Sept 17 (Reuters) - Merck & Co Inc said it had licensed its experimental psoriasis drug to Indian generic maker Sun Pharmaceutical Industries Ltd for $80 million.

Under the agreement, Sun Pharma will acquire the worldwide rights to the drug, tildrakizumab, for all possible indications.

The drug is currently in late-stage trials for use in chronic plaque psoriasis, an inflammatory skin disease.

Merck will continue all clinical development and regulatory activities, which will be funded by Sun Pharma. Upon product approval, Sun Pharma will be responsible for regulatory activities, including manufacturing and marketing the approved product, the companies said.

Merck's shares were down about 1 percent at $59.41 on the New York Stock Exchange on Wednesday. Sun Pharmaceutical's shares closed at 792.40 rupees on the National Stock Exchange of India.

(Reporting By Samantha Kareen Nair; Editing by Simon Jennings)