Bayer has reported positive Phase II results with its oral Factor Xa inhibitor BAY 59-7939 in the prevention of venous thromboembolism in patients undergoing hip replacement surgery, and selected a dose to take forward into pivotal testing.

VTE – an umbrella term for pulmonary embolism and deep vein thrombosis – is currently treated mainly with injectable low molecular weight heparin products, such as Sanofi-Aventis’ market-leading Lovenox (enoxaparin) which reported sales of 550 million euros in the third quarter of this year. In the Phase II trial, a once-daily oral dose of BAY 59-7939 was found to be at least as safe and effective as enoxaparin.

In addition to its oral rather than injectable dosing, unlike LMWH drugs BAY 59-7939 does not require monitoring of blood coagulation or adjustments in dosing so should be a more convenient treatment option in preventing VTE, notes Bayer.

In the Phase II study, all doses of BAY 59-7939 (between 5mg and 40mg a day) were effective compared to a standard 40mg subcutaneous dose of enoxaparin, with between 6.4% and 14.9% of patients treated with Bayer’s drug reporting a DVT, PE or death from any cause. For enoxaparin the rate was 25.2%, although this was not a statistically significant difference.

In terms of safety, the two lowest doses of BAY 59-7939 – 5mg and 10mg – were equivalent to enoxaparin in the incidence of major post-operative bleeding in the first two days after dosing.

Based on these positive data, has decided to take the 10 mg once-daily dose into Phase III clinical trials for prevention of VTE. BAY 59-7939 is also in Phase II testing in the treatment of VTE and in stroke prevention in patients with atrial fibrillation.

Bayer recently signed a co-marketing agreement for BAY 59-7939 with Johnson & Johnson subsidiary Ortho-McNeil Pharmaceutical. In the USA, Ortho-McNeil has exclusive marketing rights for the cardiology, primary care and hospital specialty markets, with Bayer retaining an option to co-promote the drug in the USA, as well as sole marketing rights for the compound outside the USA.

BAY 59-739 is one of two drugs intended to revitalize the fortunes of Bayer’s healthcare business, which has been badly hit of late by a $1 billion recall of cholesterol drug Baikal (cerivastatin), generic competition to its blockbuster antibiotic Cipro (ciprofloxacin) and a dearth of new product launches. The other is Nexavar (sorafenib), filed in the USA and Europe for the treatment of kidney cancer.