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Leadership and Team

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The NexEos Bio management team and NexEos’ collaborators at The University of Utah include highly-seasoned biopharmaceutical professionals with several decades of experience in both the field of eosinophil research and pharmaceutical development and commercialization. Scientific Founder and Chief Scientific Officer Gerald Gleich, MD, was the clinical investigator who first identified and characterized the major proteins of the distinctive eosinophil granules and described several novel clinical syndromes, including Episodic Angioedema with Eosinophilia (EAE), which is also known as Gleich Syndrome. Other collaborators on the team actively manage patients with EoE in their clinical practices. A number of team members have been leaders in the development of therapeutics for the treatment of a host of eosinophil-mediated disorders including EoE, eosinophil-mediated asthma and the hypereosinophilic syndrome (HES). Collectively, they have brought several programs successfully through U.S. Food & Drug Administration (FDA) approval and to the market to further science and improve patients’ lives.

"Many NexEos executive team members have been leaders in the development of therapeutics for the treatment of a host of eosinophil-mediated disorders. Collectively, we have brought several programs successfully through FDA approval and to the market to further science and improve patients’ lives. We look forward to doing the same on the diagnostics side here at NexEos."

Theresa Mansi, Chief Business Officer

Theresa Mansi
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Stephen Tullman

Co-Founder, Executive Chairman, and Chief Executive Officer

Steve has taken over the CEO role in late 2022. In addition, Steve has served as Chairman of NexEos Bio since its inception and is a founding member of the company.  Steve Tullman's career in life sciences spans more than 30 years and includes numerous Chairman, CEO, and founding credits, with the creation of ten biotechnology companies. He currently serves as the Managing Member of Nexstone Innovation and Executive Chairman of Nexstone Immunology. Steve co-founded NeXeption, Inc. in 2011 and NeXeption, LLC in 2012 to focus on building biotech. Steve co-founded NeXeption, Inc. in 2011 and NeXeption, LLC in 2012 to focus on building biotech organizations designed to identify and advance programs with significant unmet medical needs. His previous chairmanships include serving Onspira Therapeutics, Inc. (acquired by Altavant Sciences / Sumitomo Dainippon Pharma in 2019), Aclaris Therapeutics, Inc. (NASDAQ: ACRS), Ralexar Therapeutics, Inc., and Vicept Therapeutics, Inc. until its acquisition by Allergan, Inc. He also served as Chairman, President and CEO of Ceptaris Therapeutics, Inc. until its acquisition by Actelion in 2013. He created Ception Therapeutics, Inc. in 2005 and served as its President and CEO until its acquisition by Cephalon, Inc. in 2010.  Steve received a BS in Accounting from Rutgers University.  

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Theresa Mansi

Co-Founder and Chief Business Officer; Chief Executive Officer (2019-2022)

Theresa Mansi served as CEO and member of the Board of Directors at NexEos since its inception in 2019 through 2022, working closely with the Chairman to achieve several key milestones including receiving FDA approval for the IND to be open for NDX-3315, as well as receiving ODD for EoE, completing several funding rounds, and receiving 2 NIH grants.  In 2023, Theresa will shift her role and focus to the business side as Chief Business Officer. Over 30 years in the pharmaceutical and biotech industry, Theresa’s accomplishments have spanned Global Business Development, Ventures, Product Development, Strategic Marketing and Market Research. Formerly, Theresa was Vice President of the Global Business Insights division of DRG, the premier provider of healthcare data and insights. Prior to DRG, Theresa worked for GSK for more than 20 years in roles of increasing responsibility. As Senior Director Worldwide Business Development, she negotiated complex deals, closing several U.S., Japanese and European licensing and M&A deals. Theresa also headed GSK’s Ventures group where she led a team of entrepreneurs who created start-up companies with funding from a variety of sources. Early on, Theresa established GSK’s Global Marketing Research department while living in London. Theresa is a Certified Licensing Professional with an MBA in International Marketing from Saint Joseph’s University. She has completed Executive Education Programs at Darden University and the Wharton School. 

