Ipsen is expanding in the USA and buying a 20% stake in Inspiration Biopharmaceuticals as part of a bid to create “a world-leading haemophilia franchise”.

At the heart of the partnership are two product candidates scheduled to begin Phase III trials this year – Ipsen’s recombinant porcine factor VIII, OBI-1, for the treatment of patients with acquired haemophilia and haemophilia A who have developed an inhibitory immune reaction to human forms of factor VIII, and Inspiration’s recombinant factor IX product, IB1001, for the acute and preventative treatment of bleeding in patients with haemophilia B.

Ipsen is sublicensing OBI-1 to Inspiration for $50 million in convertible notes, plus a 27.5% royalty on sales and the French drugmaker will supply the product. It is also buying a 20% stake in the California-based firm for $85 million and has the option to raise that holding to 47% for up to $174 million, based on milestones linked to the development of the haemophilia treatments. There is also an option for Ipsen to acquire full control.

The Paris-headquartered drugmaker’s chief executive, Jean-Luc Belingard, said “we are confident that the structure we have designed will continue to foster the exceptional environment that has made Inspiration successful until a time when the company has OBI-1 and IB1001 commercialised”. If they get to the market, the products could exceed sales of $1 billion in the next ten years, he added.

Ipsen entered the US market in 2008, buying out partner Tercica, acquiring the US subsidiary of Vernalis and purchasing Octagen, the developer of OBI-1. Mr Belingard concluded by saying that “we remain committed to growing Ipsen’s specialist disease areas on a global basis”.