Meet our Team

David J. Earp, J.D., Ph.D.
President & CEO
David J. Earp, J.D., Ph.D. - President & CEO
David J. Earp, J.D., Ph.D., has served as the President & CEO of Circle since October 2013. Previously, David held various roles at Geron Corporation (GERN), including chief patent counsel, chief legal officer and senior vice president of corporate transactions, building a broad IP portfolio and playing an integral role in numerous partnering, licensing and collaboration deals. He led the spin-out of Geron’s nuclear transfer technology into StART Licensing, Inc., and its subsequent acquisition by Viagen Corp. (Austin, Texas). He served on the boards of StART and Viagen, including as executive chairman of Viagen and led the sale of the company to TransOva Genetics (subsequently acquired by Intrexon). David was also a member of the board of directors of TA Therapeutics Ltd. (Hong Kong, PRC). He was previously a partner in the intellectual property law firm of Klarquist Sparkman, LLP (Portland, Oregon). He currently also serves as a board member of Sienna Cancer Diagnostics (Melbourne, Australia).
David received his B.Sc. (with first class honours) in microbiology from the University of Leeds, his Ph.D. in biochemistry and molecular biology from the University of Cambridge, and his J.D. (magna cum laude) from the Northwestern School of Law of Lewis and Clark College. He was a postdoctoral research fellow at the University of California, Berkeley / USDA PGEC.

Rajinder Singh, Ph.D.
Chief Scientific Officer
Rajinder Singh, Ph.D. - Chief Scientific Officer
Rajinder Singh, Ph.D., has served as our Chief Scientific Officer since July 2020. From 2016 to 2020, Dr. Singh held the position of Senior Vice President of Research & Pharmaceutics at ChemoCentryx – where he worked on the complement system (C5aR inhibition with avacopan), diverse chemokine receptors (such as CCR1, CCR2, CCR6, CXCR2, CXCR7) and immune-oncology with small molecules targeting PD-1/PD-L1. From 1998 to 2016, Dr. Singh held various management positions including Vice President, Chemistry at Rigel Pharmaceuticals, Inc., where he oversaw the advancement of numerous drug candidates from discovery to clinical development, which included the filing of numerous Investigational New Drug applications leading to the approval of Tavalisse (fostamatinib) a Syk kinase inhibitor in the areas of immunology and oncology. Prior to joining Rigel, Dr. Singh was a lead chemist at Chiron Corporation from 1994 to 1998. From 1992 to 1994, Dr. Singh was a Postdoctoral Fellow at Eli Lilly & Company. Dr. Singh received his Ph.D. degree in Organic Chemistry from the University of Oxford and B.Sc in Chemistry from University of Cardiff.

Jim Aggen, Ph.D.
VP, Medicinal Chemistry
Jim Aggen, Ph.D. - VP, Medicinal Chemistry
Dr. Aggen has over 20 years of experience in medicinal chemistry. He most recently served as the Senior Director of Medicinal Chemistry at Revolution Medicines and earlier in his career held various positions at Oligiasis, Achaogen, Chemocentryx, Gilead Sciences and Theravance, as well as Associate Professor of Medicinal and Natural Products Chemistry at Northeastern University. Dr. Aggen has successfully led teams engaged in targeted drug discovery against multiple oncology targets including mTORC1 and KRAS, and has experience in the medicinal chemistry of larger molecules, including as an inventor of the aminoglycoside antibiotic plazomicin, now marketed as Zemdri. He also served in the US Marine Corps Reserves. Dr. Aggen was awarded a doctorate in synthetic organic chemistry from the University of California, Irvine, where he studied under Prof. Richard Chamberlin.

David C. Spellmeyer, Ph.D.
Advisor, Informatics and Computational Chemistry
David C. Spellmeyer, Ph.D. - Advisor, Informatics and Computational Chemistry
David Spellmeyer brings over 25 years of scientific leadership experience to Circle, having served in senior positions at several drug development and life science services companies. These roles include CTO & CIO at Nodality, CSO at Signature BioScience, and vice president of computational sciences at CombiChem(acquired by DuPont). David was involved in the development of peptoids as therapeutics at Chiron. He serves as an Executive-in-Residence at ShangPharma Innovation, which is an investor in Circle. He heads Interlaken Associates, a life sciences advisory company, and is Adjunct Associate Professor in the Department of Pharmaceutical Chemistry at U.C. San Francisco, where he completed his postdoctoral studies. David received his PhD in theoretical organic chemistry at U.C. Los Angeles and a BS in computer science and chemistry from Purdue University.

