Steady-state pharmacokinetics of hydroxychloroquine in patients with cutaneous lupus erythematosus

Hydroxychloroquine blood concentrations and effects in Chinese patients with IgA nephropathy

BACKGROUND

Hydroxychloroquine (HCQ) is recommended for Chinese patients with immunoglobulin A nephropathy (IgAN). However, the relationship between HCQ blood concentration and the therapeutic effect for IgAN has not yet been defined. This study investigates the optimal and efficacious range of HCQ blood concentrations in Chinese patients with IgAN.

METHODS

Seventy-three patients with biopsy-proven IgAN who were at risk of progression were included in this study. Thirty-eight patients with IgAN were treated with HCQ plus an optimized renin-angiotensin-aldosterone system inhibitor (RAASi), and thirty-five patients received only RAASi. Blood HCQ concentration and 24-h proteinuria were examined at three and six months after treatment.

RESULTS

The baseline proteinuria levels were comparable between the RAASi and HCQ groups. The HCQ group had lower 24-h proteinuria than the RAASi group three months after treatment, though the difference was not significant (p = 0.38). After six months, the median proteinuria level was significantly lower in the HCQ group than in the RAASi group (p < 0.05). The percentage reduction in 24-h proteinuria in the HCQ group was greater than that in the RAASi group at three (p < 0.05) and six months (p < 0.05). Hydroxychlorquine blood concentration and efficacy were positively correlated at three months (r = 0.428, p < 0.05) and six months (r = 0.48, p < 0.05). Moreover, the optimal blood concentration of HCQ for three-month efficacy was 418.96 ng/mL and that for six-month efficacy was 582.48 ng/mL. No serious adverse events were reported during HCQ treatment.

CONCLUSIONS

Hydroxyhloroquine safely reduces proteinuria in Chinese patients with IgAN. The efficacy of HCQ is positively correlated with its blood concentration.

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.

Hydroxychloroquine and the associated risk of arrhythmias

Hydroxychloroquine (HCQ), which was initially used as an antimalarial drug, is now being used to treat other illnesses, especially rheumatic autoimmune disorders  such as systemic lupus erythematosus, primary Sjögren's syndrome, and rheumatoid arthritis, because it is safe, effective, and cost efficient. This drug has shown high efficacy and has become the first-line treatment for many of these diseases. Although HCQ has many therapeutic effects, it has unfortunately shown some complications, especially with its long-term use. One of these side effects is arrhythmia through prolongation of the QT interval. This narrative literature review focuses on the effects of HCQ on the QT interval in patients with rheumatologic diseases who have been prescribed this drug. In particular, we will focus on the increased risk of arrhythmia when HCQ is administered with other drugs, such as azithromycin and many others, along with drug-drug interactions. In addition, we investigated the safety of this drug in pregnant women.

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.

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.

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.

A linked physiologically based pharmacokinetic model for hydroxychloroquine and metabolite desethylhydroxychloroquine in SARS-CoV-2(-)/(+) populations

Hydroxychloroquine (HCQ) is Food and Drug Administration (FDA)-approved for malaria, systemic and chronic discoid lupus erythematosus, and rheumatoid arthritis. Because HCQ has a proposed multimodal mechanism of action and a well-established safety profile, it is often investigated as a repurposed therapeutic for a range of indications. There is a large degree of uncertainty in HCQ pharmacokinetic (PK) parameters which complicates dose selection when investigating its use in new disease states. Complications with HCQ dose selection emerged as multiple clinical trials investigated HCQ as a potential therapeutic in the early stages of the COVID-19 pandemic. In addition to uncertainty in baseline HCQ PK parameters, it was not clear if disease-related consequences of SARS-CoV-2 infection/COVID-19 would be expected to impact the PK of HCQ and its primary metabolite desethylhydroxychloroquine (DHCQ). To address the question whether SARS-CoV-2 infection/COVID-19 impacted HCQ and DHCQ PK, dried blood spot samples were collected from SARS-CoV-2(-)/(+) participants administered HCQ. When a previously published physiologically based pharmacokinetic (PBPK) model was used to fit the data, the variability in exposure of HCQ and DHCQ was not adequately captured and DHCQ concentrations were overestimated. Improvements to the previous PBPK model were made by incorporating the known range of blood to plasma concentration ratios (B/P) for each compound, adjusting HCQ and DHCQ distribution settings, and optimizing DHCQ clearance. The final PBPK model adequately captured the HCQ and DHCQ concentrations observed in SARS-CoV-2(-)/(+)participants, and incorporating COVID-19-associated changes in cytochrome P450 activity did not further improve model performance for the SARS-CoV-2(+) population.

