Japanese drugmaker Takeda Pharmaceutical Co. Ltd. said Wednesday it will pay $800 million upfront to buy the privately held U.S. gout treatment maker URL Pharma Inc.

The deal also may include future performance-based payments. URL is headquartered in Philadelphia, and its lead product is Colcrys, which is used to treat gout flare-ups. The treatment brought in more than $430 million in revenue last year.

Gout develops when excess uric acid crystallizes and builds up in joints and tendons, causing intense pain and swelling. In healthy people, uric acid is dissolved in the blood and excreted from the body in urine. Many patients experience their first attack of gout in the big toe. The disease can progress, causing deformities.

Takeda is Japan’s largest drugmaker, but most of its sales come from the United States. Its product portfolio includes the diabetes treatment Actos, which loses patent protection later this year. It also includes Uloric, a once-daily drug that lowers blood uric acid levels in adults with gout.

Takeda expects the URL deal to close within 60 days.