By Ludwig Burger
FRANKFURT (Reuters) - A new stroke prevention drug developed by Bayer and Johnson & Johnson proved a safe alternative to the standard treatment, lifting their chances of entering a $12 billion plus market, the German drug company said.
A late-stage study called Rocket-AF showed that the Xarelto pill was as good as the established warfarin pill at reducing the risk of strokes due to a form of irregular heartbeat that is common among the elderly, Bayer said on Sunday.
The preliminary results also revealed that patients on Xarelto, an anti-blood-clotting drug also known as rivaroxaban, ran a risk of bleeding that was comparable to those on warfarin.
"The rates of the composite of major and non-major clinically relevant bleeding were comparable," Bayer said in its brief statement.
The risk of hemorrhaging -- a common side effect in anti-clotting drug -- was a main focus of the Phase III trial whose participants were in their mid-70s.
Xarelto's efficacy had largely become evident in previous studies, where it was used to prevent thrombosis in patients bed-ridden after surgery, the company said.
Detailed results of the Rocket-AF trial are scheduled to be presented at the American Heart Association conference in Chicago on November 15.
A Bayer spokesman declined to provide more details ahead of the conference.
Bayer has said it is eyeing more than 2 billion euros ($2.78 billion) in annual sales from Xarelto in a market worth an estimated $12 billion to $15 billion in total, a commercial potential only matched by its cancer treatment Nexavar.
Analysts' projections of that market range between $10 billion and $20 billion in annual sales.
Before Sunday's results, analysts had forecast Xarelto sales of $2.2 billion in 2014, according to Thomson Reuters Pharma.
As part of a 2005 agreement with Bayer, J&J will market the pill in the United States and pay royalties of up to 30 percent of its revenue to Bayer. Deutsche Bank analysts estimate that Bayer stands to retain about 61 percent of worldwide sales in 2015.
Xarelto is already approved in Europe to prevent thrombosis in patients bed-ridden after surgery.
But prevention of strokes in patients with a type of irregular heartbeat called atrial fibrillation (AF) is a far bigger opportunity for the new anticoagulants.
In that market, Bayer's unlisted German rival Boehringer Ingelheim is in the lead with a product called Pradaxa that won U.S. regulatory approval on Oct 19 and which will be priced at $6.75 per day.
Bristol-Myers Squibb and Pfizer are also vying to enter the stroke prevention market with their experimental apixaban pill.
In total, at least eight companies are racing to launch new oral anti-coagulants to replace warfarin, a problematic 65-year-old medicine originally developed as rat poison.
Warfarin interacts badly with food as well as other medicines and requires regular blood tests, making it a particularly onerous therapy for the elderly -- the patient group most affected by AF.
AF patients run a five-times higher risk of stroke and 15 percent to 20 percent of all strokes may be associated with the condition, according to Bayer.
(Editing by Leslie Gevirtz)