Antimalarials in the management of discoid and systemic lupus erythematosus

GNS561 (ezurpimtrostat), a small basic lipophilic molecule, prevents lupus phenotype in a pristane-induced lupus mouse model

BACKGROUND AND PURPOSE

Systemic lupus erythematosus is an autoimmune, multisystemic disease affecting all organs in the body. Accrued evidence has elucidated a role for autophagy in the onset and severity of systemic lupus erythematosus. The antimalarial drug hydroxychloroquine constitutes the cornerstone of standard of care for systemic lupus erythematosus, together with glucocorticoids and immunosuppressants or biologics, and all accompanied by various side effects.

EXPERIMENTAL APPROACH AND OBJECTIVE

Our study aimed to investigate the potential of GNS561 (ezurpimtrostat) treatment, a small basic lipophilic molecule that induces lysosomal dysregulation, using the pristane-induced lupus mouse model.

KEY RESULTS

Compared with hydroxychloroquine, GNS561 treatment presents a more pronounced impact on the development of pathogenic anti-antibodies in pristane-induced lupus mice. Next, focussing on clinical impact, we showed that GNS561 significantly reduced clinical signs of lupus in pristane-induced lupus by preventing the incidence and severity of arthritis, occurrence of nephritis and lung damage. Finally, GNS561 modulated the inflammatory profile in pristane-induced lupus mice through a reduction of the lipogranuloma score. Interestingly, focussing on interferon-α, only pristane-induced lupus mice treated by GNS561 presented a significant decrease of the cytokine, suggesting a higher efficacy for GNS561 in the modulation of lupus-induced inflammation compared with hydroxychloroquine.

CONCLUSION

All results show that GNS561, but not hydroxychloroquine, represents as an effective treatment to prevent clinical and inflammatory signs of lupus in this mouse model.

IMPLICATIONS

Altogether, this study highlights GNS561 as a promising investigational drug for systemic lupus erythematosus.

Does hydroxychloroquine reduce the risk of infection in patients with systemic lupus erythematosus? a systematic review and meta-analysis

OBJECTIVES

This study aimed to investigate the anti-infective utility of hydroxychloroquine in patients with systemic lupus erythematosus (SLE) by analyzing published case-control and cohort studies.

METHODS

A systematic literature review was conducted on January 28, 2024, using PubMed, Cochrane, Embase, and Web of Science Core Collection databases. Odds ratios (OR) were used for statistical analysis.

RESULTS

Hydroxychloroquine exhibits a propensity to diminish infection risk in systemic lupus erythematosus patients, albeit without statistical significance (OR = 0.77, 95%CI 0.51-1.18, p = 0.23). Subgroup analyses revealed a significant prevention of serious infections (OR = 0.40, 95%CI 0.25-0.64, p = 0.0001). Interestingly, a potential causal relationship between hydroxychloroquine use and lower infection risk was observed in the cohort studies subgroup (OR = 0.66, 95%CI 0.44-0.99, p = 0.04), but not in the case-control studies subgroup (OR = 1.06, 95%CI 0.63-1.79, p = 0.83). It is important to note the risks associated with high-dose use, such as retinopathy.

CONCLUSIONS

Although hydroxychloroquine tends to reduce infection risk in SLE patients, the evidence is not strong. It can decrease severe infections, but high doses should be used cautiously and selectively in patients with impaired renal function. Further studies are required to establish optimal dosing and efficacy for specific diseases, considering the potential influence of study design on the observed associations between hydroxychloroquine use and infection risk in SLE patients.

The Impact of Tobacco Smoking on Systemic Sclerosis, Idiopathic Inflammatory Myositis, and Systemic Lupus Erythematosus

This narrative review aims specifically to explore the relationship between tobacco exposure and systemic sclerosis (SSc), idiopathic inflammatory myositis (IIM), and systemic lupus erythematosus (SLE). Relevant articles were obtained by searching key terms such as "tobacco," "smoking," "scleroderma," "myositis," "lupus," and "Sjögren's" in PubMed and Google Scholar databases. The selected articles ranged from the years 2010 to 2023. Inclusion criteria were based on the relevance and contribution to the field of study. Systemic sclerosis is a complex condition involving multiple immune cell lines that can be influenced by tobacco. However, the existing literature does not provide sufficient evidence to support an increased risk of SSc in smokers or the impact on treatment options. Cigarette smoking does increase the risk of skin ulcerations in SSc patients. In addition, cigarette smoking has been associated with IIM through genetic and molecular mechanisms. Smokers with dermatomyositis or polymyositis are at an elevated risk of atherosclerosis and interstitial lung disease. Similarly, smoking in patients with SLE increases the risk of organ damage, thrombosis, and disease severity compared with non-smokers. Smokers with SLE also have more difficulty in controlling disease flares compared with non-smokers. Tobacco exposure can lead to secondary complications in patients with IIM and SLE, although the course of treatment may not differ significantly. No definitive conclusions can be drawn to the clear relationship between tobacco smoking and Sjögren's's syndrome.

Elucidating the mechanisms and efficacy of antimalarial drugs in systemic lupus erythematosus

INTRODUCTION

Antimalarials (AMs) are old drugs with a wide range of beneficial effects in systemic lupus erythematosus (SLE) beyond the control of activity. The most recent debate is focused on defining the optimal doses to assure the best benefit/risk ratio.

AREAS COVERED

We have reviewed the pharmacological basis underlying the various therapeutic effects of AMs and the beneficial and toxic effects of HCQ, also discussing the role of mepacrine not only as a substitute in cases of maculopathy, but also as a very effective therapy combined with HCQ. We searched PubMed and Embase for articles published in English at any time. We used the terms "hydroxychloroquine" or "mepacrine" or "chloroquine" or "antimalarials", "pharmacokinetics", "efficacy", "remission", "toxicity", "adherence". We reviewed original research articles, large observational studies, systematic reviews, and expert consensus statements. Additionally, studies were identified through the assessment of the reference lists of the evaluated manuscripts.

EXPERT OPINION

We advocate for the widespread use of HCQ at stable doses of 200 mg/d (≤4 mg/kg/d for most patients) and also for the early combination therapy with mepacrine to assure a good control of SLE activity, and also a durable and safe use of these essential drugs for the management of SLE.

