The FDA released its long-awaited draft guidance (along with helpful commentary) regarding the interchangeability of biosimilars last week, offering a new pathway to establish interchangeability on top of a biosimilar designation. Most notably, biosimilar manufacturers will be required to conduct switching studies – with at least two switches back and forth between the originator and biosimilar therapy – to establish that there are no adverse effects associated with switches. This requirement applies to medications that are administered more than once (like insulin), as opposed to one-time treatments. Additionally, the FDA notes that the proposed interchangeable biosimilar product should be administered via the same delivery mechanism as the originator product, so as not to confuse patients and caregivers. For example, biosimilar products should not be delivered via auto-injector pen if the originator products are only offered in vial and syringe form. Importantly, an interchangeability designation for a biosimilar product would allow pharmacy-level substitutions of the biosimilar for the prescribed reference product, without the intervention of the prescriber. Thus, a pharmacist could substitute a biosimilar product that has an interchangeable designation if the prescribed originator product is not available, without checking with the healthcare provider who originally prescribed the medication. Notably, neither Lilly/BI’s Basaglar nor Merck’s recently-submitted biosimilar insulin glargine MK-1293 sought an interchangeability designation and thus cannot be switched in this manner; neither product is technically considered a “biosimilar” for that matter – the products are both considered follow-on biologics and submitted through the 505(b)(2) regulatory pathway rather than the newer 351(k) biosimilar approval pathway. Nonetheless, we’re pleased to finally see clear, specific guidelines toward establishing interchangeability in the complex biosimilar landscape – this issue was essentially dodged in the 2015 biosimilar guidance and in the 2016 draft guidance on labeling for biosimilar products. On the other hand, the 351(k) biosimilar pathway was established as a part of the ACA and it’s unclear what the impact of the new US administration’s efforts to repeal the ACA will have on both the broader biosimilar regulatory pathway and this interchangeability guidance. The draft interchangeability guidance is open for comment until March 20, 2017. We are curious what readers would advise – if you have advice for us on how to comment, please let us know.
-- by Helen Gao and Kelly Close