Alchemia heartened by thumbs-up for Glaxo drug

Shares in Brisbane biopharma Alchemia (ASX:ACL) rose 7 per cent today on news that the US Food and Drug Administration has approved GlaxoSmithKline's anti-thrombotic drug Arixtra in surgical patients at high risk of life-threatening venous blood clots.

Arixtra is a synthetic form of the natural anti-clotting agent heparin, and Alchemia has an identical, generic molecule ready for launch when GSK's five-year market exclusivity expires next year.

GSK's patent on Arixtra ran out in 2003, but the FDA then gave the company a five-year extension free of competition from generics manufacturers. Alchemia MD Dr Tracie Ramsdale said the market exclusivity period was normally embedded within the normal life of the patent, but in Arixtra's case, was an add-on.

When GSK's exclusivity finally expires next year, Alchemia's US partner, American Pharmaceutical Partners (APP), will file an application to market their generic synthetic heparin.

Ramsdale said APP had considerable experience and success selling generic drugs to the US hospital market.

Arixtra (fondaparinux sodium) is an injectable drug that is already widely used to prevent deep-vein thrombosis (DVT). DVT can be life-threatening, because of the risk of a clot breaking free and travelling to the lungs, causing a pulmonary embolism.

To preserve as much of its market share as possible when the patent extension expires, GSK has filed applications with the FDA to extend the range of applications -- applications that will also be available to generic heparin manufacturers like Alchemia.

The FDA has approved Arixtra's use in patients who have undergone surgery for hip fracture or hip replacement, or knee replacement surgery. It is the first time synthetic heparin has been approved for this type of surgery.

The FDA approval was based on randomised, double-blind clinical trials in 8100 patients, half of whom received Arixtra. The patients ranged in age from 17 to 97. The drug proved at least as effective as dalteparin (low molecular weight heparin) in reducing the risk of venous thromboembolism -- 4.6 per cent of patients on Axtra experienced a clot, compared with 6.1 per cent of patients on dalteparin.

Ramsdale said Arixtra also been approved for use in patients undergoing abdominal surgery, and in February this year, the European Medicines Agency granted GSK approval to use Arixtra to prevent venous thromboses in medical patients judged to be at high risk of thromboembolic complications.

Ramsdale said given that Alchemia's drug would be significantly cheaper than the GSK product, because of Alchemia's manufacturing technology, it was likely to capture a significant portion of the growing market in a short period of time. Historically, generic drugs had captured up to 80 per cent of the market share from branded counterparts.