Board of Directors
GTA Board of Directors and Committee Chairs
Board of Directors
Chair (2023)
Penny Leavitt MS DABT
Penny Leavitt has been dedicated to Genetic Toxicology efforts since joining Bristol Myers Squibb (BMS) in 2011. Current responsibilities are heavily weighted in mutagenic impurities risk assessment with a cross-functional role in Chemical Process Development and CMC Regulatory. Efforts support IND and NDA dossier submissions as well as responding to Health Authority requests as they arise. External efforts include data sharing projects with commercial in silico providers for genotoxic endpoints and contributing expert knowledge in external working groups. In addition, Penny is responsible for ensuring effective external partnerships with CROs and monitoring of Genetox studies. Prior to tenure at BMS, Penny’s career experience spanned multiple areas of drug discovery utilizing a breadth of techniques in both industry and academia, with a particular aptitude for microbiology, biochemistry, and chemistry SAR. Most recently, Penny has expanded horizons in general and regulatory Toxicology, with culmination of earning status as a Diplomate of American Board of Toxicology, achieving position of Nonclinical Safety Project Representative, and responsibilities in review/authoring internal exposure monographs deriving chemical exposure limits to support chemical development and related quality events. Penny has been a member of GTA since 2011. For the past few years she has volunteered to support efforts for the GTA annual meeting, in particular co-chairing the GTA student outreach, aligning with her demonstrated advocacy for mentoring young scientists throughout her 20+ career. Prior to tenure at BMS, Penny’s career experience spanned multiple areas of drug discovery utilizing a breadth of techniques in both industry and academia, with a particular aptitude for microbiology, biochemistry, and chemistry SAR. Most recently, Penny has expanded horizons in general and regulatory Toxicology, with culmination of earning status as a Diplomate of American Board of Toxicology, achieving position of Nonclinical Safety Project Representative, and responsibilities in review/authoring internal exposure monographs deriving chemical exposure limits to support chemical development and related quality events. Penny has been a member of GTA since 2011. For the past few years she has volunteered to support efforts for the GTA annual meeting, in particular co-chairing the GTA student outreach, aligning with her demonstrated advocacy for mentoring young scientists throughout her 20+ career.
Chair ELECT (2023)
Wen Sun
Wen Sun is a Principal Scientist in the Genetic Toxicology Department at Pfizer. She received her PhD in Molecular and Cellular Biology (molecular medicine) from the University of Iowa and worked as a post-doctoral researcher at Yale University Pharmacology department prior to joining Pfizer three and half years ago. Since joining Pfizer, Wen lead the development, validation, and implementation of the multiplexed imaging screening platform, which enabled the delivery of regulatory endpoint and mode of action information to project teams in a single assay. The platform also incorporated computational predictive modeling and quantitative dose-response assessment to support pharmaceutical development. Currently, Wen oversees the screening laboratory, provides subject matter expertise guiding teams and chemists away from genotoxicity liabilities. In addition, she serves as the drug safety team lead on projects and participates in genetic toxicology impurity assessment. Wen is an active member of the Genetic Toxicology Association, the Environmental Mutagenesis and Genomics Society, and Health and Environmental Sciences Institute. She has presented her work at numerous conferences and currently contributing to manuscript and AOP preparation. Wen has a particular passion in in vitro assays, adverse outcome pathways, innovative technologies, and alternative testing methods. Ashley J. Allemang MS
Ashley has over 10 years of industry experience in applied genetic toxicology in the context of in vitro-based safety support. Her research has primarily focused on mode of action determination and distinguishing direct and indirect genotoxicity through various in vitro methods such as the micronucleus assay, the ToxTracker assay and other genomics-based methods such as the TGx-DDI biomarker. More recently her research has employed the HepaRG micronucleus assay to develop in vitro-based genotoxicity potency rankings of pyrrolizidine alkaloids, as well as genotoxicity evaluation of mixtures. In addition to her research activities, her expertise has also expanded to include SAR based risk assessment. Ashley has been actively involved in the HESI GTTC committee since 2017 and has participated in the development of genetox-related AOPs and is currently co-leading the Indirect Genotoxicity subgroup of the In Vitro Work Group evaluating NAMs for genetic toxicity testing.
Maria Engel
Maria Engel is currently responsible for providing nonclinical toxicology support for submissions to regulatory agencies worldwide at Pfizer. Maria contributes to genetic toxicology mutagenicity assessments for marketed products. She previously worked in the genetic toxicology department gaining over 20 years of practical experience in the application of genotoxicity assessment to support pharmaceutical development. She is a long time member and volunteer of the Genetic Toxicology Association and served as the Newsletter Editor (2008-2010), Secretary (2011-2015), Student Outreach Chair (2010-2019), previous member of the Board of Directors (2012-2014). Maria holds a BS in Diagnostic Genetic Sciences (cytogenetics) from the University of Connecticut and a MS in Pharmaceutical Regulatory Affairs from Temple University. Melisa Masuda-Herrera MS
Melisa Masuda-Herrera is a Senior Associate Scientist in the Environmental and Occupational Toxicology group within Nonclinical Safety & Pathobiology at Gilead. Her responsibilities include authoring health-based risk assessments to support product quality and occupational toxicology programs, monitoring and reviewing worker safety studies and environmental risk assessments, and providing toxicology support to the Environmental Health and Safety group for global hazard communication programs.
