Jonathan E. Lim, M.D.
Managing Partner and Founder

Jonathan E. Lim, MD, is a physician-turned-venturepreneur and philanthropist who is dedicated to founding, funding, and leading mission-driven ventures that restore human health. Jonathan founded City Hill Ventures in December 2010 and serves as Managing Partner, focused on building or helping other health care entrepreneurs build great companies with a transformative impact on patients, the health care industry, and society. Jonathan also serves as Venture Partner at ARCH Venture Partners, one of the largest seed and early stage technology venture firms in the U.S., which he joined in December 2018. Within the City Hill and/or ARCH portfolios, Jonathan serves as Chairman and CEO of Erasca, which he co-founded in July 2018; as Chairman and Co-founder of Boundless Bio, which he joined in December 2018; and Board Director of Maze Therapeutics, which he joined in October 2019.

From 2003 to 2018, Jonathan was a leader and founding investor of four biotechnology startups that delivered novel therapies for the benefit of patients globally, raised a combined $1 billion in capital and generated more than $4 billion of shareholder value. Jonathan’s most recent operational role was serving as Chairman, President, CEO and Co-founder of Ignyta (RXDX), from August 2011 until its acquisition by Roche in February 2018, and overseeing its subsequent integration into Roche and Genentech until July 2018. Previously, he was Chairman and Co-founder of Bonti from August 2015 until its October 2018 acquisition by Allergan; Chairman, CEO and Co-founder of Eclipse Therapeutics from March 2011 to its September 2012 acquisition by Bionomics; and President, CEO and Chairman-then-Director of Halozyme Therapeutics (HALO) from May 2003 to December 2010. 

Jonathan also serves as Co-President of City Hill Foundation, which he launched with his wife in December 2011. He is an advisor to nonprofit organizations, including Stanford University, University of California, San Diego, The Scripps Research Institute and UrbanLife. Earlier in his career, Jonathan was a management consulting at McKinsey & Company, an NIH Postdoctoral Fellow at Harvard Medical School and Dana Farber Cancer Institute, and a general surgery resident at New York Hospital-Cornell and Memorial Sloan Kettering Cancer Center. He holds B.S. and M.S. degrees from Stanford University, an M.D. from McGill University, and an M.P.H. from Harvard University.

Zachary Hornby
Operating Partner

Zachary (“Zach”) Hornby has served in both operating and director roles for multiple different City Hill portfolio companies. He is currently the Chief Executive Officer, President and a Director at Optera Therapeutics Corp. Prior to joining Optera, Zach was most recently Chief Operating Officer at Ignyta, where he oversaw development of the company’s portfolio of four clinical stage therapeutics and was the team leader for the company’s lead program, entrectinib, which was the first drug in pharmaceutical history to garner the coveted BTD (FDA), PRIME (EMA) and Sakigake (PMDA) designations. In that role, he also led the business development process that led to Ignyta’s acquisition by Roche for $1.7 billion; after the Roche acquisition, Zach served as the Ignyta site-head where he was responsible for overseeing the integration into Roche. Before assuming the COO role, Zach was Ignyta’s CFO, helping the company go public and raise $120M in capital. Prior to joining Ignyta, Zach served in roles of increasing responsibility across business development, marketing, new product planning, finance and regulatory affairs at Fate Therapeutics, Halozyme Therapeutics, Neurocrine Biosciences and TKT (now the Human Genetic Therapies division within Takeda/Shire) and was a life sciences consultant at L.E.K. Consulting. Zach holds B.S. and M.S. degrees in biology, with a concentration in neuroscience, from Stanford University and an M.B.A. from Harvard Business School.

Karen Gilmore, CPA

Karen Gilmore joined City Hill Ventures in early 2011 as Controller and has supported multiple portfolio companies of City Hill, including Erasca, Ignyta, Eclipse Therapeutics, and Medenovo. She has over 25 years’ experience serving both public and private companies in multiple industries with a heavy concentration over the past decade in biotech and medical device. Currently, Karen provides CFO/Controller services to various start-ups and small corporations from early stage on, as they scale their business. Karen began her career with Coopers & Lybrand (currently PriceWaterhouseCoopers). She has a Bachelor of Science degree from California State Polytechnic University, Pomona and is a Certified Public Accountant.