About Us

Focused on breakthroughs

We are dedicated to a brighter future for patients with Graves’ disease and thyroid eye disease. With experts in scientific innovation, clinical development and company building, our veteran team focuses on giving patients a potentially first-in-class treatment option that delivers direct inhibition of the central mechanism of these devastating autoimmune conditions.

Leadership Team

Yarrow’s team members have extensive experience and a history of collaborating to develop innovative treatments with the potential to make a significant impact on patients’ lives.

Rebecca V. Frey, PharmD

Rebecca V. Frey, PharmD

President and Chief Executive Officer
Rebecca V. Frey, PharmD

Rebecca V. Frey, PharmD

President and Chief Executive Officer

Rebecca Frey is a seasoned biotech leader with 25 years of experience in positions driving drug development from pre-clinical to commercial stage. Prior to joining Yarrow, Dr. Frey served as a venture partner at RTW Investments and the interim CEO of Prolium Bioscience. Prior to RTW, she served as CEO of Siduma Therapeutics. She has previously held key operational leadership roles in emerging biotech companies including EvolveImmune Therapeutics, Cardurion Pharmaceuticals and Prevail Therapeutics. Prior to these roles, she spent 11 years working in medical affairs, development, corporate affairs and manufacturing at Alexion Pharmaceuticals. At Alexion, Dr. Frey spearheaded the development of Soliris® in new indications, which have become multibillion dollar franchises, and contributed to approvals of multiple new rare disease products. Earlier in her career she worked in development and medical affairs at Novartis Pharmaceuticals and was an Assistant Professor at Northeastern University.

In addition to her leadership and operating roles, Dr. Frey also served on the board of Halda Therapeutics, prior to its acquisition by Johnson & Johnson. She also currently serves on the board of Octant Bio. Dr. Frey was recently honored as a Luminary in the BLOC 100 list of the Most Impactful Women of Color & Allies Shaping the Future of Healthcare, Life Sciences & Biopharma.

Dr. Frey earned a Doctorate in Pharmacy from Northeastern University and completed her post-doctoral clinical research fellowship at Tufts Medical Center in the field of organ transplant therapeutics. She additionally holds an Executive Certificate in Management and Leadership from the MIT Sloan School of Management and is Directorship Certified by the National Association of Corporate Directors.

Rachael Alford

Rachael Alford, PhD

Chief Operating Officer
Rachael Alford

Rachael Alford, PhD

Chief Operating Officer

Dr. Alford brings more than 20 years of operational biotech experience to Yarrow. Most recently, she served as Head of Chemistry, Manufacturing and Controls at Rallybio, where she oversaw key functions supporting clinical development. Prior to Rallybio, Dr. Alford was Vice President, Global Process Development at Alexion Pharmaceuticals, where she led both biologic and small molecule process development across the lifecycle, analytical and formulation development, device development, tech transfer and clinical tech services. During her tenure at Alexion, Dr. Alford assumed positions of increasing responsibility in technical operations, developing expertise across the CMC spectrum. Prior to joining Alexion, Dr. Alford was a postdoctoral research associate in the Department of Molecular Biophysics and Biochemistry at Yale University. Dr. Alford has a PhD in biophysical chemistry and a BSc in Chemistry from Imperial College, London.

Lori Payton, PhD

Lori Payton, PhD

Chief Development Officer
Lori Payton, PhD

Lori Payton, PhD

Chief Development Officer

Dr. Payton brings more than 25 years of broad experience leading strategic planning, clinical development and operational management in the biopharmaceutical industry. Prior to joining Yarrow, Dr. Payton served as Principal Consultant and Chief Executive Officer at Harkness Consulting, where she was responsible for strategic planning and development consulting to several bioscience clients. She previously served as Senior Vice President, Development Strategy and Operations at AlloVir, where she led multiple functions that support clinical development of the company’s pipeline including, clinical operations, outsourcing & contracts, program management, and clinical quality & compliance. In addition, Dr. Payton was a member of the executive leadership team of Allovir that was responsible for achievement of critical development milestones.