Pablo D. Garcia, Ph.D.
Sr. Director, Biology Research
Pablo D. Garcia, Ph.D. - Sr. Director, Biology Research
Pablo D. Garcia, Ph.D., is a cellular and molecular biologist with extensive experience in oncology drug discovery and preclinical development. With over 17 years of experience at Chiron Corporation and the Novartis Institutes for Biomedical Research in Emeryville, he made significant contributions to the areas of target identification and validation, the implementation of diverse discovery platforms and the management of a cancer biology discovery group. Pablo has led several drug discovery projects, including the PIM kinase inhibitor project at Chiron/Novartis. As the project leader, he oversaw all stages of preclinical development, from the initial validation of relevance to human disease to delivery of a drug candidate to clinical development. Pablo has a B.A. in Biology, a Masters in Genetics from Universidad Católica de Valparaíso (Chile) and a Ph.D. in Biochemistry from the University of California, San Francisco (UCSF).

Amy Cowgill
Director, Business Operations and Administration
Amy Cowgill - Director, Business Operations and Administration
Amy Cowgill brings a wealth of business and technology leadership experience to Circle, having successfully built solutions and organizational capacity in multiple industries for a range of organizations. Prior to joining Circle, Amy worked at Genentech in leadership roles within the Personalized Healthcare business unit and the Bioinformatics department. Prior to Genentech, Amy spent time at Tech and Financial Services organizations where she led initiatives as well as groups that delivered impactful solutions using both data and technology to enable company objectives. Amy holds a Master’s degree in International Development and a Bachelor’s degree in Mathematics.

Siegfried S.F. Leung, Ph.D.
Sr. Scientist, Computational Chemistry
Siegfried S.F. Leung, Ph.D. - Sr. Scientist, Computational Chemistry
Siegfried Leung, Ph.D., specializes in computational drug design and has over a decade of experience in macrocycle design and modeling. He joined Circle after undertaking postdoctoral research in the laboratory of Circle founder Matt Jacobson at UC San Francisco. His work there focused on the development of physics-based predictive models for passive membrane permeability and the application of these methods in designing cell permeable cyclic peptides. He was a key member of the Pfizer / Jacobson laboratory collaboration investigating the engineering of permeability into macrocyclic peptides, developing computational protocols for target-based design of permeable macrocycles. Siegfried received a B.S. (cum laude) from University of San Francisco and his Ph.D. in chemistry from Yale University under the mentorship of Prof. William Jorgensen.

Andrew T. Bockus, Ph.D.
Sr. Scientist, Chemistry
Andrew T. Bockus, Ph.D. - Sr. Scientist, Chemistry
Andrew T. Bockus, Ph.D., leads Circle’s chemistry team. Andrew is a chemist with over a decade of experience in the field of passively-permeable peptidic macrocycles. Prior to joining Circle Pharma, Andrew worked in the lab of Prof. Scott Lokey, a co-founder of Circle, where he synthesized natural product-like cyclic peptides and identified drivers of structure-permeability relationships in diverse peptidic scaffolds. He then developed applications for synthetic receptors and taught undergraduate courses in organic chemistry as a postdoc for Prof. Adam Urbach at Trinity University. Andrew holds a B.A. in Chemistry and Biochemistry from Skidmore College and a Ph.D. in Chemistry from the University of California, Santa Cruz.

Catherine Gleason, Ph.D.
Sr. Scientist, Biology Research
Catherine Gleason, Ph.D. - Sr. Scientist, Biology Research
Catherine Gleason, Ph.D., received her B.S. in biochemistry from the University of Washington and earned her Ph.D. from the University of Pennsylvania under the mentorship of Prof. Morris Birnbaum. She trained as a postdoctoral research fellow with Prof. Philip Cohen at the Medical Research Council’s Protein Phosphorylation Unit at the University of Dundee, UK, where she studied the interplay of protein phosphorylation and ubiquitylation in Toll-like receptor signaling and the innate immune response. Before joining Circle Pharma, she was an Adjunct Assistant Professor at the University of California San Francisco, investigating the mTOR signaling pathway in regulation of renal metabolism and ion transport.

Luis Hernandez
Manager, Chemistry
Luis Hernandez - Manager, Chemistry
Luis Hernandez is a member of Circle’s chemistry team. Luis has applied his continuous improvement and management experience from his previous role in a manufacturing facility to streamline macrocycle production and information workflows for Circle. Luis previously held positions at Ingredion, Inc. and Formulation Technology, Inc. He holds a B.S. in Chemical Biology from the University of California, Berkeley.

