Last week, Apotex filed a Citizen Petition requesting that FDA “take certain actions to ensure a robust approval process” for proposed biosimilars to Amgen’s Neulasta (pegfilgrastim).

Among its requests, Apotex asks that FDA require each biosimilar applicant to conduct comparative clinical efficacy studies, including pharmacokinetics, pharmacodynamics, and immunogenicity studies, in at least one intended patient population, rather than conducting such studies only in healthy subjects.  Apotex notes in its petition that Coherus has filed an aBLA for a Neulasta biosimilar, which relies on comparative data in healthy volunteers only.

In support of its petition, Apotex points to a prior FDA guidance providing that “a population that is representative of the patient population to which the drug would be targeted will be appropriate unless a study in a different population would be more sensitive to detect potential differences between the proposed biosimilar product and the reference product.”  Apotex argues that because Neulasta reduces infection by “boosting an individual’s ANC count,” pegfilgrastim’s “duration of action is dependent on an individual’s ANC at the start of administration, which by definition is different between cancer chemotherapy patients and healthy subjects.”  Thus, Apotex argues, a biosimilar applicant’s reliance on studies conducted only in healthy subjects is inappropriate for this molecule.

Neulasta was approved by FDA under BLA No. 125031, held by Amgen, Inc. and Amgen USA Inc., on January 31, 2002.  Proposed biosimilars to Neulasta by Sandoz and Apotex have been the subject of ongoing BPCIA litigation, and Coherus recently announced that it has completed the patent dance exchange in connection with its Neulasta biosimilar.