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The R&D Leadership Team

Our Research & Development Leadership Team


We share an overarching mission: to discover and develop innovative medicines and solutions that transform individuals’ lives and solve the most important unmet medical needs of our time. As Janssen R&D, we work together to harness our combined knowledge and resources, leverage the power and promise of outstanding science and enhance the length and quality of life for people throughout the world.

Research & Development

Research & Development

Judith Hinton Andrew, Rock Composite 22
Judith Hinton Andrew, Rock Composite 22



As Global Head of R&D at the Janssen Pharmaceutical Companies of Johnson & Johnson, Mathai’s mission is to work with the best research and development teams in the world to make meaningful medicines that impact the lives of patients, their families and communities. Mathai practices source-agonistic innovation, leading one of the most powerful, creative and productive teams of professionals in the industry, and greatly valuing partnerships of numerous types with the Life Sciences ecosystem including small and large life science companies, technology companies, universities, venture groups and government. He focuses energy at the intersection of profound unmet medical need and actionable breakthroughs in science and technology to make medicines of unequivocal benefit for humanity.

Prior to joining Janssen in June 2017, Mathai was Senior Vice President at Merck Research Laboratories, responsible for research in the areas of Cardiovascular, Metabolic and Renal Diseases, Oncology/Immuno-Oncology and Immunology. Jointly with his team, he initiated numerous new programs and progressed eight into early clinical development. Prior to Merck, Mathai led R&D at Theravance, a company he co-founded in the San Francisco Bay Area in 1997 based on his work at Harvard University. His talented team of 200 scientists nominated 31 development candidates in 17 years, created four approved products, filed for approval of a fifth and created a pipeline containing many additional development-stage compounds in 2016. In 2014, he and the Theravance Leadership Team separated Theravance into two publicly traded companies: Innoviva (INVA) and Theravance Biopharma (TBPH).

Mathai has more than 150 peer-reviewed publications and patents and serves on various boards and advisory committees. He received his M.D. from Harvard Medical School/Massachusetts Institute of Technology (HST program) and his Ph.D. in Chemistry from Harvard University's Department of Chemistry, working with George Whitesides. He received his Bachelors of Science in Chemistry and Biochemistry from Dalhousie University in Halifax, Nova Scotia.

Mathai Mammen, M.D., Ph.D.

GLOBAL HEAD, Research & Development



As Chief Operating Officer, Development, Janssen R&D, Stef Heylen, M.D., leads Development Management, Operations and Analytics. In addition, he is responsible for the Beerse campus as Managing Director, Janssen Pharmaceutica NV Belgium. In his global role, he oversees the development process overall, as well as essential analytical capabilities (portfolio, statistics, clinical operations), and is accountable for operationalizing and managing the extensive development portfolio.

During his career with Johnson & Johnson (J&J), Stef served with the Johnson & Johnson Innovation Program Office supporting the Johnson & Johnson Chief Scientific Officer in driving meaningful innovation and leveraging innovation capabilities across all sectors of the enterprise. He also was Head of R&D and Chief Medical Officer for Janssen Alzheimer Immunotherapy R&D, LLC, and he developed and implemented an integrated Research and Early Development (RED) Neuroscience strategy for the Beerse, Belgium site as Chief Medical Officer, Johnson & Johnson Pharmaceutical R&D, RED EU. From 2003 to 2007, Stef served as Site Head, Vice President of Development and Chairman of the Development Management Committee for Tibotec, a company acquired by J&J in 2002. During his tenure, two of the company’s HIV medicines were granted accelerated approval.

Before joining Tibotec, Stef was Vice President, Development & Regulatory Affairs at Crucell in Leiden, the Netherlands, and held several senior positions within Janssen including Vice President, Global Regulatory Affairs and Pharmacovigilance, and Vice President, Medical Affairs for the Europe, Middle East and Asia (EMEA) region. He joined the Janssen Research Foundation in 1987 and led the global clinical development of one of the most successful Janssen antipsychotic medicines.

