Adaptive Seamless Design for Establishing Pharmacokinetic and Efficacy Equivalence in Developing Biosimilars.

BACKGROUND: Recently, numerous pharmaceutical sponsors have expressed a great deal of interest in the development of biosimilars, which requires clinical trials to demonstrate that the pharmacokinetic (PK) and clinical efficacy are equivalent. Pharmacodynamics (PD) may be used in evaluating efficacy if there are relevant PD markers available. However, in their absence, it is necessary to design the associated clinical trials to include efficacy measures as the primary endpoint.

METHODS: In this study, we propose a novel adaptive seamless PK and efficacy design with an efficient framework to remedy the risk of misspecification of efficacy parameters and to discontinue the trial evaluating the efficacy for futility based on the PK evaluation. Here, we consider the clinical development of biosimilars including their evaluation in patients rather than healthy volunteers under a situation where both PK and efficacy parameters are required to demonstrate equivalence. The original idea of the proposed method was to organize a clinical trial that includes the statistical analysis of PK as an interim analysis, with sample size recalculation of the efficacy data.

RESULTS: Our simulation study indicated that the proposed design would allow trials to be more efficient than with the classical design.

CONCLUSIONS: This proposal provides appealing advantages, such as a shorter time period, additional cost savings, and a smaller number of patients required.