LONDON (Reuters) - Britain's health costs watchdog is asking Bayer for more information on its anti-clotting drug Xarelto before deciding whether to recommend it for use on the state health service.
The National Institute for Health and Clinical Excellence (NICE) said data provided so far by Bayer on the drug, known generically as rivaroxaban, were not enough to judge whether it would be cost effective for the prevention of strokes and embolisms in people with an irregular heartbeat condition known as atrial fibrillation.
For now, it said, it would not be recommending Xarelto for use on country's National Health Service (NHS).
"Evidence of rivaroxaban's cost-effectiveness was not reflective of all the people with atrial fibrillation in the UK who would be eligible for treatment with the drug," the watchdog said in a statement on Monday.
"The committee is therefore minded not to recommend the drug on the basis of the available evidence pending the receipt of additional information from the manufacturer."
Germany's Bayer is developing Xarelto with U.S. drugmaker Johnson & Johnson.
NICE's decision suggests a cautious approach to a wave of new treatments for preventing stroke in people with atrial fibrillation, a common heart arrhythmia.
Other drugs battling with Xarelto in this market include Bristol-Myers Squibb and Pfizer's Eliquis and Boehringer Ingelheim's Pradaxa.
Analysts say the big commercial opportunity for new anti-clotting pills lies in their long-term use for preventing strokes in patients with atrial fibrillation.
All the newly-developed drugs are designed to replace the decades-old blood thinner warfarin, which requires regular blood monitoring and is notoriously difficult to use.
In November 2011, NICE backed the use of Pradaxa for stroke prevention on the NHS after getting additional information about the drug from its manufacturer Boehringer.
The cost agency also gave its backing in November to Eliquis, but only in a relatively limited market of prevention of blood clots after hip and knee surgery.
Giving details of its concerns about the Xarelto data presented, NICE said Bayer had based its application on the results of a clinical trial whose participants NICE did not believe gave an accurate picture of UK patients.
"(The committee was) concerned that the risk of stroke and systemic embolism for the population in the trial was higher than for the overall population eligible for treatment with rivaroxaban," it said, adding that this could mean the relative effectiveness of Xarelto compared with warfarin had been overestimated.
NICE said the provisional cost to the NHS of rivaroxaban is 2.10 pounds per day and 766.50 pounds a year.
(Reporting by Kate Kelland; Editing by Jon Loades-Carter and Helen Massy-Beresford)