FDA proposes guidance for biosimilar product labels

In proposed draft guidance issued on March 29, FDA is filling out more of the details about how biosimilars will be regulated; in this case, how product labels and medication guides should be worded to include (or exclude) certain information present on the originator (reference) product label. A comment period is open for the next 60 days. But FDA is still holding off on deciding how specifically to allow for “interchangeability,” the determination that a biosimilar could be substituted for a reference product without the prescriber’s intervention (as is the case, most of the time, with small-molecule generics).

In this document, “Labeling for Biosimilar Products,” the Office of Medical Policy in CDER, and CBER, are following through on their earlier proposed guidance on naming conventions issued last fall. Get used to some new terminology: proprietary (branded) name; proper name, and core name. For a fictional product originally given the nonproprietary name of “replicamab,” and branded by its fictional originator as “Junexant,” and which is followed by a biosimilar branded by its fictional developer as “Nexsymeo,” Junexant will now have a proper name of “replicamab-hjxf,” and Nexsymeo will have a proper name of “replicamab-cznm.” Both have the core name of replicamab; the four-letter extension is a way to distinguish Nexsymeo both from the originator drug and from any other biosimilar entrances from other developers. (FDA’s proposed four-letter extension, which is intentionally noninformational, has strong advocates and strong opponents; its adoption awaits FDA’s final guidance on the topic.)

Then, per the new guidance, the biosimilar’s product label will mention the originator drug by its proprietary name, and to pick up relevant information on adverse reactions and clinical studies from the reference product label. However, other information, such as warnings, contraindications and adverse reactions (from postmarketing experience) should use the core name only. For information relevant to the specific biosimilar that is distinct from the originator drug (for example, dosage quantities), FDA suggests using either the biosimilar’s proprietary name (if it has one) or its proper name—in the example above, replicamab-cznm.

All this works for biosimilars used for the same indications as the reference product. But it is likely that the biosimilar will not be approved for all indications that the reference product is, at least initially; moreover, there is the possibility that the biosimilar could be approved (with additional clinical trials) for indications that the reference product has not, as yet, been approved. Product managers will need to navigate the differences closely in label texts, all of which are subject to prior review by FDA before the biosimilar enters the market.