Lexeo team

R. Nolan Townsend has served as Lexeo Therapeutics Chief Executive Officer and member of the Board of Directors since January 2020. Lexeo Therapeutics is a New York City-based, clinical stage biotechnology company that aims to apply transformational science to address some of the world’s most devastating genetic diseases.

Prior to Lexeo, Mr. Townsend held roles as President, Pfizer Rare Disease for the North America region and President, Pfizer Rare Disease for the International markets; overseeing overall strategy, the cross functional organization and operating budget in those regions.  Mr. Townsend has over a decade of experience with Pfizer first joining the company in Corporate Finance and subsequently in roles of increasing responsibility across Corporate Finance, Corporate Strategy, Operations, Marketing, General Management and Commercial leadership in Pfizer’s New York headquarters, Asia, Africa/Middle East and Europe.  Prior to Pfizer, Mr. Townsend worked in the healthcare investment banking group at Lehman Brothers, advising healthcare companies on strategic financing transactions and mergers and acquisitions.

Mr. Townsend currently serves on the Board of Directors of Arbor Biotechnologies, the Biotechnology Innovation Organization (BIO), and the Martha’s Vineyard Museum, in addition to an appointment to the New York City Economic Development Corporation’s Life Sciences Advisory Council. Mr. Townsend previously served as Chairman of the Board and is currently an Advisor to Life Science Cares New York.

Mr. Townsend received his Masters in Business Administration from the Harvard Business School and his Bachelor of Arts in Economics from the University of Pennsylvania.

Dr. Narinder (Nani) Bhalla joined Lexeo in 2026. Dr. Bhalla is a physician-executive with more than 20 years of experience as an interventional cardiologist and nearly a decade of leadership in the biopharmaceutical industry. Since transitioning to industry in 2015, he has held senior leadership roles at AstraZeneca and Bristol Myers Squibb, where he most recently served as Senior Vice President and Head of Global Medical, Immunology & Cardiovascular. Dr. Bhalla is widely recognized for building and scaling high-impact medical and clinical development organizations as well as leading successful global product launches that deliver meaningful outcomes for patients.

Dr. Bhalla completed his training at NYU Langone Medical Center. He received his MD from the University at Buffalo and his Bachelor of Science from Binghamton University.

Dr. José Manuel (Manny) Otero joined Lexeo in 2024, serving as Chief Technical Officer until his appointment as Chief Operating Officer in 2026. Dr. Otero was previously Chief Technical Officer at Auregen Biotherapeutics, leading R&D and manufacturing in the development of autologous, 3D bioprinted cell-based restorative anatomy (cartilage based), in Phase 1b/2 clinical development for patients suffering from microtia. Prior to joining Auregen in 2023, Dr. Otero was Chief Technology Officer at Turnstone Biologics (NASDAQ: TSBX), joining in 2017 and responsible for building and leading bioprocess development, manufacturing, supply chain, quality control and CMC. His team enabled the development of several clinical-stage viral immunotherapies, across multiple jurisdictions, and later, pivoted to develop a TIL cell therapy platform (Selected TIL) currently in Phase 1b/2 clinical development. He came to Turnstone from his position as Vice President, Bioprocess Development and Manufacturing of Seres Therapeutics, Inc., (NASDAQ: MCRB) a leader in human microbiome therapeutics.  Dr. Otero was similarly an early member of CMC leadership, oversaw the expansion of the bioprocess development and manufacturing group and was the overall corporate team leader for the first synthetic microbiome therapeutic entering US Phase 1b clinical studies.

Prior to Seres Therapeutics, Dr. Otero was Director of Engineering and an Integrated Development & Supply Team Leader within Vaccine Manufacturing Sciences & Commercialization at Merck. He specialized in supporting development programs for the Varivax™, Zostavax™, ProQuad™, and MMRII™ franchises. Prior to this role, he was Head of Fermentation Process Development, Vaccine Process Development within Merck Research Labs. Dr. Otero joined Merck in 2002 and was part of the team that developed GARDASIL™ – a S. cerevisiae based virus-like particle human papillomavirus vaccine. Dr. Otero received his PhD in Biological and Chemical Engineering from Chalmers University of Technology as a Merck Doctoral Fellow, a Master of Engineering in Biomedical Engineering from the Massachusetts Institute of Technology, and a Bachelor of Science degree in Chemical Engineering from the Massachusetts Institute of Technology.