Antimalarial Drugs Induce the Selective Folding of Human Telomeric G-Quadruplex in a Cancer-Mimicking Microenvironment

Regulating the equilibrium between the duplex form of DNA and G-quadruplex (Gq) and stabilizing the folded Gq are the critical factors for any drug to be effective in cancer therapy due to the direct involvement of Gq in controlling the transcription process. Antimalarial drugs are in the trial stage for different types of cancer diseases; however, the plausible mechanism of action of these drug molecules is not well known. Hence, we investigate the plausible role of antimalarial drugs in the folding and stabilization of Gq-forming DNA sequences from the telomere and promoter gene regions by varying the salt (KCl) concentrations, mimicking the in vitro cancerous and normal cell microenvironments. The study reveals that antimalarial drugs fold and stabilize specifically to telomere Gq-forming sequences in the cancerous microenvironment than the DNA sequences located in the promoter region of the gene. Antimalarial drugs are not only able to fold Gq but also efficiently protect them from unfolding by their complementary strands, hence significantly biasing the equilibrium toward the Gq formation from the duplex. In contrast, in a normal cell microenvironment, K+ controls the folding of telomeres, and the role of antimalarial drugs is not prominent. This study suggests that the action of antimalarial drugs is sensitive to the cancer microenvironment as well as selective to the Gq-forming region.

In vitro effect of hydroxychloroquine on pluripotent stem cells and their cardiomyocytes derivatives

Introduction: Hydroxychloroquine (HDQ) is an antimalarial drug that has also shown its effectiveness in autoimmune diseases. Despite having side effects such as retinopathy, neuromyopathy and controversial cardiac toxicity, HDQ has been presented and now intensively studied for the treatment and prevention of coronavirus disease 2019 (COVID-19). Recent works revealed both beneficial and toxic effects during HDQ treatment. The cardiotoxic profile of HDQ remains unclear and identifying risk factors is challenging. Methods: Here, we used well-established cell-cultured to study the cytotoxic effect of HDQ, mouse induced pluripotent stem cells (miPSC) and their cardiomyocytes (CMs) derivatives were exposed to different concentrations of HDQ. Cell colony morphology was assessed by microscopy whereas cell viability was measured by flow cytometry and impedance-based methods. The effect of HDQ on beating activity of mouse and human induced pluripotent stem cell-derived CMs (miPSC-CMs and hiPSC-CMs, respectively) and mouse embryonic stem cell-derived CMs (mESC-CMs) were captured by the xCELLigence RTCA and microelectrode array (MEA) systems. Results and discussion: Our results revealed that 20 µM of HDQ promotes proliferation of stem cells used suggesting that if appropriately monitored, HDQ may have a cardioprotective effect and may also represent a possible candidate for tissue repair. In addition, the field potential signals revealed that higher doses of this medication caused bradycardia that could be reversed with a higher concentration of ß-adrenergic agonist, Isoproterenol (Iso). On the contrary, HDQ caused an increase in the beating rate of hiPSC-CMs, which was further helped upon application of Isoproterenol (Iso) suggesting that HDQ and Iso may also work synergistically. These results indicate that HDQ is potentially toxic at high concentrations and can modulate the beating activity of cardiomyocytes. Moreover, HDQ could have a synergistic inotropic effect with isoproterenol on cardiac cells.

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.

Screening for Fabry Disease in patients with unexplained left ventricular hypertrophy

Fabry Disease (FD) is a systemic disorder that can result in cardiovascular, renal, and neurovascular disease leading to reduced life expectancy. FD should be considered in the differential of all patients with unexplained left ventricular hypertrophy (LVH). We therefore performed a prospective screening study in Edmonton and Hong Kong using Dried Blood Spot (DBS) testing on patients with undiagnosed LVH. Participants found to have unexplained LVH on echocardiography were invited to participate and subsequently subjected to DBS testing. DBS testing was used to measure α-galactosidase (α-GAL) enzyme activity and for mutation analysis of the α-galactosidase (GLA) gene, both of which are required to make a diagnosis of FD. DBS testing was performed as a screening tool on patients (n = 266) in Edmonton and Hong Kong, allowing for detection of five patients with FD (2% prevalence of FD) and one patient with hydroxychloroquine-induced phenocopy. Left ventricular mass index (LVMI) by GLA genotype showed a higher LVMI in patients with IVS4 + 919G > A mutations compared to those without the mutation. Two patients were initiated on ERT and hydroxychloroquine was discontinued in the patient with a phenocopy of FD. Overall, we detected FD in 2% of our screening cohort using DBS testing as an effective and easy to administer screening tool in patients with unexplained LVH. Utilizing DBS testing to screen for FD in patients with otherwise undiagnosed LVH is clinically important due to the availability of effective therapies and the value of cascade screening in extended families.

Therapeutic use of chloroquine and hydroxychloroquine in COVID-19 and other viral infections: A narrative review

The rapidly spreading Coronavirus Disease (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2), represents an unprecedented serious challenge to the global public health community. The extremely rapid international spread of the disease with significant morbidity and mortality made finding possible therapeutic interventions a global priority. While approved specific antiviral drugs against SARS-CoV-2 are still lacking, a large number of existing drugs are being explored as a possible treatment for COVID-19 infected patients. Recent publications have re-examined the use of Chloroquine (CQ) and/or Hydroxychloroquine (HCQ) as a potential therapeutic option for these patients. In an attempt to explore the evidence that supports their use in COVID-19 patients, we comprehensively reviewed the previous studies which used CQ or HCQ as an antiviral treatment. Both CQ and HCQ demonstrated promising in vitro results, however, such data have not yet been translated into meaningful in vivo studies. While few clinical trials have suggested some beneficial effects of CQ and HCQ in COVID-19 patients, most of the reported data are still preliminary. Given the current uncertainty, it is worth being mindful of the potential risks and strictly rationalise the use of these drugs in COVID-19 patients until further high quality randomized clinical trials are available to clarify their role in the treatment or prevention of COVID-19.

The history of antimalarials

In the city of Lima, capital of Peru, the wife of the Viceroy, at that time the Count of Cinchon fell sick... Her illness was tertian fever... The rumour of her illness... became known by the people in the city, spread to neighboring places and reached Loxa. I believe since then thirty or forty years have passed. A Spaniard, the prefect in that place was told of the illness of the Countess, and thought to inform by letter her husband the Viceroy ... that he had a secret remedy he could recommend without hesitation ... she accepted at once ... and once taken, like something miraculous, she was cured to the amazement of all.