Stef obtained his M.D. at the University of Leuven, Belgium, and the Prince Leopold Institute for Tropical Medicine in Antwerp, Belgium. He is a 1993 recipient of the Dr. Paul Janssen Award for R&D.

Stef Heylen, M.D.

Chief Operating Officer, Development
Janssen Research & Development

As Global Head, Discovery Sciences at Janssen Research & Development, Dash Dhanak, Ph.D. leads an organization responsible for supporting and enabling the discovery and early development of novel small molecule therapeutics.

Prior to joining Janssen, Dash spent 25 years at GlaxoSmithKline (GSK), most recently as Vice President and Head of the Cancer Epigenetics Discovery Performance Unit. Dash received a B.S. in Chemistry from the University Of Manchester Institute of Science and Technology and a Ph.D. from the University of London, both in the United Kingdom. He subsequently carried out postdoctoral research in natural product synthesis at Northwestern University in Illinois, United States prior to joining GSK. In addition, he has published extensively on a variety of drug discovery topics.

Dash is a member of the American Association of Cancer Research Epigenome Task Force, has participated in the American Chemical Society Pharma Leaders Forum, as well as the American Cancer Society Peer Review Committee on Cancer Drug Development and the Multiple Myeloma Research Foundation Peer Review Committee. In addition, he has been an invited speaker at major scientific conferences.

Dash Dhanak , Ph.D.

Global Head, Discovery Sciences

As Global Therapeutic Area Head of Oncology, Peter Lebowitz, M.D., Ph.D. has end-to-end responsibility for Oncology Research & Development, from discovery through development and life cycle management. He leads a global team focused on combining internal and external innovation approaches to discover and develop new solutions for oncologic and hematologic diseases with high unmet medical need.

Prior to taking on the Therapeutic Area Head role, Peter was Head of the Hematologic Malignancy Disease Area. In this role, he was responsible for strategic oversight and execution of the Janssen hematologic malignancy drug discovery and development programs. Before joining Janssen, Peter was Vice President in both early and late-stage clinical development for another leading pharmaceutical company, where he successfully filed 10 Investigational New Drug (IND) applications with the United States Federal Drug Administration (FDA), played a major role in the global registration of three oncology drugs and led major projects from preclinical discovery through pivotal Phase 3 trials.

Prior to joining the industry, Peter was Assistant Professor of Medicine, Division of Hematology/Oncology at the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center in Washington, D.C., where he established an independently funded translational and clinical research program and was a Principal Investigator on numerous clinical research trials. Peter graduated from Harvard University in Cambridge, Massachusetts and earned his M.D. and Ph.D. from the University of Pennsylvania School of Medicine in Philadelphia, Pennsylvania. He then completed his hematology/oncology fellowship at the National Cancer Institute, National Institutes of Health.

Peter Lebowitz, M.D., Ph.D.

Global Therapeutic Area Head, Oncology

James F. List, M.D., Ph.D. is the Global Therapeutic Area Head of Cardiovascular & Metabolism (CVM), leading a global team focused on creating new solutions for improving cardiovascular and diabetes care and disease interception. Jim has end-to-end research and development responsibility for the Janssen CVM portfolio, including drug discovery, clinical development, and external innovation. Jim joined Janssen in 2014.

Prior to joining Janssen, James served with Bristol-Myers Squibb as Vice President, Diabetes Development with responsibility for the diabetes joint venture alliance with AstraZeneca.

Earlier in his career, James was a faculty member of the Harvard Medical School in Cambridge, Massachusetts with clinical responsibilities in General Endocrinology and Thyroid. He graduated from Stanford University in Stanford, California and completed his M.D. and Ph.D. from the University of Minnesota in Minneapolis, Minnesota. He completed his medical training at Brigham and Women’s Hospital, Boston Children’s Hospital and the Massachusetts General Hospital, and is board certified in Internal Medicine, Pediatrics and Endocrinology.