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Gerald Gleich, MD

Co-Founder and Chief Scientific Officer

Dr. Jerry Gleich has had a life-long passion and professional commitment to understanding the eosinophil in human biology. This interest began during his residency training and was stimulated by caring for patients with bronchial asthma hospitalized at Mayo Clinic. The focus of his work on the eosinophil has been on the distinctive granules. He and his colleagues have isolated, characterized, identified the cDNAs and the genes, and established assays for measurement and localization of all of the granule proteins. In turn, these efforts led to the recognition that eosinophil degranulation with release of cytotoxic and cytostimulatory cationic molecules into tissues is characteristic of eosinophil-related diseases. These efforts also led to the recognition of several novel syndromes, including episodic angioedema associated with eosinophilia (Gleich syndrome) and the eosinophil-myalgia syndrome. 

Jerry received his medical degree from the University of Michigan. He obtained residency training in Internal Medicine at the Philadelphia General Hospital and the Jackson Memorial Hospital at the University of Miami and was a flight surgeon in the United States Air Force. He received postdoctoral training at the University of Rochester and then established a research laboratory for allergic diseases at the Mayo Clinic. While at Mayo, he was Professor of Medicine and Immunology, Chairman of the Department of Immunology. Jerry is an emeritus Professor of Pediatrics at Primary Children’s Medical Center in Salt Lake City, Utah, and has had an allergy medicine practice for 11 years at the Veterans Administration Medical Center in Salt Lake City, Utah. Presently, he is Professor of Dermatology and Medicine at The University of Utah as well as a founder and Chief Scientific Officer of NexEos Bio.


Jerry has served as Chairman of the World Health Organization Subcommittee on Standardization of Allergens, on the Allergy and Clinical Immunology Research Committee of the National Institute of Allergy and Infectious Diseases, on the editorial board of Journal of Allergy And Clinical Immunology, on the editorial board of the Journal of Immunology, as Member and Chairman of the Board of Scientific Counselors, National Institute of Allergy and Infectious Diseases (NIAID), and as Member and Chair of the Data and Safety Monitoring Board of NIAID. Jerry is a charter member and past president of the International Eosinophil Society (IES). He is a medical advisor to the American Partnership for Eosinophilic Disorders (APFED) Board of Directors. 

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Chrissie Oveis

Director of Operations

Chrissie Oveis has over 15 years of experience in the biotech industry. Prior to working at NexEos, Chrissie worked at Cortexyme, where she managed the company’s global clinical program in Alzheimer’s Disease as the Associate Director of Clinical Operations. She previously oversaw irritable bowel disease (IBD) and multiple sclerosis clinical trials at Celgene. At Fate Therapeutics, she transitioned from working in the lab to working in Clinical Operations overseeing adult and pediatric clinical trials in oncology and rare metabolic disorders. She performed laboratory research at Millennium Pharmaceutics, Fibrogen, Exelixis and Arbor Vita in therapeutic indications such as oncology, muscular dystrophy and anemia. Chrissie has a BS in genetics and minor in communications from the University of California, Davis.

Jennifer Cargo, CMA

Financial Controller

Jennifer has 14 years of experience in the biotech industry.  Her biotech career started with Ception Therapeutics as a Senior Accountant.  Following Ception, she owned and operated her own accounting business, DanJenn, Inc. where she continued to work for various start-up biotech companies (Ceptaris Therapeutics, Inc., Velicept Therapeutics, Inc. and Onspira Therapeutics, Inc.) on a consulting basis. Jennifer worked alongside the company's CFO by maintaining accounting records, assisting auditors, and reviewing prepared tax returns. Through DanJenn, she has worked with various types of businesses offering account management and tax return preparation.  Jennifer has received a BS in Accounting from Ursinus College.

Jennifer Cargo
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