Dr. Payton started her career at Pfizer, where she held various roles spanning the entire drug development continuum and led the teams responsible for the registration and commercialization of several medicines, including the blockbuster treatments Celebrex and Eliquis. She also served as Senior Vice President, Strategy, Portfolio and Program Management at Sage Therapeutics, where she led generation of the research & development strategy and portfolio planning process that informed investment in the Sage pipeline and established the operating model for the growing organization. Previously, Dr. Payton was also Vice President and Global Development Team Leader at Alexion Pharmaceuticals, where she led a multi-indication team through strategic planning and execution to achieve global registrations for a new therapy to treat compliment-mediated rare diseases with industry leading timing. Dr. Payton received her PhD in Pharmacology and Experimental Medicine from Boston University School of Medicine and BA from Wheaton College.

Steve Ryder, MD

Chief Medical Officer

Steve Ryder, MD

Chief Medical Officer

Dr. Ryder has more than 30 years of leadership experience in global healthcare development and a proven track record in advancing clinical-stage drug candidates to patients. Prior to joining Yarrow, Dr. Ryder was Chief Medical Officer of Rallybio, a clinical-stage biotechnology company with a mission to develop and commercialize life-transforming therapies for patients with severe and rare diseases. Prior to Rallybio, he served as Senior Vice President, Chief Development Officer at Alexion Pharmaceuticals, where he led the global development, registration, and approval of new drug candidates for rare diseases and contributed to the overall growth of the company. Previously, he was founding President of Astellas Pharma Global Development and spent 21 years in development at Pfizer.

Dr. Ryder received his MD from the Icahn School of Medicine at Mount Sinai.

Tyler Zeronda

Tyler Zeronda

Chief Financial Officer
Tyler Zeronda

Tyler Zeronda

Chief Financial Officer

Tyler Zeronda has extensive experience in public company financial leadership, joining Yarrow after serving as Chief Financial Officer and Treasurer of VYNE Therapeutics. Mr. Zeronda joined Foamix Pharmaceuticals Ltd. prior to its merger with VYNE where he helped lead the buildout of the company’s finance department in the U.S. and was responsible for financial planning, commercial finance and supply chain matters of VYNE post-merger. Prior to Foamix and VYNE, Mr. Zeronda held positions across corporate and operational finance at Aerie Pharmaceuticals Inc., where he helped the company scale and transition from a pre-IPO, clinical-stage company to a commercial-stage public company. Mr. Zeronda began his career at Ernst & Young, LLP where he focused on assurance services in the healthcare industry. Mr. Zeronda received his Master of Science in accounting from the University of Virginia, holds a Bachelor of Arts with a double major in economics and business and history from Lafayette College and is a licensed CPA.

Board of directors

Bill Lundberg, MD

Board Chair

Bill Lundberg, MD

Board Chair

Dr. Lundberg has served as Chair of Yarrow’s board of directors since April 2026. Since August 2018, Dr. Lundberg has served as a Partner at Cold Spring Partners, LLC, an investment firm. Dr. Lundberg previously served as President and Chief Executive Officer of Merus N.V. (formerly, Nasdaq: MRUS), a biotechnology company, from December 2019 until Merus was acquired by Genmab A/S in December 2025, and as the Principal Financial Officer of Merus from December 2019 to June 2023. Dr. Lundberg also served as a member of the board of directors of Merus from June 2019 to December 2025. Prior to joining Merus, he served as Chief Scientific Officer of CRISPR Therapeutics AG (Nasdaq: CRSP), a biotechnology company, from January 2015 to February 2018. From February 2011 to January 2015, Dr. Lundberg served as Vice President and Head of Translational Medicine at Alexion Pharmaceuticals, Inc. (formerly, Nasdaq: ALXN), a biopharmaceutical company. Prior to that, he served as Director and Chief Medical Officer of Taligen Therapeutics, Inc., a biotechnology company acquired by Alexion in 2011. Dr. Lundberg held roles of increasing responsibility in clinical drug development and medical affairs at Xanthus Pharmaceuticals, Inc. (acquired by Antisoma plc), Wyeth (acquired by Pfizer Inc.), and Genzyme Corporation (formerly, Nasdaq: GENZ). Dr. Lundberg has served as a member of the board of directors of Q32 Bio Inc. (Nasdaq: QTTB) since September 2017 and previously served on the board of directors of Vor Biopharma Inc. (Nasdaq: VOR) from July 2019 to July 2025. Dr. Lundberg received his MD from Stanford University and his MBA from the University of Massachusetts. He completed post-doctoral training at the Whitehead Institute/MIT and clinical training in Medicine and Medical Oncology at Harvard Medical School and the Dana-Farber Cancer Institute.

