Tesaro Inc. is a pharmaceutical company based in Waltham, Massachusetts.

[1] The company's first commercial product, Varubi, was approved by the FDA in October 2015.

[3] The company's product Niraparib was granted priority review and was given a target action date of June 2017 by the FDA.

[4] In March 2017, Tesaro won approval for its drug Zejula to treat ovarian cancer.

[5] On December 3, 2018, GSK announced it would acquire the company for $5.1 billion,[6] and the deal was completed on January 22, 2019.