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Erschienen in:
20.06.2017 | Original Article
Assessment of cabozantinib treatment on QT interval in a phase 3 study in medullary thyroid cancer: evaluation of indirect QT effects mediated through treatment-induced changes in serum electrolytes
Erschienen in: Cancer Chemotherapy and Pharmacology | Ausgabe 2/2017
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Purpose
This study evaluated factors impacting QTc interval in a phase 3 trial of cabozantinib in progressive, metastatic, medullary thyroid cancer (MTC).
Methods
Electrocardiogram (12-lead ECG) measurements were obtained at screening, and at pre-dose, and 2, 4, and 6 h post-dose on Days 1 and 29 in a phase 3 study in patients with MTC treated with cabozantinib (140 mg/day). Central tendency analyses were conducted on baseline-corrected QTc values. Linear and nonlinear mixed-effects models were used to evaluate potential factors affecting the QTc interval, including serum electrolytes, patient demographics, and cabozantinib concentration.
Results
Central tendency analysis showed that oral cabozantinib (140 mg/day) produced a 10–15 ms increase in delta–delta Fridericia corrected QT (∆∆QTcF) and delta–delta study-specific corrected QT (∆∆QTcS) on Day 29, but not on Day 1. Further analysis showed that QTcS provided a slightly more accurate QT correction than QTcF. Mixed-effects models evaluating serum electrolytes, age, sex, and cabozantinib concentration showed that decreased serum calcium and potassium could explain the majority of cabozantinib treatment-associated QTcS prolongation observed in this study.
Conclusions
Cabozantinib treatment prolongs the ∆∆QTcF interval by 10–15 ms. There was the absence of a strong relationship between cabozantinib concentration and QTcS prolongation. Cabozantinib treatment effects on serum calcium and potassium best explain the QTcS prolongation observed in this study.