The first biosimilar has been approved by FDA:
This includes ZARXIO, the finished product, and the placeholder nonproprietary name both defined in the product insert as a specific protein:
ZARXIO (filgrastim-sndz) is a 175 amino acid human granulocyte colony-stimulating factor (G-CSF) manufactured by recombinant DNA technology."
But the FDA press release states, "For this approval, the FDA has designated a placeholder nonproprietary name for this product as "filgrastim-sndz." Thus, as designated by FDA, "filgrastim-sndz" is the official non-proprietary name applying to Zarxio, the finished product (drug product). Or as also stated, is "filgrastim-sndz" the active agent (drug substance), the version of recombinant G-CSF in this product? Or is "filgrastim-sndz" the name for both the product and active agent (seems so)? Or with it never mentioned, is the current official INN/USAN for G-CSF, "filgrastim," actually the name of the active agent? And besides not knowing what it refers to, "filgrastim-sndz" remains unclear regarding the underlying basis for such naming, whether the name is defined by entity/material (the active agent and/or product), by entity but varying with each manufacturer/sponsor, by entity but varying by approvals (linked to specific BLA(s)), or rational consideration of the agent/product. For example, if this version of G-CSF (same active agent/API from Sandoz/Novartis) was used in a liposomal-encapsulated formulation (a non-biosimilar product) from a different company, would that product (and its active agent) also be officially named "filgrastim-sndz?"
If this approval is indicative of FDA's approach to biosimilars nomenclature/identifiers, it is going to be an abysmal failure and embarrassment for the agency, besides presenting problems for industry, health care community and patients. With this approval, FDA simply took the official INN/USAN (filgrastim), by design a generic name for the active agent (G-CSF), added a (unique or generic, not stated) character string and by edict ruled this to be the U.S. estabished/official non-proprietary name for the product (with this suffix-differentiated name violating, outside, the INN/USAN system). FDA has been working on biosimilar nomenclature/identifier issues since even before BPCIA, for how many years now?, and this is what we get! But this is nothing new -- FDA and preceding U.S. biologics regulatory agencies have avoided developing functional definitions and nomenclature for biologics now for over 100 years of their regulation! Names being totally vague and also never disclosing any useful biologic agent or product definitions, CMC information, etc., has become part of FDA's corporate culture.
Let's hope the FDA's actual policies and whatever nomenclature/identifier system(s) it adopts are not as lame as this -- essentially the same legacy, pre-recombinant DNA, generic drug-oriented, nomenclature system (INN/USAN/official non-proprietary names) somehow still being applied to modern biologics and now biosimilars! As discussed in my pending Citizen Petition to FDA and U.S. BIOPHARMACOPEIA proposal (see below), both unique and generic names/identifiers (which simply need be functional, not anything official) are obviously needed for biologic products and their active agents, with two routes to this proposed - my petition seeks FDA develop needed names/identifiers and the BIOPHARMACOPEIA proposes nomenclature be handled by industry, as is common with some other, including FDA-regulated, products.