About

Innovation Rare Diseases

X4 Pharmaceuticals is a late-stage clinical biopharmaceutical company and a leader in the discovery and development of novel therapies for the treatment of diseases of the immune system, with a focus on rare diseases and those with limited treatment options.

Our lead clinical candidate, mavorixafor, is a small molecule antagonist of the chemokine receptor CXCR4 being developed as a once-daily, oral therapy. We believe that successfully developing mavorixafor and providing a new therapeutic option for individuals diagnosed with chronic neutropenic disorders and WHIM syndrome has the potential to revolutionize the treatment landscape, which is currently only served by injectable therapies often associated with treatment-limiting side effects.

WHIM syndrome

Following acceptance of our New Drug Application (NDA) to the United States Food and Drug Administration (FDA) for Priority Review, we are currently awaiting approval of once-daily, oral mavorixafor to treat individuals aged 12 and older with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare primary immunodeficiency. The NDA is supported by reported positive results from our global, Phase 3 clinical trial (4WHIM) evaluating the safety and efficacy of mavorixafor in people with WHIM syndrome. The 4WHIM trial met its primary endpoint, a key secondary endpoint, and several exploratory endpoints, and showed mavorixafor to be generally well tolerated.

chronic neutropenic disorders

We are also evaluating mavorixafor in people with a variety of chronic neutropenic disorders. Following positive results from a Phase 1b clinical trial evaluating the safety and efficacy of a single dose of mavorixafor in people with idiopathic, cyclic, or congenital neutropenia, we are conducting a Phase 2 trial evaluating the safety and efficacy of chronic dosing with mavorixafor in the same patient population. We anticipate initiating a Phase 3 clinical trial of mavorixafor in people with certain chronic neutropenic disorders in the first half of 2024.

X4 is a global company headquartered in Boston, Massachusetts with a research center of excellence in Vienna, Austria.

The Boston Globe Top Places To Work 2023 Massachusetts award

core values

Our core values define us and act as guideposts for our thoughts, behaviors, and decisions every day as we strive to innovate for patients.

excellence

Do all things with rigor.

accountability

Hold each other and ourselves accountable for our actions and to live our values.

camaraderie

Work together as a team aligned to achieve our goals and be respectful of each other.

integrity

Act with honesty and transparency.

sense of urgency

Demonstrate a higher sense of purpose: to alleviate human suffering and cure disease.

grit

Move forward with firmness of mind and unyielding courage.

we are tizens!

Management Team

Board of Directors

Mr. Wyzga has served as Chairman of the X4 Board of Directors since July 2018. Mr. Wyzga is currently the President of MSW Consulting Inc., a strategic consulting group focused in the lifesciences area. From December 2011 until November 2013, Mr. Wyzga served as President and Chief Executive Officer and a member of the board of directors of Radius Health, Inc., a publicly traded biopharmaceutical company. Prior to that, Mr. Wyzga served in various senior management positions at Genzyme Corporation, a publicly traded global biotechnology company. Mr. Wyzga joined Genzyme in February 1998 and most recently served as Executive Vice President, Finance from May 2003 until November 2011 and as chief financial officer from July 1999 until November 2011. From February 2014 to December 2018, Mr. Wyzga served as a member of the board of directors of Akebia Therapeutics, Inc., a publicly traded biopharmaceutical company, where he was also a member of the compensation committee and chair of the audit committee.

Since February 2015, Mr. Wyzga has also served as a member of the board of directors of Exact Sciences Corporation, a publicly traded medical technology company, where he is also a member of the audit and compensation committees. Since October 2013, Mr. Wyzga has also served as a member of the board of directors of Oncomed Pharmaceuticals, Inc., where he is also a member of the audit committee. Since February 2016, Mr. Wyzga has also served as Chairman of the board of directors of GenSight Biologics S.A., a Euronext traded biopharmaceutical company. Mr. Wyzga also previously served as a member of the board of directors of Idenix Pharmaceuticals, Inc., a publicly traded biotechnology company that was acquired by Merck in August 2014, where he also served as the chair of the audit committee and a member of the compensation committee, and as a member of the Supervisory Board of Prosensa Holding B.V., a publicly traded biopharmaceutical company, from June 2014 until the Prosensa acquisition by BioMarin Falcon B.V. in December 2014. He received an M.B.A. from Providence College and a B.S. from Suffolk University.

Mr. Aliski has served as a member of the X4 Board of Directors since September 2019. He has more than two decades of biopharmaceutical executive leadership experience at both public and private companies, with significant expertise in global rare disease commercialization, including a particular focus on commercial strategy, pricing, reimbursement and market access. Since 2011, Mr. Aliski has served as an independent consultant to life sciences companies focused on orphan diseases. Prior to 2011, he was Chief Commercial Officer for FoldRX Pharmaceuticals, an early stage company purchased by Pfizer in 2011, served as General Manager for Biomarin Europe, and held executive level positions at Transkaryotic Therapies (TKT)/Shire and Genzyme Corp.

