Shares in British pharmaceutical company GlaxoSmithKline (GSK) soared 58% on Monday after it unveiled its acquisition of Cancer Biotech company TESARO for $5.1 billion.

The deal was approved by TESARO’s board of directors unanimously. According to a Bloomberg report, TESARO was exploring the opportunity of a sale after its shares fell 20% upon the release of their drug trial results for small-cell lung cancer treatment last month.

The deal which accounts for $75 price per share represents roughly 60% more than the value of TESARO’s closing price of $46.38 per share. The total deal price is said to include TESARO’s net debt.

TESARO is a Boston-based oncology-focused biopharmaceutical company with a major marketed product Zejula (Niraparib), an oral PARP inhibitor for the treatment of ovarian cancer. GSK believes PARP inhibitors have significant potential for use in the treatment of multiple cancer types including lung, breast and prostate cancer.

GSK is aiming to explore more Zejula’s efficacy to help many more cancer patients. Moreover, in addition to Zejula, TESARO has various oncology assets in its pipeline including the anti-PD-1 antibody drug (Dostarlimab, formerly known as TSR-042).

GSK CEO Emma Walmsley is hoping that their purchase of TESARO would significantly strengthen their cancer drug pipeline and commercial capability. They are expecting the deal to complete in the first quarter of 2019.