Mona Ashiya, PhD

Board Member

Mona Ashiya, PhD

Board Member

Mona Ashiya is a General Partner of OrbiMed and has been with OrbiMed since 2010. Prior to OrbiMed, Dr. Ashiya covered the biotechnology industry as a member of J.P. Morgan’s biotechnology equity research team. Her previous experience includes positions at the Global Alliance for TB Drug Development and the Harvard Business School. Dr. Ashiya currently serves on the boards of directors of Shattuck Labs and several private companies. Dr. Ashiya earned a BA degree from the University of California at Berkeley, a PhD in Cellular, Molecular, and Developmental Biology from the University of Pittsburgh, and was a post-doctoral fellow at the Dana Farber Cancer Institute.

William White, JD

Board Member

William White, JD

Board Member

Mr. White is the Chief Financial Officer and Head of Corporate Development at Avere Therapeutics. He has served as a member of Yarrow’s board of directors since April 2026. Previously, Mr. White served as the Executive Vice President, Chief Financial Officer and Head of Corporate Development and Treasurer at Akero Therapeutics, Inc. (Nasdaq: AKRO), a biotechnology company, from April 2019 until its acquisition by Novo Nordisk in December 2025. Before joining Akero, Mr. White served as a Managing Director and Head of US Life Sciences Investment Banking at Deutsche Bank AG, an investment banking company, from September 2017 until March 2019. Prior to that position, Mr. White was a Managing Director in Healthcare Investment Banking at Citigroup Inc., a multinational investment bank and financial services company, from May 2006 until September 2017. Previously, he served as an associate and later as a Vice President in Healthcare Investment Banking at Goldman, Sachs & Co., a global financial institution, from November 2000 to March 2006. Mr. White has served as a member of the board of directors of Disc Medicine, Inc. (Nasdaq: IRON) since December 2020 and previously served on the board of directors of Ventyx Biosciences, Inc. (formerly, Nasdaq: VTYX) from May 2021 until its acquisition by Eli Lilly and Company in March 2026. Mr. White received an AB from Princeton University, an MPP from Harvard University and a JD from Columbia University.

