs 31.2%, p = 0.004), recurring oral ulcers (25% vs 50.5%, p = 0.001), and substantial hair loss (87.1% vs 98.5%, p = 0.009) in comparison to non-adherents. The number of yearly outpatient visits was considerably greater in adherents (p = 0.007), while the number of prior hospitalizations was higher in non-adherents (p < 0.001). Non-adherents believed that taking medicines disrupt patients' daily routine (p < 0.001) and were more afraid of the occurrence of an adverse drug reaction (p < 0.001).

CONCLUSIONS

Egyptian SLE patients have an alarmingly high percentage of medication non-adherence. There is a strong association between medication non-adherence and frequency of hospitalization and cumulative clinical manifestations.

Pharmacokinetics of hydroxychloroquine in Japanese systemic lupus erythematosus patients with renal impairment

OBJECTIVES

Reduction of the hydroxychloroquine (HCQ) dosage is recommended in systemic lupus erythematosus (SLE) patients with renal impairment, but a pharmacokinetics (PK) study of patients with renal impairment has not yet been performed.

METHODS

We investigated the PK of both single and multiple doses of HCQ and its metabolites in SLE patients with renal impairment who newly started HCQ at a daily dose of 300 mg based on an ideal body weight dosage of 6.5 mg/kg. Population PK analysis was performed using a non-linear mixed-effects model.

RESULTS

In total, 219 samples from 21 patients were analysed. The PK of HCQ in blood after single and multiple oral administrations followed the two-compartment model. At steady state, the concentration ratio of HCQ to each metabolite was HCQ:desethylhydroxychloroquine:desethylchloroquine:bisdesethylchloroquine = 1:0.28:0.1:0.06. The HCQ concentration correlated positively with that of each metabolite. The estimated values (relative standard error) of the population PK parameters were the total clearance at 110 l/h (31%) and a central volume of distribution of 398 l (19%). Co-administration of prednisolone and age, but not renal impairment, were factors affecting the total clearance of HCQ.

CONCLUSIONS

From the PK perspective, a dosage reduction is unnecessary in SLE patients with impaired renal function.

Cost-related prescription non-adherence and patient-reported outcomes in systemic lupus erythematosus: The Michigan Lupus Epidemiology & Surveillance program

OBJECTIVES

Medication access and adherence play key roles in determining patient outcomes. We investigated whether cost-related non-adherence (CRNA) to prescription medications was associated with worse patient-reported outcomes in a population-based systemic lupus erythematosus (SLE) cohort.

METHODS

Sociodemographic and prescription data were collected by structured interviews in 2014-2015 from patients meeting SLE criteria in the established Michigan Lupus Epidemiology & Surveillance (MILES) Cohort. We examined the associations between CRNA and potential confounders such as sociodemographics and health insurance coverage, and outcome measures of SLE activity and damage using multivariable linear regression.

RESULTS

462 SLE participants completed the study visit: 430 (93.1%) female, 208 (45%) Black, and mean age 53.3 years. 100 (21.6%) participants with SLE reported CRNA in the preceding 12 months. After adjusting for covariates, CRNA was associated with both higher levels of current SLE disease activity [SLAQ: β coeff 2.7 (95% CI 1.3, 4.1), p < 0.001] and damage [LDIQ β coeff 1.4 (95% CI 0.5, 2.4), p = 0.003]. Race, health insurance status, and fulfilling Fibromyalgia (FM) Survey Criteria were independently associated with both higher (worse) SLAQ and LDIQ scores; female sex was further associated with higher SLAQ scores.

CONCLUSION

Patients with SLE who reported CRNA in the previous 12 months had significantly worse self-reported current disease activity and damage scores compared to those not reporting CRNA. Raising awareness and addressing barriers or concerns related to financial implications and accessibility issues in care plans may help to improve these outcomes.