Before joining Gilead, Melisa worked as a Scientific Researcher at Genentech in the Product Quality and Occupational Toxicology group.
While at Genentech, her primary focus was on authoring and reviewing documents to support Genentech product quality and occupational toxicology programs and conducting and interpreting in silico assessments of impurities for potential genotoxic activity using quantitative structure–activity relationship programs. Prior to graduate school, she worked as a Laboratory Assistant/Field Technician at the California Department of Public Health where she assumed the lead role in validating new methods, and assisting in standard methods, of chemical analysis of marine toxins for biotoxin monitoring. Melisa received her Bachelor of Science degree at UC Berkeley in Molecular Toxicology and her Master of Science degree at UC Santa Cruz in Environmental toxicology. She is currently a member of the Society of Toxicology, American College of Toxicology, Society of Chemical Hazard Communication, and Occupational Toxicology Roundtable.
Liz Rubitski
Liz is a Senior Scientist at Pfizer, holds a B.S. in Diagnostic Genetic Sciences from the University of Connecticut and has been working in Genetic Toxicology for over 25 years. Current portfolio responsibilities include serving as technical lead for the high content iScreen assay providing micronucleus results with mechanism of action to project teams and as a POA for the ex vivo portion of the Big Blue Assay. Liz also works on developmental projects involving data management, 6-well Ames imaging, continuous improvement of routine assays and serves as the image analysis specialist to groups within Drug Safety and Development.
As well as roles on the board for the Society of Biomolecular Imaging and Informatics (SBI2) since its founding, she has been a member of GTA for over 20 years, serving as a board member and scientific program chair in years past.
Yi Yang
Dr. Yi Yang is currently Director of Genetic, Environmental, and Occupational Toxicology at AbbVie. She is also a Therapeutic Area Leader overseeing preclinical safety portfolios in Specialty and Cell Therapy area. Dr. Yang has 20 years of experience in preclinical safety assessment for a variety of therapeutic modalities, including small molecules, monoclonal antibodies, degradomers, cell and gene therapy. Her areas of expertise include regulatory toxicology, predictive and mechanistic toxicology, genetic toxicology, toxicogenomics, toxicity biomarkers, and biostatistics.
Dr. Yang received her MD from Sun Yet-Sen University of Medical Sciences, her Ph.D. in Toxicology and M.S. in Biostatistics from University of Cincinnati. She is also certified as a Diplomat of the American Board of Toxicology. She authored 25 peer-reviewed publications and over 20 regulatory submissions supporting Phase 1 and Phase 2 clinical trials. She is actively involved in several industry-wide collaborations, including the Predictive Safety Testing Consortium and the ILSI-HESI consortium. She also served as Secretary to the American Association of Chinese in Toxicology (2010-2012), Chair to the Applied Pharmaceutical Toxicology (2015-2016), and President to the Midwest Regional Chapter of SOT (2017-2019). Dr. Yang joined GTA in 2022 and is co-chair of the Scientific Program Committee for the 2023 annual meeting. Zhiying Ji
Dr. Zhiying Ji is currently a toxicologist at Incyte Corporation in Wilmington, DE. He manages toxicology programs in accordance with global regulatory requirements to support drug discovery and development.
Prior to joining Incyte, Dr. Ji worked for Bristol Myers Squibb Company (BMS) in New Brunswick, NJ from 2017 to 2022. He provided scientific leadership in developing genotoxicity testing strategies in support of drug discovery and development of different modalities; conducted mutagenicity hazard assessment for intermediates/impurities in accordance with ICH M7 guideline; and leaded genetic toxicology innovation activities.
He also served as Project Toxicologist for multiple programs to support drug discovery and development.
Dr. Ji was a Lead Scientist – Genetic Toxicology at Dow Chemical Company from 2012 to 2017. He provided science leadership in genetic toxicology studies to support product development and global registration; acted as Study Director for in-house GLP and non-GLP genetic toxicology studies; acted as Study monitor for GLP and non-GLP genetic toxicology studies conducted at CROs; leaded capability development of innovative genotoxicity techniques.
Dr. Ji received his Ph.D. degree in Toxicology from Chinese Center for Disease Control and Prevention in 2004 and his post-doctoral training under the supervision of Prof. Martyn Smith at University of California, Berkeley. He applied fluorescence in situ hybridization (FISH) in the development of early effect biomarkers for benzene and formaldehyde exposure and investigated the genetic and epigenetic mechanisms of chemical mutagenesis and carcinogenesis.
Dr. Ji has authored or co-authored over 20 peer-reviewed publications. He is an active member of GTA, EMGS and SOT.