Sebastiano Bado, in Anastasis corticis Peruviae seu Chinae Chinae defensio (1663), pp. 20–21

Anti-malarial drugs: possible mechanisms of action in autoimmune disease and prospects for drug development

A wide variety of mechanisms of anti-rheumatic action have been proposed for antimalarial agents. The molecular actions of chloroquine have been most thoroughly studied in vitro and in vivo, but it is likely that hydroxychloroquine works by a similar mechanism. Both agents are weak diprotic bases that can pass through the lipid cell membrane and preferentially concentrate in acidic cyto-plasmic vesicles. The resulting slight elevation of pH within these vesicles in macrophages or other antigen-presenting cells may influence the immune response to autoantigens. We hypothesize that anti-malarial agents influence the association of autoantigenic peptides with class II MHC molecules in the compartment for peptide loading and/or the subsequent processing and transport of the peptide-MHC complex to the cell membrane. This model of anti-malarial action provides a method to test additional drugs for their ability to modulate the immune response.

The efficacy of antimalarials in systemic lupus erythematosus

The use of antimalarial drugs to treat systemic lupus erythematosus (SLE) is receiving increased attention. A retrospective controlled study suggested that antimalarials were useful in suppressing disease activity in SLE. A randomized discontinuation trial of hydroxychloroquine sulphate supported the clinical belief that antimalarials are of benefit in SLE of mild to moderate disease activity and might have a role as adjunctive therapy to protect against more severe relapses of SLE. A randomized trial of the ability of hydroxychloroquine sulphate to suppress articular manifestations of SLE demonstrated no consistent statistically significant benefit, although the sample size was small. Anecdotal reports and the experience of expert clinicians have suggested a corticosteroid sparing role for antimalarials, although no controlled study has been conducted to specifically address this hypothesis. Thus, the evidence favors a role for antimalarials in suppressing mild to moderate disease activity in SLE and possibly in preventing severe disease exacerbations. Their role as corticosteroid sparing agents in SLE is widely believed, but unproven.

The Efficacy of Antimalarials in Systemic Lupus Erythematosus

The use of antimalarial drugs to treat systemic lupus erythematosus (SLE) is reviewed regarding their value in SLE of mild-to-moderate disease activity, as corticosteroid-sparing agents, and as an adjunctive therapy in severe SLE. A retrospective controlled study of a variety of antimalarials and a randomized discontinuation trial of hydroxychloroquine support the considerable clinical belief that antimalarials are of benefit in mild-to-moderate SLE. Anecdotal reports and the opinion of experienced clinicians suggest that antimalarials permit the use of lower doses of corticosteroids. No controlled study has confirmed a corticosteroid-sparing role for antimalarials, although no controlled study has been conducted specifically to address this hypothesis. The data on antimalarials in severe SLE are scant.

Antimalarials are likely effective in at least a subgroup of SLE patients with mild-to-moderate disease activity. Whether these agents are corticosteroid sparing and prevent severe disease exacerbations is unproven. Given the low toxicity of antimalarials, further studies are clearly warranted.

Treatment of primary Sjögren's syndrome with hydroxychloroquine: a retrospective, open-label study

Objectives

To determine whether patients with primary Sjögren's syndrome (SS), diagnosed according to San Diego criteria, had improvement in their laboratory or clinical features during treatment with hydroxychloroquine (6–7 mg/kg/day) for at least two years., Methods: The study population included 50 consecutive patients with primary SS who were diagnosed according to San Diego criteria, and in whom hydroxychloroquine was suggested as treatment. This group included 10 patients who were early dropouts (side effects or desire not to take antimalarial drugs) and 40 patients who received drugs for at least two years (range 24-48 months). In a subset of SS patients, values for ESR (westergren) and quantitative immunoglobulins were available for comparison. Improvement with therapy was defined as: (a) ≥20% improvement in variables of tear flow (Schirmer's test I) or corneal integrity (rose Bengal): (b) ≥20% salivary function (flow rate); and (c) improvement in at least two of the following measures: physicians assessment of global disease activity by ≥ 20%, patient assessment of improvement in pain or fatigue by ≥20%, and ESR improved by ≥20mm/ hr.

Results

In a retrospective study of SS patients who completed the trial, a significant improvement was noted in ocular symptoms (pain and dryness) in patients (55 and 57%) and improved corneal integrity (rose Bengal straining) in 53% of patients. The Schirmer's test was improved by ≥ 2 mm/5 minutes in 50% in patients. Improvement was noted in oral symptoms (pain and dryness) in patients (57 and 60%) and salivary flow rate was increased in 82% of patients. In a subset of SS patients evaluated, the ESR improved by ≥20mm/hr in 17/32 patients (53%) and quantitative IgG level by ≥20% in 8/13 patients (61%). Physician global assessment of overall patient status and patient assessment of overall status indicated improvement in over 62% of patients.

Conclusion

In a retrospective study of patients fulfilling San Diego Criteria for SS, we found: (a) sustained improvement of local symptoms (painful eyes, painful mouth) and improvement of systemic manifestations (arthralgias and myalgias) after treatment with hydroxychloroquine 6-7 mg/kg/day over mean three-year follow-up; (b) laboratory analysis showed a significant improvement in their ESR and their quantitative IgG levels; (c) no significant late toxicity was observed in this study cohort. A prospective study of hydroxychloroquine in patients fulfilling San Diego criteria for SS is indicated.

Repurposing Drugs in Oncology (ReDO)-chloroquine and hydroxychloroquine as anti-cancer agents

Chloroquine (CQ) and hydroxychloroquine (HCQ) are well-known 4-aminoquinoline antimalarial agents. Scientific evidence also supports the use of CQ and HCQ in the treatment of cancer. Overall, preclinical studies support CQ and HCQ use in anti-cancer therapy, especially in combination with conventional anti-cancer treatments since they are able to sensitise tumour cells to a variety of drugs, potentiating the therapeutic activity. Thus far, clinical results are mostly in favour of the repurposing of CQ. However, over 30 clinical studies are still evaluating the activity of both CQ and HCQ in different cancer types and in combination with various standard treatments. Interestingly, CQ and HCQ exert effects both on cancer cells and on the tumour microenvironment. In addition to inhibition of the autophagic flux, which is the most studied anti-cancer effect of CQ and HCQ, these drugs affect the Toll-like receptor 9, p53 and CXCR4-CXCL12 pathway in cancer cells. In the tumour stroma, CQ was shown to affect the tumour vasculature, cancer-associated fibroblasts and the immune system. The evidence reviewed in this paper indicates that both CQ and HCQ deserve further clinical investigations in several cancer types. Special attention about the drug (CQ versus HCQ), the dose and the schedule of administration should be taken in the design of new trials.

