Our Team

Leadership

Percival Barretto-Ko

President & Chief Executive Officer

Percival is the President & Chief Executive Officer of Plexium, the premier next-generation Targeted Protein Degradation company.

Percival joined Plexium in 2021 with extensive biopharmaceutical experience across various therapeutic areas, functions, and geographies. Prior to Plexium, Percival was the Chief Business Officer of Astellas Pharma Inc., where he spearheaded the execution of the company’s Corporate Strategic Plan and its efforts to enhance internal and external innovation. Percival’s earlier roles at Astellas included President of Astellas Pharma US, SVP International, and SVP Corporate Strategy, Business Development & Government Affairs. Before joining Astellas, Percival held increasingly senior commercial positions with the Roche Group in the United States and the United Kingdom. Percival earned a BS in Biological Sciences and Chemistry with Honors from Cornell University and an MBA from Yale University. In addition, Percival served as a Sloan Fellow for Innovation and Global Leadership at the MIT Sloan School of Management, where he was awarded an MS degree in Management. Percival is a board member of Americares, a health-focused relief and development organization that serves people affected by poverty or disaster with life-changing medicine and health programs.

Simon Bailey, Ph.D., MBA

Executive Vice President, Drug Discovery

The Head of Drug Discovery at Plexium, Simon oversees the company’s efforts to identify novel protein degrader drugs that address significant unmet medical needs.

Simon joined Plexium in 2019, bringing more than 25 years of experience in medicinal chemistry and small molecule drug discovery leadership. From 1995-2015, Simon held positions of increasing responsibility at Pfizer, including leading the Diabetes and Oncology Medicinal Chemistry Departments. Subsequently, Simon was the Head of Research and Global Pipeline Leader for Intercept Pharmaceuticals. There, he led the company’s programs from inception to Phase 2 in the area of fibrotic liver disease. Simon holds a Ph.D. and was the Hibbert Prize winner in synthetic organic chemistry from the University of Manchester. He completed postdoctoral studies under Prof. Leo Paquette at the Ohio State University and obtained an MBA from the University of California, San Diego. Simon is a 2021 recipient of the American Chemical Society’s Hero of Chemistry award for his role in the discovery of Lorbrena™.

Kevin Eastwood

Executive Vice President, Corporate Business Development

Kevin is the Executive Vice President of Corporate Development for Plexium.

He leads corporate strategy and is responsible for establishing external partnerships, managing strategic alliances, and supporting corporate financing initiatives. With over 30 years of industry experience, Kevin joined Plexium after working with large biotechnology companies, such as Agouron Pharmaceuticals and Gilead, and venture-backed start-ups, such as Achillion Pharmaceuticals and eFFECTOR Therapeutics. Prior to joining Plexium, Kevin was the Vice President of Corporate Development for the California Institute for Biomedical Research. He began his business development career at Agouron Pharmaceuticals and has significant experience across strategic partnerships, in-licensing, out-licensing, and M&A. Kevin graduated from Missouri State University with a degree in biology.

Peggy Thompson, Ph.D.

Vice President, Biology

Peggy is the Vice President of Biology, leading the targeted protein degradation drug discovery efforts at Plexium.

Peggy joined Plexium in 2020 with more than 20 years of experience in drug discovery and development in the biotechnology industry. Prior to Plexium, she was a co-founder and Executive Director of Biology at eFFECTOR Therapeutics, where she established their technology platform for targeting dysregulated mRNA translation for supporting oncology drug development. She also led their eIF4A program (Zotatifin, Phase II) from concept to clinical development in solid tumor malignancies. Before that, Peggy served as the Director of Biology at Anadys Pharmaceuticals, Inc., where she held positions of increasing responsibility, including leading the drug discovery biology efforts and supporting the development of Setrobuvir until the acquisition by Roche Pharmaceuticals. Prior to Anadys, Peggy held positions at Biopraxis and the National Institutes of Health. She was an NIH postdoctoral fellow in Biophysics at the University of California, Berkeley, and completed her Ph.D. in Chemistry from the University of California, San Diego. She received her B.S. with Highest Distinction in Biochemistry from Washington State University.

Yi Zhang, Ph.D.

Vice President, Engineering

As Vice President of Engineering, Yi directs the screening platform development for Plexium.

Yi joined Plexium in 2018, with more than 20 years of experience in instrument, bio-instrument, device, and assay design & development. Prior to Plexium, he was the Director of Engineering for Omniome, Inc. (now PacBio), a San Diego-based next-generation sequencing technology company. Yi spent the majority of his career at Celula, Inc. As the Director of Engineering and Assay Integration, he led a multidisciplinary team, including engineers and biologists, to develop multiple bio-instruments and assays for Non-Invasive Prenatal Test (NIPT) and fetal cell program. Yi began his career in the optical data storage field, developed 2-photon 3D optical data-storage technology. He earned a bachelor’s degree in Optical Engineering from Tsinghua University and graduated with a Ph.D. in Engineering.

Phyllis Balan, MBA

Vice President, Human Resources

Phyllis is the Vice President of Human Resources for Plexium.

Her responsibilities include managing people operations and overseeing organization effectiveness. Phyllis joined Plexium in March 2021, bringing over 20 years of experience in all aspects of human resources. Her skills and experience include talent management, talent acquisition, total rewards, and organizational development. Phyllis has held Human Resources leadership positions at AnaptysBio, Sotera Wireless, and Biogen. Prior to that, she held positions of increased responsibility in the technology industry. Phyllis received a Bachelor of Science and a Master of Business Administration from Michigan State University and an MA from San Diego State University in Educational Technology.

Emily Arsenault, CPA, MBA

Executive Director, Finance & Operations

The Executive Director of Finance & Operations, Emily develops and directs financial and operational strategy for Plexium.

Emily joined the Plexium team in 2020, bringing with her more than 15 years of experience in accounting, finance, administration, and operations. Prior to Plexium, Emily was the Director of Finance and Controller for Mirati Therapeutics, Inc. Mirati Therapeutics is a publicly-traded targeted oncology company based out of San Diego, California. Emily has spent the majority of her career with early and growth-stage life sciences companies. She earned her Bachelor of Arts and Master of Business Administration from San Diego State University and is a Certified Public Accountant licensed in the state of California.

Board of Directors

Mike Grey

Executive Chairman

Percival Barretto-Ko

President & CEO, Plexium

Adam Goulburn

Partner, Lux Capital

Rob Hopfner

Managing Partner, Pivotal Bioventure Partners

Tim Kutzkey

Managing Partner, The Column Group

Kiersten Stead

Managing Partner, DCVC Bio

Investors