Despite the seemingly ground-breaking nature of the approval, the FDA explicitly limited the extent of the Omnitrope decision in important ways and emphasized that this action does not create new pathways for the approval of other biosimilar products.
The FDA distinguished the approval pathway of Omnitrope from that of other generic biologics. The Omnitrope application was filed under the approval pathway of section 505(b)(2) of the Federal Food, Drug, and Cosmetic Act (FDC Act). This section provides an abbreviated approval process for pharmaceuticals, including follow-on protein products that are substantially similar to other protein products approved under the FDC Act. Other protein and biological products are licensed through section 351 of the Public Health Service Act (PHS Act), which does not have an analogous process for approval of biosimilar products.In approving Omnitrope, FDA refused to extend the 505(b)(2) approval mechanism to generic biologics generally. Rather, it was approved as a follow-on protein product—it is sufficiently similar to another approved protein product (Genotropin) to allow the manufacturers to rely on findings from clinical data regarding the safety and effectiveness of the other protein product. Moreover, Omnitrope was not determined to be therapeutically equivalent to Genotropin and thus was not "AB rated."
FDA also relied on specific properties of Omnitrope as a basis for the approval, such as: it has only one active ingredient; its mechanism of action is well understood; its proteins can be "extensively and adequately characterized"; and it is not glycosylated. FDA limited its decision to protein products with similar characteristics. Currently, the US Congress is not considering any legislation that would clarify or expand FDA authority to regulate and approve generic biologics. Other FDA issues pending before the legislature, including drug safety and reauthorization of the user-fee provisions, make it unlikely that Congress will significantly turn its attention to the issue of generic biologics in the near future.
Legislative inaction, coupled with the stated reluctance of FDA to expand approval beyond protein products with similarly straightforward characteristics, indicates that the impact of the decision, in terms of establishing a pathway for approval for other generic biologics, is quite limited. Nevertheless, in light of the continued growth and research in this area and public pressure for greater availability of low-cost and generic drugs, this issue will reappear. The question is, When will the FDA and Congress be willing to listen and take action? The answer appears to be: no time soon.
Nathan A. Beaver is a senior counsel in the FDA Practice of Foley & Lardner, LLP, 3000 K St., Ste. 500, Washington, DC 20036, firstname.lastname@example.org