Proof of efficacy trials: choosing the dose

Area of Science:

• Pharmacology
• Clinical Trials
• Drug Development

Background:

• Current clinical doses of antiepileptic drugs (AEDs) often differ from those used in initial trials.
• This discrepancy highlights a gap in understanding how optimal dose and titration schedules are determined during early drug development.

Purpose of the Study:

• To emphasize the importance of dose-response assessment in drug development programs.
• To outline key elements of dosing that require characterization according to regulatory guidelines.
• To review various study designs for assessing dose-response relationships in early drug development.

Main Methods:

• Review of retrospective data on antiepileptic drug (AED) usage and development programs.
• Analysis of International Council on Harmonization (ICH) E4 guidelines for dose-response information.
• Categorization of dose-response study designs: free titration, forced titration/dose escalation, parallel dose response, and dose reduction studies.
• Consideration of concentration-defined trials as an alternative approach.

Main Results:

• Regulatory guidelines mandate characterization of maximum well-tolerated dose, minimum effective dose, and titration rate.
• Multiple study designs exist for dose-response assessment, each suited to different developmental stages and disease severities.
• Concentration-defined trials offer a successful alternative in specific circumstances for newer AEDs.

Conclusions:

• Integrating robust dose-response studies early in the drug development process is essential.
• Earlier dose-response evaluations can potentially decrease the incidence of failed Phase 3 clinical trials.
• Optimizing dose selection and titration strategies early can lead to more efficient and successful drug registration.