On January 17, the FDA released its draft guidance on demonstrating biosimilar interchangeability. Originally expected to be released in late 2015, the long-awaited guidance concentrates on recommendations for proving that a potential therapeutic protein product, specifically, can be interchangeable with an FDA-licensed biological reference product when submitting a marketing application or supplement under Section 351(k) of the Public Health Service (PHS) Act.

Since 2015, the FDA has approved four biosimilars under the Act: Sandoz’s Zarxio and Erelzi, Pfizer and Celltrion’s Inflectra, and Amgen’s Amjevita. In contrast, 20 biosimilars have been approved in Europe. Interchangeability is a significant component of the development of biosimilars, as biosimilars can be replaced with their respective reference products at a pharmacy level as per the PHS Act.

The draft guidance recommends that sponsors consult with the FDA early in their development of biosimilars to gain information on how to adequately demonstrate interchangeability for their products, since each interchangeable product is different. It also suggests that studies should take place on alternating the biosimilars and its reference product two or more times to ensure that the product is still safe and effective. For these studies in particular, the Agency states that the reference product should be US-licensed to limit the number of “subtle differences” between US biological products and biological products in other regions. However, if the product is only to be used once, sponsors then need to provide an explanation justifying their decision to not conduct the alternating study.

Source: FDA