QTc Prolongation in COVID-19 Patients Using Chloroquine

Hydroxychloroquine Blood Concentrations Can Be Clinically Relevant Also After Drug Discontinuation

BACKGROUND AND OBJECTIVE

Hydroxychloroquine was widely used during the severe acute respiratory syndrome coronavirus 2 pandemic as an antiviral drug. Most previous pharmacokinetic/pharmacodynamic studies on hydroxychloroquine were conducted on healthy volunteers or patients receiving long-term therapy. There are no studies on the elimination of hydroxychloroquine after short-term treatments. Hydroxychloroquine is known to have a pro-arrhythmic effect through QT interval prolongation, but data in this setting are not conclusive. Our aims were to estimate the time needed for hydroxychloroquine concentrations (CHCQ) to drop to a safe concentration (500 ng/mL) after a short-term therapeutic cycle and to correlate the corrected QT interval with CHCQ.

METHODS

We collected blood samples and electrocardiograms of patients who underwent short-term therapy with hydroxychloroquine during drug intake and after discontinuation. Hydroxychloroquine concentrations were determined by high-performance liquid chromatography-tandem mass spectrometry and analysed with a linear regression model to estimate the elimination time of the drug after its discontinuation. We conducted a multivariate analysis of the corrected QT interval correlation with CHCQ.

RESULTS

Our data suggest that short-term hydroxychloroquine courses can generate significant CHCQ persisting above 500 ng/mL up to 16 days after discontinuation of treatment. Corrected QT interval prolongation significantly correlates with CHCQ.

CONCLUSIONS

The study confirms the long half-life of hydroxychloroquine and its effect on the corrected QT interval even after short-term courses of the drug. This can inform the clinician using hydroxychloroquine treatments that it would be safer to start or re-initiate treatments with corrected QT interval-prolonging potential 16 days after hydroxychloroquine discontinuation.

Assessment of proarrhythmogenic risk for chloroquine and hydroxychloroquine using the CiPA concept

Chloroquine and hydroxychloroquine have been proposed recently as therapy for SARS-CoV-2-infected patients, but during 3 months of extensive use concerns were raised related to their clinical effectiveness and arrhythmogenic risk. Therefore, we estimated for these compounds several proarrhythmogenic risk predictors according to the Comprehensive in vitro Proarrhythmia Assay (CiPA) paradigm. Experiments were performed with either CytoPatch™2 automated or manual patch-clamp setups on HEK293T cells stably or transiently transfected with hERG1, hNav1.5, hKir2.1, hKv7.1+hMinK, and on Pluricyte® cardiomyocytes (Ncardia), using physiological solutions. Dose-response plots of hERG1 inhibition fitted with Hill functions yielded IC50 values in the low micromolar range for both compounds. We found hyperpolarizing shifts of tens of mV, larger for chloroquine, in the voltage-dependent activation but not inactivation, as well as a voltage-dependent block of hERG current, larger at positive potentials. We also found inhibitory effects on peak and late I_Na and on I_K1, with IC50 of tens of μM and larger for chloroquine. The two compounds, tested on Pluricyte® cardiomyocytes using the β-escin-perforated method, inhibited I_Kr, I_CaL, I_{Na peak}, but had no effect on I_f. In current-clamp they caused action potential prolongation. Our data and those from literature for I_to were used to compute proarrhythmogenic risk predictors B_net (Mistry HB, 2018) and Q_net (Dutta S et al., 2017), with hERG1 blocking/unblocking rates estimated from time constants of fractional block. Although the two antimalarials are successfully used in autoimmune diseases, and chloroquine may be effective in atrial fibrillation, assays place these drugs in the intermediate proarrhythmogenic risk group.

Computational studies reveal Fluorine based quinolines to be potent inhibitors for proteins involved in SARS-CoV-2 assembly

World is witnessing one of the worst pandemics of this century caused by SARS-CoV-2 virus which has affected millions of individuals. Despite rapid efforts to develop vaccines and drugs for COVID-19, the disease is still not under control. Chloroquine (CQ) and Hydroxychloroquine (HCQ) are two very promising inhibitors which have shown positive effect in combating the disease in preliminary experimental studies, but their use was reduced due to severe side-effects. Here, we performed a theoretical investigation of the same by studying the binding of the molecules with SARS-COV-2 Spike protein, the complex formed by Spike and ACE2 human receptor and a human serine protease TMPRSS2 which aids in cleavage of the Spike protein to initiate the viral activation in the body. Both the molecules had shown very good docking energies in the range of -6kcal/mol. Subsequently, we did a high throughput screening for other potential quinoline candidates which could be used as inhibitors. From the large pool of ligand candidates, we shortlisted the top three ligands (binding energy -8kcal/mol). We tested the stability of the docked complexes by running Molecular Dynamics (MD) simulations where we observed the stability of the quinoline analogues with the Spike-ACE2 and TMPRSS2 nevertheless the quinolines were not stable with the Spike protein alone. Thus, although the inhibitors bond very well with the protein molecules their intrinsic binding affinity depends on the protein dynamics. Moreover, the quinolines were stable when bound to electronegative pockets of Spike-ACE2 or TMPRSS2 but not with Viral Spike protein. We also observed that a Fluoride based compound: 3-[3-(Trifluoromethyl)phenyl]quinoline helps the inhibitor to bind with both Spike-ACE2 and TMPRSS2 with equal probability. The molecular details presented in this study would be very useful for developing quinoline based drugs for COVID-19 treatment.