* FDA pushes back decision date for Onglyza by 3 months
* U.S. agency now plans to give verdict by July 30
* Onglyza a potential rival for Merck's Januvia
* AstraZeneca shares off 1.4 pct, Bristol up 0.7 pct
(Adds more analyst reaction, commment from Bristol spokesman)
LONDON, April 23 (Reuters) - U.S. regulators need more time to review a new diabetes drug from AstraZeneca Plc (AZN.L) and Bristol-Myers Squibb Co (BMY.N), delaying by three months a decision on whether the product should be approved.
The Food and Drug Administration has set a revised Prescription Drug User Fee Act (PDUFA) date for Onglyza of July 30 from April 30 previously, the two partners on the drug said on Thursday.
AstraZeneca and Bristol-Myers hope their product, which won backing from a U.S. advisory panel earlier this month, will carve out substantial sales by competing against Merck & Co Inc's (MRK.N) blockbuster Januvia.
Both drugs aim to enhance the body's ability to lower elevated blood sugar levels and are part of a class of drugs known as DPP-4 inhibitors.
Simon Mather, an industry analyst at WestLB, said the delay was no great surprise, given a trial is underway in patients with kidney damage to rule out the possibility of skin-related side effects -- a problem that prevented Novartis AG's (NOVN.VX) DPP-4 drug Galvus from winning FDA approval.
A spokesman for Bristol-Myers, however, said he was not aware of the FDA asking for any additional information or analysis about Onglyza.
Deutsche Bank analysts said they did not see anything sinister in the FDA delay, noting that a number of diabetes drugs have been delayed due to a heavy workload for this division of the agency.
Shares in AstraZeneca slipped 1.4 pct by 1450 GMT, while Bristol-Myers rose 0.7 pct
The FDA's advisory panel concluded on April 1 that Onglyza posed no excessive heart risk and could be a promising treatment, but said more data would be needed after approval to weigh any possible long-term risks.
Regulators have paid much greater attention to the heart safety of drugs addressing the $6 billion diabetes market after researchers linked GlaxoSmithKline Plc's (GSK.L) diabetes pill Avandia to greater heart risks in 2007. (Editing by Greg Mahlich and Andrew Callus)