Last Tuesday, on the same day the FDA approved Sandoz's application for Omnitrope, a recombinant human growth hormone (rhGH) that Sandoz is calling the first-ever "biogeneric" drug, the FDA also released a 53-page response to a series of citizen petitions that had opposed FDA approval of Omnitrope. Consistent with its approval of Sandoz's Omnitrope application, the FDA denied the citizen petitions. Sandoz filed its application for Omnitrope in 2003; the citizen petitions were filed by Pfizer, Genentech, and the Biotechnology Industrial Organization (BIO) in 2003 and 2004.
The citizen petitions primarily objected to Sandoz's reliance on the FDA's finding of safety and effectiveness of Genotropin, Pfizer's rhGH, which is approved for the same indications that Sandoz sought for Omnitrope (pediatric and adult growth hormone deficiencies). The BIO petition went a bit further, requesting the FDA to refuse any application for a therapeutic protein product that relies on information contained in another approved application.
Sandoz filed its application for Omnitrope approval under section 505(b)(2) of the FFDCA, which allows for NDA's containing full reports of safety and effectiveness in which at least some of the information required for approval comes from non-applicant studies and for which the applicant has not obtained a right of reference. 505(b)(2) applications are sometimes also referred to as "paper NDA's."
The FDA has interpreted this section to mean that a 505(b)(2) NDA applicant can rely on published literature that describes the study result, or on a reference to FDA's finding of safety and effectiveness of a previously approved drug, provided such reliance is scientifically justified and the 505(b)(2) applicant complies with the applicable statutory requirements regarding patent certification.
Among other arguments, the citizen petitions asserted that it was not scientifically justifiable to find that Omnitrope and Genotropin were similar enough to satisfy the requirements of section 505(b)(2), and that the only possible way to compare the two drugs to find such similarly would be to access Pfizer's proprietary information submitted in the Genotropin NDA, in order to assess manufacturing differences between the two rhGH's.
In denying the citizen petitions, the FDA found that Sandoz had provided adequate data, including Sandoz's own clinical trial data, to establish that its reliance on the FDA finding of safety and effectiveness for Genotropin was justified without the need to access any proprietary Pfizer information. This finding was made, in spite of acknowledged manufacturing differences between Omnitrope and Genotropin, based on the highly similar nature of the end products, which the FDA characterized as "relatively simple recombinant proteins." It appears this statement is based on the fact that Omnitrope is a non-glycosylated recombinant protein. Thus, glycosylated recombinant proteins may face stricter FDA scrutiny under 505(b)(2).
Thanks very much to a helpful reader for sending us a copy of the FDA citizen petition response!
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