Pregnancy outcomes among Egyptian women with systemic lupus erythematosus: A prospective cohort study

Pregnant patients with systemic lupus erythematosus (SLE) represent a high-risk group. The aim of this study is to describe the pregnancy outcomes among SLE patients who were followed prospectively at a conjoint high-risk pregnancy/rheumatology clinic from 2007 to 2021 and to identify predictors of adverse maternal and fetal outcomes. This study included 201 singleton pregnancies of 123 women with SLE. Their mean age was 27.16 ± 4.80 years, and their mean disease duration was 7.35 ± 5.46 years. Secondary antiphospholipid syndrome (APS) was diagnosed in 77 (38.3%) pregnancies. The pregnancy was planned in 104 (51.7%) pregnancies. Flares occurred in 83 (41.3%) and pre-eclampsia in 15 (7.5%) pregnancies. Full-term pregnancy occurred in 93 (46.3%), fetal loss (miscarriage and intra-uterine fetal death) in 41 (20.4%), and prematurity in 67 (33.3%) of the pregnancies, respectively. Seven neonates died from complications of prematurity, and another one died from cardiac congenital anomalies. In the multivariate analyses, unplanned pregnancy was associated with eight times higher risk of disease flare OR = 7.92 (p < 0.001), lupus nephritis flare during pregnancy increased the odds of pre-eclampsia occurrence four times OR = 3.98 (p = 0.02), while disease flares during pregnancy predicted prematurity OR = 2.49, p = 0.049. Patients with secondary APS had three times increased risk of fetal loss OR = 2.97, p = 0.049. To conclude, unplanned pregnancy, disease flares, and APS have been identified as predictors for adverse maternal and/or fetal outcomes. Pregnancy planning is necessary to reduce maternal and fetal complications.

Hydroxychloroquine lowers Alzheimer's disease and related dementias risk and rescues molecular phenotypes related to Alzheimer's disease

We recently nominated cytokine signaling through the Janus-kinase-signal transducer and activator of transcription (JAK/STAT) pathway as a potential AD drug target. As hydroxychloroquine (HCQ) has recently been shown to inactivate STAT3, we hypothesized that it may impact AD pathogenesis and risk. Among 109,124 rheumatoid arthritis patients from routine clinical care, HCQ initiation was associated with a lower risk of incident AD compared to methotrexate initiation across 4 alternative analyses schemes addressing specific types of biases including informative censoring, reverse causality, and outcome misclassification (hazard ratio [95% confidence interval] of 0.92 [0.83-1.00], 0.87 [0.81-0.93], 0.84 [0.76-0.93], and 0.87 [0.75-1.01]). We additionally show that HCQ exerts dose-dependent effects on late long-term potentiation (LTP) and rescues impaired hippocampal synaptic plasticity prior to significant accumulation of amyloid plaques and neurodegeneration in APP/PS1 mice. Additionally, HCQ treatment enhances microglial clearance of Aβ_1-42, lowers neuroinflammation, and reduces tau phosphorylation in cell culture-based phenotypic assays. Finally, we show that HCQ inactivates STAT3 in microglia, neurons, and astrocytes suggesting a plausible mechanism associated with its observed effects on AD pathogenesis. HCQ, a relatively safe and inexpensive drug in current use may be a promising disease-modifying AD treatment. This hypothesis merits testing through adequately powered clinical trials in at-risk individuals during preclinical stages of disease progression.