Systemic lupus erythematosus: An approach to pharmacologic interventions

ABSTRACT

Drug therapy for patients with systemic lupus erythematosus (SLE) aims to decrease symptom severity. Pharmacologic interventions are divided into four categories: antimalarials, glucocorticoids (GCs), immunosuppressants (ISs), and biological agents. Hydroxychloroquine, the most commonly used antimalarial treatment for this disease, is a mainstay in treating all patients with SLE. The multitude of adverse reactions of GCs has led clinicians to minimize their dosages or discontinue them whenever possible. To speed up the discontinuation or minimization of GCs, ISs are used for their steroid-sparing properties. Furthermore, certain ISs such as cyclophosphamide are recommended as maintenance agents to prevent flares and reduce the reoccurrence and severity of the disease state. Biological agents are recommended when other treatment options have failed due to intolerance or inefficacy. This article presents pharmacologic approaches for managing SLE in patients based on clinical practice guidelines and data from randomized controlled trials.

Major Infections of Newly Diagnosed Childhood-Onset Systemic Lupus Erythematosus

Objective

To evaluate the risk of major infections in children with newly diagnosed childhood-onset systemic lupus erythematosus (cSLE).

Methods

Predictors of major infections were identified by the multivariable logistic regression. Major infection free was defined as no major infection events within 6 months after the diagnosis of cSLE. The Kaplan-Meier survival plot was performed. A prediction model for major infection events was established and examined by receiver operating characteristic (ROC) curve analysis.

Results

A total of 98 eligible patients were recorded in the medical charts. Sixty-three documented events of major infections were found in 60 (61.2%) cSLE patients. Furthermore, 90.5% (57/63) of infection events occurred within the first 6 months after the diagnosis of cSLE. The high SLEDAI (SLEDAI >10), lupus nephritis and lymphocyte count <0.8×109/L were predictors for major infections. The CALL score (Children with high disease activity [SLEDAI >10], lymphopenia, and LN) was defined by the number of predictors. Patients were then categorized into two groups: low-risk (score 0-1) and high-risk (score 2-3). Patients in the high-risk group had higher rates of the major infection occurrence than those in the low-risk group during the 6 months after the diagnosis of the cSLE (P<0.001) (HR:14.10, 95% CI 8.43 to 23.59). The ROC curve analysis indicated that the CALL score was effective both in the whole cSLE cohort [area under the curve (AUC) = 0.89, 95% CI: 0.81-0.97] and in the subgroup of lung infections (n = 35) (AUC = 0.79, 95% CI: 0.57-0.99).

Conclusion

High disease activity, LN and lymphopenia were predictors for major infections in newly diagnosed cSLE patients. Specific predictors help identify the cSLE patients with the high risk of major infections. The CALL score could be a useful tool to stratify cSLE patients in practice.

Hydroxychloroquine daily dose, hydroxychloroquine blood levels and the risk of flares in patients with systemic lupus erythematosus

BACKGROUND

Recent guidelines for SLE recommend using a hydroxychloroquine (HCQ) dose less than 5.0 mg/kg/day to reduce the risk of retinopathy. To determine if this dose reduction would have an impact on the clinical course of SLE, we compared flare incidence in a cohort of patients with SLE treated with two different oral HCQ dosages (≤5 mg/kg/day or >5 mg/kg/day). As a secondary analysis, we compared HCQ blood levels between the two different oral dosages, and evaluated the frequency of non-adherence in patients with SLE treated with HCQ.

METHODS

We identified a cohort of patients with SLE taking HCQ for at least 6 months and followed for 24 months. At study entry and 6 months later, a blood venous sample was taken to measure HCQ blood levels by liquid chromatography. Incidence of new SLE flares after recruitment was put in relation to daily HCQ dose and mean HCQ blood levels. Cox regression analysis served to identify factors associated with SLE flares.

RESULTS

83 patients were enrolled. We observed 11 (16%) flares that developed in mean 14.8 months of follow-up. The difference in terms of flare rate and mean HCQ blood levels between the two oral dosages was not statistically significant. There was a trend (p=0.08) for high HCQ dose being associated with a lower flare rate. At Cox analysis, higher HCQ blood levels and older age at baseline were protective against flare occurrence, while concomitant immunosuppressant therapy showed significant positive association. HCQ blood levels did not correlate with prescribed HCQ dose.

