Healthcare is one of several sectors the kingdom wants to reform under its 2030 plan to diversify the economy away from a reliance on oil.

Before the acquisition, GSK owned 49 percent of Glaxo Saudi Arabia, a business it formed in 1992 with local partner Banaja KSA Holding Company.

In addition to the acquisition, GSK plans to invest more than 900 million riyals (£180 million) in its Saudi operations over the next three years. It plans to expand production at its Jeddah manufacture site by 30 percent.

"The acquisition represents a step forward towards the strengthening of our operations in the kingdom," said Andrew Miles, vice president and general manager of GSK in the Gulf Cooperation Council states. "Today, 80 percent of our portfolio is locally manufactured in Jeddah."

(Reporting by Tom Arnold; editing by Jason Neely)