* Onglyza to go on sale in Q4 after final European approval
* New DPP-4 drug a rival for Merck's blockbuster Januvia
* Onglyza as good as Januvia when added to metformin - study (Adds detail, background)
LONDON, Oct 5 (Reuters) - A new diabetes drug from AstraZeneca and Bristol-Myers Squibb has been approved for sale in Europe, clearing the way for a head-to-head battle with Merck & Co's Januvia in EU markets.
The green light for Onglyza from the European Commission had been widely expected, following a positive recommendation from the European Medicines Agency in June.
The two pharmaceutical partners said on Monday they expected to launch Onglyza in Europe in the fourth quarter of 2009 as an add-on therapy for use alongside the older medicines metformin, thiazolidinedione or sulphonylurea.
Both Onglyza and Januvia, which sold $1.4 billion worldwide in 2008, aim to enhance the body's ability to lower elevated blood sugar levels and are part of a class of drugs known as dipeptidyl peptidase-4 (DPP-4) inhibitors.
Though there are numerous diabetes therapies on the market, some can cause weight gain or other complications and many patients are still not reaching optimal blood sugar levels, creating an opportunity for new treatments.
In the United States, the AstraZeneca and Bristol-Myers drug won approval for regulators in July.
Results of a clinical study, also released on Monday, underscored the looming battle between Onglyza and Januvia by showing the newcomer was as good as Merck's medicine in reducing blood sugar levels when added to metformin.
Complete findings from the study will be submitted for publication in the first half of 2010. (Reporting by Ben Hirschler; Editing by Rupert Winchester)