Understanding the dynamics of hydroxychloroquine blood levels in lupus nephritis

Deciphering the clinical significance of longitudinal antiphospholipid antibody titers

In antiphospholipid syndrome (APS), the risk of clinical manifestations increases with higher titers of antiphospholipid antibodies (aPL). Despite the adoption of aPL titers in the classification approach to aPL-positive subjects, the value of longitudinal monitoring of those titers in the follow-up is still debated, being well studied only in systemic lupus erythematosus (SLE). The literature suggests that the rate of aPL positivity decreases during follow-up in primary APS, estimating that seroconversion occurs in between 8.9 and 59% of patients over time. Negativisation of aPL occurs more frequently in asymptomatic aPL carriers than in patients with full-blown APS as well as in subjects with single aPL positivity or low aPL antibody titers. In patients with SLE, aPL typically behave fluctuating from positive to negative and back again in the course of follow-up. The few studies assessing the longitudinal course of aPL positivity with no associated systemic connective tissue disease reported a progressive decrement of aPL titers over time, in particular of antibodies against β2 glycoprotein I (antiβ2GPI) and cardiolipin (aCL) of IgG isotype. After a thrombotic event, aPL titers tend to decrease, as emerged from cohorts of both primary and secondary APS. Hydroxychloroquine has been identified as the most effective pharmacological agent to reduce aPL titers, with multiple studies demonstrating a parallel reduction in thrombosis rate. This review addresses available evidence on the significance of aPL titer fluctuation from clinical, therapeutic and pathogenic perspectives.

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.

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.

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.

How toxic is an old friend? A review of the safety of hydroxychloroquine in clinical practice

Hydroxychloroquine (HCQ) and its close relative chloroquine (CQ) were initially used as antimalarial agents but are now widely prescribed in rheumatology, dermatology and immunology for the management of autoimmune diseases. HCQ is considered to have a better long-term safety profile than CQ and is therefore more commonly used. HCQ has a key role in the treatment of connective tissue diseases including systemic lupus erythematosus (SLE), where it provides beneficial immunomodulation without clinically significant immunosuppression. HCQ can also assist in managing inflammatory arthritis, including rheumatoid arthritis (RA). Debate around toxicity of HCQ in COVID-19 has challenged those who regularly prescribe HCQ to discuss its potential toxicities. Accordingly, we have reviewed the adverse effect profile of HCQ to provide guidance about this therapeutic agent in clinical practice.

Autophagy in lupus nephritis: A delicate balance between regulation and disease

Autophagy is a highly regulated process wherein an unwanted cargo of damaged and dysfunctional cytoplasmic components is removed, delivered to lysosomes for degradation, and released back into the cytoplasm. Accumulating evidence suggests an important role of autophagy in the pathophysiology of systemic lupus erythematosus, with profound effects on both innate and adaptive immunity. Autophagy downregulation results in the inhibition of antigen presenting cells, reduced release of neutrophil extracellular traps and decreased activation of effector T and B cells, leading to reduced autoantibody production and attenuated type 1 interferon signaling. However, defective autophagy may accelerate the production of other inflammatory cytokines and reduce the clearance of apoptotic cells, promoting lupus development. In addition, autophagy dysfunction can concur to the pathogenesis of kidney injury in lupus nephritis. Autophagy is a pivotal mechanism to maintain podocyte integrity and endothelial cell survival. Several animal models have demonstrated that defective autophagy leads to podocyte injury and can promote an endothelial pro-inflammatory and atherogenic phenotype. Moreover, autophagy is a key homeostatic regulator of renal tubular cells, and recent evidence has pointed out that chronic autophagy deficiency may accelerate kidney fibrosis. Targeting autophagy may theoretically improve lupus nephritis outcomes, but novel, non-invasive methods to measure and monitor autophagic activity are urgently needed. In addition, the extent and timing of autophagy inhibition still require additional studies before clinical translation may be attempted. In this review, we will also discuss the effect of several clinically available drugs that can regulate the autophagic flux and their effect in lupus nephritis patients.

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.

Hydroxychloroquine blood levels predicts flare in childhood-onset lupus nephritis

OBJECTIVE

Low hydroxychloroquine (HCQ) blood levels are predictors of flare in adult lupus. Childhood-onset systemic lupus erythematosus (cSLE) has high morbidity with renal involvement in up to 80% of cases. The aim of this study is to determine the HCQ cut-off levels which predicts flare in childhood-onset lupus nephritis (LN).

METHODS

Sixty LN patients on HCQ use for at least 6-months were prospectively evaluated at baseline (BL) and about 6-months later for cSLE flare and HCQ blood levels (ng/mL) measured by liquid chromatography-tandem mass spectrometry.

