AstraZeneca is taking over all of Bristol-Myers Squibb’s interest in their diabetes joint venture for up to $4.3 billion. The deal comes just a little more than a year after the U.K.-based pharmaceutical paid $3.4 billion to join with Bristol-Myers in a diabetes alliance after the U.S. pharmaceutical bought Amylin Pharmaceuticals for about $7 billion and gained its diabetes franchise including Byetta and Bydureon.

AstraZeneca will pay $2.7 billion upfront and up to $1.4 billion in regulatory, launch, and sales-related payments. It has also agreed to pay various sales-related royalties until 2025. It may also make additional payments up to $225 million when certain assets are transferred.

The deal strengthens AstraZeneca’s marketed drug portfolio while giving Bristol-Myers cash to pursue more deals in its core focus area of oncology.

“Diabetes is rapidly becoming a global challenge of epidemic proportions that is expected to affect more than 550 million people by 2030. Much of this impact will be felt in emerging markets where AstraZeneca has a strong presence,” says Pascal Soriot, CEO of AstraZeneca. “Today’s announcement reinforces AstraZeneca’s long-term commitment to diabetes, a core strategic area for us and an important platform for returning AstraZeneca to growth.”

Bristol-Myers and AstraZeneca have been partners in developing diabetes drugs since 2007 with limited success. Their first partnered drug Onglyza competes against Merck’s Januvia. Their most recent diabetes compound, dapaglifloxin, was rejected by U.S. regulators in January 2013, but recently passed an advisory committee review and could be approved in early 2014.

The transaction is expected to become final by the end of the first quarter of 2014.