CONCLUSION

Patients with low oral HCQ dosage tend to have more flares, although the difference was not statistically significant. Higher HCQ blood levels were protective against flare occurrence. The risks and benefits must be balanced in choosing HCQ dose.

Extrapolation of Adult Efficacy Data to Pediatric Systemic Lupus Erythematosus: Evaluating Similarities in Exposure-Response

To streamline drug development, the United States Food and Drug Administration (FDA) can consider the extrapolation of adult efficacy data to children when the disease and drug effects are sufficiently similar. This study explored whether the relationship between drug exposure and response for selected drugs in systemic lupus erythematosus (SLE) was sufficiently similar to support a consideration of the extrapolation of adult efficacy data to children of ≥5 years of age. An exposure-response analysis of drugs used to treat SLE was conducted using published exposure versus response and efficacy versus time data. Statistical analyses included noncompartmental analysis of a drug's area under the effect curve and direct Imax pharmacodynamic (PD) modeling. Six drugs were included: azathioprine, belimumab, cyclophosphamide, hydroxychloroquine, mycophenolate/mycophenolic acid, and rituximab. For belimumab, the net change in responders at week 52 (the primary end point) was nearly identical between 1 adult trial and the pediatric trial. For mycophenolate, PD modeling suggested no significant differences in exposure and SLE disease activity between adults and children. For azathioprine, cyclophosphamide, hydroxychloroquine, and rituximab the data were not sufficient to quantitatively characterize the exposure-response relationship, but the clinical or pharmacologic response between children and adults was similar overall. Adult SLE data should be leveraged to guide pediatric drug development programs and identify areas with residual uncertainty regarding the effectiveness or safety of a drug in children. The degree to which efficacy extrapolation can reduce clinical trial requirements in pediatric SLE should be individualized for each new drug product, depending in part on the mechanism of action of the drug and the similarity of disease manifestations in children and adults.

Adherence to medication by adolescents and young adults with childhood-onset systemic lupus erythematosus

Background: Approximately 20% of all cases systemic lupus erythematous (SLE) are juvenile onset. Children and adolescents with SLE usually present with more severe illness and have a higher mortality rate compared to adults with SLE. Adherence to medications in children and adolescents has a major impact on disease control as well as short- and long-term outcomes. Improved understanding of adherence rates, risk factors for non-adherence, and barriers to adherence are essential in order to increase patient adherence with medication regimens. The aim of our study was to evaluate adherence to medications among children and young adults with pediatric-onset SLE and identify barriers for non-adherence by utilizing several adherence evaluation methods.

Methods: Adherence to medications of patients aged 12–25, with childhood-onset SLE was assessed as follows: (1). The brief medication questionnaire (BMQ): self-report tool for screening adherence and barriers to adherence. (2). Mycophenolic acid (MPA) serum level. (3). Medication possession ratio (MPR): data assessing 90-day refills and dispense prior to patient’s enrollment was collected.

Results: Of the 38 patients who were enrolled in the study, 65% were found to be non-adherent according to at least 1 measurement method. Forty-four percent of patients were found to be non-adherent based on the self-reported questionnaire (BMQ). Of those taking MMF, 33% had an MPA level < 1 mcg/mL and were defined as non-adherent. Seventeen percent of patients were found to be non-adherent according to pharmacy refills rate. Forty-six percent of patients stated that their medications caused side effects, 33% of patients indicated difficulty remembering to take the medications, and 25% reported difficulty paying for medications. The disease activity index (SLEDAI) score of the “adherent group” at diagnosis was significantly lower compared to the “non-adherent” group. Patients with private insurance had more access barriers to obtaining medications compared to patients with public insurance.

Conclusion: Non-adherence to medications is highly prevalent among cSLE patients. Higher SLEDAI score is a risk factor for non-adherence. Adherence to medications should be routinely evaluated among adolescence and young adults with cSLE and barriers to adherence need to be addressed to decrease morbidity and improve patient outcomes.