Steven L. Hoerter

Board Member

Steven L. Hoerter

Board Member

Mr. Hoerter is the CEO and Chairman of MBX Biosciences and has served as a member of Yarrow’s board of directors since April 2026. Previously, Mr. Hoerter served as President and Chief Executive Officer of Deciphera Pharmaceuticals, Inc. (formerly, Nasdaq: DCPH), a biopharmaceutical company, from March 2019 to June 2024, when Deciphera was acquired by ONO Pharmaceutical. He also served as a member of the board of directors of Deciphera from May 2018 to June 2024. Prior to Deciphera, he served as Chief Commercial Officer of Agios Pharmaceuticals, Inc. (Nasdaq: AGIO), a biotechnology company, from February 2016 to March 2019. From August 2011 to March 2015, Mr. Hoerter served as Senior Vice President, Commercial at Clovis Oncology, Inc., a biotechnology company, and from March 2015 to February 2016, he served as Chief Commercial Officer. Prior to that, he held roles of increasing responsibility at F. Hoffman-La Roche, AG, Genentech, Inc. (acquired by Roche), Chiron Corporation (acquired by Novartis AG) and Eli Lilly and Company. Mr. Hoerter has served as a member of the board of directors of ORIC Pharmaceuticals, Inc. (Nasdaq: ORIC) since August 2021, C4 Therapeutics, Inc. (Nasdaq: CCCC) since November 2024 and MBX Biosciences, Inc. (Nasdaq: MBX) since April 2025. Mr. Hoerter previously served on the board of directors of Constellation Pharmaceuticals, Inc. (formerly, Nasdaq: CNST) from September 2018 until it was acquired by MorphoSys AG in July 2021 and Ignyta, Inc. (formerly, Nasdaq: RXDX) from December 2016 until it was acquired by Roche in February 2018. Mr. Hoerter received his BA from Bucknell University, his MBA from Tilburg University and his MS in management from Purdue University.

Peter B. Silverman, JD

Board Member

Peter B. Silverman, JD

Board Member

Mr. Silverman has served as a member of Yarrow’s board of directors since April 2026. Mr. Silverman previously served as Chief Operating Officer of Merus N.V. (formerly, Nasdaq: MRUS), a biotechnology company, from January 2023 until its acquisition by Genmab A/S in December 2025. Prior to serving as Chief Operating Officer, Mr. Silverman held several leadership roles at Merus, including Head of Utrecht from April 2020 to January 2023, General Counsel from February 2018 to December 2025, and Chief Intellectual Property Officer and Head of U.S. Legal from February 2017 to February 2018. Before joining Merus, Mr. Silverman was a Partner at Kirkland & Ellis LLP, an international law firm, where he represented numerous life sciences companies concerning an array of legal matters and technologies. Previously, Mr. Silverman was an associate at Kaye Scholer LLP (now Arnold & Porter Kaye Scholer LLP), and prior to that Mr. Silverman also served as judicial law clerk to U.S. District Court Judge Anne E. Thompson of the District of New Jersey. He holds a JD from Fordham University School of Law and a BA in biology from the University of Rochester.

Rebecca V. Frey, PharmD

President and Chief Executive Officer

Rebecca V. Frey, PharmD

President and Chief Executive Officer

Rebecca Frey is a seasoned biotech leader with 25 years of experience in positions driving drug development from pre-clinical to commercial stage. Prior to joining Yarrow, Dr. Frey served as a venture partner at RTW Investments and the interim CEO of Prolium Bioscience. Prior to RTW, she served as CEO of Siduma Therapeutics. She has previously held key operational leadership roles in emerging biotech companies including EvolveImmune Therapeutics, Cardurion Pharmaceuticals and Prevail Therapeutics. Prior to these roles, she spent 11 years working in medical affairs, development, corporate affairs and manufacturing at Alexion Pharmaceuticals. At Alexion, Dr. Frey spearheaded the development of Soliris® in new indications, which have become multibillion dollar franchises, and contributed to approvals of multiple new rare disease products. Earlier in her career she worked in development and medical affairs at Novartis Pharmaceuticals and was an Assistant Professor at Northeastern University.

In addition to her leadership and operating roles, Dr. Frey also served on the board of Halda Therapeutics, prior to its acquisition by Johnson & Johnson. She also currently serves on the board of Octant Bio. Dr. Frey was recently honored as a Luminary in the BLOC 100 list of the Most Impactful Women of Color & Allies Shaping the Future of Healthcare, Life Sciences & Biopharma.

Dr. Frey earned a Doctorate in Pharmacy from Northeastern University and completed her post-doctoral clinical research fellowship at Tufts Medical Center in the field of organ transplant therapeutics. She additionally holds an Executive Certificate in Management and Leadership from the MIT Sloan School of Management and is Directorship Certified by the National Association of Corporate Directors.

Investors

Founding Investor

LlifeSci Partners