Breena Fraga
Scientist, Chemistry
Breena Fraga - Scientist, Chemistry
Breena Walton earned a B.S. in Molecular Synthesis at the University of California, San Diego. After studying total synthesis at the University of Pennsylvania under Prof. Madeleine Joullie and earning an M.S., she went on to work at E.I Dupont de Nemours in the Crop Protection division where she was a co-inventor on several patent applications for bicyclic azoles and helped move a product towards market. She subsequently worked in medicinal chemistry at Theravance Biopharma, and now at Circle Pharma in the chemistry team where her work focuses on advanced chemical synthesis and design.

Meisam Nosrati, Ph.D.
Scientist, Biochemistry
Meisam Nosrati, Ph.D. - Scientist, Biochemistry
Meisam Nosrati, Ph.D., is an interdisciplinary scientist with track record accomplishments in the fields of biochemistry, structural biology and organic synthesis. Meisam is passionate about contributing to public health via translational research. His postdoc at Emory University was on bacterial aminoglycoside resistance through ribosome methylation under the supervision of Prof. Graeme L. Conn. His Ph.D work at Michigan State University was focused on protein engineering to make novel proteins and protein probes under the supervision of Prof. James H. Geiger. He holds a B.S. and M.S. from University of Tehran in Chemistry and Organic Chemistry, respectively.

Nathan Dupper, Ph.D.
Scientist, Organic Chemistry
Nathan Dupper, Ph.D. - Scientist, Organic Chemistry
Nathan Dupper, Ph.D., earned his doctorate at UCLA studying Synthetic Organic Chemistry under Professor Ohyun Kwon. After completing his graduate studies, he worked as a postdoc in the laboratory of Professor Charles McKenna at USC. Here, he helped develop antifungal agents targeting the bromodomain containing protein Bdf1. Before joining the Circle Pharma team, he worked as a Synthetic Chemist at AIM Biosciences (WuXi). His work is currently directed toward chemical synthesis and design.

Miles W. Membreno
Research Associate, Biology
Miles W. Membreno - Research Associate, Biology
Miles Membreno has worked in both the Biology and Chemistry teams at Circle and currently focuses on developing and running assays for hit identification and lead optimization. Miles previously worked at CS Bio, where he focused on peptide purification. He holds a B.S. in Pharmacology from the University of California, Santa Barbara.

Miguel P. Baldomero
Sr. Research Associate, Chemistry
Miguel P. Baldomero - Sr. Research Associate, Chemistry
Miguel Baldomero is a member of Circle’s chemistry team where he focuses on macrocycle synthesis. Miguel previously held positions at CS Bio and Bachem Americas. He holds a B.S. in Chemistry from the University of Wisconsin, Oshkosh.

Bryan M. Lent
Research Associate, Chemistry
Bryan M. Lent - Research Associate, Chemistry
Bryan Lent works with the chemistry team at Circle Pharma and manages lab operations. Bryan holds a B.S. in Biochemistry from California Polytechnic University, San Luis Obispo and undertook post-graduate studies in Biological Chemistry at Ohio State University with Prof. Jen Ottesen.

Frances Hamkins-Indik
Research Associate, Biology
Frances Hamkins-Indik - Research Associate, Biology
Frances Hamkins-Indik is a research associate at Circle Pharma working with the Biology and Chemistry teams. Frances previously worked in Prof. Phil Crews’ group at UC Santa Cruz as an undergraduate researcher and received their B.S. in Chemistry from UC Santa Cruz.

Alex Aronson
Research Associate, Chemistry
Alex Aronson - Research Associate, Chemistry
Alex Aronson earned his B.S. in Chemistry at UCLA where he worked on the synthesis of templated peptidomimetic macrocycles. After completing his undergraduate degree, Alex attended UC Riverside, where he received his M.S. degree in Chemistry. At UCR, he worked on the development of peptide-based agents to bind various oncological targets, before joining the Chemistry team here at Circle Pharma.

Yuliana Gritsenko
Research Associate, Chemistry
Yuliana Gritsenko - Research Associate, Chemistry
Yuliana holds a B.S. in Chemistry from UC Santa Cruz. Before graduating, she interned in the Environmental Fate and Metabolism department at Valent USA, where she determined degradation paths of radio-labeled chemicals. Previous to joining Circle’s chemistry team, she worked at Deibel Laboratories where she looked at sample analysis for pesticide content and also worked on analytical method development projects.

Manesh Chand
Research Associate, Chemistry
Manesh Chand - Research Associate, Chemistry
Manesh Chand received his B.S. in Pharmaceutical Chemistry from the University of California, Davis. During his time there, he worked as an undergraduate researcher for the Heffern Lab, analyzing metal-binding peptide hormones. Upon receiving his degree, he began working for Eurofins Test America, where he utilized LC-MS/MS to determine the accurate concentration of perfluoroalkyl substances in various sample matrices.