Louis Tamayo joined Lexeo in 2025. Mr. Tamayo brings extensive commercial finance experience, having previously served as Senior Vice President at Siemens Healthineers AG, responsible for driving revenue growth and market expansion for the company’s $5 billion global diagnostics division. In this role, he built and led high-performing finance organizations that supported multiple global product launches and strategic partnerships, directed R&D capital allocation, and oversaw large-scale transformation initiatives. Prior to Siemens Healthineers, Mr. Tamayo was the Business Unit CFO for Becton, Dickinson and Company’s $1.2 billion global diabetes care business. Mr. Tamayo began his career at Pfizer where he held a series of financial, strategic, and analytical leadership roles across U.S. and international markets. Mr. Tamayo holds a BBA in Finance and Marketing from Northeastern University.

Gregory Aubert, MD, PhD, is a cardiologist and physician-scientist specializing in cardiovascular genetics, gene therapy, and cardiometabolic research. He previously served as Director of the Clinical and Translational Research Division at the Loyola University Cardiovascular Research Institute, where he led preclinical, early-stage and clinical research programs focused on cardiometabolism and inherited cardiovascular diseases. During his time at Loyola, he also founded the institution’s Cardiovascular Genetics Clinic, which he continues to support through ongoing, part-time patient care.

Dr. Aubert later led late-stage clinical trials at CSL Vifor, advancing therapies for complex cardiovascular conditions. He earned his MD and PhD from the University of Lausanne, Switzerland, with postgraduate training in internal medicine and cardiology at UT Southwestern and Northwestern University. He has served on NIH study sections and is a peer reviewer for several scientific journals. His experience spans the full spectrum of drug development from preclinical discovery to late-phase clinical trials.

Youjin Choi joined Lexeo in 2024. Ms. Choi has managed Lexeo’s various legal and compliance functions including public company reporting and SEC compliance, corporate governance and healthcare law compliance, and she supports Lexeo’s fundraising efforts and business development activities. Prior to Lexeo, she was a Senior Corporate Counsel at Pfizer, serving as the lead brand attorney for Pfizer’s migraine and cancer drugs and counseling clients on their brand marketing activities as well as broader commercial, clinical development and medical strategies. Before Pfizer, she was a corporate associate at a large international law firm in New York City and worked in-house at Merck & Co., advising clients in complex life sciences and healthcare transactions. Ms. Choi holds a BA from University of Virginia in Economics and Psychology, and a JD from Cornell Law School.

Timothy Fenn joined Lexeo in 2021. Tim has worked in several industry and biotech roles, leading drug development teams and supporting biophysical methods used to characterize and release biologics. His experience includes Merck in Discovery Biologics, Boehringer Ingelheim in Antibody Discovery, and helping build the preclinical and CMC functions at Prevail Therapeutics. Over the course of this work, Tim has been involved in the successful CMC packages for multiple INDs and release of multiple drug batches for use in clinical studies. Additionally, Tim has led comparability studies to enable the transition of gene therapy products from early phase to larger, scalable processes, with the intent of easing commercial drug manufacturing.

Tim has a PhD in biochemistry from Brandeis University, and did postdoctoral work in structural biology at Stanford University.

Ryan McHenry joined Lexeo Therapeutics as Vice President, Corporate Controller in 2022. Prior to Lexeo, Mr. McHenry served as Vice President, Controller and Assistant Secretary at Sio Gene Therapies, where he oversaw the SEC filing, financial reporting, technical accounting, internal control, income tax and procurement functions, and executed a transformational international corporate structure simplification effort. Prior to Sio, Mr. McHenry worked at Biocept, where he scaled-up the accounting and SEC reporting functions following its IPO, and CareFusion (since acquired by Becton, Dickinson and Company), where he led accounting for M&A transactions among other responsibilities. At the start of his career, Mr. McHenry held roles of increasing responsibility at PwC in the audit and assurance practice focusing on publicly traded and private clients in the pharmaceutical, biotechnology/life sciences and defense contractor industries. Mr. McHenry received his BSBA, Accounting and his Certificate in Advanced Accountancy from Boston University. He is an actively licensed CPA in New York and California, as well as a member of the American Institute of Certified Public Accountants.

Jenny Speer joined Lexeo Therapeutics as Vice President, People Experience in 2023. Following her passion for enabling brilliant people who do impactful work, Ms. Speer has held people leadership roles at several biotech startups. Most recently, Ms. Speer served as the head of people at Mammoth Biosciences, scaling the organization from 40 to over 200 employees. Ms. Speer holds a bachelor’s degree in English and Journalism from Boston University.

