In 1984, the partnership had formed Kirin-Amgen to fund the global development of Epogen (epoetin alfa).
Later, Kirin-Amgen also involved in the development of Neupogen, Neulasta (pegfilgrastim), Aranesp (darbepoetin alfa) and Nplate (romiplostim) and brodalumab.
Kirin-Amgen has intellectual property rights for each of these products. It licensed the associated marketing rights in certain Asian countries to its pharmaceutical subsidiary Kyowa Hakko Kirin (KHK) and in other territories to Amgen in exchange for royalty rights.
As per terms of the deal, Kirin will secure $780m, as well as additional payments from Amgen based on the achievement of certain sales.
Amgen will hold the product rights as sole shareholder, while the remaining cash will be owned by Kirin-Amgen.
Once the deal concludes, Kirin-Amgen will operate as a wholly-owned subsidiary of Amgen.
As per terms of the deal, Kirin will secure $780m, as well as additional payments from Amgen based on the achievement of certain sales.
Amgen will hold the product rights as sole shareholder, while the remaining cash will be owned by Kirin-Amgen.
Subject to receipt of all necessary approvals, the deal is expected to complete in fourth quarter of this year or the first quarter of 2018.
Amgen chairman and CEO Robert Bradway said: "Our historic partnership with Kirin played a pivotal role in the growth of Amgen from a small, venture-backed start-up to one of the world's largest biotechnology companies.
“I would like to thank Kirin for more than three decades of partnership, which has enabled us to reach patients suffering from serious illness around the world with meaningful therapies.”