UPDATE 1-Takeda, Amylin to co-develop obesity drugs

* Worldwide agreement to co-develop obesity drugs

* Amylin to receive $75 mln up-front

* Milestone payments to Amylin could top $1bln

* Includes two Amylin drugs in Phase II trials (Adds details)

TOKYO, Nov 2 (Reuters) - Japan's Takeda Pharmaceutical (4502.T: 行情) and U.S. Amylin Pharmaceuticals (AMLN.O: 行情) said on Monday they will co-develop and commercialise drugs to treat obesity, including two Amylin drugs in mid-stage trials.

Takeda, Japan's biggest drugmaker and best known for its diabetes drug Actos, will pay Amylin $75 million in a one-time up-front payment under the exclusive worldwide agreement.

Amylin, maker of the diabetes drug Byetta, could also receive development and sales-based milestones worth more than $1 billion if the compounds in the agreement were successful, the companies said in a statement.

The agreement includes Amylin's pramlintide/metreleptin and davalintide, which are in Phase II studies in the United States.

Takeda will lead development activities beyond Phase II and all development activities outside the United States. It will shoulder 80 percent of U.S. development costs and 100 percent of costs for obtaining approval for products outside the United States.

Takeda will lead product commercialisation and pay 100 percent of the costs for product commercialisation in and outside the United States, they said. (Reporting by Taiga Uranaka; Editing by Edwina Gibbs)