Antibody-free quantification of serum infliximab using LC-MS/MS

Area of Science:

• Analytical Chemistry
• Pharmacology
• Immunology

Background:

• Infliximab (IFX) is a key biologic therapy for inflammatory bowel disease (IBD).
• Serum IFX concentrations correlate with IBD clinical outcomes.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers superior selectivity and sensitivity compared to immunoassays.

Purpose of the Study:

• To develop an efficient, antibody-free LC-MS/MS method for quantifying serum IFX levels.
• To validate the method's accuracy and precision.
• To compare LC-MS/MS results with immunoassay findings.

Main Methods:

• Utilized Protein G-coated magnetic beads for IFX and cadonilimab (internal standard) capture from human serum.
• Employed trypsin digestion and selected peptide analysis via LC-MS/MS.
• Compared developed method's results against a standard immunoassay.

Main Results:

• Achieved good peptide specificity with total precision within 10.5%.
• Demonstrated accuracy ranging from 92.8% to 97.6% within the 0.5-100 mg/L linear range.
• Showed agreement between LC-MS/MS and immunoassay results for sample analysis.

Conclusions:

• The developed LC-MS/MS method provides a more sensitive and robust determination of IFX compared to existing analytical techniques.
• This method holds significant potential for therapeutic drug monitoring in IBD.
• The approach may facilitate the development of individualized treatment strategies for IBD patients.