Effect of axitinib on the QT interval in healthy volunteers
Ana Ruiz-Garcia1, Brett E Houk, Yazdi K Pithavala
1Clinical Pharmacology, Pfizer Inc, San Diego, CA, USA.
Purpose:
Axitinib is a potent and selective inhibitor of vascular endothelial growth factor receptors 1-3, approved for second-line treatment of advanced renal cell carcinoma (RCC). Preclinical studies did not indicate potential for axitinib-induced delayed cardiac repolarization.
Methods:
The effect of axitinib on corrected QT (QTc) prolongation was evaluated with one-stage concentration-QTc response modeling using data from a definitive randomized crossover QT phase I study in healthy volunteers administered one single 5-mg axitinib dose alone or in the presence of steady-state ketoconazole (400 mg once daily).
Results:
Axitinib and ketoconazole had opposite effects on heart rate: Axitinib lowered it, ketoconazole raised it. The final analysis showed a flat relationship between QTc and axitinib concentration (slope -0.0314 ms·mL/ng) for axitinib alone. Mean highest placebo-matched change from baseline in QTc was -3.0 [90 % confidence interval (CI) -5.4, -0.6] ms. At supratherapeutic axitinib exposures achieved with potent cytochrome P450 3A4/5 inhibition by ketoconazole, the model predicted mean QTc change of 6.5 (90 % CI 4.4-8.5) ms. The slope population mean estimate was -0.331 (95 % CI -0.860, 0.198) ms·mL/µg for ketoconazole alone and 0.0725 (0.0445-0.1005) ms·mL/ng for axitinib in the presence of ketoconazole. The results were then compared with those obtained based on more widely used Fridericia's, Bazett's, and study-specific correction methods.
Conclusions:
Since axitinib plasma concentrations observed in this study exceeded the range of concentrations observed in patients with RCC at the highest approved clinical dose (10 mg twice daily), axitinib was not associated with clinically significant QTc prolongation in target populations.
Insights
Axitinib, used for advanced renal cell carcinoma, did not cause significant QTc prolongation in healthy volunteers, even at high doses. This finding supports its safety profile in patients.
Area of Science:
- Pharmacology
- Cardiology
- Oncology
Background:
- Axitinib is a targeted therapy for advanced renal cell carcinoma (RCC).
- Preclinical data suggested axitinib does not prolong the corrected QT interval (QTc).
Purpose of the Study:
- To assess the effect of axitinib on QTc prolongation in healthy volunteers.
- To evaluate QTc changes using concentration-QTc response modeling.
Main Methods:
- A single 5-mg dose of axitinib was administered to healthy volunteers.
- QTc prolongation was assessed alone and with ketoconazole (a CYP3A4/5 inhibitor).
- One-stage concentration-QTc response modeling was employed.
Main Results:
- Axitinib alone showed a flat QTc-concentration relationship, with a mean highest placebo-matched QTc change of -3.0 ms.
- Ketoconazole increased heart rate, while axitinib decreased it.
- At supratherapeutic axitinib exposure (with ketoconazole), the model predicted a mean QTc change of 6.5 ms.
Conclusions:
- Axitinib was not associated with clinically significant QTc prolongation.
- Observed axitinib concentrations exceeded those in RCC patients at the highest approved dose.
- The study supports the cardiac safety of axitinib in its therapeutic use.
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