Currently, Mr. Aliski serves as a member of the Boards of Directors of Ultragenyx Pharmaceutical Inc. and Applied Genetic Therapies Corporation. In addition to Mr. Aliski’s current Board appointments, he previously served on the Boards of Edimer Pharmaceuticals, a development stage company backed by Third Rock Ventures, and Scioderm Pharmaceuticals, Inc. (acquired in 2015 by Amicus Therapeutics). Mr. Aliski holds a Master of Public Administration from Harvard University and a Master of Social Planning from Boston College.

Dr. Bridger has served as a member of the X4 Board of Directors since October 2018. From February 2015 to December 2017, Dr. Bridger served as a consultant to Xenon Pharmaceuticals Inc., a biopharmaceutical company, where he previously served as the Executive Vice President of Research and Development from January 2013 to February 2015. From October 2013 to October 2015, Dr. Bridger served as a Managing Director at Five Corners Capital Inc. From June 2010 to June 2012, Dr. Bridger served as a venture partner at Venture West Capital Management, a venture capital firm. From November 2006 to December 2007, Dr. Bridger served as Senior Vice President of Research and Development of Genzyme Corporation, a biotechnology company, which was acquired by Sanofi, S.A. In June 1996, Dr. Bridger co-founded AnorMED Inc., a biopharmaceutical company, and was its Vice President of Research and Development and Chief Scientific Officer from 2000 until its acquisition by Genzyme in November 2006. Dr. Bridger has served on the board of directors of Aquinox Pharmaceuticals, Inc. since 2013.

Dr. Bridger previously served on the board of directors of Alder BioPharmaceuticals, Inc., a biopharmaceutical company, from 2013 to 2016. Dr. Bridger serves on the scientific advisory board of Alectos Therapeutics Inc., a biopharmaceutical company. Dr. Bridger holds a Ph.D. in Organic Chemistry from the University of Manchester Institute of Science and Technology.

Ms. de Craecker has served as a member of the X4 Board of Directors since October 2021 following a distinguished career building multi-functional teams, formulating global commercial strategies for orphan drug and gene therapy products, and successfully launching multiple products across the globe. She also currently serves as an Independent Director of the French biopharmaceutical company GenSight. Previously, she served as General Manager Europe, Middle East, and Africa (EMEA) at AveXis Europe (now a Novartis company), building the team to market, network, and distribute Zolgensma for the treatment of Spinal Muscular Atrophy (SMA) across the region. Prior to that, Ms. de Craecker served as Senior Vice President and General Manager EMEA at Raptor Pharmaceuticals Europe, where she oversaw commercial operations, medical affairs, pharmacovigilance, legal, finance, human resources, and technology operations.

For nearly 15 years, Ms. de Craecker served in roles of increasing responsibility at Shire within their Rare Disease Business Unit, ending her tenure there as Vice President and General Manager Europe, responsible for leading a team developing and launching multiple enzyme replacement therapies. Her previous positions also include Product Manager and Sales roles at Pharmacia, Nutricia, and Smith & Nephew. Ms. de Craecker obtained a master’s degree in Nutrition from the Faculty of Medicine, University of Leuven, Belgium.

Alison Lawton joined the X4 Pharmaceuticals board of directors in October 2020. She has more than 30 years of experience in a wide range of senior executive and operational roles in the industry, with significant expertise across the full spectrum of drug development and commercialization activities. Ms. Lawton currently serves as a special advisor and board member at Kaleido Biosciences, Inc. and as an independent director of ProQR Therapeutics N.V. Previously, she served as Kaleido’s Chief Executive Officer, after initially joining the company as President and Chief Operating Officer.

Prior to her time at Kaleido, Ms. Lawton was a member of X4’s corporate advisory board and served as consulting Chief Operating Officer. She also previously held Chief Operating Officer roles at Aura Biosciences and OvaScience Inc. Prior to this, Ms. Lawton spent more than 20 years at Genzyme Corporation. She served as Senior Vice President and General Manager of Sanofi Biosurgery, a $750 million business that included surgical, orthopedics, cell therapy and regenerative medicine franchises. Earlier, as Senior Vice President of Global Market Access for Genzyme, Ms. Lawton led global functional organizations, including regulatory affairs and quality systems, public policy, health outcomes and strategic pricing, product safety and risk management.

Ms. Lawton began her career at Warner-Lambert/Parke-Davis, where she held several increasingly senior regulatory affairs positions. Additionally, she served two terms as the industry representative on the U.S. Food & Drug Administration’s (FDA) Cell & Gene Therapy Advisory Committee and as Chairman of the Board of the Regulatory Affairs Professional Society (RAPS). Ms. Lawton also previously served as director on the boards of Verastem Inc., Cubist Pharmaceuticals, CoLucid Pharmaceuticals and Magenta Therapeutics. She earned her B.S. in pharmacology from King’s College London.

