UPDATE 1-Allergan licenses drug for retinal diseases

NEW YORK May 4 (Reuters) - Allergan Inc (AGN.N) said on Wednesday it will pay up to $420 million to privately held Molecular Partners AG to license its experimental drug to treat diseases of the retina.

Allergan said it will obtain exclusive global rights to market the product, called MPO0112, for eye conditions. It works by blocking a protein called vascular endothelial growth factor A (VEGF-A), responsible for excessive growth of blood vessels in the eye.

The drug has been tested in early-stage studies for treatment of the "wet" form of age-related macular degeneration, a leading cause of blindness caused by leaky blood vessels near the center of the retina.

The drug is also being tested to treat diabetic macular edema, a sight-robbing condition among patients with diabetes.

Allergan, which sells a wide array of prescription eye medicines, said it would be responsible for late-stage trials of the product. It is obliged to pay Molecular Partners $45 million upfront, and up to another $375 million should the drug meet development, regulatory and sales milestones.

Allergan earlier on Wednesday said first quarter sales of its eye care pharmaceuticals rose almost 16 percent to $592 million -- by far the company's biggest product line. Its brands includes the Lumigan and Alphagan treatments for glaucoma. [ID:nN04188913]

Allergan is perhaps better known, however, for Botox -- its drug to treat wrinkles and a number of medical conditions, including migraine headaches. Botox sales rose 10 percent in the quarter to $365 million. (Reporting by Ransdell Pierson, editing by Gerald E. McCormick)