A novel approach for quantifying therapeutic monoclonal antibodies in blood through liquid chromatography-tandem mass spectrometry

In AML and CLL, 91% of VAMS venetoclax results fell within 20% of plasma after individualised haematocrit correction; in home sampling, 18 of 21 patients self-sampled independently and 76% of returned samples were analysable, which shows home microsampling is workable, though the authors ask for multicentre validation.

Clinical Validation of Venetoclax Volumetric Microsampling in Leukemia, with Whole-Blood-to-Plasma Conversion and Self-Microsampling Feasibility — Levens et al., Clinical Pharmacokinetics (paywalled) · source ↗

• vams
• venous-agreement
• blood
• dbs
• tdm
• self-collection
• haematocrit
• dried
• oncology
• capillary
• validation

An LC-MS/MS method for tamoxifen and six metabolites in VAMS was developed and validated, with water prerinsing improving recoveries and poor room temperature stability but stability for at least 100 days at minus 80 degrees Celsius. Plasma to blood ratios were used to estimate plasma equivalent concentrations, and paired VAMS and plasma samples from ten breast cancer patients showed strong correlations and good agreement on Bland-Altman analysis, supporting reliable decentralised TDM.

Development and validation of an LC-MS/MS method for the comprehensive quantification of tamoxifen and its metabolites in volumetric absorptive microsampling: clinical application in breast cancer patients — Kuo et al., Analytical and bioanalytical chemistry (paywalled) · source ↗

• blood
• dried
• vams
• neoteryx-mitra
• validation
• venous-agreement
• tdm
• oncology

The study found volumetric absorptive microsampling showed high agreement between capillary and venous concentrations, with 94% of dasatinib and 95% of imatinib samples meeting the 20% acceptance criterion. VAMS is viable for imatinib monitoring and may allow longitudinal follow-up for dasatinib; however, VAMS results for imatinib, but not dasatinib, could be converted to plasma concentrations using prior ratios.

Toward Clinical Implementation of a Volumetric Absorptive Microsampling-Based Method for Dasatinib and Imatinib Therapeutic Drug Monitoring — Verougstraete et al., Therapeutic drug monitoring (paywalled) · source ↗

• blood
• dried
• capillary
• vams
• validation
• venous-agreement
• tdm
• oncology

This study established conversion methods for estimating plasma concentrations from whole blood VAMS samples for seven out of ten oral anticancer drugs, finding good agreement between capillary and venous samples. Patients reported a positive experience with home sampling using this microsampling technique.

Clinical Application of Volumetric Absorptive Microsampling for Therapeutic Drug Monitoring of Oral Targeted Anticancer Drugs — Meertens et al., Therapeutic drug monitoring · source ↗

• vams
• volumetric
• venous-agreement
• acceptability
• blood
• tdm
• self-collection
• dried
• oncology
• capillary
• validation

Microsampling with Mitra® devices correlated strongly with venous plasma for capecitabine therapeutic drug monitoring (r=0.97), but yielded consistently lower concentrations. Patients preferred this method and reported minimal pain, suggesting it is suitable for patient-centric oncology drug monitoring in decentralised settings.

Comparison of capecitabine concentrations determined by microsampling versus plasma concentrations for therapeutic drug monitoring: a pilot study — Shafiei et al., The Journal of pharmacy and pharmacology (paywalled) · source ↗

• blood
• dried
• capillary
• vams
• neoteryx-mitra
• validation
• venous-agreement
• acceptability
• tdm
• oncology