Ropes & Gray, Hogan Lovells and Shearman & Sterling have taken the lead roles on a $5.1bn deal that has seen GlaxoSmithKline (GSK) acquire US biopharmaceutical firm TESARO.

The deal is expected to strengthen GSK’s presence in cancer treatment and the treatment of tumours – an area in which TESARO is a pioneer. One of TESARO’s trademark products is the drug Zejula, which is approved for use in the US and Europe and has revolutionised the treatment of ovarian cancer.