RESULTS

There were 19 patients (32%) with flare, during the study with median SLEDAI increase of 4 (0-8). Median (IQR) BL HCQ levels of the flare group were lower compared to stable patients [557.5 (68.6-980.3) vs. 1061.9 (534.8-1590.0 ng/mL); p=0.012]. ROC curve analysis demonstrated that HCQ levels≤1075 ng/mL were associated with a 5.08 (95%CI 1.28-20.13; p=0.021) times increased risk of flare. Six-month HCQ levels revealed that most patients 24/54 (44%) had persistently low levels (≤1075) during follow-up. Among those, 11/24 (46%) had flare. Multiple logistic regression analysis including prednisone use, baseline SLEDAI-2K, adherence based on pharmacy refill and BL HCQ blood levels as possible predictors of flare revealed that only HCQ blood level was independently associated with flare (OR 0.999, 95%CI 0.998-1.0, p=0.013).

CONCLUSIONS

We demonstrated that HCQ blood cut-off level under 1075 ng/mL predicts flare in childhood-onset LN patients under prescribed HCQ dose of 4.0-5.5 mg/kg/day. We further observed that most of these patients have compliance issues reinforcing the need for a close surveillance particularly in those with levels below the defined cut-off.

One-year prospective nerve conduction study of thalidomide neuropathy in lupus erythematosus: Incidence, coasting effect and drug plasma levels

BACKGROUND

Few prospective studies in cutaneous and systemic lupus erythematosus (CLE/SLE) assessed thalidomide-induced peripheral neuropathy (TiPN) incidence/reversibility, and most have not excluded confounding causes neither monitored thalidomide plasma levels.

OBJECTIVES

To evaluate TiPN incidence/reversibility, coasting effect and its association with thalidomide plasma levels in CLE/SLE.

METHODS

One-year prospective study of thalidomide in 20 CLE/SLE patients without pregnancy potential, with normal nerve conduction study (NCS), and excluded other PN causes. Thalidomide levels were determined by high-performance liquid chromatography/tandem mass spectrometry.

RESULTS

Twelve patients (60%) developed TiPN: 33.3% were symptomatic and 66.6% asymptomatic. Half of this latter group developed coasting effect (TiPN symptoms 1-3 months after drug withdrawal). The main predictive factors for TiPN were treatment duration ≥6 months (p = 0.025) and cumulative dose (p = 0.023). No difference in plasma thalidomide levels between patients with/without TiPN was observed (p = 0.464). After drug withdrawal, 75% symptomatic TiPN patients improved their symptoms. Seven TiPN patients underwent an additional NCS after drug withdrawal: 42.8% worsened NCS, 14.2% was stable, and 42.8% had improved NCS.

CONCLUSION

Our data provides novel evidence of coasting effect in half of asymptomatic patients with TiPN. The irreversible nature of this lesion in 25% of TiPN patients reinforces the relevance of early NCS monitoring, and suggests thalidomide use solely as a bridge for other effective therapy for refractory cutaneous lupus patients.

Hydroxychloroquine blood levels in stable lupus nephritis under low dose (2-3 mg/kg/day): 12-month prospective randomized controlled trial

INTRODUCTION

The American Academy of Ophthalmology (2016-AAO) recommended hydroxychloroquine (HCQ) dose not to exceed 5 mg/kg/day (real body weight). Recently, it was reported that prescribed 2016-AAO dose provided adequate HCQ levels for most lupus nephritis (LN) patients, with low flare risk. However, the minimum HCQ dose required to keep adequate levels is unknown.

OBJECTIVES

To evaluate if a further reduction in 2016-AAO dose (2-3 mg/kg/day) would sustain 12-month HCQ levels in LN patients with stable inactive disease.

METHODS

Seventy-three stable LN patients under prescribed full HCQ 2016-AAO dose for ≥6 months and adequate baseline HCQ levels (≥613.5 ng/mL) were divided in two groups: reduced 2016-AAO dose (2-3 mg/kg/day), n = 32, and full 2016-AAO dose (5 mg/kg/day), n = 41. All patients were assessed at baseline, 3, 6, and 12 months. HCQ levels were measured by liquid chromatography-tandem mass spectrometry. Flare was defined as augment ≥ 3 in SLE Disease Activity Index-2000 and/or change in treatment. Rigorous clinical/laboratorial surveillance was performed.

RESULTS

Prospective evaluation revealed for reduced 2016-AAO dose group a decrease of HCQ levels from baseline to 3 months (1,404.9 ± 492.0 vs. 731.6 ± 385.0 ng/mL, p < 0.01), and sustained levels at 6 months (p = 0.273) and 12 months (p = 0.091) compared to 3 months. For the full 2016-AAO dose group, a decrease occurred only from baseline to 12 months (1343.5 ± 521.5 vs. 991.6 ± 576.3 ng/mL, p < 0.001). Frequencies of patients with inadequate levels at 6 months was higher in reduced 2016-AAO group than full 2016-AAO dose (59% vs. 24%, p = 0.005), as well as at 12 months (66% vs. 32%, p = 0.002). Six-month and 12-month flare frequencies were comparable for both groups (p > 0.05).