Keith Wonnacott, PhD joined Lexeo Therapeutics as Vice President of Regulatory Affairs in 2021. Prior to joining Lexeo, Dr. Wonnacott was an Executive Director of Regulatory Affairs at Pfizer where he had responsibility for gene therapies within the Rare Disease Business Unit. He provided guidance on regulatory strategy and led regulatory policy for the gene therapy portfolio, which included advancing 3 late-stage programs into phase 3 clinical trials. Dr. Wonnacott also worked at Novartis where he was a Director of regulatory CMC and led the development of Module 3 for the Kymriah BLA, which became the first gene therapy product to receive FDA approval in 2017. Dr. Wonnacott also held roles of increasing responsibility at FDA at the start of his career. He spent 13 years in the Division of Cell and Gene Therapies at FDA, the last 10 of which were as Chief of the Cellular Therapies Branch. He is a respected leader in the field, speaker, and published author, and is currently serving as the Chair of the Regulatory Affairs Committee for the American Society of Gene and Cell Therapy. Dr. Wonnacott received his PhD from the Pennsylvania State University and his undergraduate degree from Brigham Young University.

Peter Zawaneh joined Lexeo in 2026, bringing 18 years of experience working in global biotech companies such as Alnylam, Biogen, and Takeda. His roles have spanned business development, alliance management, strategy and operations, program leadership, CMC, and drug development. Over the course of his career, he has helped advance more than 20 clinical-stage and four commercial drugs, and has been part of generating $7B in value through various business development transactions. He completed his PhD in Chemical and Biomolecular Engineering from Cornell University, his MBA from the MIT Sloan School of Management, and his BS in Chemical Engineering from the University of Florida.

Rishi Bhattacharjee joined Lexeo Therapeutics in 2026 as Vice President, GxP Quality Assurance. He brings more than 35 years of experience in biopharmaceutical quality assurance, with leadership spanning all aspects of GxP compliance. He has established GxP quality management systems across the full development lifecycle, from preclinical and clinical stages through 16 NDAs & 9 BLA submissions and post-marketing operations covering CNS, oncology, Covid and RSV vaccines, and rare diseases, with the most notable ones being Banzel®, Aricept®, Fycompa®, Rexulti®, Lenvima®, Halaven®, Enhertu®, Aciphex®, Nuvaxovid® and Emi-le®.

Rishi has successfully hosted numerous inspections with regulatory authorities worldwide, including the FDA, EMA, MHRA, PMDA, Health Canada, and Swissmedic, and has led and executed more than 750 GCP, GLP, GCLP and pharmacovigilance audits of clinical sites, CROs, and suppliers. He has led global quality and audit teams and stewarded the implementation of ICH E6 (R2/R3), risk-based quality management, and data integrity programs across clinical, regulatory, and safety operations resulting in optimized resource allocation, budget reduction and compliant outcomes.

Before joining Lexeo, Rishi served as Vice President of Clinical Quality Assurance at Mersana Therapeutics and Vice President of Clinical and Safety QA at Novavax. He previously held senior quality leadership roles at Otsuka Pharmaceutical Development & Commercialization, Daiichi Sankyo, and Eisai. He holds an M.S. in Mechanical Engineering from the University of Mississippi.

Amanda Anderson joined Lexeo Therapeutics in 2023, previously serving as Executive Director, Commercial Development and Business Operations. She has led strategic and operational initiatives across the organization, including executive leadership operations, corporate strategy, communications, and commercial development. Prior to Lexeo, Ms. Anderson held roles of increasing responsibility at Pfizer with experience in rare disease marketing, market access, launch excellence, and commercial strategy. She was most recently the Marketing Team Lead for Pfizer’s rare endocrine portfolio in the U.S., and she previously worked on launch teams for hemophilia gene therapy and for Vyndaqel (tafamidis) in amyloidosis. Ms. Anderson began her career in healthcare consulting and holds an MBA in Health Care Management from the Wharton School, and a BA in Social and Cognitive Neuroscience from Harvard University with a minor in Health Policy.

Risa Torkin joined Lexeo Therapeutics in 2026 as Vice President, Medical Affairs, bringing more than 17 years of experience building and leading high-performing Medical Affairs teams across clinical-stage and commercial programs. Previously, Risa held Medical Affairs leadership roles at Xenon Pharmaceuticals and Acorda Therapeutics. Her experience spans medical strategy, launch readiness, scientific communications, external engagement, patient advocacy, and operations.

Risa earned her PhD from the University of Toronto and completed her postdoctoral studies at the Hospital for Sick Children (Canada) and Weill Cornell Medical College.

Ronald Crystal is a physician-scientist and pioneer in In vivo gene therapy. He is a Professor and Chairman, Department of Genetic Medicine, Weill Cornell Medical College, previously Chief, Pulmonary Branch, NHLBI. He also directs the Weill Cornell Belfer Gene Therapy Core facility, with 45 faculty/staff, including viral vector, pre-clinical translation, toxicology, regulatory and GMP manufacturing expertise.

