Mary Lynne Hedley

Venture Partner
Third Rock Ventures

Prior to joining Third Rock, Mary Lynne was a Sr Scientific Fellow at the Broad Institute where she served as a strategic advisor to scientists across the Institute. She was most recently co-founder, Director, and President and Chief Operating Officer of TESARO, a biotechnology company focused on the development and global commercialization of medicines to treat patients with cancer. As such she oversaw a team responsible for all aspects of R&D, Global Manufacturing and Operations, Business Development and Corporate Strategy. Prior to its acquisition by Glaxo Smith Kline (GSK) in 2019 for $5.1 billion, TESARO had built a robust pipeline of products and drug candidates for patients living with cancer, had received multiple drug approvals from FDA and European regulatory authorities, was commercializing medicines in the US and Europe and was recognized for its productivity and creative drug development strategies. Notably, the development and regulatory approval of the PARP inhibitor Zejula, changed the treatment paradigm for women diagnosed with ovarian cancer Prior to founding TESARO, Mary Lynne served as Executive Vice President of the Japanese Pharmaceutical company Eisai Inc, a role she assumed following the acquisition in January 2008, of MGI PHARMA by Eisai for $3.9 Billion. At MGI, Mary Lynne was Executive Vice President and Chief Scientific Officer, responsible for R&D. Prior to her role at MGI, Dr. Hedley was a co-founder of ZYCOS Inc., where she served as a Director, President and CEO prior to the acquisition of ZYCOS by MGI PHARMA in 2004.
Dr. Hedley is an immunologist by training, graduated with a B.S. with honors in Microbiology from Purdue University, and a Ph.D. in Molecular and Cellular Immunology from UT Southwestern Medical Center. She did her postdoctoral training at Harvard University in the areas of Immunology and Gene Regulation.
She is the author of multiple manuscripts and is listed as an inventor on over 50 patents and patent applications. She has received several honors, including, together with her TESARO co-founder the Ernst & Young (EY) Entrepreneur of the Year in 2017 for the United States, and represented the country at the International EY entrepreneur of the year event in Monaco in 2018. She won the New England Venture Capital Association 2016 Entrepreneur of the Year, was voted one of the Ten Most Influential Women in Biotechnology for 2013 (to which her unimpressed son replied, “Of the 10 was there a number 1 and were you it?”), one of the Fierce Top 10 Women in Biotech for 2011, and a Massachusetts Biotechnology “Woman to Watch” in 2007.
Mary Lynne sits on the boards of Veeva and Centessa, and is a board member of Helsinn Healthcare SA, the Youville Assisted Living Communities and WITH (Women Innovating Together in Healthcare). She has participated in multiple international service projects including those in Nicaragua, Venezuela, and Chile. Over the last 18 months Mary Lynne and her family have begun working with the Cambodian founder of an English school in Siem Reap, Cambodia to create a 5-year strategic plan and raise funding to implement the founder’s vision. She enjoys trekking, hiking and snowboarding with her husband and sons.