CHOROIDAL THICKNESS IN MULTISYSTEMIC AUTOIMMUNE DISEASES WITHOUT OPHTHALMOLOGIC MANIFESTATIONS

PURPOSE

To evaluate choroidal morphology and thickness at the posterior pole of individuals affected by multisystemic autoimmune diseases and without known ophthalmologic manifestations.

METHODS

Retrospective cross-sectional study including 75 patients with autoimmune diseases (divided according to their specific disease) and 80 healthy controls. A spectral-domain optical coherence tomography using enhanced depth imaging was performed and choroidal thickness was measured in the center of fovea and at 500 μm intervals along a horizontal section.

RESULTS

Lupus patients presented a thicker subfoveal choroid than controls (408.624 vs. 356.536, P < 0.001) and in all the other measurements (P < 0.001 to P = 0.003). Rheumatoid arthritis and other autoimmune diseases had an overall thinner choroid than controls (297.867 vs. 356.536 subfoveally, P = 0.004; P = 0.005-0.019 in other measurements). Results were adjusted for the covariates age (P = 0.007), spherical equivalent (P < 0.001), and systemic steroids dose (P = 0.004). Hypertension (P = 0.102), diabetes mellitus (P = 0.672), time since the beginning of therapy with hydroxychloroquine (P = 0.104) and its cumulative dose (P = 0.307), or use of other immunosuppressives (P = 0.281) had no influence on the mean choroidal thickness. No morphologic abnormalities were found.

CONCLUSION

The choroid may be subclinically involved in autoimmune diseases. However, the choroidal response seems to differ depending on the autoimmune disease. Infiltrative mechanisms specific for lupus may justify the thickened choroid found in these patients.

Factors associated with chloroquine-induced retinopathy in rheumatic diseases

Antimalarials are very useful drugs in the treatment of various rheumatic diseases. One of their main side effects is ocular toxicity, specifically retinopathy. Our objective was to identify risk factors associated with chloroquine retinopathy. A single, trained evaluator reviewed patient records with rheumatic diseases. They were taking chloroquine and identified by the ophthalmologydepartment as having retinopathy during their routine eye evaluation. These cases were classified according to clinical evaluation, visual fields and fluorangiographic study. Up to four controls were selected for each case, matched by age, gender, diagnosisand similar time on chloroquine.In all, 34 variableswere studied, among these: weight, age, disease duration, keratopathy, total cumulative dose (TCD), mean daily dose (MDD), lean body weight adjusted daily dose (LBWDD) and laboratory tests. Descriptive and inferential statistics comparing cases and controls in all patients and subgroup analysis were carried out. Significance was set at the 0.05 level. Odds ratio and 95% confidence intervals were calculated. Sixteen cases of chloroquine retinopathy were identified, eight patients with rheumatoid arthritis (RA), seven with systemic lupus erythematosus (SLE) and one with dermatomyositis. All were female. Mean age was 47.3 + 12.2 years; weight 59.5 + 10.7 kg; disease duration 12.8 + 6.0 years; time on chloroquine 54.1 + 27.8 (min-max: 30-197) months. There was a significant difference in the following variables in all patients: MDD 212.3 + 52.6 versus 170 + 51.3, p 0.009; and LBWDD 5 + 1 versus 4.2 + 1.5, p 0.03, for cases and controls, respectively. In subgroup analysis the MDD remained significantly different (235.5 + 45.8 versus 169.7 + 46.l, p 0.004) only in RA, whereas LBWDD was different both in SLE and RA. Keratopathy increased the risk for retinopathy: OR, 95% CI: 5, 1.4-l7.6, p 0.01. In conclusion, in accordance with previous studies, the MDD, LBWDD and keratopathy were risk factors associated with chloroquine retinopathy. Periodic ophthalmologic evaluations are mandatory.

Therapy and pharmacological properties of hydroxychloroquine and chloroquine in treatment of systemic lupus erythematosus, rheumatoid arthritis and related diseases

OBJECTIVES

This review examines the pharmacokinetics, modes of action and therapeutic properties of the anti-malarial drugs, hydroxychloroquine (HCQ) and chloroquine (CQ), in the treatment of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and related conditions, as well as osteoarthritis (OA).

KEY FINDINGS

Both HCQ and CQ have historically been employed successfully for the treatment of SLE and RA for over 70 years. HCQ has been used extensively for SLE where it has a good reputation for controlling the dermatological complications in SLE. It has also been reported to effectively control the symptoms of Sjøgren's syndrome, as well as preventing thrombosis in phospholipid antibody (aPL) syndrome. In RA and SLE, HCQ is preferred because of the lower incidence of gastrointestinal adverse reactions compared with CQ and it might have a lower risk of ocular adverse reactions. There is increasing evidence that HCQ may reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients. Both HCQ and CQ have been shown to improve glycaemia and reduce the risks of type II diabetes mellitus. Although both HCQ and CQ are effective in low-moderate RA, HCQ is now preferred as part of combination therapy for more severe disease. The advantages of combination therapy are that the doses of the individual drugs may be lowered so reducing adverse reactions. Both HCQ and CQ are diastereoisomers, have basic properties and are given as the sulphate and phosphate salts. While being relatively well absorbed orally and with good bioavailability, they have long and variable plasma terminal elimination half-lives (approximately 40-60 days). This reflects their high volume of distribution, V D (HCQ 44,000L; CQ 65,000L) which extends into aqueous compartments, long mean residence time (HCQ 1300 h; CQ 900 h) and with about half the drugs (metabolites) undergoing renal clearance. The strong binding to melanin reflects the ocular injury and dermatological properties of these drugs. The consensus is that the occurrence of ocular adverse reactions can be minimised by close attention to the dose (which should be set on a body weight basis) with regular (e.g. quarterly) retinal examination. Although HCQ and CQ can pass through the placenta, the use of these drugs during pregnancy does not appear to risk harm to the baby and might be beneficial to the mother with SLE and her child by controlling the SLE disease activity, which is known to be an important factor affecting pregnancy outcome. The modes of action of HCQ and CQ in these arthritides represent somewhat of an enigma. Undoubtedly, these drugs have multiple actions related, in part, their ability to accumulate in lysosomes and autophagosomes of phagocytic cells as well as affecting MHC Class II expression and antigen presentation; actions of the production of pro-inflammatory cytokines [e.g. interleukin-1 (IL-1) tumour necrosis factor-α (TNFα)]; control of toll-like receptor-9 activation; and leucocyte generation of reactive oxygen species (ROS); i.e. antioxidant activity. The actions of these drugs on T and B cells are less clear but may depend on these leucocyte-mediated actions. Anti-malarials also protect against cytokine-mediated cartilage resorption. This and other actions may underlie the potential benefits in treating OA. The exact relationships of these various actions, mostly determined in vitro, have not been specifically defined in vivo or ex vivo in relation to clinical efficacy.