Advances in the clinical use of hydroxychloroquine levels

PURPOSE OF REVIEW

This review summarizes the recent literature exploring hydroxychloroquine levels and their relationship with disease activity and risk of toxicity.

RECENT FINDINGS

There is no clear correlation between weight-based dosing of hydroxychloroquine and the resulting blood levels of the medication. Recent studies have shown that increased hydroxychloroquine levels are associated with lower lupus disease activity and likely also increased risk of medication toxicity.

SUMMARY

Mounting evidence supports use of hydroxychloroquine levels in clinical practice to document adherence and ensure safety.

Drug monitoring in systemic lupus erythematosus

Therapeutic drug monitoring (TDM) is not yet accepted by systemic lupus erythematosus (SLE) treatment guidelines. Studies in SLE, however, have proven benefit in three areas: identification of non-adherence or poor adherence; targets for clinical benefit; and ranges of toxicity. This review covers the data on three medications commonly used for SLE, drawing on studies from both the SLE and non-SLE literature.

Influence of hydroxychloroquine blood levels on adhesion molecules associated with endothelial dysfunction in patients with systemic lupus erythematosus

Background

Patients with SLE have an endothelial dysfunction (ED), which is considered the earliest marker of cardiovascular (CV) disease. Endothelial cell activation induced by proinflammatory cytokines is defined by the endothelial expression of cell-surface adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin. The aim of this study was to investigate whether serum endothelial adhesion molecule levels are influenced by blood hydroxychloroquine (HCQ) levels in SLE.

Methods

Consecutive patients with SLE taking a stable dose of HCQ were investigated. At study entry and 6 months later HCQ blood levels were quantified by tandem mass spectrometry. Serum levels of P-selectin, E-selectin, ICAM-1 and VCAM-1 were also measured using a Luminex 200 instrument. Comparison of endothelial soluble adhesion molecules in groups with different HCQ blood levels was performed by t-test.

Results

83 patients with SLE were enrolled. Correlation were demonstrated between mean blood HCQ concentrations and endothelial soluble adhesion molecules (E-selectin, ICAM-1 and VCAM-1). Moreover, serum levels of ICAM-1 and VCAM-1 were significantly lower in the patients with SLE with HCQ blood levels >500 ng/mL (83.67±52.8 ng/mL vs 158.81±125.1 ng/mL and 8.9±2.2 ng/mL vs 10.4±2.3 ng/mL). Serum levels of E-selectin were nearly significantly lower in the patients with SLE with HCQ blood levels >500 ng/mL (64.7±30.2 ng/mL vs 71.6±42.2 ng/mL, p=0.06). No significant difference in concentration of P-selectin was detected.

Conclusions

In the present study, there was a trend towards higher adhesion molecules levels with lower HCQ blood levels in patients with SLE. Further longitudinal studies will determine whether changes in endothelial biomarkers reflect decreased clinical CV events.

Flares after hydroxychloroquine reduction or discontinuation: results from the Systemic Lupus International Collaborating Clinics (SLICC) inception cohort

OBJECTIVES

To evaluate systemic lupus erythematosus (SLE) flares following hydroxychloroquine (HCQ) reduction or discontinuation versus HCQ maintenance.

METHODS

We analysed prospective data from the Systemic Lupus International Collaborating Clinics (SLICC) cohort, enrolled from 33 sites within 15 months of SLE diagnosis and followed annually (1999-2019). We evaluated person-time contributed while on the initial HCQ dose ('maintenance'), comparing this with person-time contributed after a first dose reduction, and after a first HCQ discontinuation. We estimated time to first flare, defined as either subsequent need for therapy augmentation, increase of ≥4 points in the SLE Disease Activity Index-2000, or hospitalisation for SLE. We estimated adjusted HRs (aHRs) with 95% CIs associated with reducing/discontinuing HCQ (vs maintenance). We also conducted separate multivariable hazard regressions in each HCQ subcohort to identify factors associated with flare.

