Major generics player Teva preempted the new biosimliar pathway by filing a standard BLA for its GCSF (filgrastim) product callled Neutroval, which is intended to compete with Amgen's Neupogen.  Commentators have suggested that filing a 42 USC 262(a) standard BLA instead of a Section 262(k) biosimilar application with the FDA may be the favored route for biosimilar manufactures because (1) the 12 year exclusivity period for innovators does not apply to new 262(a) applications; and (2) the differential between the data the FDA requires under the two sections might be minimal, given the FDA's discretion to develop standards for biosimilar applications. 

The FDA has now acted on Teva's Neutroval BLA.  On September 30, 2010 the FDA issued a complete response letter, which requested further information, but no additional clinical trials.  As discussed in an October 13 article in FDA Week entitled "Decision on Teva's Neutroval Forecasts Agency Posture on Biologics Data," it is believed that Teva relied on some Amgen data in its BLA package, given that it obtained European regulatory approval for the drug using the European biosimilar pathway.  The article therefore speculates that the FDA may be amenable to "skinny BLAs" that rely on reference product data.

While it seems unlikely that the FDA will allow companies to use BLAs in lieu of 262(k) biosimilar applications as an end-around the 12 year exclusivity period set in the new legislation by permitting use of reference product data, it may very well be that many prospective biosimilar entrants will stick with the tried and true BLA approach.  The FDA Week article quotes a Teva official as stating that given the regulatory uncertainty surrounding biosimilars, "Teva will continue to file BLAs in order to bring affordable biologics to the American public sooner."  Until at least one 262(k) application is fully reviewed by the FDA, we won't know whether the advantages of using innovator data are outweighed by the long exclusivity period and the uncertainty surrounding the requirements for approval.