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FDA Approves Tbo-Filgrastim for Neutropenia



August 29, 2012 — The US Food and Drug Administration (FDA) has approved tbo-filgrastim (Sicor Biotech/Teva Pharmaceuticals) for the treatment of severe neutropenia associated with use of chemotherapy in nonmyeloid malignancies.
Filgrastim is a granulocyte colony-stimulating factor (G-CSF) analog used to stimulate the proliferation and differentiation of granulocytes. Two forms of filgrastim are already available in the US — one injected daily (Neupogen, Amgen) and a pegylated form injected once per chemotherapy cycle (Neulasta, Amgen); another version of filgrastim (Tevagrastim, Teva) has been marketed outside of the US. Teva notes that Tevagrastim and Neupogen are biosimilar, and that the Neupogen patent will expire in the US next year. The company also notes that that tbo-filgrastim is a short-acting recombinant form of G-CSF, and that it is the first new G-CSF to be approved in the US in more than 10 years. Teva reports that it will start marketing tbo-filgrastim possibly as early as November 2013, in accordance with the settlement it reached with Amgen.
Approval of tbo-filgrastim was based on the findings of a clinical study of 348 adult patients with advanced breast cancer receiving treatment with the anticancer drugs doxorubicin and docetaxel. Patients were randomly assigned to receive tbo-filgrastim, a placebo, or a filgrastim product not available in the US.
Patients receiving tbo-filgrastim recovered from severe neutropenia in 1.1 days compared with 3.8 days in those receiving the placebo.
Adverse events associated with tbo-filgrastim were evaluated in 3 clinical studies including 680 adults with breast cancer, lung cancer, or non-Hodgkin's lymphoma receiving high-dose myeloablative chemotherapy. The most common side effect observed in those receiving tbo-filgrastim was bone pain.

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