LONDON, Aug 24 — Rival anti-clotting pills being developed by Bayer and Bristol-Myers Squibb are both set to show positive results next week as the race intensifies to replace the old, problematic heart drug warfarin.
At stake is a potential new market estimated at more than US$10 billion (RM31.2 billion) a year — and possibly as much as US$20 billion — for improved anticoagulants that are better and easier to use than warfarin, a drug originally developed as rat poison.
Bayer and Bristol have already said Xarelto and apixaban met their goals in respective clinical trials but the devil will be in the detail as experts scrutinise their safety, with a sharp focus on the risk of bleeding during long-term use.
Full Phase III clinical trial results on both drugs will be presented at the European Society of Cardiology (ESC) congress in Stockholm on Aug. 31.
Unlisted German company Boehringer Ingelheim is currently leading the warfarin-replacement race, after its twice-daily pill Pradaxa impressed doctors a year ago. It is now awaiting approval for preventing strokes in patients with atrial fibrillation (AF), an irregular heartbeat.
But the jury is out as to which drug will ultimately come out on top.
“At the moment it is still in the balance who will win the biggest share of that market,” said Karl-Heinz Koch, an industry analyst at Helvea.
Pradaxa has a clear first-mover advantage but any delay in it winning approval will close the gap. Jefferies analysts expect Pradaxa to be reviewed by a US Food and Drug Administration advisory panel by the end of this year or early in 2011.
Bayer plans to file for approval of Xarelto, being developed with Johnson & Johnson, in the decisive market for stroke prevention before the year-end. Apixaban, which Bristol is working on with Pfizer, is not far behind.
Leerink Swann analyst Seamus Fernandez said there was a growing view among medical specialists that Pradaxa and apixaban had more manageable bleeding profiles, although Xarelto’s once-daily dosing was an advantage.
Other trial still awaited
The potential to displace warfarin — which has been the standard of care for more than half a century but carries a high risk of dangerous bleeding and requires regular blood tests — makes the new anticoagulants key products for Bayer and Bristol.
Shares in both companies jumped around 5 per cent after they reported positive headline results with their medicines in June and early August respectively.
Bayer has said Xarelto could eventually generate more than US$2.5 billion in annual sales. Analysts currently have more modest forecasts for apixaban.
While next week’s data will be important, it will not give the full picture. The trial with Xarelto, known as EINSTEIN-DVT, looked at long-term treatment of deep vein thrombosis, rather than stroke prevention, while the AVERROES trial compared apixaban against aspirin, rather than warfarin.
Results of a second Xarelto study looking at the drug when given to significantly older patients as a stroke preventer will be presented at the American Heart Association annual meeting in November, and data from a trial comparing apixiban to warfarin is expected by analysts in the first half of 2011.
Fernandez said the new class of drugs should expand the overall market significantly, leading to eventual sales of US$10-20 billion a year, as doctors would be more willing to use the safer, newer products than warfarin.
The biggest commercial potential by far is in preventing stroke in AF patients, who are at risk of blood pooling in an upper chamber of the heart, which can cause clots and stroke.
The drugs also have potential in preventing repeat heart attacks and reducing blood clots among patients undergoing knee and hip replacement surgery.
Both Xarelto and apixiban inhibit Factor Xa, which plays a pivotal role in the biological cascade that causes coagulation, while Pradaxa is a direct inhibitor of thrombin.
Several other companies are also developing Factor Xa drugs, including Daiichi Sankyo and Merck & Co. — Reuters
