Steve Mahoney
President and Chief
Executive Officer
Steve Mahoney is Viridian’s President and Chief Executive Officer and a member of the Board of Directors. Steve has more than two decades of experience in a variety of operational, financial, commercial, legal and transactional roles in companies of different sizes and stages. He has been successful scaling organizations from founding team through commercial stage.
Prior to joining Viridian, Steve was the Chief Financial and Operating Officer of Magenta Therapeutics, where he drove operational excellence and disciplined capital allocation to high priority programs. Previously, Steve was part of the founding team of Kiniksa Pharmaceuticals, where he served as President and Chief Operating Officer. Prior to Kiniksa, he was Chief Commercial Officer of Synageva Biopharma, a company focused on ultrarare diseases, where he held roles of increasing responsibility in operations, commercial launch preparation, legal and corporate development. Steve was also a commercial attorney with Genzyme Corporation for approximately ten years. Prior to Genzyme, Steve was a corporate attorney with Mintz Levin.
Steve received his M.B.A. from Boston College’s Carroll School of Management, a J.D. from Boston College Law School, and a B.A. from Colorado College. He serves on the board of directors of Vesselon, Inc., a private company.
Tom Beetham
Chief Operating Officer
Tom Beetham joined Viridian as Chief Operating Officer in 2023. Tom has more than 20 years of experience in operations, business development, strategy and legal in the biopharmaceutical industry. Tom joined Viridian after serving as Chief Legal Officer of Magenta Therapeutics, Inc. Prior to Magenta, Tom was part of the founding team of Kiniksa Pharmaceuticals where he served as Executive Vice President, Corporate Development and Operations, and Chief Legal Officer, and had reporting responsibility for multiple functions, including strategy, business development, technical operations, medical affairs, value and access, legal, compliance, quality and human resources. Prior to Kiniksa, Tom served as Senior Vice President, Chief Legal Officer and Corporate Development of Synageva BioPharma Corp. Prior to Synageva, Tom was General Legal Counsel for New England Biolabs, Inc., and earlier, was the lead corporate attorney for Genzyme Corporation’s Oncology and Multiple Sclerosis business units.
Tom received his M.B.A. from Boston College’s Carroll School of Management, a J.D. from Boston College Law School, and a B.A. from the University of Rochester.
Shan Wu, Ph.D.
Chief Business Officer
Shan Wu joined Viridian as Chief Business Officer in 2023. She brings extensive experience in the biopharmaceutical industry with a strong track record in business development, corporate strategy, communications, and operations. Most recently, Shan served as Vice President and head of business development, investor relations, and alliance management at Magenta Therapeutics. She joined Magenta at launch and helped to build it from its scientific platform to a clinical-stage company. Shan led multiple value-creating transactions at Magenta, supported private and public financings including the company’s IPO, and helped to close Magenta’s merger with Dianthus Therapeutics. Prior to Magenta, Shan was at Biogen where she led strategic forecasting for the multiple sclerosis global commercial organization. Previously, Shan was a management consultant at Clarion Healthcare where she led projects in therapeutic area strategy, product differentiation strategy, market opportunity assessment, and global launch planning for biopharma clients.
Shan holds a Ph.D. in Biological Engineering from the Massachusetts Institute of Technology and a B.S. in Computer and Electrical Engineering from the University of Virginia.
Thomas Ciulla, M.D.
Chief Medical Officer
Tom Ciulla was appointed Viridian’s Chief Medical Officer in 2024 after previously serving as Viridian’s Chief Development Officer since 2023. Before joining Viridian, Dr. Ciulla served as Chief Medical Officer and Chief Development Officer at Clearside Bio, where he guided preclinical and clinical development, supported an NDA to first FDA approval of a suprachoroidal therapy, led an IND submission with development of a new clinical program and successful Phase 1/2 trial, and oversaw medical and professional affairs. Prior to Clearside, Dr. Ciulla served in a VP role as Medical Strategy Lead-Ophthalmology at Spark Therapeutics, where he defined and led medical strategy to support development and commercialization of the first FDA-approved gene therapy for a genetic disease. He previously served as VP, Clinical Strategy at Ophthotech Corporation.
Before launching his executive management career, Dr. Ciulla co-directed the retina service and ocular angiogenesis research lab at Indiana University School of Medicine, the largest U.S. medical school. He remains a volunteer Clinical Professor at the university and is a Fellow of the American Society of Retina Specialists, member of the American Society of Gene and Cell Therapy, Association for Research in Vision and Ophthalmology, Macula Society, Retina Society, and the American Academy of Ophthalmology.