An update on the management of refractory cutaneous lupus erythematosus

Management of cutaneous lupus erythematosus (CLE) involves a combination of preventive measures, topical and systemic drugs, fairly similar for the different subtypes. Although guidelines exist, to date, no specific drugs have been specifically licensed for CLE. Antimalarials remain the first-line systemic treatment, but many patients do not respond, making refractory lupus a challenge for clinicians. The choice of alternative medication should be based on effectiveness, safety and cost. Most of the available drugs for CLE have been adapted from systemic lupus erythematosus (SLE) treatment but the existing literature is limited to small studies and evidence often lacks. As knowledge of pathogenesis of both CLE and SLE is improving, promising new therapies are emerging. In this review, we discuss the available medications, focusing on the novelties under development for CLE.

Repurposing Itraconazole and Hydroxychloroquine to Target Lysosomal Homeostasis in Epithelial Ovarian Cancer

Drug repurposing is an attractive option for oncology drug development. Itraconazole is an antifungal ergosterol synthesis inhibitor that has pleiotropic actions including cholesterol antagonism, inhibition of Hedgehog and mTOR pathways. We tested a panel of 28 epithelial ovarian cancer (EOC) cell lines with itraconazole to define its spectrum of activity. To identify synthetic lethality in combination with itraconazole, a whole-genome drop-out genome-scale clustered regularly interspaced short palindromic repeats sensitivity screen in two cell lines (TOV1946 and OVCAR5) was performed. On this basis, we conducted a phase I dose-escalation study assessing the combination of itraconazole and hydroxychloroquine in patients with platinum refractory EOC (NCT03081702). We identified a wide spectrum of sensitivity to itraconazole across the EOC cell lines. Pathway analysis showed significant involvement of lysosomal compartments, the trans-golgi network and late endosomes/lysosomes; similar pathways are phenocopied by the autophagy inhibitor, chloroquine. We then demonstrated that the combination of itraconazole and chloroquine displayed Bliss defined synergy in EOC cancer cell lines. Furthermore, there was an association of cytotoxic synergy with the ability to induce functional lysosome dysfunction, by chloroquine. Within the clinical trial, 11 patients received at least one cycle of itraconazole and hydroxychloroquine. Treatment was safe and feasible with the recommended phase II dose of 300 and 600 mg twice daily, respectively. No objective responses were detected. Pharmacodynamic measurements on serial biopsies demonstrated limited pharmacodynamic impact. In vitro, itraconazole and chloroquine have synergistic activity and exert a potent antitumor effect by affecting lysosomal function. The drug combination had no clinical antitumor activity in dose escalation.

Significance

The combination of the antifungal drug itraconazole with antimalarial drug hydroxychloroquine leads to a cytotoxic lysosomal dysfunction, supporting the rational for further research on lysosomal targeting in ovarian cancer.

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.

Effect of chronic hydroxychloroquine use on COVID-19 risk in patients with rheumatoid arthritis and systemic lupus erythematosus: a multicenter retrospective cohort

Objective

Hydroxychloroquine (HCQ) has been used during the coronavirus disease 2019 (COVID-19) pandemic because of its reported anti-viral activity. This study examined the association of chronic HCQ use with the incidence and complications of COVID-19.

Methods

This retrospective cohort study included adults with rheumatoid arthritis and/or systemic lupus erythematosus who visited rheumatology clinics in three tertiary hospitals in Riyadh, Saudi Arabia between January 2019 and December 2020. Patients were categorized into two groups based on HCQ use. Data were obtained from the electronic health record and by interviews with patients. The primary study objective was the incidence of COVID-19 and its complications from March 2020 to February 2021.

Results

Almost 11% of the study cohort was positive for COVID-19, and the incidence of COVID-19 was similar between HCQ users (11.11%) and nonusers (10.86%). Disease complication rates were similar in the study arms, and they mainly included fever, dry cough, fatigue, and breathing difficulty.

Conclusions

This study revealed no significant association between chronic HCQ use and the incidence of COVID-19, and disease complications were similar in the study arms.

