Management

Paula Ragan, PhD
CEO and President
Dr. Ragan is a founder, as well as the Chief Executive Officer and President of X4. She has more than 18 years of experience building companies in the biotechnology industry. Most recently, Dr. Ragan consulted as Chief Business Officer at Lysosomal Therapeutics Inc (LTI), an Atlas Venture portfolio company, where she led the company’s business development activities. Prior to LTI, Dr. Ragan held leadership roles in corporate development and operations at Genzyme/Sanofi 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 BS in Mechanical Engineering from Tufts University and her PhD from MIT. She completed post-doctoral studies at Harvard Medical School. Read More
Adam Mostafa
Chief Financial Officer
Adam Mostafa is the Chief Financial Officer of X4. Adam has more than 17 years of biotechnology focused corporate finance and transactional experience. As Chief Financial Officer of Abpro Therapeutics he was instrumental to achieving key financing and business development objectives during a period of strong growth. Prior to Abpro, Mr. Mostafa was a Managing Director in the Healthcare Investment Banking group at Cantor Fitzgerald where he had relationship responsibility and led transaction origination and execution across the biotechnology sector. Before Cantor, Mr. Mostafa was a senior banker in the Healthcare Investment Banking group at Needham & Company where he led the execution of numerous biotechnology IPOs, Follow-on Offerings, M&A and other transactions. Prior to Needham, Mr. Mostafa was a Vice President in the Biotechnology Investment Banking group at CRT Capital Group. Earlier in his career, Mr. Mostafa was a Portfolio Management Associate in the Global Stock Selection group at AQR Capital Management, a large global hedge fund. Mr. Mostafa started his career as an analyst in the Healthcare Investment Banking group at Salomon Smith Barney. Mr. Mostafa earned an AB in Economics from Brown University. Read More
Kenneth J Gorelick, MD, FACP, FCCP
Interim Chief Medical Officer
Dr. Gorelick is Interim Chief Medical Officer at X4. He has 30 years of experience in the development of drugs, biologics and medical devices in the human health care sector. Dr. Gorelick has expertise with numerous approvals of BLAs, NDAs and MAAs, and he serves as a consultant to the biopharmaceutical industry. He has held the position of Vice President of Global Clinical Research and Development at Dupont Merck Research Laboratories, Inc. a research-driven pharmaceutical company. He was also Vice President of Drug Development and Chief Medical Officer at Genelabs, a biotechnology company focused on infectious and autoimmune disease. Dr. Gorelick was Clinical Associate Professor of Medicine at Stanford University until 2000. He has a BS from the State University of New York at Buffalo and a MD from Weill Medical College of Cornell University. Dr. Gorelick is Board Certified in Internal Medicine and Pulmonary Diseases and is a Fellow of the American College of Chest Physicians. Read More
Mary DiBiase, PhD
Vice President, Technical Operations and Quality
Dr. DiBiase is Vice President of Technical Operations and Quality at X4. She has more than 20 years of drug development and technical operations experience in both large and small organizations holding leadership roles in technical development, product operations and program management. Prior to X4 she was VP Technical Operations and Program Management at Epirus Biopharmaceuticals, a small biosimilar company working to expand access to biosimilar products across the globe. Other professional roles include VP Product Operations, Specialty Care Business Unit for Pfizer Global Supply, and multiple positions of increasing responsibility at Biogen including Sr Director CMC Management, Program Executive for Avonex® and Associate Director Pharmaceutical Science and Technology. Dr. DiBiase received her PhD from the University of Rhode Island and her B.Pharm. from the University of London. Read More
Celeste DiJohnson
Vice President, Clinical Operations
Ms. Celeste DiJohnson is Vice President of Clinical Operations at X4. Ms. DiJohnson brings over 25 years of industry experience in small and large biotechnology companies and has held senior leadership roles in clinical operations and global program development and has significant success in building and leading high performing clinical development teams with broad organizational impact. She worked in multiple orphan indications in the therapeutic areas of neurology, oncology, and rare disease while at Cephalon, Sanofi Genzyme, and Sarepta, respectively. While at Sarepta, Ms. DiJohnson was instrumental in the development and approval of EXONDYS 51® (eteplirsen injection) for genetic mutations amenable to exon-skipping, which was approved by the FDA for Duchenne Muscular Dystrophy in 2016. Ms. DiJohnson received her BS degree in Biology from Shippensburg University and a Master of Psychology degree from Immaculata University and is active in her community. Read More
Tarek Ebrahim, MD
Vice President Medical Affairs, Rare Disease
Dr. Ebrahim is Vice President Medical Affairs, Rare Disease at X4. He has 17 years of extensive experience in rare diseases and a strong presence among thought leaders in the U.S. and globally. Most recently, as Executive Director, he led the Paroxysmal Nocturnal Hemoglobinuria (PNH) global team in Alexion Pharmaceuticals, where he successfully implemented effective patients’ identification strategies and medical marketing educational programs. Prior to Alexion, he spent 13 years in Genzyme/Sanofi leading U.S. and global multi-disciplinary teams focusing on developing evidence-based data for physicians’ communication and patient engagement in the field of Lysosomal Storage Disorders (LSDs). He supported global medical affairs to develop the first published therapeutic goals and disease management guideline for a rare genetic disease. He managed new product development, integrated product launches and oversaw brand management. At X4, Dr. Ebrahim is leading our medical affairs strategy, patient enrollment engagement and drive key thought leadership partnerships. He earned his bachelor’s degree in medicine and surgery from Alexandria University in Egypt, where he also received training as an anesthesiologist and the designation of Diplomat of Public Health. Read More
Ronny Mosston, MBA
Vice President of Human Resources
Ms. Mosston is the Vice President of Human Resources at X4. She has held leadership positions in leading biotechnology and life sciences companies for over 20 years in Human Resources and Patient Advocacy/Engagement roles for several leading public bio-technology companies in oncology, rare disease and infertility. In addition to senior positions in Millennium Pharmaceuticals, Takeda, and OvaScience, Ms. Mosston has provided consulting services to the Executive Teams of several leading public and private biotechnology companies to help build their Patient Engagement and Human Resources strategies to align with their business and cultural goals. Prior to working in life sciences, she was a Partner and Chief Operating Officer of a Boston based staffing and executive search company which became publicly traded and was acquired by a top global Human Resources consulting companies. She is the past co-chair and serves on the Dana Farber Patient and Family Advisory Council, the Vice Chair of the Joe Andruzzi Cancer Foundation, a founding member of the MassBIO Patient Advocacy Committee and a member of the Healthcare Businesswomen’s Association (HBA). Ms. Mosston received her BS in Biology and her MBA, in Human Resources Management from Boston University and is active in the community. Read More