We live in interesting times. We just saw the approval of Zarxio, the first U.S. biosimilar product of Neupogen (filgrastim). What it means for both products is still uncertain, as U.S. rules for biosimilars are still evolving. Key questions have been the convention of proprietary names for biosimilars and the interchangeability between original and biosimilar. These two questions may be an important driver of views and actions from payers and prescribers.
In the United States, the Food and Drug Administration (FDA) has not yet given a final ruling on biosimilars, but has developed draft guidance for the new 351(k) pathway for biosimilars. The recent FDA approval of Zarxio (manufactured by Sandoz) has already been eagerly awaited by those trying to further anticipate FDA actions. Zarxio was approved with the international nonproprietary name (INN) filgrastim-sndz, not simply filgrastim. It is not considered interchangeable and the chosen naming seems to allow for separate safety-data gathering. How universally these rulings apply to other biosimilars is speculative at this stage.
The European Medicines Agency (EMA) has an established biologics pathway, but does not make recommendations on interchangeably of biosimilars with its reference medicine, as it has deemed this a matter for the national competent authorities. In France, pharmacists are allowed to substitute biosimilars for new treatments, provided that the physician has not marked the prescription as “nonsubstitutable.” In Italy, biosimilars are not considered interchangeable and can only be initiated through a specific physician prescription for that product. Other EU countries generally do not allow substitution or only under very specific conditions.
How will physicians adopt biosimilar options as part of their prescribing options as regulatory and payer decisions evolve? The U.S. launch of Zarxio, as a biosimilar option for Neupogen, and the imminent launch of biosimilar versions of Remicade (infliximab) in the United States and Europe will help further clarify physician attitudes. Many physicians are still not completely comfortable with biosimilar options, but the question is how they will respond to payer pressures and patient incentives for cheaper options.
Most payers are taking a wait-and-see attitude as regulations for biosimilars are evolving worldwide. Some payers have been very vocal about opportunities for cost management with biosimilars, but their ability to do so will depend highly on the acceptability of those measures by physicians and patients. The jury is certainly still out on this aspect.
Interesting times indeed, as the biosimilar policies and practices evolve with some biologic blockbusters such as Neupogen, Remicade and other anti-TNFs on the block.