OUTCOMES

HCQ and CQ have a good reputation for being effective and relatively safe treatments in SLE, mild-moderate RA and Sjøgren's syndrome. There is need for (a) more information on their mode of action in relation to the control of these diseases, (b) scope for developing formulations that have improved pharmacokinetic and therapeutic properties and safety, and (c) further exploring their use in drug combinations not only with other disease modifying agents but also with biologics.

15-hydroxyprostaglandin dehydrogenase is upregulated by hydroxychloroquine in rheumatoid arthritis fibroblast-like synoviocytes

15-Hydroxyprostaglandin dehydrogenase (HPGD) is the key enzyme responsible for the metabolic inactivation of prostaglandin E2 (PGE₂) catabolism. PGE₂ is one of the predominant catabolic factors involved in rheumatoid arthritis (RA). However, the expression and regulation of HPGD in RA fibroblast-like synoviocyte (FLS) remain to be elucidated. Disease-modifying anti-rheumatic drugs (DMARDs) are the most important anti-arthritic drugs, which reduce the effect of joint injury. The aim of the present study was to assess the expression of HPGD in RA tissues and cells, and normal synovial tissues and cells. The effect of the most popular DMARDs, hydroxychloroquine, on the expression of HPGD in RA-FLS was also investigated. Western blotting and immuno-histochemical analysis demonstrated that the expression levels of HPGD in human synovium were lower in RA synovium compared with the normal and OA synovium. In RA-FLS, the expression of HPGD was increased following treatment with several DMARDs, including sulfasalazine, methotrexate, and hydroxychloroquine. Hydroxychloroquine (10 µM) treatment induced the phosphorylation of ERK, SAPK/JNK and p38. Hydroxychloroquine induced a decrease in the release of PGE₂, which was restored by mitogen-activated protein (MAP) kinase pathway inhibitors. Hydroxychloroquine may therefore, affect the pathogenesis of RA through the MAP kinase pathway by regulating the expression of HPGD.

Hydroxychloroquine in children with interstitial (diffuse parenchymal) lung diseases

Hydroxychloroquine (HCQ) is one of the drugs frequently used for the treatment of interstitial lung disease (ILD) in children (chILD). This use is off-label and studies to analyze the effect and safety of HCQ in chILD are lacking. Therefore, a literature research on the usage of chloroquine (CQ) and HCQ in these conditions was done. Eighty-five case reports and small series in the period from 1984 to 2013 were identified in which children with different diagnoses of ILD were treated with CQ or HCQ, sometimes in combination with other medication including steroids. A favorable response to HCQ or CQ was reported in 35 cases, whereas in the other cases the effect was negative or not clear. The dose of HCQ used was between 5 and 10 mg/kg body weight/day (bw/d). No pharmacokinetic studies have been done. The side effect profile in children seemed to be similar to that in adults. Most often gastrointestinal symptoms were reported. Three patients were found developing retinal changes during the treatment with CQ, whereas in none of the patients treated with HCQ retinal changes were reported. Based on retrospective case reports and small series likely to be reported with bias, the use of HCQ in chILD might be classified as safe. As no prospective data on efficacy and safety of HCQ in chILD are available, systematic collection is necessary. This may be achieved by web-based registers like the European Management Platform for Childhood Interstitial Lung Diseases. Prospective and controlled investigations of HCQ in patients with chILD are mandatory.

Regular examinations for toxic maculopathy in long-term chloroquine or hydroxychloroquine users

IMPORTANCE

According to evidence-based, expert recommendations, long-term users of chloroquine or hydroxychloroquine sulfate should undergo regular visits to eye care providers and diagnostic testing to check for maculopathy.

OBJECTIVE

To determine whether patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) taking chloroquine or hydroxychloroquine are regularly visiting eye care providers and being screened for maculopathy.

DESIGN, SETTING, AND PARTICIPANTS

Patients with RA or SLE who were continuously enrolled in a particular managed care network for at least 5 years between January 1, 2001, and December 31, 2011, were studied. Patients' amount of chloroquine or hydroxychloroquine use in the 5 years since the initial RA or SLE diagnosis was calculated, along with their number of eye care visits and diagnostic tests for maculopathy. Those at high risk for maculopathy were identified. Logistic regression was performed to assess potential factors associated with regular eye care visits (annual visits in ≥3 of 5 years) among chloroquine or hydroxychloroquine users, including those at highest risk for maculopathy.

MAIN OUTCOMES AND MEASURES

Among chloroquine or hydroxychloroquine users and those at high risk for toxic maculopathy, the proportions with regular eye care visits and diagnostic testing, as well as the likelihood of regular eye care visits.

RESULTS

Among 18 051 beneficiaries with RA or SLE, 6339 (35.1%) had at least 1 record of chloroquine or hydroxychloroquine use, and 1409 (7.8%) had used chloroquine or hydroxychloroquine for at least 4 years. Among those at high risk for maculopathy, 27.9% lacked regular eye care visits, 6.1% had no visits to eye care providers, and 34.5% had no diagnostic testing for maculopathy during the 5-year period. Among high-risk patients, each additional month of chloroquine or hydroxychloroquine use was associated with a 2.0% increased likelihood of regular eye care (adjusted odds ratio, 1.02; 95% CI, 1.01-1.03). High-risk patients whose SLE or RA was managed by rheumatologists had a 77.4% increased likelihood of regular eye care (adjusted odds ratio, 1.77; 95% CI, 1.27-2.47) relative to other patients.

CONCLUSIONS AND RELEVANCE

In this insured population, many patients at high risk for maculopathy associated with the use of chloroquine or hydroxychloroquine are not undergoing routine monitoring for this serious adverse effect. Future studies should explore factors contributing to suboptimal adherence to expert guidelines and the potential effect on patients' vision-related outcomes.

