Executive Chairman

John F. Milligan, PhD has served as the Executive Chairman of our board of directors since August 2020. Dr. Milligan had a 29-year career with Gilead, retiring as President and Chief Executive Officer in December 2018. During his tenure at Gilead, he led teams that developed, manufactured and commercialized more than 25 new therapies for significant unmet needs, including the first single tablet regimen for HIV treatment and the first 12 week, all oral cure for HCV. John led multiple transformative acquisitions including Triangle Pharmaceuticals in 2003, Myogen in 2006, CV Therapeutics in 2009, Pharmassett in 2012 and Kite in 2017. Before taking the CEO role, as CFO, John built a robust international organization that allowed the company to grow from $190 million in revenue to over $4.2 billion in just six years.


He helped the company become a global organization with direct operations in 44 countries that was able to deliver its medicines to more than 10 million patients every day. John joined Gilead when it was a private company with 32 employees, and upon retirement, 29 years later, Gilead had over 11,000 employees, sales of over $21 billion and a market cap of $85 billion. John serves as the Chair of Pacific Biosciences of California (Nasdaq: PACB) and also as the Chair of the Board of Trustees of Ohio Wesleyan University. John received a B.A. in chemistry from Ohio Wesleyan University, a Ph.D. in biochemistry from the University of Illinois at Urbana-Champaign and was an American Cancer Society post-doctoral fellow at U.C.S.F.


Chief Executive Officer

David Kirn, M.D., is our co-founder and has served as our Chief Executive Officer since our inception in 2013. Dr. Kirn is also Adjunct Professor of Bioengineering and Molecular & Cellular Biology at U.C. Berkeley.

Over his 30 year career, Dr. Kirn has co-founded and been CEO of four viral vector-based genetic medicines companies, three of which to date were either acquired or went public. Dr. Kirn also held senior clinical research and development positions at Onyx Pharmaceuticals (VP) and Celgene (SVP), and was a senior advisor to Novartis, Bayer, Pfizer, Biogen and others in the genetic medicines field.




Dr. Kirn received a B.A. in Physiology (Departmental Citation; Phi Beta Kappa) from U.C. Berkeley in 1985, an M.D. (Alpha Omega Alpha) from U.C. San Francisco Medical School in 1989 and completed internal medicine residency training at Harvard Medical School, Brigham and Women’s Hospital (including a term as Chief Medical Resident at affiliated VA hospital). He has also completed hematology-oncology and clinical research fellowships at U.C. San Francisco and completed a certificate of business excellence from the Haas Business School at U.C. Berkeley. In 2013, he was awarded the Johnson & Johnson Entrepreneur Innovator award from the J&J Innovation Center.


Board Member

Jacob Chacko, M.D., MBA, has served as a member of our board of directors since March 2019. Dr. Chacko has served as Chief Executive Officer of ORIC Pharmaceuticals, Inc., a clinical-stage oncology company focused on discovery and development of novel therapies against treatment-resistant cancers, since May 2018. Prior to ORIC, Dr. Chacko served as Chief Financial Officer of Ignyta, Inc., a publicly traded precision oncology company, from May 2014 until February 2018 when Ignyta was acquired by Roche Holdings, Inc. Prior to Ignyta, Dr. Chacko was Vice President at TPG Capital from August 2008 until May 2014. From 2002 until 2003, Dr. Chacko was a consultant serving healthcare clients at McKinsey & Company.



Dr. Chacko currently serves on the board of directors of Turning Point Therapeutics, Inc., a publicly-traded biotechnology company, from November 2018. Dr. Chacko served on the board of directors of RentPath Inc., a digital media company, from 2011 until 2014, Envision Pharmaceutical Services, LLC from 2013 until 2014, Bonti, Inc., a biotechnology company, from February 2018 until October 2018 and the Packard Children’s Health Alliance at the Lucile Packard Children’s Hospital Stanford from 2013 until June 2017. Dr. Chacko currently chairs the Western Regional Selection Committee for the Marshall Scholarship. Dr. Chacko concurrently received his M.D. from the U.C. Los Angeles and his M.B.A. from Harvard Business School. Dr. Chacko received a M.Sc. from Oxford University as a Marshall Scholar.


Board Member

Susannah Gray has served as a member of our board of directors since July 2020. Ms. Gray brings more than 30 years of biopharmaceutical experience specifically in corporate finance and capital markets roles, most recently serving as EVP, Finance & Strategy of Royalty Pharma Management, LLC. Ms. Gray spent 14 years as executive vice president and chief financial officer of Royalty Pharma before retiring in 2019 just ahead of the Company’s initial public offering. At Royalty Pharma, Ms. Gray led the Company’s efforts to maximize its financial capabilities. In her career at Royalty Pharma, she increased the debt facilities from approximately $200 million to $7 billion, and was responsible for over $20 billion in total financing. She also raised $2.0 billion equity capital for the Company.



