TESARO Announces Enrollment of First Patient in Phase 1 Clinical Trial of TSR-042

WALTHAM, Mass., March 29, 2016 -- TESARO, Inc. (Nasdaq:TSRO), an oncology-focused biopharmaceutical company, today announced it has dosed the first patient in a Phase 1, dose-escalation study of its lead anti-PD-1 monoclonal antibody candidate, TSR-042. Following identification of a dose and schedule for TSR-042, the trial is planned to expand into tumor specific cohorts.

“TSR-042 is the first antibody candidate from our immuno-oncology portfolio to enter clinical trials, and our goal is to identify a dose and schedule for TSR-042 by the end of 2016,” said Mary Lynne Hedley, Ph.D., President and COO of TESARO. “We continue to believe that immuno-oncology has the potential to transform our approach to cancer therapy and we look forward to continuing to advance our immuno-oncology portfolio. We expect to submit an investigational new drug application for a second antibody candidate from our immuno-oncology portfolio, TSR-022, our anti-TIM-3 antibody candidate, during the second quarter of this year.”

About TSR-042

TSR-042 is a monoclonal antibody candidate targeting PD-1 and was developed as part of a collaboration between TESARO and AnaptysBio, Inc. This collaboration was initiated in March of 2014, and is focused on the development of monospecific antibody drug candidates targeting TIM-3 (TSR-022), LAG-3 and PD-1 and bi-specific antibody drug candidates targeting PD-1/TIM-3 and PD-1/LAG-3, in addition to a novel bispecific antibody candidate designed to target undisclosed targets.

About TESARO

TESARO is an oncology-focused biopharmaceutical company devoted to providing transformative therapies to people bravely facing cancer. For more information, please visit www.tesarobio.com.

To the extent that statements contained in this press release are not descriptions of historical facts regarding TESARO, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as "may," "will," "expect," "anticipate," "estimate," "intend," and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. Examples of forward-looking statements contained in this press release include, among others, statements regarding our expected identification of a dose and schedule for TSR-042 by the end of 2016, subsequent expansion of the Phase 1 trial of TSR-042 into tumor specific cohorts, our belief that immuno-oncology could transform the way numerous cancers are treated, and our expectation that we will file an investigational new drug application for TSR-022 during the second quarter of 2016. Forward-looking statements in this release involve substantial risks and uncertainties that could cause our research and pre-clinical development programs, clinical development programs, future results, performance, or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, competition from other pharmaceutical companies, the uncertainties inherent in the execution and completion of pre-clinical research and clinical trials, uncertainties regarding regulatory approvals, uncertainties regarding certain expenditures, and other matters that could affect the success of the research programs described in this press release. TESARO undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the Company in general, see TESARO's Annual Report on Form 10-K for the year ended December 31, 2015.

TESARO Investor/Media Contact:
Jennifer Davis
Sr. Director, Corporate Development & Investor Relations
+1.781.325.1116 or [email protected]