Cutaneous deposits

: The cutaneous deposition disorders are a group of unrelated conditions characterized by the accumulation of either endogenous or exogenous substances within the skin. These cutaneous deposits are substances that are not normal constituents of the skin and are laid down usually in the dermis, but also in the subcutis, in a variety of different circumstances. There are 5 broad categories of cutaneous deposits. The first group includes calcium salts, bone, and cartilage. The second category includes the hyaline deposits that may be seen in the dermis in several metabolic disorders, such as amyloidosis, gout, porphyria, and lipoid proteinosis. The third category includes various pigments, heavy metals, and complex drug pigments. The fourth category, cutaneous implants, includes substances that are inserted into the skin for cosmetic purposes. The fifth category includes miscellaneous substances, such as oxalate crystals and fiberglass. In this article, the authors review the clinicopathologic characteristics of cutaneous deposition diseases, classify the different types of cutaneous deposits, and identify all the histopathologic features that may assist in diagnosing the origin of a cutaneous deposit.

Pharmacology of Chloroquine and Hydroxychloroquine

The 4-aminoquinolines are weak bases that are completely absorbed from the gastrointestinal tract, sequestered in peripheral tissues, metabolized in the liver to pharmacologically active by-products, and excreted via the kidneys and the feces. The parent drugs and metabolites are excreted with a half-life of elimination of approximately 40 days. However, slow release from sequestered stores of the drugs means that after discontinuation, they continue to be released into the plasma for years. Correct dosing is based on the ideal body weight of the patient, which depends on height. The 4AQs diminish autoimmunity without compromising immunity to infections.

Lupus erythematosus: considerations about clinical, cutaneous and therapeutic aspects

Systemic Lupus Erythematosus is a chronic inflammatory disease with multifactorial etiology. Although clinical manifestations are varied, the skin is an important target-organ, which contributes to the inclusion of skin lesions in 4 out of the 17 new criteria for the diagnosis of the disease, according to the Systemic Lupus International Collaborating Clinics. The cutaneous manifestations of lupus are pleomorphic. Depending on their clinical characteristics, they can be classified into Acute Cutaneous Lupus Erythematosus, Subacute Cutaneous Lupus Erythematosus, Chronic Cutaneous Lupus Erythematosus and Intermittent Cutaneous Lupus Erythematosus. Treatment is based on preventive measures, reversal of inflammation, prevention of damage to target organs and relief of adverse events due to pharmacological therapy. The most commonly used treatment options are topical, systemic and surgical treatment, as well as phototherapy. The correct handling of the cases depends on a careful evaluation of the morphology of the lesions and the patient's general status, always taking into consideration not only the benefits but also the side effects of each therapeutic proposal.

Multifaceted effects of hydroxychloroquine in human disease

OBJECTIVES

Hydroxychloroquine (HCQ) is a widely used medication for the treatment of rheumatoid arthritis and systemic lupus erythematosus. An increasing body of evidence supports actions of this drug that are not directly related to its immunosuppressive or anti-rheumatic properties. The objective of this systematic review is to characterize the spectrum of conditions that might be responsive to treatment with HCQ.

METHODS

PubMed was searched using the MeSH for HCQ with relevant subheadings and the limits of human topics and English language. Four-hundred and fifty-six abstracts from this search were examined individually to exclude those that were not focused on the objectives of this review. The resulting 76 articles were grouped according to topic areas and reviewed in detail.

RESULTS

HCQ has been reported to have therapeutic effects in a wide array of conditions, including diabetes mellitus, dyslipidemias, coagulopathies, infectious diseases and malignancies. Mechanisms of action responsible for these effects likely include altered signaling through cellular receptors, post-glycosylation modifications of infectious agents, changes in levels of inflammatory mediators and inhibition of autophagy. Many of the pathways are likely dependent on drug-induced changes in intra-endosomal acidity.

CONCLUSIONS

The use of, and interest in, HCQ has spread into many areas of medicine. Actions of this drug may be directly beneficial to patients with non-rheumatic conditions such as diabetes mellitus or viral infections. Further understanding of underlying mechanisms has potential to reveal modifiable pathogenic pathways that might elucidate approaches to the design of more effective therapeutics for many chronic diseases.

Response to hydroxychloroquine in Japanese patients with lupus-related skin disease using the cutaneous lupus erythematosus disease area and severity index (CLASI)

BACKGROUND

Hydroxychloroquine (HCQ) is not available in Japan. To design a clinical trial of HCQ, we evaluated the response to HCQ in Japanese patients with lupus-related skin disease using the cutaneous lupus erythematosus disease area and severity index (CLASI).

METHODS

Twenty-seven patients with lupus-related skin disease who started HCQ at four hospitals were included. Patients were categorized into responders by the CLASI response criteria. The points and the rate of improvement in the CLASI activity score after 16 weeks of treatment were analyzed, focusing on six parameters: systemic lupus erythematosus (SLE), skin manifestations, disease duration, prednisolone, smoking, and severity.

RESULTS

Twenty-seven patients, including 17 with SLE (6 with SLE/Sjögren's syndrome), were analyzed retrospectively. Twenty-three patients (85 %) were categorized as responders. The mean CLASI activity score improved from 10.1 to 4.5 (p < 0.0001). The improvement rate did not differ in these parameters except for that of annular erythema (81.6 versus 34.3 %, p = 0.036). On multivariate analysis, the baseline CLASI activity score (CLASI ≥9) correlated with the greatest decrease in CLASI activity score (F = 69.7, p < 0.0001).

CONCLUSIONS

CLASI is a reliable indicator to evaluate the efficacy of the drug, and HCQ is an effective treatment for Japanese patients with lupus-related skin disease.

Efficacy of mycophenolate mofetil in antimalarial-resistant cutaneous lupus erythematosus

BACKGROUND

Mycophenolate mofetil (MMF) is an immunomodulatory drug shown to be effective in the treatment of systemic lupus erythematosus. Several anecdotal reports have suggested that MMF may be efficacious in the treatment of cutaneous lupus erythematosus (CLE).

OBJECTIVES

Our objective was to summarize and report our experience with the use of MMF in patients with CLE recalcitrant to antimalarial therapy.

METHODS

We retrospectively analyzed our open-label observations of 24 patients with CLE refractory to antimalarial therapy. The records of all patients visiting the Rheumatic Skin Disease Clinic at the University of Texas Southwestern Medical Center at Dallas from January 1, 2001, to July 1, 2006, were reviewed.

