WASHINGTON -- The , the first so-called biosimilar drug to win the agency's OK.
To be sold as Zarxio with a generic name of filgrastim-sndz, the product will compete against Amgen's original drug, Neupogen. Both agents are recombinant granulocyte colony-stimulating factor (G-CSF) proteins, indicated for cancer patients undergoing treatments that deplete white blood cells as well as patients preparing for autologous peripheral blood stem-cell transplants or those with severe chronic neutropenia.
An FDA advisory committee had recommended in January that Zarxio be approved, determining that it met the agency's criteria for biosimilar products.
On a conference call with reporters, John Jenkins, MD, director of the FDA's Office of New Drugs in the Center for Drug Evaluation and Research, emphasized that the drug was not approved to be completely interchangeable with Neupogen. Although it is possible for biosimilars to be approved as interchangeable -- that is, allowing pharmacies to substitute the biosimilar product for prescriptions written for the branded drug -- Sandoz had not requested it, he said.
The FDA made the announcement with significant fanfare, including the media teleconference and a special statement from the Center for Drug Evaluation and Research director, Janet Woodcock, in addition to the agency release.
"Today marks a significant milestone in FDA's regulatory history," Woodcock said in the statement.
"The approval of Zarxio is quite significant as it paves the way for the future of biosimilar approvals. A successful biosimilars review process will spark the development of a new segment of the biotechnology industry in the U.S. It will also provide significant benefits for patients, making available more affordable treatments that clinicians will be assured are safe, effective, and of high-quality."
However, because the biosimilar is, by definition, functionally equivalent to the original branded drug, the only major advantage is the potential to reduce the cost. The extent to which the Zarxio approval will make G-CSF treatment more affordable remains to be seen.
In an email, a Sandoz representative said, "We're not commenting on price until the product launches, for competitive reasons. Sandoz is committed to bringing high-quality, competitively priced biosimilars to the U.S. market, including Zarxio."
Jenkins told reporters on the press call that the FDA hopes the availability of multiple similar products will reduce costs to patients and payers. "When competition comes into the market, it often results in lower prices," he said.
In Europe, where the Sandoz biosimilar has been marketed for several years (under the name Zarzio), indicated that the biosimilar cost about 30% less than Neupogen. But the rules on substitution between original and biosimilar products differ in Europe versus the U.S., as do pricing regimes more generally, so that experience may not apply. (It's also worth noting that Sandoz paid for the analysis.)
Also, Zarzio was not the only filgrastim biosimilar available in Europe, whereas Zarxio will not face competition in the U.S. from a biosimilar-designated product for some time.
Two other filgrastim products are currently available in the U.S.: Teva's Granix (originally Sicor), which was approved via a full Biologics License Application and is therefore not technically a biosimilar though it is commonly called that, and Amgen's pegfilgrastim (Neulasta), a pegylated form that requires only a single dose for each chemotherapy cycle.