Sertindole: dilemmas for its use in clinical practice

A randomized, placebo-controlled repeat-dose thorough QT study of inhaled loxapine in healthy volunteers

OBJECTIVE

This randomized, double-blind, active- and placebo-controlled, crossover, thorough QT study assessed the effect of two inhaled loxapine doses on cardiac repolarization as measured by corrected QT (QTc) interval in healthy subjects (ClinicalTrials.gov NCT01854710).

METHODS

Subjects received two doses of inhaled loxapine (10 mg) 2 hours apart + oral placebo, two doses of inhaled placebo + oral placebo, or two doses of inhaled placebo + oral moxifloxacin (400 mg; positive control), with ≥ 3 days washout between treatments. Two-sided 90% confidence intervals (CIs) were calculated around least-squares mean predose placebo-subtracted individually corrected QT durations (ΔΔQTcIs) at 12 time points throughout 24 hours after dosing. A ΔΔQTcI 95% upper CI exceeding 10 msec was the threshold indicating QTc prolongation (primary endpoint). Secondary endpoints included Fridericia- and Bazettcorrected QT duration and QTcI outliers Pharmacokinetics and adverse events (AEs) were also assessed.

RESULTS

Of 60 subjects enrolled (mean age, 33.8 years; 52% male), 44 completed the study. Post loxapine dosing, no ΔΔQTcI 95% upper CI exceeded 10 msec; the largest was 6.31 msec 5 minutes post dose 2. Methodology was validated by ΔΔQTcI 95% lower CIs exceeding 5 msec at 9 of 12 time points after moxifloxacin dosing. Loxapine plasma concentrations increased rapidly (mean Cmax, 177 ng/mL; median tmax 2 minutes after dose 2, 2.03 hours after dose 1). There were no deaths, serious AEs, or AEs leading to discontinuation, and one severe AE.

CONCLUSIONS

Primary and secondary endpoints indicated two therapeutic doses of inhaled loxapine did not cause threshold QTc prolongation in this study.

Efficacy and safety of sertindole in schizophrenia: a clinical review

Sertindole is an atypical antipsychotic reintroduced into the European market in 2005 after a reevaluation of its risks and benefits, under the agreement that close electrocardiographic screening would be conducted. It has a high affinity for dopamine D2, serotonin 5-HT2A and 5-HT2C, and α1 adrenergic receptors. Moreover, sertindole shows modest affinity for H1-histaminergic and muscarinic receptors. The pharmacological properties, clinical efficacy, safety, and tolerability of sertindole are covered in this article based on a literature review from 1990 to 2014. Given current available findings, sertindole is at least effective as haloperidol, risperidone, and olanzapine on schizophrenia symptoms. Regarding its efficacy on cognitive symptoms, sertindole effect is supported by both preclinical and clinical studies versus haloperidol and olanzapine; however, its role on cognition needs further clarification. Concerning safety and tolerability issues, sertindole is characterized by a low potential to cause sedation and extrapyramidal symptoms, and by an acceptable metabolic profile; nevertheless, cardiac safety remains a major concern, and the electrocardiographic monitoring should be carried out during treatment to substantially reduce cardiovascular risk. In conclusion, although it has an equivalent profile compared to other antipsychotic drugs, sertindole actually remains a second-line choice for schizophrenic patients intolerant to at least one other antipsychotic agent.

Cardiac effects of sertindole and quetiapine: analysis of ECGs from a randomized double-blind study in patients with schizophrenia

The QT interval is the most widely used surrogate marker for predicting TdP; however, several alternative surrogate markers, such as Tpeak-Tend (TpTe) and a quantitative T-wave morphology combination score (MCS) have emerged. This study investigated the cardiac effects of sertindole and quetiapine using the QTc interval and newer surrogate markers. Data were derived from a 12 week randomized double-blind study comparing flexible dosage of sertindole 12-20mg and quetiapine 400-600mg in patients with schizophrenia. ECGs were recorded digitally at baseline and after 3, 6 and 12 weeks. Between group effects were compared by using a mixed effect model, whereas assessment within group was compared by using a paired t-test. Treatment with sertindole was associated with QTcF and QTcB interval prolongation and an increase in MCS, T-wave asymmetry, T-wave flatness and TpTe. The mean increase in QTcF from baseline to last observation was 12.1ms for sertindole (p<0.001) and -0.5ms for quetiapine (p=0.8). Quetiapine caused no increase in MCS, T-wave asymmetry, T-wave flatness or TpTe compared to baseline. In the categorical analysis, there were 11 patients (9.6%) receiving quetiapine who experienced more than 20ms QTcF prolongation compared with 36 patients (33.3%) in the sertindole group. Sertindole (12-20mg) was associated with moderate QTc prolongation and worsening of T-wave morphology in a study population of patients with schizophrenia. Although, quetiapine (400-600mg) did not show worsening of repolarization measures some individual patients did experience significant worsening of repolarization. Clinical Trials NCT00654706.

QT dynamics during treatment with sertindole

OBJECTIVES

Sertindole is a nonsedating atypical antipsychotic drug with low propensity to cause extrapyramidal side effects but it has been associated with a 20 ms QTc prolongation and increased risk of cardiac events. It is uncertain whether this drug-induced increase in cardiac risk might also be revealed by dynamic measures of the QT interval such as the ratio of QT variability to heart rate variability (variability ratio [VR]). The aim of this study was to investigate the effect of sertindole on QT dynamics.

METHODS

QTc and the VR were assessed in an observational study using 24-hour Holter monitoring at baseline and after 3 weeks of treatment with sertindole 16 mg. The VR was calculated by dividing the standard deviation of QT intervals with the standard deviation of heart rates. Outcome measures were compared using paired t-test.

RESULTS

A total of 18 patients participated in the study, two were excluded from further analysis due to low amplitude of the T-wave. When patients were shifted to sertindole, the VR increased from 0.192 (SD 0.045) to 0.223 (SD 0.061), p = 0.02. The QTcF interval increased from 388 (SD 16) to 403 ms (SD 14), p = 0.002. There was no difference in heart rate 78 bpm (SD 8) versus 80 bpm (SD 10), p = 0.3 or heart rate variability (SDNN) 127 (SD 40) versus 115 ms (SD 45), p = 0.4.

CONCLUSION

Sertindole was associated with 19 ms QTc prolongation and an increased ratio of QT variability to heart rate variability. Both measures may contribute to the increased cardiovascular mortality found with sertindole.

How much to worry about the FDA warning in the use of citalopram?

A number of studies have suggested that antidepressants such as selective serotonin reuptake inhibitors may increase a risk of developing harmful cardiac adverse event such as QT interval prolongation. In fact, the US Food and Drug Administration (FDA) consecutively gave safety warnings to healthcare professionals that the use of citalopram may be associated with QT interval prolongation in 2011 and 2012. Despite the fact that citalopram has been one of the most acceptable antidepressants worldwide, concerns on citalopram about cardiac safety issues have become apparent to clinicians after the FDA warning. However, a recent cohort study raises some practical questions about the FDA warnings on the use of citalopram and may also provide clinicians with a good guidance for prudent use of citalopram in clinical practice.