Will “Interchangeability” Boost Biosimilar Prescribing?

Biopharmaceutical companies developing new competitive biotech therapies have pressed hard for clarity on the testing and data required by FDA to gain market approval of biosimilars that can be filled by a pharmacist without prescriber preapproval. The hope is that a clear process for developing and marketing interchangeable biologics will spur prescribing and switching to these more affordable products.

So far, progress towards interchangeability has been slow. FDA issued a draft guidance in January 2017 to clarify the data and testing process for obtaining this status, but biosimilar makers have raised objections that the added testing would not provide important additional information. The guidance recommends clinical switching studies with at least three switches and PK/PD endpoints in order to assess risk to patients alternating between use of the biosimilar and reference product. FDA also seeks studies that use U.S. licensed comparators and enroll patients to mimic real-life use.

Multiple comments on the guidance challenge many key recommendations. The Biosimilars Council of the Association for Accessible Medicines (AAM) raised concerns about measuring PK endpoints, ruling out use of non-U.S. reference product comparators, and the possibility of requiring post-marketing data and comparative human factor studies for delivery devices in applications for these products.

Still to be addressed, pointed out Hillel Cohen, executive director of scientific affairs at Sandoz, is how FDA will govern the naming and labeling of interchangeable biologics.  FDA so far has not addressed whether these products will follow the same naming convention set for other biosimilars, and if labels will specify that a product is an interchangeable biologic, Cohen commented at a recent conference sponsored by the Biosimilars Council.

And as states govern pharmacy practice in the U.S., Cohen noted that state drug substitution laws will need to be updated to permit pharmacy-level substitution of an interchangeable biologic for a reference product. More than 30 states have passed or are considering such legislation, but policies vary considerably.

Another issue is whether interchangeable biologics will be priced higher than regular biosimilars, and how both will compare to reference products. Efforts by brands to discourage biosimilar prescribing recently came to light in a lawsuit filed by Pfizer that charges Johnson & Johnson with utilizing unfair marketing practices to block sales of its biosimilar Inflecta. The Pfizer product, which was approved in early 2016, has struggled to compete with J&J’s Remicade due to J&J contracts with hospitals and insurers that allegedly offer steep rebates on Remicade only if customers exclude coverage for the Pfizer copycat. The success of J&J’s “Biosimilar Readiness Plan” reflects a reluctance of providers to switch patients that are stable on Remicade to Inflecta without a significant cost advantage.

These issues cast doubts over whether biosimilar makers will invest in the additional testing needed to gain the interchangeability designation in the face of efforts by innovators to discourage switching by physicians and health plans. Biosimilar makers claim that a current brand strategy is to advise prescribers and payers against switching patients to a biosimilar therapy at this time, but to wait for the interchangeable product -- which may be a long time coming.