J.J. (Jesse) Swen, PharmD, PhD

Area(s) of interest

  • Hospital Pharmacist
  • Associate Professor of Pharmacogenetics
  • Clinical Pharmacologist
  • Head Section Laboratory


I am an associate professor of pharmacogenetics and clinical pharmacist-pharmacologist at the Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center. Currently, I work as chair of the laboratory of the hospital pharmacy.

The long-term central goal of my career is to improve the outcomes of drug treatment by conducting first class biomedical research. To accomplish this goal I am building a research program that aims to improve drug treatment by discovery of novel pharmacogenetic biomarkers and subsequent translation to clinical practice, thereby providing a cornerstone for precision medicine. This work is seamlessly integrated with my work as chair of the pharmacy laboratory. 

I have (co-)authored more than 100 (Web of Science indexed) articles in international peer reviewed scientific journals and several chapters in books. I’m one of the primary investigators of the “Ubiquitous Pharmacogenomics” project (www.upgx.eu). U-PGx aims to implement pharmacogenetics across 7 European sites by genotyping 8,100 patients. In addition I am an active member of the Dutch Pharmacogenetics Working Group and the US Clinical Pharmacogenetics Implementation Consortium.  

Recently I have initiated a novel fundamental research line focusing on elucidating the frequently observed mismatch between the genotype and the capacity of an individual to metabolize drugs (phenotype). This phenomenon is called phenoconversion and presents a significant problem for the clinical implementation of pharmacogenetics. Underlying mechanisms involve both drug-drug interactions as well as disease state. 

Key publications

van der Lee M, Allard WG, Bollen S, Santen GWE, Ruivenkamp CAL, Hoffer MJV, Kriek M, Guchelaar HJ, Anvar SY, Swen JJ. Repurposing of Diagnostic Whole Exome Sequencing Data of 1,583 Individuals for Clinical Pharmacogenetics. Clin Pharmacol Ther 2019. This work is the basis for expanding the number of patients with a pharmacogenetics profile. Based on the results, similar approaches may be used by other medical centers (ongoing in Amsterdam UMC).

Swen JJ, Nijenhuis M, de Boer A, Grandia L, Maitland-van der Zee AH, Mulder H, Rongen GA, van Schaik RH, Schalekamp T, Touw DJ, van der Weide J, Wilffert B, Deneer VH, Guchelaar HJ. Pharmacogenetics: from bench to byte--an update of guidelines. Clinical pharmacology and therapeutics 2011;89:662-73. Foundational work explaining the work of the Dutch Pharmacogenetics Working group on developing PGx guidelines that help clinicians to use PGx test results to guide drug prescribing and dispensing.  

Swen JJ, Nijenhuis M, van Rhenen M, de Boer-Veger NJ, Buunk AM, Houwink EJF, Mulder H, Rongen GA, van Schaik RHN, van der Weide J, Wilffert B, Deneer VHM, Guchelaar HJ. Pharmacogenetic Information in Clinical Guidelines: The European Perspective. Clinical pharmacology and therapeutics 2018;103:795-801. Key paper describing how I envision PGx will change drug prescribing and dispensing in the next decade 

Lunenburg CA, van Staveren MC, Gelderblom H, Guchelaar HJ, Swen JJ. Evaluation of clinical implementation of prospective DPYD genotyping in 5-fluorouracil- or capecitabine-treated patients. Pharmacogenomics 2016;17:721-9 This paper shows that I can successfully implement a PGx strategy in routine patient care.

Lunenburg C, Henricks LM, van Kuilenburg ABP, Mathijssen RHJ, Schellens JHM, Gelderblom H, Guchelaar HJ, Swen JJ. Diagnostic and Therapeutic Strategies for Fluoropyrimidine Treatment of Patients Carrying Multiple DPYD Variants. Genes 2018;9. Paper highlighting the importance and challenges of handling the effects of multiple genetic variant for pharmacogenemics



Leiden University Medical Center
Building 1
Room L-01-019

Albinusdreef 2
2333 ZA Leiden
Tel: 71 526 6125

Postalzone L0-P
P.O. Box 9600
2300 RC Leiden
The Netherlands

E-mail: j.j.swen@lumc.nl