Mr. McGirr has served as a member of the X4 Board of Directors since September 2017. From March 2013 until June 2014, Mr. McGirr was Senior Advisor to the chief executive officer of Cubist Pharmaceuticals, Inc., a biopharmaceutical company where he also served as Senior Vice President and Chief Financial Officer from November 2002 to March 2013. Prior to joining Cubist in 2002, Mr. McGirr was the President and Chief Operating Officer of hippo inc, an internet technology, venture-financed company. From 1996 to 1999, he was the President of GAB Robins North America, Inc., a risk management company, serving also as Chief Executive Officer from 1997 to 1999. Mr. McGirr was a private equity investor from 1995 to 1996. From 1978 to 1995, Mr. McGirr served in various positions within the S.G. Warburg Group, ultimately as Chief Financial Officer, Chief Administrative Officer and Managing Director of S.G. Warburg & Co., Inc., a position held from 1992 to 1995.

Mr. McGirr is currently a member of the board of directors of Insmed Incorporated, a publicly traded biopharmaceutical company where he has served since October 2013; Rhythm Pharmaceuticals, Inc., a publicly traded biopharmaceutical company where he has served since November 2015; and Menlo Therapeutics, Inc., a publicly traded biopharmaceutical company where he has served since November 2017.

Mr. McGirr also served on the board of directors of Roka Bioscience, Inc., a molecular diagnostics company, from December 2013 to January 2018. Mr. McGirr received a B.Sc. in Civil Engineering from the University of Glasgow and received an M.B.A. from The Wharton School at the University of Pennsylvania.

Dr. Ragan has been X4’s President and Chief Executive Officer and a member of the X4 Board of Directors since July 2014. She has more than 18 years of experience building companies in the biotechnology industry. From August 2012 to September 2014, Dr. Ragan consulted as Chief Business Officer at Lysosomal Therapeutics Inc., a private biopharmaceutical company, where she led the company’s business development activities.

Prior to that, from January 2007 to August 2012, Dr. Ragan held leadership roles in corporate development and operations at Genzyme Corporation, a Sanofi company, where she led strategic partnering efforts for Genzyme’s Rare Disease business and headed the supply chain planning for Genzyme’s flagship commercial products. Other professional roles include business roles at Hydra Biosciences, Oscient Corporation and Celera Corporation. Dr. Ragan received her B.S. from Tufts University and her Ph.D. from Massachusetts Institute of Technology and completed post-doctoral studies at Harvard Medical School.

Dr. Stewart has served as a member of the X4 Board of Directors since March 2019 and recently served as interim Chief Medical Officer of the company. He previously served as Chief Medical Officer of Rhythm Pharmaceuticals, Inc., where he led the successful NDA submission and approval of ImcivreeTM (setmelanotide), an innovative treatment for rare causes of obesity, and as Head of R&D for Novelion Therapeutics Inc., where he oversaw global medical affairs for Juxtapid® and Myalept®, two marketed products for rare metabolic diseases.

Prior to that, Dr. Stewart was Chief Medical Officer at GlaxoSmithKline (GSK), with global responsibility for patient well-being across the vaccine, pharmaceutical, and consumer business units. During his 18-year tenure at GSK, Dr. Stewart also held multiple research and development leadership roles, including Clinical Head of the Biopharma Unit and Therapy Area Head for metabolic and cardiovascular diseases. Prior to his tenure with GSK, he worked as a consultant physician and honorary senior lecturer at the Diabetes Center in Newcastle upon Tyne in the U.K. Dr. Stewart holds an MD from Southampton Medical School and is a Fellow of the Royal College of Physicians.

R. Keith Woods joined the X4 Pharmaceuticals Board of Directors in October 2023, bringing more than 30 years of life science experience spanning sales, global operations, supply chain, business strategy, and rare disease product commercialization. Most recently, he served as Chief Operating Officer of argenx, a company focused on rare diseases, where he helped lead argenx through its transition from an R&D organization to a global commercial organization, successfully implementing and overseeing core commercial and medical teams in preparation for the company’s first product launch. Following his retirement from argenx, Mr. Woods continues to serve as an advisor to the argenx Board of Directors. Mr. Woods also currently serves as a member of the Boards of Directors of Neurogene, Rocket Pharmaceuticals, and TScan Therapeutics.

Mr. Woods previously served in a variety of roles at Alexion Pharmaceuticals, including Vice President and Managing Director of Alexion UK, overseeing all aspects of Alexion’s UK business, and Vice President, U.S. Commercial Operations, ending his tenure there as Senior Vice President of North America Business Operations. Prior to that, he spent more than two decades in roles of increasing responsibility at Roche, Amgen, and Eisai, where he gained valuable experience crafting effective commercial strategies and developing and leading U.S. national sales teams.

Mr. Woods holds a Bachelor of Science degree in marketing from Florida State University.