The first biosimilar product, Zarxio (Filgrastim-sndz), approved by the FDA

Biological products are generally derived from a living organism. They can come from many sources, including humans, animals, microorganisms or yeast. A biosimilar product is a biological product that is approved based on a showing that it is highly similar to an already-approved biological product, known as a reference product. The biosimilar also must show it has no clinically meaningful differences in terms of safety and effectiveness from the reference product. Only minor differences in clinically inactive components are allowable in biosimilar products.

Zarxio is biosimilar to Neupogen (filgrastim), which was originally licensed in 1991. Zarxio is approved for the same indications as Neupogen, and can be prescribed by a health care professional for:

• patients with cancer receiving myelosuppressive chemotherapy;
• patients with acute myeloid leukemia receiving induction or consolidation chemotherapy;
• patients with cancer undergoing bone marrow transplantation;
• patients undergoing autologous peripheral blood progenitor cell collection and therapy; and
• patients with severe chronic neutropenia.

“Biosimilars will provide access to important therapies for patients who need them,” said FDA Commissioner Margaret A. Hamburg, M.D. “Patients and the health care community can be confident that biosimilar products approved by the FDA meet the agency’s rigorous safety, efficacy and quality standards.”

The Biologics Price Competition and Innovation Act of 2009 (BPCI Act) was passed as part of the Affordable Care Act that President Obama signed into law in March 2010. The BPCI Act created an abbreviated licensure pathway for biological products shown to be “biosimilar” to or “interchangeable” with an FDA-licensed biological product, called the “reference product.” This abbreviated licensure pathway under section 351(k) of the Public Health Service Act permits reliance on certain existing scientific knowledge about the safety and effectiveness of the reference product, and enables a biosimilar biological product to be licensed based on less than a full complement of product-specific preclinical and clinical data.

A biosimilar product can only be approved by the FDA if it has the same mechanism(s) of action, route(s) of administration, dosage form(s) and strength(s) as the reference product, and only for the indication(s) and condition(s) of use that have been approved for the reference product. The facilities where biosimilars are manufactured must also meet the FDA’s standards.

The FDA’s approval of Zarxio is based on review of evidence that included structural and functional characterization, animal study data, human pharmacokinetic and pharmacodynamics data, clinical immunogenicity data and other clinical safety and effectiveness data that demonstrates Zarxio is biosimilar to Neupogen. Zarxio has been approved as biosimilar, not as an interchangeable product. Under the BPCI Act, a biological product that that has been approved as an “interchangeable” may be substituted for the reference product without the intervention of the health care provider who prescribed the reference product.

The most common expected side effects of Zarxio are aching in the bones or muscles and redness, swelling or itching at injection site. Serious side effects may include spleen rupture; serious allergic reactions that may cause rash, shortness of breath, wheezing and/or swelling around the mouth and eyes; fast pulse and sweating; and acute respiratory distress syndrome, a lung disease that can cause shortness of breath, difficulty breathing or increase the rate of breathing.

For this approval, the FDA has designated a placeholder nonproprietary name for this product as “filgrastim-sndz.” The provision of a placeholder nonproprietary name for this product should not be viewed as reflective of the agency’s decision on a comprehensive naming policy for biosimilar and other biological products. While the FDA has not yet issued draft guidance on how current and future biological products marketed in the United States should be named, the agency intends to do so in the near future.