Amgen loses ruling over drug’s infringement case

Wilmington • Amgen Inc lost a court ruling and pledged to appeal, as it tries to block generic versions of its kidney disease drug Sensipar. Three generic-drug makers — Amneal Pharmaceuticals Inc, Teva Pharmaceutical Industries Ltd’s Watson and Piramal Enterprises Ltd’s healthcare unit — don’t infringe an Amgen patent that expires in 2026, US District Judge Mitchell S Goldberg in Wilmington, Delaware, ruled last Friday.

A fourth generic-drug maker, Cadila Healthcare Ltd’s Zydus, does infringe the patent for a fast-dissolving version of the drug, but the judge said the validity of the patent is still at issue. Zydus is the only one of the four with tentative regulatory approval, Evercore ISI analyst Umer Raffat said in a note to clients. He said the “base case assumption” should be that a generic version will enter the market in the fourth quarter at the earliest, but most likely next year.

Sensipar, a drug for adults with chronic kidney disease on dialysis, had global sales of US$1.7 billion (RM6.9 billion), 7.5% of Amgen’s overall revenue, in 2017, according to data compiled by Bloomberg. The patent for Sensipar’s active ingredient, cinacalcet hydrochlo- ride, expired on March 8. This case centred on a patent that addresses the ingredient’s poor solubility in water; the patent covers a method that ensures an effective dosage reaches the patient.

Different Compounds

Goldberg said Amneal, Watson and Piramal used different compounds to ensure the breakup of the drug, so it can be absorbed by the body, rejecting Amgen’s arguments that they were close enough to what’s covered by its patent.

Amgen said it will ask an appeals court to overturn the non-infringement decisions. It warned that “any potential launch by one of the companies that the district court found not to infringe would be at risk,” meaning it would ask that they compensate Amgen for any lost profits should it later win the appeal.

Since generic-drug makers charge less than the brand companies, the cost of repaying the brand could be higher than total sales of the generic version, so most generic-drug makers wait until they hear from the US Court of Appeals for the Federal Circuit, which handles all patent appeals. Officials at Amneal, Watson, Piramal and Zydus didn’t immediately respond to requests for comment. Amgen is still trying to get a six-month extension on the patent that expired in March. A federal appeals court in May heard Amgen’s arguments that it was entitled to the extension because it complied with US Food and Drug Administration requirements related to the testing of medicine in children.

Amgen earlier reached agreements with other generic-drug companies, including Aurobindo Pharma Ltd, Strides Pharma Global Pte Ltd, Dr Reddy’s Laboratories Ltd, Cipla Ltd, Breckenridge Pharmaceutical Inc, Sun Pharmaceutical Industries Ltd, Hetero USA Inc and Ajanta Pharma Ltd.

The case is Amgen Inc vs Amneal Pharmaceuticals Inc, 16-cv-853, US District Court, District of Delaware (Wilmington). — Bloomberg