Dr. Ciulla has held numerous leadership roles in clinical research, including principal investigator, medical monitor, and member of scientific advisory, data safety monitoring or writing committees in more than 100 national clinical trials. He has served on journal editorial boards, edited several textbooks, presented at more than 200 conferences, and co-authored more than 300 publications. Dr. Ciulla graduated from Harvard College and UCSF School of Medicine, followed by an internship and residency at Harvard Medical School and a fellowship at Tufts Medical School. He also earned an M.B.A. from Indiana University’s Kelley School of Business, specializing in the business of medicine.
Tony Casciano
Chief Commercial Officer
Tony Casciano joined Viridian as Chief Commercial Officer in 2023. Most recently, Tony served as CEO of an MIT medical device spinout, where he successfully led and closed a Series A financing. Prior to that, Tony served as the COO & CCO of AMAG Pharmaceuticals, where he oversaw all commercial activities, as well as technical operations, global supply chain, corporate planning, and information technology. During his 4 years at AMAG Tony led the turnaround of the hematology oncology franchise and several successful product launches in highly competitive specialty and orphan disease markets, including infused products and subcutaneous autoinjectors. Prior to AMAG, he spent 16 years leading various commercial functions with increasing levels of responsibility at Sanofi and Genzyme.
Tony holds a B.A. in exercise science from Bridgewater State University, and executive certificates in marketing from the Wharton School of the University of Pennsylvania and in Governance from the Kellogg School of Management at Northwestern University.
Melissa Manno
Chief Human Resources Officer
Melissa joined Viridian as Chief Human Resources Officer in 2024. Melissa brings over 25 years of human resources experience to her position. Prior to joining Viridian, Melissa served as the Chief Human Resources Officer at Kiniksa Pharmaceuticals, where she oversaw all aspects of the human resources department, including recruitment, diversity, equity, and inclusion, compensation and benefits, organizational design, and employee relations. Melissa has deep experience in the life sciences industry, with demonstrated success in scaling organizations from pre-clinical to commercial stage. She has worked with multiple biotech companies over her career, holding roles of increasing responsibility at Alexion, Synageva, Alkermes, and AMAG Pharmaceuticals.
Melissa holds a B.A. in business management from Keene State College. Melissa serves on the board of advisors for Life Science Cares, a corporate partner that helps support community-based outreach and engagement.
Seth Harmon
Senior Vice President of Finance and Accounting
Seth Harmon joined Viridian as Senior Vice President of Finance and Accounting in 2023. Seth brings 20 years of strategic finance, accounting, and operations experience to his position. Prior to joining Viridian, Seth served as the CFO of BioNTech US, where he oversaw the general and administrative functions for BioNTech SE’s US subsidiary and served as a member of the BioNTech US management team supporting the growth of the organization from 56 to 500+ employees. Earlier in his career he served as Vice President of Finance at Neon Therapeutics where he contributed to the company’s successful $100M IPO and subsequently oversaw the financial aspects of the company’s restructure and strategic sales to BioNTech SE. Prior to Neon Therapeutics, Seth held several positions with increasing levels of responsibility at Merrimack Pharmaceuticals where he participated in the successful launch of company’s first commercial product and the subsequent sale of this asset to Ipsen.
Seth holds a M.S. in Accounting and M.B.A. from Northeastern University and obtained his certified public accountant license while working at Ernst and Young, LLP. Seth received his B.A. in Economics and Mathematics from Bowdoin College.
Jennifer Tousignant
Chief Legal Officer
Jennifer Tousignant joined Viridian as Chief Legal Officer in 2024. Jennifer has broad legal experience and leadership in the biotechnology industry working across a breadth of technologies such as small molecules, biologics, cell and gene therapies, and in the therapeutic categories of rare disease, immune-mediated disease, neurodegenerative disease, and oncology. Prior to Viridian, Jennifer served as Senior Vice President of Legal for Sana Biotechnology where she was a leading a team responsible for legal support for strategic transactions, business development, intellectual property, litigation, quality, regulatory, research and development, investor relations, and general contracting as well as being involved in corporate governance and financings. She joined Sana from Xilio Therapeutics where she was the Head of Legal and responsible for all legal and compliance matters. Prior to Xilio, Jennifer was Chief IP Counsel at TESARO, where she built and led the intellectual property function, and was a key member of the global launch teams for several products. Before TESARO, she worked at Genzyme Corporation in roles of increasing responsibility, first in research and then in legal, and ultimately leading a legal team with worldwide intellectual property responsibility for products from early research to commercial.
Jennifer received her J.D. from Suffolk University School of Law, and her B.A. in Chemistry from the University of Virginia.
Kyle Haraldsen
Chief Technical Operations Officer
Kyle Haraldsen joined Viridian as Chief Technical Operations Officer in 2024. He has over 20 years of development and operations experience in the biopharmaceutical industry. Most recently, Kyle served as the Chief Technology Officer at Lyndra Therapeutics, a drug delivery company developing the first long-acting oral drug platform. While there he led the product and platform R&D activities for the LYNX™ drug delivery platform and manufacturing strategy. Prior to Lyndra, Kyle served as Chief Technical Operations Officer at Saniona, where he established the technical operations department and led efforts to develop a complex long-acting multi-product formulation of their lead asset. Before Saniona, he held roles of increasing responsibility in technical operations and manufacturing at AMAG Pharmaceuticals, most recently servicing as Vice President, Technical Operations & Project Management.
