US biopharmaceutical group Amgen is buying back from GlaxoSmithKline (GSK) all of its remaining rights to the bone drugs Prolia (denosumab), Xgeva (denosumab) and Vectibix (panitumumab) in 48 countries around the world.

Amgen said the agreement includes key expansion markets such as Brazil, China, Colombia, Hong Kong, Israel, Singapore, South Korea, Taiwan and Thailand.

Under license from Amgen, GSK has held select regional rights to Prolia and Xgeva since 2009, and to Vectibix since 2010. These licenses generated sales of approximately $111 million for the UK drugmaker in 2014.

Amgen will make undisclosed milestone payments to GSK on signing and on the successful transfer of products, after which Amgen will book all sales.

GSK will continue to hold the license and sell the products for an interim transition period that will vary by country, but most of the markets are planned to be returned to Amgen within 12 months.

Robert Bradway, Amgen’s chairman and CEO, said the deal allows the company to build additional commercial infrastructure in oncology and bone health, two of the company’s strategically important therapeutic areas with emerging late-stage pipeline assets.