CONCLUSIONS

Prescribed HCQ low-dose regimen (2-3 mg/kg/day) does not sustain, for most patients, 6- and 12-month adequate HCQ levels. Full 2016-AAO dose maintained HCQ levels way above this limit.

TRAIL REGISTRATION

ClinicalTrials.gov : NCT03122431, registered on April 20, 2017 Key Points • Reduced American Academy of Ophthalmology (2016-AAO) hydroxychloroquine (HCQ) dose (2-3 mg/kg/day, real body weight) is unable to sustain HCQ blood levels within the safe cut-off defined for flare risk. • Full 2016-AAO dose (5 mg/kg/day) maintains a safe pattern of HCQ levels up to 12 months.

The influence of obesity on hydroxychloroquine blood levels in lupus nephritis patients

INTRODUCTION

In 2016 the American Academy of Ophthalmology(2016-AAO) recommended a maximum daily HCQ use of 5.0 mg/kg real body weight(RBW) taking into consideration minimizing eye toxicity. Retinopathy in systemic lupus erythematosus(SLE) patients was recently associated with obesity and this condition is progressively more common in these patients. However, the impact of obesity in HCQ blood levels remains controversial.

OBJECTIVE

To determine if the 2016-AAO recommendation based on RBW with and without maximum daily dose restriction results in adequate and safe blood levels in obese lupus nephritis(LN) patients.

METHODS

A cross-sectional study was performed with 108 LN patients under the prescribed 2016-AAO dose for at least 3 months. LN patients were assessed for demographic characteristics, body mass index(BMI), disease parameters, HCQ dose, concomitant treatment and HCQ blood levels measured by liquid chromatography-tandem mass spectrometry. Obesity was defined as BMI ≥30kg/m².

RESULTS

Obesity was identified in 35/108(32%) LN patients. The calculation of HCQ daily dosage revealed that obese patients were under a lower prescribed daily dose according to the real body weight (RBW) [4.4(2.9-5.4) vs. 4.9(4-5.5)mg/Kg/day, p < 0.001] due to the maximum limit used. Regardless of that the median of HCQ blood levels was significantly higher in obese compared to non-obese patients (1562 ± 548.6 vs. 1208 ± 448.9 ng/mL, p = 0.002). Further analysis of patients under the 20016-AAO recommendation by RBW without the restriction of maximum daily dose confirmed that in spite of comparable daily dose in 14 obese patients and 61 non-obese patients [4.8 (4.5-5.4) vs. 5.0(4.5-5.5) mg/kg, p = 0.312], the median of HCQ blood levels was significantly higher in obese patients than in non-obese (1734 ± 457.3 vs. 1189 ± 449.4 ng/mL, p < 0.001).

CONCLUSION

Obese patients under the 2016-AAO prescribed dose of HCQ based on RBW with and without maximum daily dose restriction have a very high HCQ blood levels compared to non-obese patients, with a potential increased risk of ocular toxicity. The use of 2016-AAO dose of HCQ according to the ideal body weight for this group of patients should be considered.Clinicaltrials.gov #NCT0312243.

Update on antimalarials and systemic lupus erythematosus

PURPOSE OF REVIEW

The purpose of this review is highlighting the most recent evidence on the clinical efficacy and toxicity of antimalarials in systemic lupus erythematosus (SLE).

RECENT FINDINGS

New data confirm the effects of antimalarials in preventing SLE activity, damage and infections and in decreasing mortality. An important reduction in use of health resources is related to continued antimalarial use. Hydroxychloroquine (HCQ) may prevent preeclampsia in pregnant women with SLE. HCQ ocular toxicity is infrequent and could be associated with blood levels. Gastrointestinal and skin toxicity are underrecognized and could influence adherence. Prolongation of QT interval is extremely unusual with HCQ. Doses of HCQ of 200 mg/day seem to offer a good efficacy/toxicity balance. HCQ protection against herpes zoster and Pneumocystis jirovecii infection has been shown. On the contrary, HCQ prescription by doctors and adherence by patients are both under recommended standards. The recent coronavirus disease 2019 pandemic has resulted in a significant shortage of HCQ in many countries with possible consequences in the correct treatment of lupus patients.

SUMMARY

Recent evidence reinforces the central role of HCQ in SLE therapy. The reduction in activity, damage accrual and mortality is consistent across studies, countries and ethnical groups. On the contrary, and despite the well established beneficial effects of prolonged regular HCQ therapy, many SLE patients do never take this drug or it is eventually stopped in the setting of severe flares, pregnancy or presumed toxicity. Every effort must be made to assure the correct prescription of HCQ and not to withdraw the drug unless unequivocal signs of toxicity are present.

COVID-19 prevention and treatment: A critical analysis of chloroquine and hydroxychloroquine clinical pharmacology

Nicholas White and coauthors discuss chloroquine and hydroxychloroquine pharmacology in the context of possible treatment of SARS-CoV-2 infection.