On Friday, March 6, the FDA announced its approval of Sandoz, Inc.’s (“Sandoz’s”) Zarxio®, a biosimilar of Amgen Inc.’s (“Amgen’s”) Neupogen® (filgrastim), for the same five indications approved for Neupogen®. This follows the January 7, 2015 Oncologic Drugs Advisory Committee Meeting at which the committee unanimously voted for licensure of Zarxio® for all five indications, discussed in our previous alert ODAC Committee Votes to License Sandoz’s Zarxio®.
The FDA based its approval of Zarxio® on its review of evidence submitted by Sandoz, which included “structural and functional characterization, animal study data, human pharmacokinetic and pharmacodynamics data, clinical immunogenicity data and other clinical safety and effectiveness data” that demonstrated that Zarxio® is biosimilar to Neupogen®. (FDA March 6, 2015 News Release: FDA approves first biosimilar product Zarxio.) The FDA was careful to note that its approval of Zarxio® is only as a biosimilar and not as an interchangeable product. Additionally, the FDA explained that a biosimilar product can only be approved if it has the same mechanism of action, route of administration, dosage form, and strength as the referenced product for the same indications and conditions of use that were approved for the reference product. This suggests that any deviation from the specific conditions that were approved for the reference product could be fatal to a biosimilar’s approval.
The FDA also provided guidance regarding the nonproprietary name for Zarxio®. Although careful to note that it has not yet reached a decision on how to name biological products marketed in the United States, the FDA has designated “filgrastim-sndz” as a placeholder nonproprietary name for Zarxio®. This will certainly cause speculation as to whether the FDA will be issuing its naming guidance soon and whether the guidance will require use of biological qualifiers, such as “sndz,” for all biosimilars. Use of a biological qualifier would be in line with the World Heath Organization’s Draft Biological Qualifiers Proposal from July 2014 and could be seen as a middle ground between brand companies’ requests for unique nonproprietary names and generic companies’ requests to use the same nonproprietary name as the reference product.
At this point, it is unclear what impact Amgen’s pending lawsuit against Sandoz and its citizen petition will have on Sandoz’s ability to bring Zarxio® to the market. Amgen’s request for a preliminary injunction against Sandoz is currently pending in the litigation and scheduled for a hearing March 13, 2015.
K&L Gates will be closely monitoring the Amgen litigation and the issuance of the FDA’s naming guidance.
