Toward Clinical Implementation of a Volumetric Absorptive Microsampling-Based Method for Dasatinib and Imatinib Therapeutic Drug Monitoring

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

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

VAMS matched serum for the kinase inhibitors nilotinib, cabozantinib, dabrafenib and ruxolitinib, r 0.94–0.97, with serum reliably predictable for the first three, and 93% of at-home samples were collected correctly: at-home VAMS shown feasible for routine cancer-drug monitoring.

Clinical validation and feasibility of VAMS for monitoring of nilotinib, cabozantinib, dabrafenib, trametinib and ruxolitinib — Zimmermann et al., J. Pharmaceutical and Biomedical Analysis (paywalled) · source ↗

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

Capillary blood collected with the Mitra® device showed correlation with venous samples for paclitaxel therapeutic drug monitoring, but wide confidence intervals suggest the methods may not be interchangeable. While plasma and whole blood concentrations were more closely aligned, the variability raises questions about using self-collected capillary samples for dose individualisation without further validation.

Paclitaxel and Therapeutic Drug Monitoring with Microsampling in Clinical Practice — Radovanovic et al., Pharmaceuticals · source ↗

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