Description of Business

3 Months Ended

Mar. 31, 2013

Description of Business

Description of Business

1. Description of Business

TESARO, Inc. (the “Company” or “TESARO”), is a development stage company that was incorporated in Delaware on March 26, 2010 and commenced operations in May 2010. TESARO is headquartered in Waltham, Massachusetts.

TESARO is an oncology-focused biopharmaceutical company dedicated to improving the lives of cancer patients by identifying, acquiring, developing and commercializing cancer therapeutics and oncology supportive care products in the United States, Europe and other international markets. Since incorporation, primary activities have consisted of acquiring product candidates, advancing development of its product candidates, developing intellectual property, recruiting personnel and raising capital. The Company intends to in-license or acquire additional product candidates across various stages of development.  The Company has never earned revenue from these activities, and, accordingly, the Company is considered to be in the development stage as of March 31, 2013. The Company is subject to a number of risks similar to those of other development stage companies, including dependence on key individuals, the need to develop commercially viable products, competition from other companies, many of whom are larger and better capitalized, and the need to obtain adequate additional financing to fund the development of its product candidates and further its in-licensing and acquisition activities.

The Company has incurred significant operating losses since inception and has relied on its ability to fund its operations through public and private equity financings, and management expects operating losses and negative cash flows to continue for the foreseeable future. As the Company continues to incur losses, transition to profitability is dependent upon the successful development, approval, and commercialization of its product candidates and achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. Management intends to fund future operations through additional private or public debt or equity offerings, and may seek additional capital through arrangements with strategic partners or from other sources.