Amgen fails to block Neupogen biosimilar

Amgen has failed in a legal attempt to block the sale of a biosimilar version of its white blood cell stimulator Neupogen developed by Novartis' Sandoz subsidiary.

The biosimilar – called Zarxio – was the first biosimilar to be approved for marketing in the US earlier this month although it has been on sale elsewhere for many years, debuting in the EU in 2009.

Sandoz has not yet launched Zarxio (filgrastim-sndz) onto the US market but when it does so it will be the first direct competitor there for Neupogen, which had sales of $1.16 billion last year, and will be prescribable for all of Neupogen's five approved indications.

There is already another version of filgrastim on the market in the US – Teva's Granix (tbo-filgrastim) – although this is not a biosimilar as it was approved via the traditional route and is approved only for boosting white blood cells in patients undergoing chemotherapy for cancer.

Ruling on the case, Judge Richard Seeborg suggested that the dispute between the two pharma companies was based on differing interpretations of the Biologics Price Competition and Innovation Act (BPCIA), which created the regulatory route to market for biosimilars.

Amgen argued that Sandoz had violated the law by failing to provide it with a copy of its FDA application and maintains that Novartis' unit should have to wait six months before launching the drug.

Amgen has said it will appeal the decision in the San Francisco federal court, which denied a preliminary injunction to prevent the launch of Zarxio. Sandoz had already agreed to delay a launch until either 10 April or the federal court verdict, whichever came first.

The big question now is whether Sandoz will press ahead with a launch straight away or await the outcome of the appeal, although some observers have suggested that, given the time it may take for an appeals verdict to come through, an 'at-risk' launch is likely.

Sandoz indicated in a statement that "given the importance of this case for future biosimilars, we agreed with Amgen before this hearing to jointly request expedited review of any appeal to the federal circuit."

The lack of competition for Neupogen in the US has propped up the product well after its patents expired, with domestic sales accounting for $839 million of the product's total turnover last year.

Commenting on the approval of Zarxio, US health insurer Express Scripts estimated that the biosimilar could reduce US healthcare spending by as much as $5.7 billion over the next 10 years.

Amgen makes the lion's share of its white cell stimulator franchise from long-acting follow-up Neulasta (pegfilgrastim), which posted sales of $4.6 billion in 2014, once again with the bulk ($3.65 billion) coming from the US.

Neulasta is also facing biosimilar competition, however, as its US patents expire in October and a rival version from Apotex has already been submitted to the FDA for approval.