Safety, pharmacokinetic, and positron emission tomography evaluation of serotonin and dopamine transporter occupancy following multiple-dose administration of the triple monoamine reuptake inhibitor BMS-820836

A systematic review of the potential effects of medications and drugs of abuse on dopamine transporter imaging using [123I]I-FP-CIT SPECT in routine practice

PURPOSE

In routine practice, dopamine transporter (DAT) imaging is frequently used as a diagnostic tool to support the diagnosis of Parkinson's disease or dementia with Lewy bodies. In 2008, we published a review on which medications and drugs of abuse may influence striatal [123I]I-FP-CIT binding and consequently may influence the visual read of an [123I]I-FP-CIT SPECT scan. We made recommendations on which drugs should be withdrawn before performing DAT imaging in routine practice. Here, we provide an update of the original work based on published research since 2008.

METHODS

We performed a systematic review of literature without language restriction from January 2008 until November 2022 to evaluate the possible effects of medications and drugs of abuse, including the use of tobacco and alcohol, on striatal DAT binding in humans.

RESULTS

The systematic literature search identified 838 unique publications, of which 44 clinical studies were selected. Using this approach, we found additional evidence to support our original recommendations as well as some new findings on potential effect of other medications on striatal DAT binding. Consequently, we updated the list of medications and drugs of abuse that may influence the visual read of [123I]I-FP-CIT SPECT scans in routine clinical practice.

CONCLUSION

We expect that a timely withdrawal of these medications and drugs of abuse before DAT imaging may reduce the incidence of false-positive reporting. Nevertheless, the decision to withdraw any medication must be made by the specialist in charge of the patient's care and considering the pros and cons of doing so.

Assessment of the Efficacy and Safety of BMS-820836 in Patients With Treatment-Resistant Major Depression: Results From 2 Randomized, Double-Blind Studies

Two phase 2B, randomized, double-blind studies assessed the efficacy and safety of fixed or flexible dose of triple monoamine uptake inhibitor BMS-820836 in patients with treatment-resistant depression to demonstrate whether switching to BMS-820836 was superior to the continuation of standard antidepressant treatment. Patients with a history of inadequate response to 1 to 3 adequate trials of antidepressant therapies were prospectively treated with duloxetine 60 mg/d for 8 weeks (CN162-006) or duloxetine 60 mg/d or escitalopram 20 mg/d for 7 weeks (CN162-007). Inadequate responders were randomized to continue their prospective phase treatment or switch to flexible-dose (0.5-2 mg/d; CN162-006) or fixed-dose (0.25, 0.5, 1, or 2 mg/d; CN162-007) BMS-820836 for 6 weeks. The primary end point in both studies was mean change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from randomization to study end point. BMS-820836 flexible (0.5-2 mg/d) or fixed dose of 1 mg/d or greater showed efficacy similar to the continuation of antidepressant treatment, with no statistically significant or clinically meaningful differences. In the CN162-006 study, the adjusted mean (SE) change in MADRS total score was -8.7 (0.661) and -8.1 (0.656) for BMS-820836 and duloxetine, respectively (P = 0.526). In the CN162-007 study, the adjusted mean (SE) change in MADRS total score was -7.3 (0.830) and -6.6 (0.842) for BMS-820836 of 1 and 2 mg, respectively, and -6.9 (0.602) for the continuation group (P = 0.910). Thus, BMS-820836 was well tolerated, with no evidence of dose-dependent discontinuations due to adverse events, but it failed to demonstrate superiority to the continuation of an existing antidepressant in patients with treatment-resistant depression.

Comparison of different QT interval correction methods for heart rate and QT beat-to-beat method in a thorough QT study of triple monoamine reuptake inhibitor BMS-820836

As BMS-820836 causes dose-dependent heart rate increases, QTcI, QTcF, QTcB, and QT beat-to-beat methods were compared in this thorough QT study in healthy subjects. Two parallel groups of subjects (n = 60 per group) received 2 mg (maximum therapeutic) or 4 mg (supratherapeutic) of BMS-820836 once daily for 14 days with uptitration. Another 60 subjects received encapsulated moxifloxacin (400 mg) or matching placebo in a nested-crossover study design. Compared with QTcF and QTcB, baseline QTcI had the smallest and near-zero Pearson correlation coefficient with heart rate (0.0938), which supported the choice of QTcI as the primary electrocardiographic end point. BMS-820836 was not associated with prolongation of the QT interval at the doses tested; however, ΔΔQTbtb showed the smallest deviation from 0 milliseconds compared with ΔΔQTcI and ΔΔQTcF. The ΔΔQTbtb results appeared to be more consistent with the very low likelihood of any effect on the QT interval by BMS-820836 based on the wide margin (>400×) of the in vitro hERG IC50 and free plasma concentration. Further, this is the first published study that used the nested-crossover design and QTbtb analysis in a thorough QT study. Assay sensitivity was confirmed with encapsulated moxifloxacin.