James List, M.D., Ph.D.

Global Therapeutic Area Head, Cardiovascular & Metabolism

The Neuroscience Therapeutic Area is headed by Husseini Manji, M.D., F.R.C.P.C. Husseini was previously Chief, Laboratory of Molecular Pathophysiology & Experimental Therapeutics, National Institutes of Health (NIH), and Director of the NIH Mood and Anxiety Disorders Program, the largest program of its kind in the world. He is also a visiting professor at Duke University in Durham, North Carolina. Husseini received his B.S. (Biochemistry) and M.D. from the University of British Columbia in Vancouver. Following residency training, he completed fellowship training at the National Institute of Mental Health (NIMH) and obtained extensive additional training in cellular and molecular biology at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

The major focus of Husseini’s research has been the investigation of disease- and treatment-induced changes in gene and protein networks that regulate synaptic and neural plasticity in neuropsychiatric disorders. His work has helped to conceptualize these illnesses as genetically influenced disorders of synaptic and neural plasticity, and has led to the investigation of novel therapeutics for refractory patients. He has also been actively involved in the development of biomarkers to help refine these multifactoral diseases into mechanism-based subcategories to develop targeted therapeutics.

Husseini is the recipient of numerous research and clinical awards, including the NIMH Director’s Career Award for Significant Scientific Achievement, the A.E. Bennett Award for Neuropsychiatric Research, the Ziskind-Somerfeld Award for Neuropsychiatric Research, the National Alliance for Research on Schizophrenia and Depression (NARS AD) Mood Disorders Prize, the Mogens Schou Distinguished Research Award, the Joel Elkes Award for distinguished research from the American College of Neuropsychopharmacology (ACNP), the Canadian Association of Professors Award, the Brown University School of Medicine Distinguished Researcher Award, the Depression and Bipolar Support Alliance (DBSA) Klerman Senior Distinguished Researcher Award, the American Federation for Aging Research Award of Distinction and the NIMH award for excellence in clinical care and research.

In addition to his neuroscience research and biomarker and therapeutics development endeavors, Husseini has also been actively involved in medical and neuroscience education undertakings, and has served as a member of the National Board of Medical Examiners (NMBE) Behavioral Science Test Committee, the Howard Hughes Medical Institute Research Scholars Program Selection and Advisory Committee and numerous national curriculum committees.

He founded and co-directed the NIH Foundation for the Advanced Education in the Sciences Graduate Course in the Neurobiology of Neuropsychiatric Illness and received both the NIMH Mentor of the year and NIMH Supervisor of the year awards and the Henry and Page Laughlin Distinguished Teacher Award.

Husseini has published extensively on the molecular and cellular neurobiology of severe neuropsychiatric disorders and the development of novel therapeutics. He was editor of Neuropsychopharmacology Reviews: The Next Generation of Progress, deputy editor of Biological Psychiatry, associate editor of the journal Bipolar Disorders and has been a member of the editorial board of numerous journals. He was inducted into the National Academy of Sciences’ Institute of Medicine (IOM), has been a Councilor of both the ACNP and Society of Biological Psychiatry, co-chairs the NIH Biomarkers Neuroscience Steering Committee, chaired the ACNP’s Task Force on New Medication Development, is a scientific advisor to the One Mind campaign (a public-private partnership that seeks to develop the United States’ first 10-year plan for research in neuroscience), has been named to the board of the International Neuroethics Society and is recent past president of the Society of Biological Psychiatry.

Husseini K. Manji, M.D., F.R.C.P.C.

Global Therapeutic Area Head, Neuroscience

James Merson, Ph.D., is the Global Therapeutic Area Head for Infectious Diseases at Janssen Research & Development, L.L.C. He leads a global team focused on continuously creating and progressing transformational medicines to help fight infectious diseases including influenza, respiratory syncytial virus (RSV), HIV and hepatitis B.

