Astrazeneca and Glaxosmithkline facing explosive legal battle

Pharmaceutical giants Astrazeneca and Glaxosmithkline (GSK) are facing an explosive legal battle over royalties from a top-selling cancer treatment. 

Astrazeneca has launched a court claim against its FTSE 100 rival, arguing it should have a greater share of sales from Zejula, a drug that treats ovarian and other types of cancer. 

The value of the claim could run into hundreds of millions of pounds. 

Battle: Zejula was developed using technology owned by Astra that was licensed to GSK, which is led by Dame Emma Walmsley (pictured)

Zejula was developed using technology owned by Astra that was licensed to GSK, which is led by Dame Emma Walmsley. Astra lodged the case in the High Court last month and is understood to have accused GSK of breaching the terms of its licensing agreement. 

GSK will argue that the case has no merit, the Sunday Times reported. 

The courtroom drama comes at a difficult time for both firms. 

Walmsley has laid out plans to split GSK in two. But the company is also bracing for a fight with activist investor Elliott Advisors. 

Astra has been hit with a shareholder revolt over a potential £18m pay package for chief executive Pascal Soriot.