Overcoming Drug Resistance in Advanced Prostate Cancer by Drug Repurposing

Prostate cancer (PCa) is the second most common cancer in men. Common treatments include active surveillance, surgery, or radiation. Androgen deprivation therapy and chemotherapy are usually reserved for advanced disease or biochemical recurrence, such as castration-resistant prostate cancer (CRPC), but they are not considered curative because PCa cells eventually develop drug resistance. The latter is achieved through various cellular mechanisms that ultimately circumvent the pharmaceutical’s mode of action. The need for novel therapeutic approaches is necessary under these circumstances. An alternative way to treat PCa is by repurposing of existing drugs that were initially intended for other conditions. By extrapolating the effects of previously approved drugs to the intracellular processes of PCa, treatment options will expand. In addition, drug repurposing is cost-effective and efficient because it utilizes drugs that have already demonstrated safety and efficacy. This review catalogues the drugs that can be repurposed for PCa in preclinical studies as well as clinical trials.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Development of a Physiologically Based Pharmacokinetic Model for Hydroxychloroquine and Its Application in Dose Optimization in Specific COVID-19 Patients

In Feb 2020, we developed a physiologically-based pharmacokinetic (PBPK) model of hydroxychloroquine (HCQ) and integrated in vitro anti-viral effect to support dosing design of HCQ in the treatment of COVID-19 patients in China. This, along with emerging research and clinical findings, supported broader uptake of HCQ as a potential treatment for COVID-19 globally at the beginning of the pandemics. Therefore, many COVID-19 patients have been or will be exposed to HCQ, including specific populations with underlying intrinsic and/or extrinsic characteristics that may affect the disposition and drug actions of HCQ. It is critical to update our PBPK model of HCQ with adequate drug absorption and disposition mechanisms to support optimal dosing of HCQ in these specific populations. We conducted relevant in vitro and in vivo experiments to support HCQ PBPK model update. Different aspects of this model are validated using PK study from 11 published references. With parameterization informed by results from monkeys, a permeability-limited lung model is employed to describe HCQ distribution in the lung tissues. The updated model is applied to optimize HCQ dosing regimens for specific populations, including those taking concomitant medications. In order to meet predefined HCQ exposure target, HCQ dose may need to be reduced in young children, elderly subjects with organ impairment and/or coadministration with a strong CYP2C8/CYP2D6/CYP3A4 inhibitor, and be increased in pregnant women. The updated HCQ PBPK model informed by new metabolism and distribution data can be used to effectively support dosing recommendations for clinical trials in specific COVID-19 patients and treatment of patients with malaria or autoimmune diseases.

Optimization of hydroxychloroquine dosing scheme based on COVID-19 patients' characteristics: a review of the literature and simulations

During the recent COVID-19 outbreak hydroxychloroquine (HCQ) has been proposed as a safe and effective therapeutic option. However, a wide variety of dosing schemes has been applied in the clinical practice and tested in clinical studies. An extended literature survey was performed investigating the pharmacokinetics, the efficacy and safety of HCQ in COVID-19 treatment. Population pharmacokinetic models were retrieved from the literature and after evaluation and assessment one was selected in order to perform simulations. The most commonly applied dosing schemes were explored for patients with different weights and different levels of HCQ clearance impairment. Model-based simulations of HCQ concentrations revealed that high initial doses followed by low and sparse doses may offer significant benefits to patients by decreasing the viral load without reaching levels considered to produce adverse effects. For instance, the dosing scheme proposed for a 70 kg adult with moderate COVID-19 symptoms would be 600 mg upon diagnosis, 400 mg after 12 h, 300 mg after 24 h, 200 mg after 36 h, followed by 200 mg BID for 4 d, followed by 200 mg OD for 5 d. Based on the results from simulations performed and the currently published knowledge regarding HCQ in COVID-19 treatment, this study provides evidence that a high loading dose followed by sparse doses could offer significant benefits to the patients.

The efficacy and safety of hydroxychloroquine for COVID-19 prophylaxis: A systematic review and meta-analysis of randomized trials

Background

Populations such as healthcare workers (HCW) that are unable to practice physical distancing are at high risk of acquiring Coronavirus disease-2019 (COVID-19). In these cases pharmacological prophylaxis would be a solution to reduce severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) transmission. Hydroxychloroquine has in vitro antiviral properties against SARS CoV-2. We therefore sought to determine the efficacy and safety of hydroxychloroquine as prophylaxis for COVID-19.