Kyle holds a B.S. in chemical engineering from Northeastern University. He has served as an advisory board/council member for the Friends of Parkinson’s, Dearborn STEM Academy, and Northeastern’s Biopharmaceutical Analysis Training Lab (BATL) and Chemical Engineering Industrial Advisory Board (IAB).
Diane Stroehmann
SVP, Regulatory Affairs
Diane Stroehmann joined Viridian as Senior Vice President, Regulatory Affairs in 2024. She has 25 years of experience in the biopharmaceutical industry with broad expertise in developing global regulatory strategies and ensuring regulatory compliance for small molecules and biologics. Most recently, Diane served as the Vice President of Regulatory Affairs and Global Patient Safety at Ironwood Pharmaceuticals where she contributed significantly to the development and execution of regulatory strategies, including a first-in-class pediatric approval for Linzess®, ensuring compliance with global regulations, and overseeing patient safety initiatives. Prior to that, Diane was Chief of Staff to the CEO and Head of Regulatory Affairs and Quality at Sienna Pharmaceuticals, where she led the development of multiple clinical-stage assets. Prior to Sienna, Diane was Vice President of Regulatory Affairs, Pharmacovigilance and Research Compliance at Kythera Biopharmaceuticals, where she led the successful submission and approval of Kybella®/Belkyra® in the U.S. and Canada in addition to the submission of multiple international marketing applications. Previously, Diane was Head of Regulatory Affairs at Medicis Pharmaceutical Corporation.
Diane holds a M.S. in Regulatory Affairs from San Diego State University and received her a B.S. in Biology at the University of Illinois Urbana-Champaign.
Christian Zdybowicz
SVP, Portfolio Strategy and Leadership
Christian joined Viridian as Senior Vice President of Portfolio Strategy and Leadership in 2023. Prior to joining Viridian, Christian spent over 20 years in a variety of project management and leadership roles within the life sciences industry. Most recently, Christian served as the Vice President of Program Leadership and Management at Magenta Therapeutics, where he was the program lead for Magenta’s condition and mobilization programs, accountable for strategy development and operational execution, escalation of risks, deliver of program goals, and stakeholder management. Christian is an accomplished business, program, and operations leader, with a proven track record leading complex pre-clinical and clinical programs. Prior to Magenta, Christian held several positions with increasing levels of responsibility at Immunogen, Nitto Avecia, Avecia Biotechnology, and Zeneca.
Christian holds a M.B.A. from Nichols College and a B.A. in business administration from Becker College.
Kirk Bertelsen, Ph.D.
SVP, Head of Research
Kirk Bertelsen joined Viridian as Head of Research in April 2024. Kirk has more than 19 years of experience throughout drug development, with responsibilities spanning preclinical, early and late development programs with various drug platforms within oncology, immunology, neuroscience, and endocrinology indications. Throughout his career, Kirk has led collaborative efforts of quantitative model-based approaches, focusing on data generation, knowledge derivation, and strategic application throughout complex R&D organizations. Prior to joining Viridian, Kirk served as the Head of Clinical Pharmacology & Translational Sciences of Magenta Therapeutics, supporting the overall strategy, design and execution of the company’s preclinical and clinical pipeline. Before Magenta, Kirk held various leadership positions at Allergan and Janssen Pharmaceuticals for 15 years, culminating in his role as Executive Director, Clinical Pharmacology and Non-Clinical Translational Sciences with Allergan.
Kirk received his Ph.D. from Tufts Medical School, Sackler School of Biomedical Sciences, Department of Clinical Pharmacology and Experimental Therapeutics, and holds a B.S. from the University of Oregon.
Tomas Kiselak
Managing Member, Fairmount Funds Management LLC
Tomas Kiselak is a Managing Member at Fairmount Funds Management LLC, a healthcare investment firm he co-founded in April 2016. Prior to Fairmount, Mr. Kiselak was a managing director at RA Capital Management, LLC. Mr. Kiselak currently serves on the board of Viridian Therapeutics, Inc. as its chairman. He also serves as a director of Apogee Therapeutics, Inc., Dianthus Therapeutics, Inc., Spyre Therapeutics, Inc., and Zenas BioPharma, Inc., as well as several private companies. He received a bachelor’s degree in Neuroscience and Economics from Amherst College.
Sarah Gheuens, M.D., Ph.D.
