TESARO, Inc. is an oncology-focused biopharmaceutical company. The Company acquires, in-licenses and develops oncology product candidates. It operates in business of developing and commercializing oncology-focused therapeutics segment. It has in-licensed and are developing oncology-related product candidates, including intravenous (IV) rolapitant and niraparib, as well as product candidates under its immuno-oncology platform. It offers VARUBI (rolapitant), which is an oral substance P/neurokinin 1 (NK-1) receptor antagonist for use in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy. It is developing IV formulation of rolapitant, which has completed various Phase 1 clinical trials. Its niraparib is an orally active and poly (ADP-ribose) polymerase (PARP) inhibitor. Its immuno-oncology platform has immuno-oncology programs, which include TSR-022 and TSR-042.