FDA's request of additional information from Teva to complete review of its biological license application for a version of Amgen's Neupogen (filgrastim) shows that even a full BLA does not guarantee a biosimilar's smooth review.

Teva announced on Sept. 30 that FDA issued a complete response letter for its application for Neutroval, its version of the granulocyte colony-stimulating factor for chemotherapy-induced neutropenia. It said the agency had requested "several items" but was not requiring additional pre-marketing clinical trials. Teva did not specify what items FDA had requested.

Pharma companies are eager to know what data the agency will require for approval of biosimilars. They have also debated the merits of using the new abbreviated pathway for follow-on biologics versus a full BLA. Merck has said it plans to use the abbreviated pathway to file its biosimilar referencing Neupogen (Also see "Merck Prepares To Test Drive Biosimilar Pathway In The U.S." - Pink Sheet, 5 July, 2010.).

FDA gave some indication of how it would handle biosimilars in its approval of Sandoz's generic version of Sanofi-Aventis's Lovenox (enoxaparin). While the anticoagulant is not a biologic, it is a complex compound that raises some of the same safety, efficacy and comparability issues involved in approval of follow-on biologics. FDA required Sandoz to submit three types of studies comparing the immunogenicity of its product with Lovenox.

A court shot down Sandoz's argument that these tests were the equivalent of a full new drug application (Also see "Court Backs FDA Rationale For Approving Generic Lovenox" - Pink Sheet, 26 August, 2010.).

The agency will be holding a public hearing on Nov. 2-3 to get public input on how to implement the legislation that created the approval pathway for biosimilars (Also see "FDA Biosimilars Meeting Seeks Input On Product Naming, Foreign Data And Exclusivity" - Pink Sheet, 20 September, 2010.). One of the key questions to be addressed is what scientific and technical factors can be used to show that a product is highly similar to its reference product.

-Brenda Sandburg (b.sandburg@elsevier.com)

Biosimilar Road Bump: Teva Filgrastim's Complete Response Shows Even Full BLAs Can Stumble

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