Methods and findings

We electronically searched EMBASE, MEDLINE, the Cochrane COVID-19 Register of Controlled Trials, Epistemonikos COVID-19, clinicaltrials.gov, and the World Health Organization International Clinical Trials Registry Platform up to September 28^th, 2020 for randomized controlled trials (RCTs). We calculated pooled relative risks (RRs) for dichotomous outcomes with the corresponding 95% confidence intervals (CIs) using a random-effect model. We identified four RCTs (n = 4921) that met our eligibility criteria. The use of hydroxychloroquine, compared to placebo, did not reduce the risks of developing COVID-19 (RR 0.82, 95% CI 0.65 to 1.04, moderate certainty), hospitalization (RR 0.72, 95% CI 0.34 to 1.50, moderate certainty), or mortality (RR 3.26, 95% CI 0.13 to 79.74, low certainty), however, hydroxychloroquine use increased the risk of adverse events (RR 2.76, 95% CI 1.38 to 5.55, moderate certainty).

Conclusion

Although pharmacologic prophylaxis is an attractive preventive strategy against COVID-19, the current body of evidence failed to show clinical benefit for prophylactic hydroxychloroquine and showed a higher risk of adverse events when compared to placebo or no prophylaxis.

Hydroxychloroquine in Coronavirus Disease 2019 Patients: What Still Needs to Be Known About the Kinetics

Different dosage regimens of hydroxychloroquine are used to manage COVID-19 patients, without information on the pharmacokinetics in this population.Blood samples (n=101) were collected from 57 COVID-19 patients for 7 days and concentrations were compared with simulated kinetic profiles.Hydroxychloroquine exposure is low and cannot be predicted by other populations.

Towards Optimization of Hydroxychloroquine Dosing in Intensive Care Unit COVID-19 Patients

Hydroxychloroquine (HCQ) appears to be a promising treatment for COVID-19. However, all ongoing clinical trials with HCQ use different dosing regimens, resulting on various concentrations PK studies are therefore needed to define the optimal dosing regimen.

Efficacy and Safety of Hydroxychloroquine Therapy for Systemic Lupus Erythematosus Patients Depend on Administration Dose

Objective Hydroxychloroquine (HCQ) has been prescribed in Japan only relatively recently and is recommended for the treatment of skin lesions, arthritis and renal lesions according to the Japanese Guideline for the Management of systemic lupus erythematosus (SLE) (2019). However, the associations between the efficacy and safety and the HCQ dose in Japanese SLE patients remain unclear. We investigated the efficacy and safety of different HCQ doses in Japanese SLE patients with a low disease activity who were not receiving immunosuppressants. Methods The disease activity was evaluated using the SELENA-SLEDAI 2011 criteria, the Cutaneous Lupus Erythematous Disease Area and Severity Index (CLASI) and serum biomarkers. Safety was evaluated via the frequency of adverse events over a period of three months. Results We enrolled 61 SLE patients treated with HCQ and no additional immunosuppressive therapy for more than 3 months. HCQ was administered to 46 patients at the usual dose and to 15 cases at a lower than usual dose. Although the CLASI activity scores decreased significantly in both groups, the magnitude of this decrease was larger in the usual-dose HCQ group than in the low-dose HCQ group. SLEDAI scores and immunological activity were significantly improved only in the usual-dose HCQ group. In addition, changes in the serum complement levels in the usual-dose HCQ group were more dramatic than in the low-dose HCQ group six months after the initiation of HCQ administration. Adverse events were more frequent in the usual-dose HCQ group than in the low-dose HCQ group (30.4% and 13.3%, respectively). Conclusion HCQ therapy is effective for maintenance therapy of SLE patients. The usual dose of HCQ may have some advantage in ameliorating low complement levels.

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.

