Filgrastim Biosimilar: Curb Your Enthusiasm in the US, and Celebrate in the EU, Canada, and Japan

We review regulatory, legal, clinical, practical, and economic considerations for biosimilar filgrastims. Biosimilar filgrastim is the only oncology biosimilar marketed in the European Union (EU), Japan, Canada, and the United States (US). EU countries have the longest biosimilar filgrastim regulatory approval history (2008). In Japan, three biosimilar filgrastims are approved (2012, 2013, and 2014). Canada, the US, and Japan all had shorter regulatory review times (10, 10, 11 to 13 months, respectively) versus EU countries (16 to 20 months) and fewer approved biosimilar filgrastims (1, 1, 3, and 8, respectively). Patent litigation delayed marketing in the US, but not the other three regions. Clinical guidelines encourage biosimilar filgrastim use in Japan and EU countries, but not in the US or Canada. Pharmaceutical substitution is allowed in most EU countries and Canadian provinces, but not in most US states or Japan. Interchangeability is allowed for new starts in several EU countries and Canadian provinces, but not in US or Japan. Each region supports unique filgrastim names and labels identifying each product as biosimilar. Empirical data on biosimilar filgrastim use is difficult to obtain in Canada and the US as the approvals are so recent. In Japan, 26% market share is reported by a national survey and in the European Union countries, 38% market share is reported based on IMS data. Pricing data in each region are difficult to obtain as these data vary based on site of care (inpatient versus outpatient), insurer, legislation, polices, regions, states, provinces, and countries. Intra- and international variability in regulatory policies and insurance practices represent large obstacles to adoption in the US, but do not present obstacles in the other regions. Overall, biosimilar filgrastrim's clinical and regulatory policies and procedures and obstacles for adoption are extremely variable and are likely to deter utilization in the US, but not in Canada, Japan, or European Union countries.