Australian vaccines and blood products developer CSL says it will vigorously fight a patent infringement claim launched by US-based biotech Bioverativ in relation to CSL's haemophilia B drug, Idelvion. Bioverativ, which develops treatments for haemophilia and other rare blood disorders, has filed complaints in the US District Court for the District of Delaware and with the International Trade Commission. Bioverativ claims that Idelvion infringes three Bioverativ patents. "CSL is highly confident of its intellectual property position for Idelvion, a product of over a decade of innovative research by CSL Behring and
representative of a major advance for patients suffering haemophilia B, and will vigorously defend against the claim," CSL said in a statement on Monday. The US Food and Drug Administration approved Idelvion in March 2016 to prevent and manage bleeding episodes in children and adults with haemophilia B. CSL said it could not provide specific details of the infringement claim because it was a litigation matter. CSL said in February that there had been a strong uptake of Idelvion following the launch of the product into markets in the US and Europe. Sales of recombinant haemophilia products generated $US232 million in sales, led by Idelvion.Shares in CSL were 19 cents lower at $133.98 at 1215 AEST.