Research Progress of Chloroquine and Hydroxychloroquine on the COVID-19 and Their Potential Risks in Clinic Use

In December 2019, a severe outbreak of a novel coronavirus (COVID-19) occurred in the whole world, posing a great threat to people's health. With the outbreak and development of the epidemic, how to improve the cure rate, find effective drugs against this virus, has been the most urgent problem. Chloroquine (CQ) was verified effective against COVID-19 in vitro. As CQ's analogue, hydroxychloroquine (HCQ) was also reminded as a potential candidate for treating COVID-19. This review summarizes the latest clinical trials of CQ and HCQ against COVID-19 and its therapeutic regimen in China aiming to share their current usage to the whole world and provide insight into its appropriate future use in the treatment of COVID-19. Through searching the CNKI and Wangfang databases in Chinese language and PubMed, EMBASE, and Ovid databases in English language to identify published reports with the keywords including "coronavirus/COVID, chloroquine, hyroxychloroquine" in alone or combined, we found out the potential preclinical or clinical evidence for using CQ and HCQ against COVID-19. Consequently, we also searched the website of Chinese Clinical Trial Registry (http://www.chictr.org.cn/) till the day on 27th, June, 2020. This review found that there are 23 programs aimed to treat the different phases under COVID-19 pipeline in clinic with CQ and HCQ, totally. The inclusion criteria, exclusion criteria and therapeutic regimen were all shared to consult. Among them, seven have been canceled due to lack of patients or other objective factors. There are two trials have completed, which the potential relationship between usage and adverse reactions was discussed emphatically. Through literature research, we suggested that paid close attention to retinal toxicity and ophthalmologic adverse symptom of CQ and HCQ. And the outcome of HCQ in clinic shows better than CQ especially in protective effect with low dosage.

Overcoming cancer therapeutic bottleneck by drug repurposing

Ever present hurdles for the discovery of new drugs for cancer therapy have necessitated the development of the alternative strategy of drug repurposing, the development of old drugs for new therapeutic purposes. This strategy with a cost-effective way offers a rare opportunity for the treatment of human neoplastic disease, facilitating rapid clinical translation. With an increased understanding of the hallmarks of cancer and the development of various data-driven approaches, drug repurposing further promotes the holistic productivity of drug discovery and reasonably focuses on target-defined antineoplastic compounds. The "treasure trove" of non-oncology drugs should not be ignored since they could target not only known but also hitherto unknown vulnerabilities of cancer. Indeed, different from targeted drugs, these old generic drugs, usually used in a multi-target strategy may bring benefit to patients. In this review, aiming to demonstrate the full potential of drug repurposing, we present various promising repurposed non-oncology drugs for clinical cancer management and classify these candidates into their proposed administration for either mono- or drug combination therapy. We also summarize approaches used for drug repurposing and discuss the main barriers to its uptake.

Intracellular ABCB1 as a Possible Mechanism to Explain the Synergistic Effect of Hydroxychloroquine-Azithromycin Combination in COVID-19 Therapy

The co-administration of hydroxychloroquine with azithromycin is proposed in COVID-19 therapy. We hypothesize a new mechanism supporting the synergistic interaction between these drugs. Azithromycin is a substrate of ABCB1 (P-glycoprotein) which is localized in endosomes and lysosomes with a polarized substrate transport from the cell cytosol into the vesicle interior. SARS-CoV-2 and drugs meet in these acidic organelles and both basic drugs, which are potent lysosomotropic compounds, will become protonated and trapped within these vesicles. Consequently, their intra-vesicular concentrations can attain low micromolar effective cytotoxic concentrations on SARS-CoV-2 while concomitantly increase the intra-vesicular pH up to around neutrality. This last effect inhibits lysosomal enzyme activities responsible in virus entry and replication cycle. Based on these considerations, we hypothesize that ABCB1 could be a possible enhancer by confining azithromycin more extensively than expected when the trapping is solely dependent on the passive diffusion. This additional mechanism may therefore explain the synergistic effect when azithromycin is added to hydroxychloroquine, leading to apparently more rapid virus clearance and better clinical benefit, when compared to monotherapy with hydroxychloroquine alone.

