Abstract
Objective. To characterize hydroxychloroquine (HCQ) exposure in patients with rheumatic disease receiving longterm HCQ compared to target concentrations with reported antiviral activity against the coronavirus disease 2019 caused by SARS-CoV-2 (COVID-19).
Method. We evaluated total HCQ concentrations in serum and plasma from published literature values, frozen serum samples from a pediatric systemic lupus erythematosus trial, and simulated concentrations using a published pharmacokinetic model during pregnancy. For each source, we compared observed or predicted HCQ concentrations to target concentrations with reported antiviral activity against SARS-CoV-2.
Results. The average total serum/plasma HCQ concentrations were below the lowest SARS-CoV-2 target of 0.48 mg/l in all studies. Assuming the highest antiviral target exposure (total plasma concentration of 4.1 mg/l), all studies had about one-tenth the necessary concentration for in vitro viral inhibition. Pharmacokinetic model simulations confirmed that pregnant adults receiving common dosing for rheumatic diseases did not achieve target exposures; however, the models predict that a dosage of 600 mg once a day during pregnancy would obtain the lowest median target exposure for most patients after the first dose.
Conclusion. We found that the average patient receiving treatment with HCQ for rheumatic diseases, including children and non-pregnant/pregnant adults, are unlikely to achieve total serum or plasma concentrations shown to inhibit SARS-CoV-2 in vitro. Nevertheless, patients receiving HCQ long term may have tissue concentrations far exceeding that of serum/plasma. Because the therapeutic window for HCQ in the setting of SARS-CoV-2 is unknown, well-designed clinical trials that include patients with rheumatic disease are urgently needed to characterize the efficacy, safety, and target exposures for HCQ.
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This study was supported by the Rheumatology Research Foundation’s Scientist Development Award, the Thrasher Research Fund, the Childhood Arthritis and Rheumatology Research Alliance/Arthritis Foundation, the Derfner Foundation, NIGMS/NICHD (2T32GM086330-06), NICHD (5R01-HD076676-04, HHSN275201000003I), and a Duke Health/Private Diagnostic Clinic ENABLE grant. The Atherosclerosis Prevention in Pediatric Lupus Erythematosus [APPLE (ClinicalTrials.gov: NCT00065806)] trial is supported by the US National Institutes of Health (NIH) National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) contract N01-AR-2-2265, the Edna and Fred L. Mandel Jr. Center for Hypertension and Atherosclerosis, and Pfizer, which provided atorvastatin and matching placebo.
- Accepted for publication May 14, 2019.
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