Posted 06 March 2015 | By Alexander Gaffney, RAC,

The US Food and Drug Administration (FDA) has announced the landmark approval of the US' first biosimilar product, Sandoz' Zarxio (filgrastim-sndz), a drug biologically similar to Amgen's Neupogen.

The product is the first to be approved under the 351(k) biosimilar pathway, which was first established under the Patient Protection and Affordable Care Act—Obamacare—in 2010.

The approval of Zarxio, which is marketed in several other markets under the brand name Zarzio, had largely been expected by most analysts. In January 2015, an FDA Advisory Committee voted 14-0 in favor of its approval, finding it to be similarly safe and effective as the product it references. The drug is now approved for the same indications as Neupogen.

Notably, Zarxio was approved "as biosimilar, not as an interchangeable product," meaning it can't be automatically substituted for its reference biologic, Neupogen. Many states have also passed laws prohibiting pharmacists from substituting biosimilars that have not been found to be interchangeable.

Even still, FDA's press announcement about the approval was largely focused on reassuring the public that the drug is as safe and effective as its reference biologic. "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," said Margaret Hamburg, FDA's commissioner.

The Name Game: A Temporary Solution

FDA's approval also marks the first time the agency has applied a new nonproprietary name to a biosimilar.

As Regulatory Focus speculated earlier this week, FDA's approval of Zarxio was expected to be accompanied by the release of a new biosimilar naming guidance, which would describe whether FDA would require each biosimilar to have its own unique nonproprietary name, the same nonproprietary name as its reference biologic, or the same nonproprietary name with an add-on signifying its biosimilar status.

However, FDA's approval of Zarxio was not accompanied by a guidance document, but instead by what the agency calls a temporary "placeholder" name for the drug, which will be known 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," FDA explained in a press statement. "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."

For now, it's unclear whether FDA plans to use the current temporary name as a test case for an eventual policy, or how it would reassign biosimilar nonproprietary names if it decides to adopt a different policy in its eventual guidance document.

FDA Approval Announcement