RESULTS

MMF was tolerated well and, in conjunction with other therapies, was highly effective in the treatment of antimalarial-resistant CLE. With the addition of MMF to the existing regimen, a majority of patients achieved full control of disease signs and symptoms. All patients experienced some degree of improvement.

LIMITATIONS

This is an open-label retrospective review. Severity of disease was assessed by qualitative assessment of the clinician. MMF was not used as monotherapy.

CONCLUSIONS

Our results indicate that MMF, used as an additional agent in conjunction with standard therapy, is both well tolerated and efficacious in the treatment of refractory CLE. Despite the obvious limitations of the study, we believe this represents further evidence that MMF should be considered early in the treatment of patients refractory to antimalarial therapy.

Response to antimalarial agents in cutaneous lupus erythematosus: a prospective analysis

OBJECTIVE

To demonstrate response to antimalarial agents in patients with cutaneous lupus erythematosus (CLE) using activity scores from the Cutaneous Lupus Erythematosus Disease Area and Severity Index, a validated outcome measure.

DESIGN

Prospective, longitudinal cohort study.

SETTING

University cutaneous autoimmune disease clinic.

PARTICIPANTS

A total of 128 patients with CLE who presented from January 2007 to July 2010 and had at least 2 visits with activity scores.

INTERVENTION

Administration of antimalarial agents.

MAIN OUTCOME MEASURES

Response was defined by a 4-point or 20% decrease in activity score. Response to initiation was determined by the difference between the scores before treatment and at the first visit at least 2 months after treatment. Response to continuation was determined by the difference between the scores at the first visit and the most recent visit while undergoing treatment.

RESULTS

Of 11 patients who initiated treatment with hydroxychloroquine, 55% were responders (n = 6), showing a decrease in median (interquartile range [IQR]) activity score from 8.0 (3.5-13.0) to 3.0 (1.8-7.3) (P = .03). Of 15 patients for whom hydroxychloroquine failed, 67% were responders to initiation of hydroxychloroquine-quinacrine therapy (n = 10), showing a decrease in median (IQR) activity score from 6.0 (4.8-8.3) to 3.0 (0.75-5.0) (P = .004). Nine of 21 patients who continued hydroxychloroquine treatment (43%), and 9 of 21 patients who continued hydroxychloroquine-quinacrine (43%) were responders, showing a decrease in median (IQR) activity score from 6.0 (1.5-9.5) to 1.0 (0.0-4.5) (P = .01) and 8.5 (4.25-17.5) to 5.0 (0.5-11.5) (P = .01), respectively.

CONCLUSIONS

The use of quinacrine with hydroxychloroquine is associated with response in patients for whom hydroxychloroquine monotherapy fails. Further reduction in disease activity can be associated with continuation of treatment with antimalarial agents.

The role of antimalarial agents in the treatment of SLE and lupus nephritis

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease that affects various organs. Lupus nephritis is one of the most common, and most important, serious manifestations of SLE. Antimalarial agents are part of the immunomodulatory regimen used to treat patients with SLE; however, their role in the treatment of patients with lupus nephritis in particular is less well recognized, especially by nephrologists. Not all antimalarial agents have been used in the treatment of lupus; this Review will focus on studies using chloroquine and hydroxychloroquine. In addition, this Review will briefly describe the history of antimalarial drug use in patients with SLE, the theorized mechanisms of action of the agents chloroquine and hydroxychloroquine, their efficacy in patients with SLE and those with lupus nephritis, their use in pregnancy, and potential adverse effects. The Review will also cover the latest recommendations regarding monitoring for hydroxychloroquine-associated or chloroquine-associated retinopathy. Overall, antimalarial drugs have numerous beneficial effects in patients with SLE and lupus nephritis, and have a good safety profile.

Treatment of cutaneous lupus erythematosus

In patients with cutaneous lupus erythematosus (CLE) and mild skin involvement, local therapy consisting of topically applied pharmacological agents, e.g., topical/intralesional steroids, may be sufficient. Recent reports have also shown efficacy of topical calcineurin inhibitors in patients with CLE, particularly on the face. Special attention receives consistent sun protection through photoresistant clothing and application of light-shielding substances with highly potent chemical or physical UVA- and UVB-protective filters. These substances should be applied in sufficient amount (ca. 2 mg/cm(2)) at least 20-30 minutes before sun exposure in order to avoid induction and exacerbation of cutaneous lesions. The mainstay of treatment for disfiguring and widespread skin manifestations in patients with CLE, irrespective of the subtype of the disease, is antimalarial agents. Our understanding of the use of combinations of antimalarials and proper dosing according to the ideal bodyweight limits problems with toxicity. Further therapies, such as methotrexate, or retinoids, dapsone, mycophenolate mofetil, and thalidomide in selected cases, can be helpful for patients with resistant disease; however, side effects need to be taken into consideration. Recent advances in biotechnology resulted in the development of novel systemic agents, but randomized controlled trials are necessary for the approval of new therapeutic strategies in CLE.

Cutaneous lupus erythematosus: update of therapeutic options part I

In patients with cutaneous lupus erythematosus (CLE), it is important to provide instructions concerning methods of protection from sunlight and artificial sources of ultraviolet radiation. Topical corticosteroids are the mainstay of treatment for patients with CLE; however, they are of limited value because of their well-known side effects. Recently, calcineurin inhibitors have been shown to be efficient as topical therapy in various CLE subtypes. The first-line treatment for severe and widespread skin manifestations is antimalarials; hydroxychloroquine or chloroquine can each be combined with quinacrine in refractory CLE. Systemic steroids can be used additionally in exacerbations of the disease. In the first part of this review, recent information on topical and first-line systemic treatment is described in detail while providing the reader with up-to-date information on efficacy, side effects, and dosage for the various agents. In the second part, additional systemic agents for the treatment of CLE will be discussed.

[Antimalarials. A treatment option for every lupus patient!?]

In contrast to many other medications, chloroquine and hydroxychloroquine are approved treatment options for systemic lupus erythematosus (SLE). Antimalarials reduce the frequency of disease flares and contribute to the maintenance of remission. Apart from its direct effects on SLE activity, antimalarials seem to protect against thrombotic events and have a beneficial effect on glucose and lipid profiles, which might help reduce the high cardiovascular risk of SLE. Hydroxychloroquine is the only treatment shown to be effective in reducing the risk of damage accrual in SLE patients. Finally, antimalarials are inexpensive, especially compared with more recent treatments, and are well tolerated in SLE. Despite all these benefits, still only about 40%-50% of SLE patients are treated with (hydroxy)chloroquine. Particularly in early disease phases, antimalarials should be considered for every lupus patient, assuming there are no contraindications.