Prior to joining Royalty Pharma, Ms. Gray had a 14-year career in investment banking. In her most recent role, she was a managing director and the senior analyst covering the healthcare sector for CIBC World Market’s high yield group from 2002 to 2004. She worked in a similar capacity at Merrill Lynch prior to joining CIBC World Markets. Ms. Gray joined Merrill Lynch in April 1999 after nine years at Chase Securities (a predecessor of JP Morgan), working in various capacities within the high yield and the structured finance groups. Ms. Gray received a BA with honors from Wesleyan University and holds an MBA degree from Columbia University. Ms. Gray currently serves on the board of directors of Susan G. Komen and is on the board of trustees at Wesleyan University.


Board Member

Noriyuki Kasahara, MD, PhD, has served as a member of our board of directors since September 2022. Dr. Kasahara brings more than 30 years of experience and has authored more than 150 peer-reviewed articles in the fields of gene therapy and genetic engineering. He is currently Professor and Alvera L. Kan Endowed Chair of Neurological Surgery and Radiation Oncology at the University of California San Francisco (“UCSF”), and a principal investigator in the UCSF Brain Tumor Center. The goals of Dr. Kasahara’s research include optimizing the application of multiple and diverse viral vector delivery systems to achieve maximal therapeutic potential, as well as developing next-generation gene transfer technologies with greater therapeutic efficacy in vivo.



He pioneered the development of tumor-selective retroviral replicating vectors (RRV) for gene therapy of cancer, including first-in-human multi-center clinical trials. Dr. Kasahara serves as a member of the Scientific Committee on Cancer Gene and Cell Therapy for the American Society of Gene and Cell Therapy, is on the Board of Directors of the Japan Society of Gene and Cell Therapy and is a past president of the International Society for Cell and Gene Therapy of Cancer.


Board Member

Nancy Miller-Rich has served as a member of our board of directors since November 2020. Ms. Miller-Rich has 35 years of experience in the healthcare industry, with significant expertise in business development and commercial strategy. Since September 2017, Ms. Miller-Rich has served as a consultant to the pharmaceutical industry. Previously, Ms. Miller-Rich served in a number of leadership roles at Merck & Co., Inc. and, prior to the merger of the two companies, at Schering-Plough Corporation, including most recently as Senior Vice President, Global Human Health Business Development & Licensing, Strategy and Commercial Support from November 2013 to September 2017 and as Group Vice President, Consumer Care Global New Ventures and Strategic Commercial Development from January 2007 to November 2013.



Prior to joining Schering-Plough in 1990, Ms. Miller-Rich served in a variety of commercial and marketing roles at Sandoz Pharmaceuticals and Sterling Drug, Inc. She is currently a director of Aldeyra Therapeutics, Inc., as well as a board member of a number of private and not-for-profit entities. She received her B.S. in Business Administration, Marketing from Ithaca College in Ithaca, New York.


Board Member

Charles Theuer, M.D., Ph.D., has served as a member of our board of directors since December 2015. Dr. Theuer has served as President and Chief Executive Officer at Tracon Pharmaceuticals, Inc., since June 2006. He previously served as Chief Medical Officer at TargeGen Pharmaceuticals, Inc. until June 2006.



He currently serves on the board of directors of the following publicly-held companies: Tracon Pharmaceuticals Inc., since June 2006 and Oncternal Therapeutics Inc. since May 2018, where he serves on the Science and Development and Nominating and Corporate Governance committees. Dr. Theuer received a B.S. in Life Sciences from the Massachusetts Institute of Technology in 1985. He received his M.D. from U.C. San Francisco in 1989. He received his Ph.D. in Environmental Health Science from U.C. Irvine in 2002.


Board Member

Shawn Tomasello has served as a member of our board of directors since November 2020. Ms. Tomasello brings over 30 years of experience in the life sciences industry and most recently served as Chief Commercial Officer of Kite Pharma (subsequently Kite, a Gilead Company), where she led the commercialization of Yescarta, the first approved CAR-T therapy for the treatment of adult patients with relapsed or refractory non-Hodgkin lymphoma. Prior to joining Kite, she served as Chief Commercial Officer at Pharmacyclics (subsequently Pharmacyclics, an Abbvie Company), during which time the brand Imbruvica was awarded the prestigious 2015 Prix Galien Award for Best Pharmaceutical Agent. Previously, she held senior leadership positions at Celgene, including President of the Americas, Hematology and Oncology.



During her tenure at Celgene, Ms. Tomasello was responsible for all aspects of commercial sales and marketing for five brands encompassing 11 indications. Prior to this, she was National Director of Hematology for Rituxan at Genentech, representing the most significant portion of the company’s product revenue during her tenure. Ms. Tomasello currently serves on the Board of Directors of the following publicly-held companies: Urogen Pharma, Gamida Cell, and Mesoblast. Ms. Tomasello holds a B.S. degree in marketing from the University of Cincinnati and an M.B.A. from Murray State University, KY.