A US court has concluded that Regeneron and Sanofi's cholesterol drug Praluent is infringing two patents protecting Amgen's rival therapy Repatha.
Both Repatha (evolocumab) and Praluent (alirocumab) are in the new class of PCSK9 inhibitors and are approved in the US to help patients who cannot meet their cholesterol targets with existing therapy, such as statin drugs, or who have inherited disorders that cause elevated cholesterol.
Amgen filed a lawsuit in the US District Court of Delaware in October 2014 alleging that Praluent infringed three of its US patents (Nos. 8,563,698, 8,829,165 and 8,859,741) shortly after Sanofi and Regeneron unveiled their plans to seek marketing approval for the drug in the US.
In a statement, Sanofi and Regeneron said they "strongly disagree" with the jury's verdict in the District Court that two of Amgen's patents (Nos. 8,829,165, and 8,859,741) are valid and infringed by their product, adding that they intend to appeal.
"This decision is the first step in this ongoing litigation and does not impact Praluent or our ability to deliver it to physicians and patients at this time," they asserted.
Amgen has requested a permanent injunction on sales of Praluent and a hearing has been scheduled to take place later this month.
At stake is a market estimated by some analysts to be potentially worth $10bn to $20bn at peak, given the sizeable proportion of patients who fail to meet cholesterol targets with current drugs.
Early sales of Repatha and Praluent have been modest however, according to some analysts, who suggest that the prices of the two drugs (around $14,000 a year in the US) are creating headwinds on reimbursement. For example, some payers are insisting that patients on statins try adding Merck & Co's selective cholesterol-absorption inhibitor Zetia (ezetimibe) before moving on to a PCSK9 inhibitor.
Both Amgen and Sanofi declined to break out sales for the drug in their fourth quarter results statements and have suggested that 2015 was focused on securing access to their drugs with sales acceleration expected in 2016 and onwards.
Meanwhile, there are more than a dozen PCSK9 inhibitors coming through the pharma R&D pipeline - including candidates from Pfizer, Eli Lilly and Alder Biopharmaceuticals in mid- to late-stage trials.