Finding the Dose for Hydroxychloroquine Prophylaxis for COVID-19: The Desperate Search for Effectiveness

Hydroxychloroquine is an antimalarial drug being tested as a potential treatment for the novel coronavirus disease 2019 (COVID‐19) pandemic caused by the severe acute respiratory syndrome coronavirus 2. Although the efficacy of hydroxychloroquine for COVID‐19 remains uncertain, it may serve as a potential prophylactic agent especially in those at high risk, such as healthcare workers, household contacts of infected patients, and the immunocompromised. Our aim was to identify possible hydroxychloroquine dosing regimens through simulation in those at high risk of infections by optimizing exposures above the in vitro generated half maximal effective concentration (EC₅₀) and to help guide researchers in dose‐selection for COVID‐19 prophylactic studies. To maintain weekly troughs above EC₅₀ in > 50% of subjects at steady‐state in a pre‐exposure prophylaxis setting, an 800 mg loading dose followed by 400 mg twice or 3 times weekly is required. In an exposure driven, post‐exposure prophylaxis setting, 800 mg loading dose followed in 6 hours by 600 mg, then 600 mg daily for 4 more days achieved daily troughs above EC₅₀ in > 50% subjects. These doses are higher than recommended for malaria chemoprophylaxis, and clinical trials are needed to establish safety and efficacy.

Adherence to hydroxychloroquine in patients with systemic lupus: Contrasting results and weak correlation between assessment tools

OBJECTIVES

Hydroxychloroquine (HCQ) is an anchor drug in the treatment of systemic lupus erythematosus (SLE). Adherence to HCQ is key for efficacy. Inaccurate evaluation of adherence could lead to non-justified switch to more expensive or less tolerated drugs.

METHODS

Severe non-adherence rate to HCQ was estimated in a sample of SLE patients during a routine visit using blood HCQ concentration<200μg/L. Adherence was assessesd by the Medication Adherence Self-Report Inventory (MASRI)<80/100, 8-item Morisky Medication Adherence Scale (MMAS-8) ≤6/8, Health Care Provider (HCP) visual analog scale (VAS)<80/100. Same procedures were to be repeated during a further routine visit 6 to 12 months later. We described agreement and correlations between tools and compared severely non-adherent patients and others on their characteristics.

RESULTS

The study involved 158 patients (86.1% females) aged 42.2±12.6 years treated with HCQ for 9.6±6.9 years. Blood HCQ concentration (mean±standard deviation) was 1046±662μg/L at visit 1 and 855±577μg/L at visit 2. At visit 1, the non-adherence rate varied from 3.2% (blood HCQ level<200μg/L) to 7.7% (MASRI), 12.4% (HCP-VAS) or 32.5% (MMAS-8). 37.8% of patients met at least one of the definitions of non-adherence. Patients' characteristics including SLE activity, damage and quality of life were similar between severely non-adherent patients and others. Correlations between blood HCQ-concentration and self-questionnaires were weak (r<0.25) and agreement between methods was poor.

CONCLUSION

Blood HCQ concentration<200μg/L reveals severe non-adherence. Combining blood HCQ concentration with MASRI and MMAS-8 may help to better identify non-adherence in SLE. Agreement between methods was poor and correlations with HCQ level and SLE activity were weak.

Low hydroxychloroquine blood levels in patients who have had gastric bypass surgery

Gastric bypass surgery, also called Roux-en-Y gastric bypass (RYGB), can result in the malabsorption of medications, requiring the use of higher than usual doses in order to achieve a therapeutic effect. We describe the results of hydroxychloroquine (HCQ) blood levels in three patients with systemic autoimmune disease taking standard HCQ doses and their associated disease activity levels. This is a retrospective review of all patients who had undergone RYGB and were taking HCQ in a rheumatology community-based practice. Two patients with SLE and one patient with primary Sjogren's syndrome had previously undergone RYGB. All three had subtherapeutic HCQ blood levels and active disease. Increasing their HCQ doses above the recommended 400 mg a day dosing resulted in therapeutic HCQ levels in all three patients and better disease control in two of the three patients. RYGB patients may not absorb HCQ adequately, resulting in subtherapeutic HCQ blood levels and inadequate disease control. Patients who have undergone RYGB and are taking HCQ should have drug levels monitored. RYGB patients may require higher than recommended doses of HCQ in order to achieve better disease control and avoid unneeded additional immunosuppressive agents.