James holds more than 25 years of R&D experience in antivirals, vaccines (prophylactic and therapeutic) and immuno-oncology. Previously at Pfizer, Inc., he held a succession of leadership positions including Chief Scientific Officer of the Vaccine Immunotherapeutics Research Unit, co-leader of Infectious Diseases and Head of their Antiviral Therapeutic Area. Throughout his tenure, James led the development of a series antiviral molecules for the treatment of HIV (CCR5 antagonist) and hepatitis C. He also realized the potential of antibacterial macromolecules and the clinical evaluation of novel broad-spectrum antibiotics.

James is committed to exploring new avenues of research in the fight against infectious diseases. In addition to his antiviral expertise, his research has been focused on immuno-oncology and the combination of vaccines, oncolytic viruses and immunomodulators to treat chronic diseases which include various types of cancers.

He holds a Ph.D. in microbiology and immunology from Baylor College of Medicine, Houston, Texas and a B.A. in biology from Bellarmine College, Louisville, Kentucky. He is a member of the New York Academy of Sciences, the British Society of Immunology and the International Society of Vaccines, and has served on several scientific advisory and company boards.

James Merson, Ph.D.

Global Therapeutic Head,
Infectious Diseases

Sanjaya Singh, Ph.D., is Global Head, Janssen BioTherapeutics within Janssen Research & Development. Sanjaya is responsible for leading an organization focused on biotherapeutic research, discovery, toxicology, clinical pharmacology and strategic external collaboration. In this role, Sanjaya drives the strategy and overall vision to expand and apply the capabilities of Janssen Research & Development to the discovery and development of protein, peptide and cell-based therapeutics.

Sanjaya is an accomplished scientific and business leader with more than 25 years of industry and academic experience. Prior to joining Johnson & Johnson, Sanjaya spent nine years at Boehringer Ingelheim, most recently serving as Vice President, Biotherapeutics Discovery. During his tenure, Sanjaya led a global team responsible for building a competitive and productive pre-clinical and clinical biotherapeutics pipeline. He has successfully led the identification of therapeutic targets in the field of immunomodulation and has developed biologic molecules in the fields of immunology, oncology, ophthalmology, cardio-metabolic and infectious disease.

In the realm of academia, Sanjaya held a faculty position in the Department of Molecular Biology at the Institute of Life Sciences in India. An author of numerous peer-reviewed articles, Sanjaya also is co-author on more than 25 patents.

Sanjaya earned a Ph.D. in Molecular Biology from Banaras Hindu University, Varanasi, Uttar Pradesh, India. He served as a Postdoctoral Fellow in the Department of Molecular Oncology at the University of Texas MD Anderson Cancer Center, Houston, Texas, and as a Research Associate in the Department of Biochemistry and Molecular Biology, also at MD Anderson Cancer Center in Texas.


Global Head, Janssen BioTherapeutics

Richard Tillyer, Ph.D, is Global Head, Discovery and Manufacturing Sciences, Janssen Research and Development. In this role, he leads an integrated discovery and manufacturing sciences organization that comprises all modalities including small molecules, traditional and non-traditional single molecule biologics, and larger, more complex multicomponent biologics including RNA, viruses and cells.

Rich joins Janssen in February 2018 from Merck & Co (MSD outside the United States), where he acquired extensive experience in all stages of drug discovery and product development across numerous therapeutic areas and modalities. During his 25-year tenure, he led large and varying aspects of Merck Research Labs, including Process Chemistry, Toxicology, Drug Metabolism and Pharmacokinetics, Formulation, Biologics and Vaccines Process Development, High Throughput Screening, Discovery Biology, Medicinal Chemistry, Computational Chemistry and various platform groups. Under his leadership, Rich’s teams contributed to the discovery and development of most major products introduced by Merck over the last two decades and significantly advanced the company’s current pipeline. He led or actively contributed to major strategic initiatives including large and small-scale mergers and R&D integrations (most notably, the integration of Schering-Plough announced in 2009).

