FRANKFURT Nov 12 Boehringer Ingelheim said that 260 cases of fatal bleeding have been linked to its new stroke prevention pill Pradaxa so far, adding that the risk of death was still below the rate that emerged in the clinical trial that led to the drug's approval.
In early November, the German drugmaker had said that 50 reported deaths were a "reasonable order of magnitude".
The company on Saturday confirmed in a statement the new global number more than five times higher than the previous one, initially reported by magazines Der Spiegel and Die Zeit.
Like other anti-blood-clotting treatments, Pradaxa's benefit of cutting the rate of fatal or debilitating strokes comes at the risk of internal bleeding, which can also cost lives.
Unlisted Boehringer also said there have been fewer cases of fatal side effects linked to Pradaxa than what would have been expected if they had been treated by the standard drug warfarin, which Boehringer is trying to replace.
Warfarin has been used for decades but it is difficult to handle because it interacts with certain vegetables and requires frequent blood tests.
Pradaxa, the first in a promising new class of medicines to overcome these drawbacks, is designed to prevent strokes in patients suffering from atrial fibrillation, a form of irregular heartbeat common among the elderly.
Boehringer said in its statement that the risk of deadly bleeding linked to warfarin was more than 40 percent higher than that associated with Pradaxa, citing figures from the RE-LY study that led to the new pill's approval.
Still, some healthcare watchdogs' attention has been heightened.
European regulators last month said that patients about to take Pradaxa should have their kidneys checked, and Japanese regulators told Boehringer in August to issue a strong warning to doctors of potentially deadly bleeding as a result of use of Pradaxa.
Rival anti-clotting drugs include Xarelto from Bayer and Johnson & Johnson, Eliquis from Bristol-Myers Squibb and Pfizer, and Daiichi Sankyo's Lixiana.
The are all vying for a market that analysts estimate at somewhere between $10 billion and $20 billion per year.
Pradaxa won regulatory clearance in the United States for stroke prevention in October 2010, followed by other important markets this year.
Bayer and Johnson & Johnson's Xarelto could make major gains this weekend at the annual American Heart Association meeting in Orlando, where more clinical data is due to be release.