RESULTS

We studied 1460 (90% female) patients initiating HCQ. aHRs for first SLE flare were 1.20 (95% CI 1.04 to 1.38) and 1.56 (95% CI 1.31 to 1.86) for the HCQ reduction and discontinuation groups, respectively, versus HCQ maintenance. Patients with low educational level were at particular risk of flaring after HCQ discontinuation (aHR 1.43, 95% CI 1.09 to 1.87). Prednisone use at time-zero was associated with over 1.5-fold increase in flare risk in all HCQ subcohorts.

CONCLUSIONS

SLE flare risk was higher after HCQ taper/discontinuation versus HCQ maintenance. Decisions to maintain, reduce or stop HCQ may affect specific subgroups differently, including those on prednisone and/or with low education. Further study of special groups (eg, seniors) may be helpful.

Hydroxychloroquine in systemic lupus erythematosus: overview of current knowledge

The antimalarial hydroxychloroquine (HCQ) has demonstrated several crucial properties for the treatment of systemic lupus erythematosus (SLE). Herein, we reviewed the main HCQ pharmacologic features, detailed its mechanism of action, and summarized the existing guidelines and recommendations for HCQ use in rheumatology with a systematic literature search for the randomized controlled trials focused on lupus. HCQ has been shown to decrease SLE activity, especially in mild and moderate disease, to prevent disease flare and to lower the long-term glucocorticoid need. The numerous benefits of HCQ are extended to pregnancy and breastfeeding period. Based on cohort studies, antithrombotic and metabolic HCQ’s effects were shown, including lipid-lowering properties, which might contribute to an improved cardiovascular risk. Moreover, early HCQ use in antinuclear antibodies positive individuals might delay the progression to SLE. Finally, HCQ has a significant favorable impact on long-term outcomes such as damage accrual and mortality in SLE. Based on these multiple benefits, HCQ is now the mainstay long-term treatment in SLE, recommended by current guidelines in all patients unless contraindications or side effects. The daily dose associated with the best compromise between efficacy and safety is matter of debate. The concern regarding retinal toxicity rather than proper efficacy data is the one that dictated the daily dosage of ⩽5 mg/kg/day actual body weight currently agreed upon.

Increased IL-23R+ Th Cells Population Exhibits Higher SLEDAI-2K Scores in Systemic Lupus Erythematosus Patients

The IL-23/IL-17 axis plays causative roles in the development and progression of systemic lupus erythematosus (SLE). However, it remains unclear if the IL-17RA⁺ and IL-23R⁺ T helper (Th) cells populations are associated with the serum IL-17 and IL-23 levels, or with the immunological parameters and disease activities in SLE patients. Herein, we examined the proportion of IL-17RA⁺ and IL-23R⁺ Th cells and serum levels of IL-17 and IL-23 in established SLE patients (n = 50) compared with healthy controls (n = 50). The associations of these interleukins and their receptors with immunological parameters [anti-nuclear antibody (ANA), anti-dsDNA antibody, and C-reactive protein (CRP)] and SLE disease activity (SLEDAI-2K scores) in SLE patients were assessed. CD3⁺CD4⁺ Th cells of SLE patients demonstrated significantly elevated IL-17RA⁺ (p = 1.12 x 10^-4) or IL-23R⁺ (p = 1.98 x 10^-29) populations compared with the healthy controls. Serum IL-17 levels were significantly lower in SLE patients compared with the healthy controls (p = 8.32 x 10^-5), while no significant difference was observed for the IL-23 serum levels between both groups. IL-23R⁺ Th cells population was significantly associated with higher SLEDAI-2K scores (p = 0.017). In multivariate analysis, the proportion of IL-23R⁺ Th cells remained significantly associated with higher SLEDAI-2K scores independent of prednisolone intake (p = 0.027). No associations were observed between the interleukin parameters (i.e., IL-17, IL-23, IL-17RA⁺ Th cells, and IL-23R⁺ Th cells) with ANA, anti-dsDNA, and CRP status, suggesting that the IL-17/IL-23 axis acts independently of these immunological parameters. In conclusion, our results support that therapeutic inhibition of the IL-23/IL-17 axis receptors on Th cells, particularly IL-23R, is potentially relevant in SLE patients.

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.