Rich obtained his Ph.D. in Chemistry from the University of British Columbia, Canada, and a post-doctoral research fellowship in Chemistry from the University of Cambridge, UK. He has published more than 70 scientific articles and publications and he holds several patents.

Richard Tillyer, Ph.D.

Global Head, Discovery and Manufacturing Sciences
Janssen Research & Development

As head of the Global Regulatory Affairs (GRA) within Janssen Pharma, Karin Van Baelen leads an organization of approximately 900 highly qualified colleagues who foster relationships with Health Authorities around the world and deliver innovative healthcare solutions to patients. Under her leadership, the GRA organization influences and interprets global regulatory requirements and enables our company to meet those guidelines. In addition, GRA oversees the development of regulatory strategy for products from all therapeutic areas, as well as the delivery of high-quality, on-time regulatory submissions and approvals. GRA also engages in policy development at national and international levels in the regulatory, biotechnology and clinical development arenas

Previously, Karin served as Vice President of Regional Regulatory Affairs and Global Regulatory Operations, leading activities in Europe, Middle East, Africa, Russia (EMEA), Asia Pacific and Latin America and overseeing the Labeling & Submissions Management organization.  From 2008 to 2013, she led the EMEA Regional Regulatory Affairs team in all regulatory aspects for all therapeutic areas and all operating company regulatory organizations in the region. Karin also served as Vice President of Global Regulatory Affairs for Tibotec BVBA where she created and led its global regulatory team and contributed to the development and approvals of several products in the Janssen Infectious Diseases & Vaccines portfolio. She also worked with GRA at the Janssen Research Foundation and was responsible for the worldwide registrations of several key products, including medications for severe mood disorders and pain. Karin joined Johnson & Johnson in 1993 from Upjohn Benelux where she submitted numerous Marketing Authorization Applications and obtained approvals in Europe and emerging markets.

Karin has a strong record of developing successful leaders and served as the EMEA Diversity & Inclusion regional champion.

Karin obtained her Doctor of Pharmacy (Pharm.D.) degree at the University of Antwerp, Belgium in 1988. Karin serves with the European Federation of Pharmaceutical Industries and Associations’ (EFPIA) Scientific Regulatory & Manufacturing Policy Committee (SRMPC) and with the Pharmaceutical Research and Manufacturers of America’s Regulatory Affairs Coordination Committee (RACC). 

Karin Van Baelen, Pharm. D.

Head, Global Regulatory Affairs

Johan Van Hoof, M.D. received his medical degree (cum laude) from the University of Antwerp, Belgium, in the Department of Anatomy and Embryology at Rijksuniversitair Centrum Antwerpen, Belgium. He studied business management at Krauthammer International School and the International Executive Programme INSEAD, Fontainebleau, France.

Johan joined the Johnson & Johnson Family of Companies in April 2005 as Vice President, Data Management and Early Clinical Development. Following roles as Chief Operating Officer (COO) of Johnson & Johnson Pharmaceutical Research, LLC, and Head of the Global Development Organization, he was appointed Global Therapeutic Area Head for Infectious Diseases & Vaccines in 2010. Since 2011 he has been overseeing research & development at Janssen Vaccines as Managing Director.

Before joining the Johnson & Johnson Family of Companies, Johan acquired more than 20 years of experience in the vaccine industry, having worked with Pasteur Mérieux Connaught, Chiron Vaccines and GlaxoSmithKline (GSK) Biologicals. During this period, he held leadership roles with increasing responsibilities, including Head New Product Development at GSK Biologicals. Johan was actively involved in the development and licensing of a new generation of childhood and adult vaccines in disease areas such as pertussis (pediatric combined vaccines), meningitis, rotaviral diarrhea, hepatitis, flu and HPV.

Johan Van Hoof, M.D.

Global Therapeutic Area Head
IDV, Vaccines
Managing Director
Janssen Vaccines and Prevention, B.V.