Daphne He
Research Associate, Biochemistry
Daphne He - Research Associate, Biochemistry
Daphne He received her B.S. in Biochemistry/Chemistry from UC San Diego. Daphne previously worked at Pfizer in La Jolla during her undergraduate studies, first helping with compound management within Sample Logistics and later running enzyme-based assays and working with LC/MS within Biochemistry and Primary Screening.

Megan DeMart
Research Associate, Chemistry
Megan DeMart - Research Associate, Chemistry
Megan DeMart earned her B.S in Chemistry from the University of North Florida where she graduated Cum Laude. Megan previously worked under Dr. Bryan Knuckley at the University of North Florida, synthesizing and characterizing inhibitors for the protein arginine methyltransferase (PRMT) family of proteins. She previously held internship positions during her undergraduate studies at both Bacardi and ADPEN laboratories. Megan also enjoyed teaching students and held positions as a Supplemental Instructor (SI) and a peer chemistry tutor.

Nick Vaquera
Laboratory Technician
Nick Vaquera - Laboratory Technician
Nick Vaquera is a Laboratory Technician at Circle Pharma, supporting both the Chemistry and Biology teams. In his previous role, Nick worked at BioElectron, where he was responsible for compound management. Receiving an A.S. in Mathematics and Science from City College of San Francisco, Nick served in the US Navy in support of Operation Enduring Freedom and Operation Iraqi Freedom.

Eleonor Lim
Executive Assistant
Eleonor Lim - Executive Assistant
Eleonor is a seasoned Executive Assistant and Office Manager with over 20 years of experience and a track record of strong performance in fast-paced, high-pressure environments. Having held positions in semiconductor, biotech, and fintech start-ups, Eleonor is able to tailor her approach to meet the needs of any organization. From managing executive calendars and providing general staff support, to handling matters related to HR and facilities, Eleonor handles challenges with ease. Prior to Circle, Eleonor worked as an Executive Business Partner at Credit Karma supporting Tax, Savings, and Product Design executives and directors.
Board of Directors

Matthew P. Jacobson, Ph.D.
Co-Founder
Matthew P. Jacobson, Ph.D. - Co-Founder
Matt Jacobson, Ph.D., is the Chair of the Department of Pharmaceutical Chemistry at UC San Francisco. He earned his Ph.D. in physical chemistry at MIT, and completed post-doctoral research at Oxford and Columbia. Matt’s research focuses on computational biophysics and computer-aided drug design; he is the author of over 120 publications. Software written by Matt and his collaborators is widely used in the pharmaceutical industry; he serves on the Scientific Advisory Board of Schrödinger, LLC, and is also a co-founder of Global Blood Therapeutics (NASDAQ: GBT), Relay Therapeutics and Cedilla Therapeutics. Matt received the NSF CAREER award, an Alfred P. Sloan Fellowship, and a School of Pharmacy teaching award. He has served on the editorial boards of several journals, including Biochemistry and PLoS Computational Biology.

John Josey, Ph.D.
Chairman of the Board
John Josey, Ph.D.

Peter Svennilson, Ph.D.
The Column Group
Peter Svennilson, Ph.D.
Peter Svennilson is the founder and managing partner of The Column Group. He was the chairman of Aragon Pharmaceuticals (acquired by Johnson & Johnson) and Seragon Pharmaceuticals (acquired by Roche / Genentech) and was a board director of Gritstone Oncology, NGM Biopharmaceuticals, Immune Design and Constellation Pharmaceuticals. He is currently a board director of ORIC Pharmaceuticals, Ribon Therapeutics and Carmot Therapeutics.

Thilo Schroeder, Ph.D.
Nextech Invest
Thilo Schroeder, Ph.D.
Thilo Schroeder, Ph.D., is a partner at Nextech Invest, a Zurich-based oncology-focused investment firm. He previously served on the board of Peloton Therapeutics (acquired by Merck) and Blueprint Medicines. He is currently a board director at IDEAYA Biosciences, Revolution Medicines, PMV Pharma, Silverback Therapeutics and a board observer at Black Diamond Therapeutics.