​Dr. Crystal has 14 approved gene therapy investigational new drug applications with experience in CNS, cardiac, pulmonary and liver human gene therapy.

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Dr. Crystal is the founder/co-founder of several gene therapy companies including GenVec, Adverum and XyloCor.

Steven Altschuler, MD, joined Lexeo as Chairman in January 2021, bringing nearly 20 years of experience building and leading world-class, integrated, translational, value-based health care systems and transformational biotechnology companies. Dr. Altschuler currently serves as Managing Director of Healthcare Ventures at Ziff Capital Partners and was previously chair of the board of directors at Spark Therapeutics (now part of Roche) for six years, from its founding until it was acquired in 2019. Dr. Altschuler previously co-founded Spark Therapeutics to develop and commercialize the preclinical and clinical gene therapy programs advanced at the Children’s Hospital of Philadelphia (CHOP) and other institutions. Dr. Altschuler served as Spark’s board chair from its founding through its acquisition in 2019, which included leading the company through a successful transition to a public company and the launch of an approved commercial product, which was the first gene therapy for an inherited disease approved by the U.S. Food and Drug Administration and European Medicines Agency. Dr. Altschuler formerly held chief executive positions at CHOP and University of Miami Health System. He is a member of the board of directors of WW (formerly Weight Watchers International), Orchard Therapeutics, AsclepiX Therapeutics, ImVaX and Platelet Biogenesis. He is also an independent trustee of the Brigham and Women’s Physician Organization at Mass General Brigham. Dr. Altschuler holds a BA in Mathematics and an MD from Case Western Reserve University.

Mette Kirstine Agger is a Senior Advisor and board member for numerous biopharmaceutical companies, where she utilizes her extensive industry experience as a strategic advisor. Ms. Agger currently serves on several boards, including Abzu, KLIFO, ScPharmaceuticals, D.O.F (an independent Danish foundation) and C.V Obel A/S, an investment company.

Previously, Ms. Agger was a managing partner of Lundbeckfonden Ventures, a life science venture fund, and later served as a Senior Advisor for Lundbeckfonden BioCapital (succeeding Lundbeckfonden Ventures). Earlier in her career, she was a co-founder of 7TM Pharma A/S, a biotech company engaged in therapeutic drug discovery and development and served as its Chief Executive Officer from founding to 2009. Prior to founding 7TM Pharma, Ms. Agger was part of the management team of NeuroSearch A/S, a former drug research and development company.

Ms. Agger graduated with an MSc in Biology from the University of Copenhagen and has an MBA from Henley Business School University of Reading.

Paula Cholmondeley currently serves as Principal of The Sorrel Group, a company focused on individualized board education. Ms. Cholmondeley is also a member of the Board of Directors of Terex Corporation (NYSE) and Bank OZK (NASDAQ).

Ms. Cholmondeley’s previous public company boards include Dentsply Corporation, Ultralife Inc., Armco Steel Inc., Albany International, Mineral Technologies, and Nationwide Mutual Funds. During her executive career, Ms. Cholmondeley has had a profit and loss responsibility for global divisions with revenues up to $750M, served as CFO of companies with revenues up to $2B, brought new technologies to market, served as head of strategy for two large corporations and held seats on numerous non-profit boards. Across her board career, Ms. Cholmondeley has served on the audit, investments, governance, strategy, corporate social responsibility, and compensation committees across various companies.

Ms. Cholmondeley currently chairs the Terex audit committee, and is a member of the faculty of the National Association of Corporate Directors In-Board Room and Board Advisory Services where she teaches and conducts board evaluations. Ms. Cholmondeley is a NACD Certified Director and a Board Leadership Fellow. In 2015, she was elected to NACD Directorship 100. She also holds NACD certifications in Cyber Risk Oversight and Digital Transformation.

Brenda Cooperstone, MD, joined Lexeo’s board as an Independent Director in 2023. Dr. Cooperstone currently serves as an Independent Director on the Boards of Senti Biosciences and Gandeeva Therapeutics. Previously, Dr. Cooperstone served as Senior Vice President and Chief Development Officer of Rare Disease at Pfizer Inc. and Site Leader for Pfizer’s Pennsylvania campus. Prior to this role, Dr. Cooperstone held varied leadership positions at Pfizer and Wyeth in both Clinical Development and Global Medical Affairs with oversight of a wide range of therapeutic areas, including both small and large molecules in early through late phase development and in-line support.

