Many biosimilar makers have tried and failed to obtain approval of biosimilar versions of Amgen’s Neulasta (pegfilgrastim), a long-acting version of Amgen’s Neupogen (filgrastim). Coherus BioSciences, Inc. is the latest biosimilar maker to encounter such hurdles. After receiving a complete response letter from FDA rejecting its proposed Neulasta biosimilar in June 2017, Coherus moved on Tuesday to stay discovery in its BPCIA litigation with Amgen until the district court resolves its motion to dismiss. Coherus seeks to stay discovery to allow it to conserve resources while preparing to resubmit its biosimilar application.
Neulasta is a blockbuster biologic medicine used by cancer patients on chemotherapy to fight off infections. It has been on the market in the U.S. and Europe since 2002. Biosimilar makers in the U.S. and Europe have tried to create biosimilar versions of Neulasta but have consistently encountered hurdles to approval of proposed biosimilar versions. Neupogen (filgrastim), a small protein of 175 amino acids with a molecular weight of 19 kilodaltons, is made in bacteria using recombinant DNA techniques. Because of its simplicity, filgrastim is relatively easy to study and characterize. In Neulasta (pegfilgrastim), the filgrastim protein is covalently bound to a 20 kilodalton polyethylene glycol (PEG) molecule, doubling its molecular weight. The presence of PEG on filgrastim reduces the rate at which the medicine is removed from the body—the reason Neulasta is long-acting—but also appears to make it more difficult to develop a biosimilar product.
Coherus has encountered obstacles in demonstrating biosimilarity to FDA. In June, FDA denied its biosimilar application, requesting a reanalysis of existing samples with a revised immunogenicity assay but stopping short of requesting a further clinical study. FDA accepted Coherus’s biosimilar application in October 2016, and shortly thereafter Coherus initiated the BPCIA’s pre-litigation exchanges (the so-called patent dance) with Amgen. Amgen then filed its complaint against Coherus in May 2017, asserting infringement of one patent.
Coherus filed a motion to dismiss Amgen’s complaint on June 1. In its motion to dismiss, Coherus argues that Amgen’s claim for infringement is precluded by prosecution history disclaimer. On July 18, the U.S. District Court for the District of Delaware ordered the parties to agree on a case scheduling order. In light of FDA’s denial of its biosimilar application, however, Coherus says it is in no position to move forward with discovery while its motion to dismiss is pending. Coherus is a biosimilar startup and currently has no products or revenues. FDA’s decision, according to Coherus, will delay launch of its proposed Neulasta biosimilar by at least a year (until June 2018), forcing Coherus to stretch its financing until that time. Coherus explains that due to rejection of its application it has to cut its expenses by 50% and already let go a third of its workforce. Coherus argues that staying the litigation until its motion to dismiss is decided would allow it to avoid potentially unnecessary expenditure of scarce resources.