Chief Medical Officer, Head of R&D, Agios Pharmaceuticals
Dr. Gheuens joined Agios in December 2019, became chief medical officer in September 2021, and took on the additional role of head of R&D in August 2022. She has been instrumental in completing the pivotal Phase 3 program for pyruvate kinase deficiency and leading simultaneous regulatory submissions to the FDA and EMA in this indication, as well as designing the pivotal programs for thalassemia, sickle cell disease and the pediatric indications. Prior to joining Agios, Dr. Gheuens worked at Biogen, where she held roles of increasing responsibility in safety, medical affairs and clinical development. Her work was critical for the approval of SPINRAZA®. Before joining Biogen, Dr. Gheuens worked at Beth Israel Deaconess Medical Center (BIDMC), taking care of patients with HIV and neurological complications and doing research on progressive multifocal leukoencephalopathy. Dr. Gheuens received her medical degree from the Free University of Brussels (VUB), Belgium, and completed her neurology residency at the University Hospital of the Free University of Brussels, Belgium, followed by an HIV/neurology fellowship at BIDMC, Boston, Mass., USA. She also holds a Ph.D. in Medical Sciences from the University of Antwerp, Belgium, and a Master’s in Medical Sciences from Harvard Medical School.
Peter Harwin
Managing Member, Fairmount Funds Management LLC
Peter Harwin is a Managing Member at Fairmount Funds Management LLC, a healthcare investment firm he co-founded in April 2016. Prior to Fairmount, Mr. Harwin was a member of the investment team at Boxer Capital, LLC, part of the Tavistock Group, based in San Diego. Mr. Harwin serves on the boards of Viridian Therapeutics, Inc., Spyre Therapeutics, Inc., Apogee Therapeutics, Inc., and Oruka Therapeutics, Inc., along with being chairman of the board of Cogent Biosciences, Inc. He is also a director of Paragon Therapeutics, Inc. Peter holds a Bachelor of Business Administration from Emory University.
Steve Mahoney
President and Chief
Executive Officer
Steve Mahoney is Viridian’s President and Chief Executive Officer and a member of the Board of Directors. Steve has more than two decades of experience in a variety of operational, financial, commercial, legal and transactional roles in companies of different sizes and stages. He has been successful scaling organizations from founding team through commercial stage.
Prior to joining Viridian, Steve was the Chief Financial and Operating Officer of Magenta Therapeutics, where he drove operational excellence and disciplined capital allocation to high priority programs. Previously, Steve was part of the founding team of Kiniksa Pharmaceuticals, where he served as President and Chief Operating Officer. Prior to Kiniksa, he was Chief Commercial Officer of Synageva Biopharma, a company focused on ultrarare diseases, where he held roles of increasing responsibility in operations, commercial launch preparation, legal and corporate development. Steve was also a commercial attorney with Genzyme Corporation for approximately ten years. Prior to Genzyme, Steve was a corporate attorney with Mintz Levin.
Steve received his M.B.A. from Boston College’s Carroll School of Management, a J.D. from Boston College Law School, and a B.A. from Colorado College. He serves on the board of directors of Vesselon, Inc., a private company.
Jennifer Moses
Chief Financial Officer, Investors Management Corporation
Jennifer Moses is currently the Chief Financial Officer of Investors Management Corporation (IMC).
Prior to joining IMC, Ms. Moses served as Chief Financial Officer of G1 Therapeutics, Inc., a commercial-stage oncology company. Previously, Ms. Moses was a partner at Rankin McKenzie, LLC, where she served as acting chief financial officer and controller for venture-backed companies. Before joining Rankin McKenzie, Ms. Moses held roles of increasing responsibility at Deloitte, including providing tax services to clients and later focusing on strategic planning and internal communications in the Office of the CEO of Deloitte Tax. Ms. Moses also serves on the board of directors for Southern Trust Insurance Group, a privately held insurance company.
Ms. Moses received her B.S. in Accounting from The Pennsylvania State University and is a certified public accountant in the State of North Carolina.
Arlene Morris
Chief Executive Officer, Willow Advisors
Arlene Morris currently serves as Chief Executive Officer at Willow Advisors, LLC, a consultancy advising biotech companies on financing, strategy and business development. Previously, she served as the President, Chief Executive Officer and a member of the board of directors of Syndax Pharmaceuticals, Inc, a privately held biotechnology company, and Affymax, Inc., a publicly traded biotechnology company. Ms. Morris has also held executive positions at Clearview Projects, Inc., Coulter Pharmaceutical, Inc., Scios Inc., Johnson & Johnson and board of director roles at Biodel Inc., and Dimension Therapeutics, Inc.
Arlene is currently a member of the board of directors of Viveve, Inc., Palatin Technologies, Inc., and Cogent Biosciences, Inc., and director emeritus for the Foundation for Research and Development at the Medical University of South Carolina where she served as Chair. She also serves as a trustee of Carlow University where she received a B.A. in Biology and Chemistry.