Abstract P3-14-07: Evaluation of the effects of talazoparib on QT interval prolongation

Background: Talazoparib (TAL), an oral poly ADP-ribose polymerase inhibitor, is under investigation in multiple oncologic clinical trials and has been submitted to the US FDA for use in patients (pts) with germline BRCA-mutated, HER2-negative advanced breast cancer.

International Conference on Harmonisation guidance recommends all new drugs be evaluated for effects on cardiac repolarization in a well-controlled clinical study. For drugs for which such evaluation cannot be conducted in healthy volunteers (eg, most anticancer agents), collection of robust corrected QT (QTc) interval data from a dedicated QTc study (hybrid thorough QT/QTc study) in pts is required in the registration dossier. The effect of steady-state (ss) TAL (1 mg once daily) on cardiac repolarization in pts with advanced solid tumors was evaluated in an open-label phase 1 study (NCT03042910).

Methods: Continuous 12-lead electrocardiogram (ECG) recordings were collected at baseline (Day -1); time-matched pharmacokinetic (PK) samples and continuous ECG recordings were obtained on Days 1, 2, and 22 (when TAL concentrations achieved ss). On Day -1, pts had continuous 12-lead ECG recording starting at Time 0 (Day 1 dosing time) for 6 hrs. On Days 1 and 22, ECG recording started 45 min before TAL administration and continued for 6 hrs post dose and blood samples for PK were collected before dose and at 1, 2, 4, and 6 hrs post dose. On Day 2, a 30-min ECG recording and a PK sample were obtained before dose at Time 0.

Continuous ECG recordings were submitted to a central laboratory; triplicate 10-sec ECGs were extracted from a 5-min extraction window beginning 15 min before each PK collection time. ECG measurements were reported via blinded manual adjudication process and included PR interval, QT interval, RR interval, and QRS complex. The QT interval was corrected for effect of heart rate using Fridericia's correction (QTcF) and Bazett's correction (QTcB).

The estimate of change from time-matched baseline and its 2-sided 90% confidence interval (CI) was calculated for each nominal time point using PROC MEANS. Additionally, a prespecified PK/pharmacodynamic (PD) model was used to describe the relationship between plasma TAL concentrations ([TAL]) and QTc. The prespecified linear mixed-effects model included [TAL], time (categorical), and treatment with random pt effects on [TAL] and the intercept. If the upper bounds (UB) of 1-sided 95% CIs of time-matched ΔQTc for all ECG time points were <20 msec and the UB of 1-sided 95% CIs of the predicted ΔQTc at the mean ss maximum [TAL] was <20 msec, the effect of TAL on QTc was not of clinical relevance.

Results: 37 of 38 pts enrolled received TAL and were included in the ECG and PK/PD analyses. No pts had a postbaseline absolute maximum QTcF or QTcB ≥500 msec or ΔQTc ≥60 msec. The UB of the 1-sided 95% CI for the time-matched ΔQTcF and ΔQTcB were <12 msec at all nominal ECG time points. In the PK/PD analysis, the slopes (95% CI) of QTcF-[TAL] and QTcB-[TAL] relationships were -0.14 (-0.78 to 0.50) msec/ng/mL and -0.24 (-0.88 to 0.41) msec/ng/mL, respectively, indicating that TAL did not have a concentration-dependent effect on QTcF or QTcB.

Conclusion: TAL does not have a clinically relevant effect on QTc.

Funding: Medivation LLC, acquired by Pfizer.

Citation Format: Hoffman J, Chakrabarti J, Wainberg ZA, Plotka A, Babu S, Milillo Naraine A, Kanamori D, Moroose R, Nguyen L, Wang D. Evaluation of the effects of talazoparib on QT interval prolongation [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-14-07.

Concomitant blockade of 5-HT(1A) receptor and 5-HT transporter: use of the Hunter Serotonin toxicity criteria in a clinical pharmacology study

There is a potential risk that 5-HT(1A) receptor blockade combined with blockade of the 5-HT transporter by an SSRI may cause a toxic increase in 5-HT within the synapse, sparking concern for 'serotonin syndrome', a rare but potentially life threatening condition. We evaluated the safety and pharmacodynamics of the combination of the 5-HT(1A) antagonist lecozotan and the SSRI citalopram in a well-controlled Clinical Pharmacology Unit setting using the Hunter Serotonin Toxicity Criteria (HSTC), a set of validated decision rules featuring neurological and body temperature measurements, to detect any clinically relevant serotonin toxicity. Forty-three young healthy male subjects were randomized, to 2 parallel double-blind treatment groups following a 10-day citalopram 40 mg run-in period: citalopram 40 mg/lecozotan 10mg or citalopram 40 mg/placebo for 9 days. Overall, the combined administration of active drugs was well tolerated, however, one subject experienced moderate hyperreflexia, tremor of the hands, and sweating of hands and feet after 3 days of combined treatment. The event prompted treatment withdrawal and was regarded as mild serotonin toxicity, as per the HSTC. The onset of the event was around the time of peak plasma concentrations (t(max)) of both lecozotan and citalopram, and its time course corresponds to the well-defined PK profile of lecozotan. No evidence of a PK interaction was detected trough lecozotan and citalopram plasma concentrations analysis. The utility of the HSTC in detecting the non-discrete group of symptoms commonly referred to as "serotonin toxicity" was demonstrated in this clinical pharmacology study combining two 5-HT agents in a clinically controlled setting.

A Positron Emission Tomography Study to Assess Binding of Lecozotan, a Novel 5-Hydroxytryptamine-1A Silent Antagonist, to Brain 5-HT1A Receptors in Healthy Young and Elderly Subjects, and in Patients With Alzheimer's Disease

This positron emission tomography (PET) study was conducted to assess binding of lecozotan, a new potent and silent 5-hydroxytryptamine-1A (5-HT1A) antagonist being developed for the treatment of Alzheimer's disease (AD), to 5-HT1A receptors in the human brain using 11C-labeled WAY-100635. Lecozotan was administered as a single dose of 0.5, 1, or 5 mg to young subjects and 5 mg to elderly subjects and AD patients. PET measurements were performed at 3-4 time points over a 25-h period. Mean peak 5-HT1A receptor occupancy (RO) in young subjects (seen at 1 h) was 10%, 18%, and 44% for the three doses, respectively. Mean peak RO was slightly higher in elderly (63%) and AD patients (55%). An Emax pharmacokinetic/pharmacodynamic model adequately described the lecozotan plasma concentration-RO relationship. Steady-state peak RO is predicted to be approximately 70% for 5 mg q12 h (twice-daily). Results demonstrate that lecozotan binds to the human brain 5-HT1A receptors and has a maximum observed RO of 50-60% following a single dose of 5 mg in elderly subjects/AD patients.

Psychiatric nursing in Poland

As the role of Polish nurses continues to expand, so does their need for education at the university level. This is particularly evident for nurses joining the therapeutic teams in Poland's psychiatric hospitals. In the new structure of psychiatric service being offered, nurses are not only doctors' partners in the diagnostic, therapeutic, resocialization and psychotherapeutic processes but also fellow promoters of mental health. They are needed as a source of new ideas and solutions as well as to initiate new forms of activities in hospitals, consulting units or whatever setting they find themselves.