Use of 11C-PE2I PET in differential diagnosis of parkinsonian disorders

In idiopathic Parkinson disease and atypical parkinsonian disorders, central dopaminergic and overall brain functional activity are altered to different degrees, causing difficulties in achieving an unambiguous clinical diagnosis. A dual examination using (123)I-FP-CIT ((123)I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane, or (123)I-ioflupane) SPECT and(18)F-FDG PET provides complementary information on dopamine transporter (DAT) availability and overall brain functional activity, respectively. Parametric images based on a single, dynamic (11)C-PE2I (N-(3-iodoprop-2E-enyl)-2β-carbomethoxy-3β-(4-methyl-phenyl)nortropane) scan potentially supply both DAT availability (nondisplaceable binding potential [BPND]) and relative cerebral blood flow (relative delivery [R1]) at voxel level. This study aimed to evaluate the validity of (11)C-PE2I PET against the dual-modality approach using (123)I-FP-CIT SPECT and (18)F-FDG PET.

METHODS

Sixteen patients with parkinsonian disorders had a dual examination with (18)F-FDG PET and (123)I-FP-CIT SPECT following clinical routines and additionally an experimental (11)C-PE2I PET scan. Parametric BPND and R1 images were generated using receptor parametric mapping with the cerebellum as a reference. T1-weighted MR imaging was used for automated definition of volumes of interest (VOI). The DAT VOIs included the basal ganglia, whereas the overall brain functional activity was examined using VOIs across the brain. BPND and R1 values were compared with normalized (123)I-FP-CIT and (18)F-FDG uptake values, respectively, using Pearson correlations and regression analyses. In addition, 2 masked interpreters evaluated the images visually, in both the routine and the experimental datasets, for comparison of patient diagnoses.

RESULTS

Parametric (11)C-PE2I BPND and R1 images showed high consistency with (123)I-FP-CIT SPECT and (18)F-FDG PET images. Correlations between (11)C-PE2I BPND and (123)I-FP-CIT uptake ratios were 0.97 and 0.76 in the putamen and caudate nucleus, respectively. Regional (11)C-PE2I R1 values were moderately to highly correlated with normalized (18)F-FDG values (range, 0.61-0.94). Visual assessment of DAT availability showed a high consistency between (11)C-PE2I BPND and (123)I-FP-CIT images, whereas the consistency was somewhat lower for appraisal of overall brain functional activity using (123)I-FP-CIT and (18)F-FDG images. Substantial differences were found between clinical diagnosis and both neuroimaging diagnoses.

CONCLUSION

A single, dynamic (11)C-PE2I PET investigation is a powerful alternative to a dual examination with (123)I-FP-CIT SPECT and (18)F-FDG PET for differential diagnosis of parkinsonian disorders. A large-scale patient study is, however, needed to further investigate distinct pathologic patterns in overall brain functional activity for various parkinsonian disorders.

Evaluation of safety and tolerability, pharmacokinetics, and pharmacodynamics of BMS-820836 in healthy subjects: a placebo-controlled, ascending single-dose study

RATIONALE

BMS-820836, a novel triple monoamine reuptake inhibitor, is an experimental monotherapy for sufferers of major depressive disorder who have had an inadequate response to an existing antidepressant treatment.

OBJECTIVES

This study was conducted to evaluate the safety and tolerability, pharmacokinetics (PK), and serotonin transporter (SERT) and dopamine transporter (DAT) occupancy for single doses of BMS-820836 in healthy subjects.

METHODS

Healthy subjects were assigned to seven BMS-820836 dose panels (0.025, 0.1, 0.5, 1, 2, 3, and 5 mg; n = 8 each), in which subjects were randomly allocated 3:1 to a single BMS-820836 dose or matched placebo. Serial blood samples were collected on Days 1, 2, 3, 4, 7, and 14 to characterize the PK of BMS-820836. Following evaluation of the maximum tolerated dose, SERT occupancy was determined by applying [(11)C]DASB positron emission tomography (PET) after single-dose BMS-820836 (0.5 or 3 mg; n = 3 each) and DAT occupancy by applying [(11)C]PE2I PET after single-dose BMS-820836 (3 mg; n = 6).

RESULTS

Single oral doses of BMS-820836 (0.025-3 mg) were generally safe and well tolerated. BMS-820836 had a median T max of 5.0-7.2 h and a mean apparent terminal T 1/2 of 34-57 h. Mean striatal SERT occupancies were 19 ± 9 % and 82 ± 8 % after single doses of 0.5 and 3 mg BMS-820836, respectively. The mean striatal DAT occupancy was 19 ± 9 % after a single 3 mg BMS-820836 dose.

CONCLUSIONS

Single doses of BMS-820836 have meaningful SERT and DAT occupancy and demonstrate an acceptable safety and tolerability profile in healthy control subjects.