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Leadership and Team

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 Uniquity Bio. 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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Dawn Rubel

President, Research and Development

Dawn Rubel joined NexEos Bio in May 2023 as President, Research and Development.  In this role, Dawn is responsible for advancing the diagnostic and therapeutic programs for the NexEos product portfolio and will be a key contributor to the strategic evaluation of new programs and partnerships in support of NexEos Bio’s mission of developing novel technologies to identify and treat underlying inflammation in eosinophil-mediated diseases. 

Dawn brings over 25 years of experience in product lifecycle management for the Pharma, Biotech, and Medical Device industries.  Prior to joining NexEos, Dawn was the Vice President, Regulatory Affairs and Quality Assurance at Arthrex, Inc, where she provided Executive Governance in Regulatory and Quality for Arthrex worldwide for a robust, multibillion dollar pipeline of medical device and biotechnology products.  Together with her global team of approximately 600, Dawn successfully propelled growth, expansion, and global alignment of the business while achieving industry-leading performance metrics in Regulatory clearance and product quality. 

Prior to her role at Arthrex, Dawn was Senior Vice President, Global Safety, Quality, & Regulatory Compliance at Drive DeVilbiss Healthcare in Port Washington, NY, where her responsibilities included medical device products, pharmaceutical products, medical consumables, and global retailer partnerships.  Her early career experience in biotech and pharma includes leadership roles at Immunomedics (acquired by Gilead) and Wyeth (now Pfizer).

Dawn earned a BA from Caldwell University in biology and chemistry, completed graduate courses in Pharmaceutics at Long Island University, and earned an MBA from Fairleigh Dickinson University.  She is currently pursuing a PhD in Global Organizational Leadership at Indiana Tech University.  Dawn is a recurrent conference speaker on Global Leadership, Regulatory, and Quality topics and has consulted on a variety of topics for regulated industries.  She is an independent advisor and remediation service provider.  Dawn was a founding member of CHIEF (NYC), a private professional organization dedicated to the advancement of women into C‑suite and Executive positions.

Dawn currently resides in Hewitt, NJ with her husband and their two children.

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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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Jeffrey Wilkins, MD

Chief Medical Officer

Dr. Jeffery Wilkins is the Chief Medical Officer of NexEos Bio. Dr. Wilkins brings deep experience in advancing clinical programs with a focus in immunology, rare diseases, and immuno-oncology.


Dr. Wilkins brings more than twenty years of clinical research experience to NexEos, including serving as Chief Medical Officer at Abcuro, Inc., a clinical-stage biotechnology company developing therapies for the treatment of autoimmune diseases and cancer through precise modulation of cytotoxic T and NK cells. Prior to Abcuro, Dr. Wilkins was Chief Medical Officer of Avalo Therapeutics, where he was responsible for clinical development for programs in immuno-oncology, immunology and orphan disease. Previously, he held the position of Chief Medical Officer at Lycera, and Ceptaris Therapeutics, where he led clinical programs from IND Phase I trials to regulatory approval (including Valchlor®). Prior to this, Dr. Wilkins was Vice President, Worldwide Clinical Research, Inflammation/Oncology at Cephalon, Inc., where he was responsible for clinical development, medical affairs, and business development efforts in both therapeutic areas. He joined Cephalon via its acquisition of Ception Therapeutics, and as Senior Vice President of Clinical Development, headed a successful program in eosinophilic asthma. Dr. Wilkins entered the pharmaceutical industry with GlaxoSmithKline, where he rose to become Vice President of Discovery Medicine for GSK’s Center of Excellence in External Drug Discovery.

Dr. Wilkins received his M.D. from Temple University School of Medicine and his B.S. from Bucknell University.

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Yves Quintin

General Counsel

Yves brings close to 40 years of experience as a business lawyer, having spent the last 23 years as a corporate partner with Duane Morris LLP. His practice encompassed M&A, venture capital, financings, governance and international transactions, including with the pharmaceutical and biotechnology industries. Yves has been involved as counsel with many successful biotech start-ups, including Ception Therapeutics, Ceptaris Therapeutics, Onspira Therapeutics, Aclaris Therapeutics and Vicept Therapeutics. Yves is admitted to practice in New York and Paris.

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Antonio Regalado

Vice President Business Alignment - Quality Assurance, Regulatory Affairs, and Compliance

Antonio is the Vice President of Business Alignment- Quality Assurance, Regulatory Affairs, and Compliance at NexEos. His role is focused on bringing the NexEos and partner teams together with effective and compliant mechanisms that advance the NexEos Portfolio. He is deeply enthusiastic about the potential to help patients that NexEos looks to offer.

Antonio has worked in Quality and Regulatory for medical device, pharmaceutical, biologic, cosmetic, and consumer products. He joins NexEos after heading Quality and Regulatory Global Alignment for Arthrex, Inc., where he aligned global subsidiaries with the Corporate Quality and Regulatory Affairs structure to create a compliant and consistent approach to distributing orthopedic medical devices to global patients. Prior to that, he held Quality and Regulatory roles of progressing responsibility with Drive Healthcare and Professional Disposables International.

Antonio received a BA from Ramapo University in History and Creative Writing.  He is a recurrent guest lecturer at the collegiate level where he is passionate about introducing young professionals to the options a Quality and Regulatory career can bring.


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Andrew MacKnight

Ocular Program Lead

Andrew MacKnight is the Ocular Program Leader at NexEos Bio. With over 30 years in the biopharmaceutical industry, Andrew has led both commercial and clinical teams in global pharmaceutical companies and contract research organizations (CROs) and brings a deep experience in strategic product development and clinical operations management. Andrew worked for GSK for 13 years in roles of increasing responsibility in Global Vaccines R&D and US Commercial Operations ultimately as Executive Director, New Product Planning and Policy for the US Vaccines business.  Andrew’s experience in the CRO industry includes working on the buy-side for Private Equity in the acquisitions of PharmaNet and inVentiv Health Clinical leading to the formation of Syneos Health.  He has led Commercial Operations teams at Covance and more recently in the role of Vice President, Clinical Operations, helped scale a specialty clinical services company, ACI Clinical Inc. leading to a successful sale and exit to WCG Clinical Inc. and Private Equity.

Andrew has an M.A. in Philosophy from the University of Glasgow.

Jennifer Cargo, CMA, CSCA

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.

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