An update on the animal studies conducted for biosimilar approvals - Regulatory requirement vs actual scenario.

Nonclinical animal studies are considered as an integral part of biosimilar development program to demonstrate similarity and safety. We have compiled, reviewed and summarized animal studies conducted for European Medicines Agency (EMA) and United States Food and Drug Administration (US FDA) submission from 2006 till December 2018. The commonest animal studies conducted included repeat-dose toxicity study along with toxicokinetic, local tolerance and immunogenicity assessments, while the least common included primary pharmacodynamic, pharmacokinetic, safety pharmacology and single-dose toxicity studies. Animal studies were designed based on pharmacology of the drug, disease condition and innovator studies. Studies mostly used EU-sourced reference products as a comparator. For biosimilars approved both in the US and European Union (EU), similar data packages were submitted to these regions. Despite the regulatory guidelines allowing waiver of animal studies based on analytical data, animal studies have been conducted for almost all the approved biosimilars in the US and EU. There is an increasing need to re-assess the relevance of animal studies to support regulatory approval of biosimilars. Stepwise assessment for biosimilarity and conducting animal studies only if required at the right instance based on residual uncertainties may assist in optimizing animal study requirement for biosimilar development.