A US Appeals Court has temporarily blocked the sale of Novartis’ Zarxio, a biosimilar version of Amgen’s Neupogen, until a legal battle between the companies is settled.

The US Court of Appeals for The Federal Circuit in Washington has granted Amgen’s request for an injunction to stop Novartis from selling its biosimilar in the country until Amgen’s appeal of the ruling granting permission for its sale is resolved.

Oral arguments regarding the case are expected to be heard by The Federal Circuit on June 3.

The Federal Circuit’s decision on the injunction opposes that reached previously by the lower district court, which had denied Amgen’s request for a stay on sales pending its appeal.

Zarxio (filgrastim-sndz) became the first biosimilar approved by the US Food and Drug Administration back in March this year, for the same indications as Neupogen (filgrastim).

Biosimilars are around 30% cheaper than their brand-named counterparts, and assuming this discount, Express Scripts is has estimated that Zarxio’s availability in the US could save $5.5 billion in the next decade.