Dr. Cooperstone earned her MD from McGill University, completed her residency in pediatrics at the Montreal Children’s Hospital, her clinical fellowship in pediatric nephrology at Children’s Hospital of Philadelphia and a research fellowship at the University of Pennsylvania, Renal Electrolyte Division. She is certified by the American Board of Pediatrics and Pediatric Nephrology and the Royal College of Physicians and Surgeons of Canada, Pediatrics. Dr. Cooperstone was on staff at Scottish Rite Children’s Hospital in Atlanta, GA as a pediatric nephrologist before joining the pharmaceutical industry.

Reinaldo Diaz is a Venture Partner of Longitude Capital. Concurrently, Mr. Diaz serves as the Chief Business Officer of Opna-IO, a Longitude portfolio company, as well as a consultant for various companies in the healthcare industry, including Auven Therapeutics, where he previously served as Managing Director from 2008 to 2018. Prior to joining Auven Therapeutics, he was a Managing Member and co-founder of Diaz & Altschul Capital Management (D&A Capital). Prior to founding D&A Capital, Mr. Diaz was a Managing Director and Head of the Healthcare group at Schroder Wertheim & Co. Mr. Diaz started his career at PaineWebber, where he was a key member of the PaineWebber Healthcare Investment Banking Group and President of PaineWebber Development Corporation. He currently serves on the board of Inozyme (INZY). Mr. Diaz holds an MBA from Harvard Business School and a BA from Harvard University.

Mr. Van Hauwermeiren is co-founder and Chairman of the Board of argenx, a global immunology company, valued at almost $60 billion, focused on severe autoimmune diseases. During his 15-year tenure, he has overseen the development and launch of the company’s first commercial product, efgartigimod, for the treatment of multiple severe autoimmune diseases, and he has expanded the company’s footprint across Europe, the U.S. and Asia. Additionally during his time at argenx, Mr. Van Hauwermeiren has secured more than $4 billion in funding through equity raises and business development transactions with major pharmaceutical companies. Prior to argenx, Mr. Van Hauwermeiren held roles with increasing levels of responsibility at Ablynx and Procter & Gamble. Mr. Van Hauwermeiren also serves on the Board of Directors of iTeos Pharmaceuticals, and previously served on the Board of Directors of RayzeBio prior to the company’s acquisition by Bristol Myers Squibb. He holds a BSc and MSc in bioengineering from Ghent University and an Executive MBA from The Vlerick School of Management.

Laura Sepp‑Lorenzino, PhD, is a seasoned biotechnology executive and Principal of GNMmeds LLC, where she advises on genomic medicine research and development. She serves on the boards of AskBio, Taysha Gene Therapies, Ursa Medicines, the American Society of Gene & Cell Therapy (ASGCT) and the Oligonucleotide Therapeutics Society, and contributes to multiple scientific advisory boards including Inverna Therapeutics, Thermo Fisher Scientific, Arsenal Capital Partners and the UK Nucleic Acid Therapy Accelerator. Previously, she was Chief Scientific Officer at Intellia Therapeutics, where she helped drive pioneering advances in in vivo CRISPR genome editing, and held senior leadership roles at Vertex Pharmaceuticals,  Alnylam Pharmaceuticals and Merck & Co. Her expertise spans small molecules, biologics, oligonucleotides, and genome‑editing therapeutics, grounded in a scientific career that began at Memorial Sloan Kettering Cancer Center. Dr. Sepp-Lorenzino holds a professional degree in biochemistry from the University of Buenos Aires and a PhD in biochemistry from New York University.

Mr. Tolga Tanguler is the Executive Vice President and Chief Commercial Officer at Alnylam Pharmaceuticals, Inc., a global leader in RNA interference therapeutics. He has been instrumental in transforming Alnylam into a fully integrated biotech company, expanding its commercial footprint both domestically and internationally, and is currently leading the launch of Amvuttra, an RNAi treatment for TTR amyloid cardiomyopathy.

With over 25 years of global leadership experience, Tolga has spearheaded commercialization efforts across various therapeutic areas, overseeing the launch and growth of notable medications such as Viagra, Eliquis, and Ultomiris. Before joining Alnylam, he was Head of U.S. at Alexion, where he drove significant growth through first-in-class neurology product launches.

He spent the majority of his early career at Pfizer, where he established and led the North America rare disease unit as its President, advancing the company’s gene therapy and rare cardiology initiatives.

Tolga holds a Bachelor of Science in Finance and Economics from Istanbul University and an MBA in Marketing and Supply Chain Management from Michigan State University. He also completed postgraduate studies in Marketing at the University of California, Santa Barbara.