Evaluating imbalances of adverse events during biosimilar development

Area of Science:

• Biopharmaceutical science
• Clinical pharmacology
• Regulatory science

Background:

• Biosimilars are highly similar to reference biologics, requiring comprehensive evidence for approval.
• Regulatory agencies recommend a stepwise approach for biosimilar evaluation, starting with pharmacokinetic similarity studies.
• Pharmacokinetic studies are primarily for demonstrating similarity, not for direct safety comparisons.

Purpose of the Study:

• To evaluate the role of pharmacokinetics similarity studies in biosimilar development.
• To illustrate how adverse event data from early studies can impact later clinical trial design.
• To highlight the case of PF-05280014, a potential biosimilar to trastuzumab.

Main Methods:

• Review of biosimilar development guidelines and stepwise evaluation approaches.
• Analysis of pharmacokinetic similarity study design and its limitations for safety assessment.
• Case study of PF-05280014 development, focusing on adverse event reporting in early trials.

Main Results:

• Pharmacokinetics studies are a foundational step in biosimilarity assessment.
• Numerical imbalances in adverse events, even in small studies, can raise safety concerns.
• The development of PF-05280014 demonstrated that early safety signals may necessitate additional clinical trials.

Conclusions:

• Pharmacokinetics similarity studies are crucial but not exhaustive for biosimilar evaluation.
• Careful monitoring and analysis of all clinical data, including adverse events, are essential.
• Unexpected findings in early-stage studies can influence the overall biosimilar development pathway and regulatory requirements.