Amgen Inc. and China's BeiGene Ltd. completed their $2.8 billion collaboration deal after meeting the closing conditions of the agreement.

Under the cancer partnership, Amgen acquired a 20.5% stake in BeiGene by purchasing 15,895,001 American depositary shares at $174.85 each.

As part of the collaboration, BeiGene will be responsible for the commercialization of Amgen cancer drugs Xgeva, Kyprolis and Blincyto in the Chinese market.

The companies will also work together in research and development for 20 new drugs in Amgen's pipeline, and BeiGene will contribute up to $1.25 billion to that effort. For that, the Chinese company will hold the commercial rights to any drugs that get the country's approval.

BeiGene also said former Amgen executive vice president of global commercial operations Anthony Hooper was added to the company's board as part of the share sale.