The FDA is not approving some 505(b)(2) drug applications for products such
as Sandoz's human growth hormone Omnitrope because the agency is concerned such
a move would set a precedent for approving biological products under Section
351 of the Public Health Service (PHS) Act, according to one industry observer.
While a handful of biologics are regulated under the 505(b)(2) statute, which does allow for generic drugs, most biologics are regulated under the PHS Act, which currently has no provision allowing generic versions of the products it regulates. Congress would have to approve any changes to the PHS Act.
"There is a pretty bright line" between the two statutes, but the FDA "appears to be still struggling" with the issue, David Rosen, a partner at Foley and Lardner, said at the recent Center for Business Intelligence's Fifth Annual Generic Drugs Forum. Rosen cited the Omnitrope case as an example. "The FDA does not have express statutory authority to approve biological products using an abbreviated process under Section 351, but it does have express statutory authority to approve certain protein products under 505(b)(2) that have been regulated and approved under section 505(b) of the Federal Food, Drug and Cosmetic Act," Rosen told FDAnews.
Looking to get its drug application out of limbo, Sandoz has sued the FDA for not acting on its application to market Omnitrope, a generic version of Pfizer's human growth hormone Genotropin (somatropin recombinant), which is no longer under patent. Earlier this month, the FDA asked the U.S. District Court for the District of Columbia to dismiss the suit, saying among other things that the agency's experts had not yet finished their review of Sandoz's application.
A number of factors scientific, economic and legal could be behind the FDA's fear that approving large-molecule drugs like Omnitrope could open the door for Section 351 approvals. For one, Omnitrope is a large-molecule biologic, and not necessarily less complex than the large-molecule products regulated under the PHS Act, which means the FDA may be holding back on some approvals so as not to spur lawsuits from generic makers that see contradictions in the FDA's logic. Furthermore, as Sandoz states in its lawsuit against the FDA, the agency approved hyaluronidase, an "uncharacterizable, more complex protein-based biologic," at roughly the same time it suspended the decision process for Omnitrope.
In its lawsuit, Sandoz acknowledged, "The approval of most follow-on protein products, licensed under the PHS Act in the U.S., will require new legislation to give the FDA the authority to approve substitutable PHS Act products."