Lovenox Dustup

Sanofi-Aventis is suing FDA, claiming the agency acted inconsistently and unlawfully in approving a generic version of its anticoagulant Lovenox. The approval of the generic, developed by Momenta Pharmaceuticals and Novartis’ Sandoz division, has sparked debate about how FDA reviews complex drugs and whether they qualify as traditional generics.

Made by breaking apart long heparin chains extracted from pig intestines, Lovenox, or enoxaparin, is a mixture of low-molecular-weight heparins (LMWHs). Sales of Lovenox were $4.4 billion last year, making the drug Sanofi’s number two product.

FDA generally approves generic drugs without requiring extensive clinical trials when they are shown to have the same active ingredients, and thus the same efficacy and safety, as the original drug. Sameness is harder to prove for biologic drugs, and follow-on versions are dubbed “biosimilars.”

The agency has never considered enoxaparin to be a biologic drug, but European regulators are treating LMWHs as biosimilars and will require clinical studies. FDA’s decision might be “an inflection point in the approval of generic versions of drugs once viewed too complex to copy,” Needham & Co. stock analysts said in a report to clients, and it is likely to increase the attention paid to regulatory hurdles for biosimilars.

Sanofi contends that FDA ignored evidence showing that small variations in manufacturing result in big structural and pharmacological changes. Only by using the identical chemical process, the firm says, would generic producers get the same unique, albeit hard to characterize, LMWH mixture. In addition, Sanofi views an FDA request for immunogenicity data on the generic drug as tantamount to admitting that the version in question isn’t the same as Lovenox.

Sandoz and Momenta assert that they have provided substantial data demonstrating equivalence during five years of back-and-forth with the agency. In particular, Momenta claims that its ability to sequence and analyze complex mixtures allowed it to analyze Lovenox and develop a process to make a version that meets FDA requirements. Because the drug is complex, FDA says it applied additional criteria to characterize the sameness.

Along with the approval, the agency responded to and largely dismissed a citizen petition filed on Sanofi’s behalf.

Chemical & Engineering News

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