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Concentration-QTc analysis for single arm studies.

Yasushi Orihashi1, Shoichi Ohwada2, Yuji Kumagai3

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Summary

For single-arm studies, using categorical time effects in concentration-QTc (C-QTc) models improves QTc interval analysis by adjusting for diurnal variations when only pre-dose baselines are available.

Keywords:
Concentration-QTc modelDiurnal variationICH E14Mixed effects modelSingle arm study

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Area of Science:

  • Pharmacometrics
  • Clinical Pharmacology
  • Cardiovascular Safety Assessment

Background:

  • Concentration-QTc (C-QTc) modeling is crucial in early phase clinical trials for assessing drug-induced QTc prolongation.
  • Single-arm studies, common in early oncology development, present challenges in accounting for diurnal variations in QTc intervals using only pre-dose baseline data.
  • Existing guidance suggests time-matched baseline adjustments may suffice, but the utility of categorical time effects in this specific context remains under investigation.

Purpose of the Study:

  • To investigate the impact of including categorical time effects in C-QTc models for single-arm studies with pre-dose baselines.
  • To evaluate the ability of these models to adjust for diurnal variations in QTc intervals.
  • To compare the performance of C-QTc models with and without categorical time effects under various simulation scenarios.

Main Methods:

  • Simulations were conducted under diverse scenarios relevant to early oncology phase studies.
  • C-QTc models with and without categorical time effects were compared.
  • Model performance was assessed based on parameter estimation bias and false negative rates (FNRs) for linear C-QTc relationships.
  • The robustness of ΔΔQTc estimations was evaluated for non-linear C-QTc relationships.

Main Results:

  • Models without categorical time effects exhibited biased parameter estimates and unreliable FNRs when diurnal variations were present and the C-QTc relationship was linear.
  • Models incorporating categorical time effects demonstrated unbiased parameter estimates and controlled FNRs under linear C-QTc conditions.
  • For non-linear C-QTc relationships, ΔΔQTc estimations using models with categorical time effects were found to be not robust.

Conclusions:

  • Categorical time effects are recommended for C-QTc models in single-arm studies with pre-dose baselines to effectively adjust for diurnal QTc variations, particularly for linear relationships.
  • Collecting QTc measurements at 24 hours post-dose is advised for accurate ΔQTc estimation at the concentration of interest.
  • The use of C-QTc models with categorical time effects is recommended for robust cardiovascular safety assessment in such study designs.