Chloroquine-induced bull’s eye maculopathy in rheumatoid arthritis: related to disease duration?

Chloroquine diphosphate has been used in the treatment of various rheumatic diseases, including rheumatoid arthritis. The most important of its side effects is retinopathy. If not diagnosed early, this lesion can evolve into irreversible bull's eye maculopathy and visual loss. The aim of this study was to define the outcome of chloroquine-induced maculopathy after cessation of chloroquine therapy and also to identify the risk factors involved in case of retinopathy evolution. The design of this cohort study was longitudinal and retrospective. Over the period spanning 2000 to 2005, out of 607 medical records of patients with rheumatoid arthritis followed in our Division of Rheumatology, 27 had been diagnosed with chloroquine-induced maculopathy through clinical funduscopy with pupil dilation. In all cases, there was immediate chloroquine intake cessation. After a mean time of 5 years, 16 of these patients were available for follow-up and underwent a new ophthalmologic evaluation by funduscopy, using biomicroscopy and angiofluorescein when necessary. Sequelae maculopathy were reconfirmed in all 16 cases, but progression to advanced stage (bull's eye maculopathy) was found in half of the cohort, even though chloroquine had been suspended. All patients complained of visual alterations, but without progression. Comparison between patient groups with and without bull's eye maculopathy revealed a statistically significant longer rheumatoid arthritis disease history in the former group. Also, the bull's eye group had higher dose intakes of chloroquine and over a longer period compared to the other group, but not statistically significant. This study corroborates the progression of maculopathy even after cessation of chloroquine intake, pointing out the need for careful screening in the high-risk patients. Furthermore, it indicates that duration of rheumatoid arthritis disease could be a possible factor linked to worse prognosis of chloroquine-induced maculopathy.

Antipaludéens de synthèse

The antimalarials, mainly chloroquine and hydroxychloroquine, derive from the quinoleine core of quinine. Their initial therapeutic indication was the treatment of malaria attacks but, because of anti-inflammatory and immuno-modulatory activities, they have been since used to treat many other pathologies, in particular dermatological ones. For some of these pathologies, lupus or porphyria cutanea tarda for example, the use of these molecules is based on obvious scientific evidence. For other pathologies (cutaneous sarcoidosis, polymyositis, polymorphous light eruption...), the data on the medical literature corroborating the daily clinical practice are extremely poor. Their toxicity is limited. Their most common toxic effects are gastrointestinal (mild nausea or diarrhea) or mucocutaneous (reversible skin or mucosal pigmentation). Their most serious and dreaded side effect, retinopathy, can be largely prevented by using amounts of APS adapted to the weight of the patients. The recommended "safe" daily dose for hydroxychloroquine is 6.5 mg per kilogramme of body weight and for chloroquine 4 mg per kilogramme of body weight. However, at 6- to 12 months intervals, follow-up eye examinations should be performed.

Optimal use of antimalarials in treating cutaneous lupus erythematosus

Antimalarials have been used to treat cutaneous and systemic lupus erythematosus (LE) for decades. Although controlled studies comparing the efficacy of antimalarials versus placebo and other treatments are generally lacking, many case reports and series support the therapeutic efficacy of these agents in treating both LE-specific and -nonspecific skin lesions. Currently, the two most frequently used antimalarial agents are chloroquine and hydroxychloroquine. There may be a delay of weeks to months in the onset of therapeutic effects of antimalarials when treating LE. Smoking appears to inhibit the therapeutic efficacy of antimalarials when treating cutaneous LE. Antimalarials have been associated with a number of potentially serious adverse effects, including irreversible loss of vision. The aim of this review is to discuss the many facets of antimalarials that will help clinicians optimally utilize these agents when treating cutaneous LE.

Hydroxychloroquine concentration-response relationships in patients with rheumatoid arthritis

OBJECTIVE

A dose-response relationship for hydroxychloroquine (HCQ), in terms of the proportion of patients achieving the Paulus 20% criteria for improvement, had previously been observed in patients with rheumatoid arthritis (RA) receiving a 6-week loading regimen of 400, 800, or 1,200 mg HCQ daily. This present retrospective analysis was performed to investigate possible relationships between the blood HCQ and HCQ-metabolite concentrations and measures of efficacy and toxicity. In addition, we sought to ascertain whether further investigation of HCQ/HCQ-metabolite levels might lead to testing of one of these substances as a new antirheumatic drug.

METHODS

Patients with active RA (n = 212) began a 6-week, double-blind trial comparing 3 different doses of HCQ at 400, 800, or 1,200 mg/day, followed by 18 weeks of open-label HCQ treatment at 400 mg/day. Patients were repeatedly evaluated for treatment efficacy and toxicity. Blood samples were available from 123 patients for analysis of HCQ, desethylhydroxychloroquine (DHCQ), desethylchloroquine (DCQ), and bisdesethylchloroquine (BDCQ) levels using high-performance liquid chromatography. Achievement of the modified Paulus 20% improvement criteria for response in RA was used as the primary efficacy parameter. Spontaneously reported adverse events were categorized and analyzed as toxicity outcome variables. The relationship between response (efficacy and toxicity) and drug levels was evaluated using logistic regression analysis.

RESULTS

The subset of patients with blood concentration data was equivalent to the larger study population in all demographic and outcome characteristics. The mean HCQ, DHCQ, and DCQ elimination half-lives were 123, 161, and 180 hours, respectively. There was a positive correlation between the Paulus 20% improvement criteria response and blood DHCQ concentrations during weeks 1-6 (P < 0.001). A potential relationship between ocular adverse events and BDCQ levels was found (P = 0.036). Logistic regression analysis of adverse events data showed that adverse gastrointestinal events were associated with higher HCQ levels (P = 0.001-0.021) during weeks 1, 2, and 3.

CONCLUSION

There is a weak, but predictable, relationship between blood DHCQ concentrations and efficacy of treatment with HCQ. In addition, there is an association between gastrointestinal adverse events and elevated blood HCQ concentrations. Further investigation of these relationships is warranted to see if DHCQ may be introduced as a new antirheumatic drug.