TESARO and Myriad Announce Companion Diagnostics Collaboration

Data Presented at the 26th EORTC-NCI-AACR Symposium

BARCELONA, November 20, 2014 - TESARO, Inc. (NASDAQ: TSRO) and Myriad Genetics (NASDAQ: MYGN) today announced a collaboration utilizing Myriad's myChoice HRD companion diagnostic (CDx) to identify tumor tissue with a deficiency in homologous recombination. Under the terms of the agreement, TESARO will utilize Myriad's test to enrich the target population for potential responders to niraparib. Myriad will provide testing services and pursue necessary regulatory approvals in support of TESARO's development of niraparib.

The Companies also described new data demonstrating that Myriad's myChoice HRD™ score is predictive of niraparib sensitivity in patient-derived xenograft models of ovarian cancer. These results were presented today by Dr. Paul Haluska, Jr., M.D., Ph.D., Associate Professor of Oncology at the Mayo Clinic, at the 26th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Barcelona, Spain.

"Myriad's myChoice HRD diagnostic test identifies the inherent biology of the tumor and differentiates tumors with homologous repair deficiencies from those without such deficiencies," said Mary Lynne Hedley, Ph.D., President and COO of TESARO. "Niraparib sensitivity in patient-derived xenograft models is associated with HRD status as defined by the myChoice HRD test."

"We are excited to be expanding our collaboration with TESARO as we strongly believe new diagnostics such as myChoice HRD, combined with targeted therapies such as niraparib, have the potential to significantly improve patient care," said Jerry Lanchbury, Ph.D., Chief Scientific Officer at Myriad. "myChoice HRD utilizes three proprietary measures to assess the genomic scar associated with the loss of DNA repair and has been shown in multiple clinical studies to be the most comprehensive predictor of tumor response to DNA damaging agents such as niraparib."

Summary of Xenograft Study Results
Patient-derived xenografts were created from more than 100 high grade serious ovarian cancer tumor samples. HRD testing was performed on each sample using myChoice HRD to define HRD status, detect BRCA 1 and 2 mutations and identify hypermethylation of BRCA genes. Approximately half of these models were HRD positive and are being evaluated for sensitivity to niraparib in vivo. Preliminary data from treated models indicate all models that responded to niraparib treatment had an HRD score above the predetermined cutoff value and included both BRCA mutant and BRCA wild type tumors. Evaluation of niraparib sensitivity across the full set of selected models is ongoing. These initial results indicate that identifying patients with homologous recombination deficiencies using myChoice HRD may help to identify patients who are most likely to respond to treatment with niraparib.

About Niraparib
Niraparib is an orally active and potent poly (ADP-ribose) polymerase, or PARP, inhibitor. A Phase 1/2 monotherapy study of niraparib has been completed in more than 100 patients with advanced solid tumors. Two Phase 3 trials are currently ongoing to evaluate a single oral dose of niraparib as a maintenance therapy for patients with ovarian cancer and as a treatment for patients with BRCA-positive breast cancer.

About myChoice HRD™
Myriad's proprietary Homologous Recombination Deficiency (HRD) test detects DNA scars that indicative of a tumor that has lost the ability to repair double-stranded DNA breaks, resulting in increased susceptibility to DNA-damaging drugs. High HRD scores reflective of DNA repair deficiencies are prevalent in all breast cancer subtypes and most other major cancers. In previously published data, Myriad showed that the myChoice HRD test predicted drug response to platinum therapy in triple-negative breast cancer patients. It is estimated that up to 1.8 million people in the United States and Europe are diagnosed with cancers annually are candidates for treatment with DNA-damaging agents.

About TESARO
TESARO is an oncology-focused biopharmaceutical company dedicated to improving the lives of cancer patients by acquiring, developing and commercializing safer and more effective therapeutics. For more information, visit www.tesarobio.com.

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

About Myriad
Myriad Genetics is a leading molecular diagnostic company dedicated to making a difference in patients' lives through the discovery and commercialization of transformative tests to assess a person's risk of developing disease, guide treatment decisions and assess risk of disease progression and recurrence. Myriad's molecular diagnostic tests are based on an understanding of the role genes play in human disease and were developed with a commitment to improving an individual's decision making process for monitoring and treating disease. Myriad is focused on strategic directives to introduce new products, including companion diagnostics, as well as expanding internationally. For more information on how Myriad is making a difference, please visit the Company's website: www.myriad.com.

Media Contact:
Ron Rogers
EVP Corporate Communications
(801) 584-3065 or [email protected]

Investor Contact:
Scott Gleason
VP of Investor Relations
(801) 584-1143 or [email protected]

To the extent that statements contained in this press release are not descriptions of historical facts regarding TESARO or Myriad, 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 our expectations regarding future clinical trials with niraparib. Forward-looking statements in this release involve substantial risks and uncertainties that could cause our 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, the uncertainties inherent in the initiation of future clinical trials, availability of data from ongoing clinical trials, expectations for regulatory approvals, and other matters that could affect the availability or commercial potential of our drug candidates. TESARO and Myriad undertake 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 TESARO and Myriad in general, see TESARO's Annual Report on Form 10-K for the year ended December 31, 2013 and other filings TESARO makes with the Securities and Exchange Commission, and Myriad's Annual Report on Form 10-K for the year ended June 30, 2014 and other filings Myriad makes with the Securities and Exchange Commission.