Glaxo's GLP-1 diabetes drug beats Byetta in test

* Syncria shows promise in Phase II clinical trial

* No sign of thyroid cancer problems in monkey tests

* Glaxo embarked on 2-3 years Phase III programme

By Ben Hirschler

LONDON, June 7 (Reuters) - An experimental diabetes drug from GlaxoSmithKline (GSK.L: Quote, Profile, Research) was more effective than Eli Lilly (LLY.N: Quote, Profile, Research) and Amylin Pharmaceuticals' (AMLN.O: Quote, Profile, Research) Byetta in controlling blood sugar, a mid-stage test unveiled on Sunday.

Glaxo's injectable Syncria belongs to the same class of medicines, called GLP-1s, as Byetta and Novo Nordisk's (NOVOb.CO: Quote, Profile, Research) Victoza, which the Danish drugmaker expects to launch in Europe this summer.

Safety issues have recently clouded prospects for the GLP-1 drug class.

In a 356-patient Phase II clinical study, presented at the annual meeting of the American Diabetes Association, Glaxo's Syncria, given once weekly, reduced HbA1C -- a common measure of blood sugar -- by 0.9 percent compared to 0.5 percent for Byetta, which is injected twice daily.