Development, validation and application of the dried blood spot analysis method for the determination of Ustekinumab in patients with Inflammatory bowel disease

Mingas, Panagiotis-Dimitrios (author), Zdovc, Jurij (author), Grabnar, Iztok (author), Drobne, David (author), Vovk, Tomaž (author)

Background: Ustekinumab (UST) is a monoclonal antibody (mAb) used in the treatment of inflammatory bowel disease (IBD). Elevated serum concentrations are typically associated with improved therapeutic outcomes, and therapeutic drug monitoring (TDM) is a useful tool for guiding mAbs treatment. This study aimed to develop a dried blood spot (DBS) method for TDM of UST in patients with IBD. Methods: The commercial enzyme-linked immunosorbent assay for plasma samples was optimized for DBS samples and subsequently validated according to international guidelines for classical and DBS-specific validation parameters. It was then applied to analyze serum and DBS samples obtained from venous and capillary blood of IBD patients undergoing UST therapy. Results: The method was linear (3–12 mg/L) with acceptable inter-day accuracy (90.1–106%) and precision (<12%). We confirmed that there was no hematocrit effect and that DBS samples were stable for one month under room conditions. A linear model was developed between venous DBS and serum UST concentrations, which showed no systemic bias, and 71% of the samples were within ±20% of the mean. In addition, a linear correlation between venous DBS and capillary DBS samples was established, showing no significant bias, with 84% of samples within ±20% of the mean. Finally, a novel strategy was developed to overcome the limitations of poor-quality samples (irregular shapes) based on area image analysis. Conclusions: The newly developed DBS method is the first to enable reliable measurement of UST in capillary blood, appropriate clinical interpretation of the measured concentrations, and remote monitoring of patients in the early phase of therapy.

• Language: English
• Keywords: ustekinumab, dried blood spots, venous blood, capillary blood, validation, inflammatory bowel disease, ELISA
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FFA - Faculty of Pharmacy; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 16 str.
• Numbering: Vol. 18, iss. 9, art. 253
• PID: 20.500.12556/RUL-171532
• UDC: 615.2:616.34-002
• ISSN on article: 1424-8247
• DOI: 10.3390/ph18091253
• COBISS.SI-ID: 246860035
• Publication date in RUL: 28.08.2025

Record is a part of a journal

• Title: Pharmaceuticals
• Shortened title: Pharmaceuticals
• Publisher: MDPI, Molecular Diversity Preservation International
• ISSN: 1424-8247
• COBISS.SI-ID: 517582617

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: ustekinumab, posušene krvne kapljice, venska kri, kapilarna kri, validacija, vnetna črevesna bolezen, kronična vnetna črevesna bolezen

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P1-0189
• Name: Farmacevtska tehnologija: od dostavnih sistemov učinkovin do terapijskih izidov zdravil pri otrocih in starostnikih

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: J3-4499
• Name: MEHANIZMI ODZIVA NA IL 12/23 ZAVIRALCE PRI ULCEROZNEM KOLITISU - NAPROTI PERSONALIZIRANI MEDICINI