Walter H. Moos, Ph.D.
ShangPharma Innovation / Pandect Bioventures
Walter H. Moos, PhD - Board Chair
Walter H. Moos, Ph.D., is the CEO of ShangPharma Innovation and a managing partner at Pandect Bioventures. He retired as President of SRI Biosciences in early 2016 after more than a decade at the independent nonprofit SRI International (Stanford Research Institute). Prior to SRI he served as Chairman and CEO of MitoKor (Migenix), and as a Vice President at Chiron (Novartis) and Warner-Lambert / Parke-Davis (Pfizer). His teams have advanced numerous pharmaceutical products from discovery to commercialization. He has served on about 20 business and scientific boards, including Amunix, Oncologic (Aduro), Onyx (Amgen), Rigel and the Biotechnology Industry Organization (BIO).
Walter holds Ph.D. and A.B. degrees in chemistry from UC Berkeley and Harvard, respectively.
Founders

R. Scott Lokey, Ph.D.
Co-Founder
R. Scott Lokey, Ph.D. - Co-Founder
Scott Lokey , Ph.D., has been a faculty member in the department of Chemistry and Biochemistry at the University of California Santa Cruz since 2002. He received his Bachelor’s of Science in Chemistry from Trinity University in San Antonio, Texas in 1989, and a Ph.D. in Chemistry from University of Texas, Austin in 1997 under the mentorship of Dr. Brent Iverson. Dr. Lokey held a NIH postdoctoral fellowship at the Harvard Institute of Chemistry and Cell Biology in Boston, Massachusetts, where he worked with Professors Timothy Mitchison and Marc Kirschner on the identification of cyclic peptide modulators of actin dynamics. His current research interests include the basic science underlying cell permeability of cyclic peptides. He has developed methodologies for synthesizing backbone-modified cyclic peptides. Dr. Lokey and Dr. Jacobson have collaborated on the application of computational approaches for predicting membrane permeability in non-Lipinski Rule-of-5 molecules, with a particular focus on macrocyclic peptides. Dr. Lokey co-founded Circle Pharma with Dr. Jacobson.
Scientific Advisory Board

William G. Kaelin Jr., M.D.
Chair, Scientific Advisory Board
William G. Kaelin Jr, M.D. - Chair, Scientific Advisory Board

Bruce Stillman, Ph.D., FRS
Scientific Advisory Board member
Bruce Stillman, Ph.D., FRS – Scientific Advisory Board member

Alan Ashworth, Ph.D., FRS
Scientific Advisory Board member
Alan Ashworth, Ph.D., FRS - Scientific Advisory Board member
Advisors

Dineli Wickramsinghe, Ph.D.
Advisor
Dineli Wickramsinghe, Ph.D.
Previously, Dr. Wickramasinghe was Chief Scientific Officer at Affinita Biosciences and site head at Amgen San Francisco. She led Translational and Oncology Research at 23andMe and Amgen San Francisco respectively, developing both protein and small molecule therapeutics. Prior to that, she led oncology teams at Genentech and BASF BioResearch, while also serving as adjunct faculty and post-doc mentor.
Dr. Wickramasinghe has a B.A. from Mount Holyoke College in Massachusetts and a Ph.D. from Tufts University in Boston. She completed her post-doctoral fellowship in molecular genetics at the National Cancer Institute in Maryland. She has authored numerous peer reviewed scientific publications, book reviews and presented at national and international conferences, in addition to being an inventor on multiple patents.

Steven Olson, Ph.D.
Advisor
Steven Olson, Ph.D.

Zaneta Nikolovska–Coleska, Ph.D.
Advisor
Zaneta Nikolovska–Coleska, Ph.D.
Dr. Nikolovska-Coleska is an Associate Professor of Pathology, Director of the Molecular & Cellular Pathology Graduate Program at the University of Michigan and Associate Director of Program in Biomedical Sciences at University of Michigan. Her research group focuses on the discovery, design and development of new molecularly targeted therapies for cancer, particularly targeting protein-protein interactions that are involved in programmed cell death and epigenetic regulation. Dr. Nikolovska-Coleska was the recipient of several awards including, Chemical Structure Association Trust (CSA Trust), New Investigator Award from Leukemia Research Foundation, Innovator Award from Harrington Discovery Institute and AACR-Bayer Innovation and Discovery Award. She is an inventor on more than 13 international and US patents and patent applications, contributing to the discovery and development of Debio 1143 (AT-406), a Smac mimetic targeting inhibitors of apoptosis proteins IAPs, which received FDA breakthrough therapy designation for front-line treatment of head & neck cancer. Currently she serves on the Board of Directors of the International Chemical Biology Society (ICBS) and in 2019 was elected President-Elect. Dr. Nikolovska-Coleska received her PhD in pharmaceutical chemistry at the Ss. Cyril and Methodius University, Skopje, Republic of Macedonia, and was a post-doctoral fellow in drug discovery at the University of Michigan.