Development and validation of a UPLC-MS/MS method with volumetric absorptive microsampling to quantitate cyclophosphamide and 4-hydroxycyclophosphamide

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 developed and validated a reliable HPLC-MS method for quantifying multiple tyrosine kinase inhibitors from VAMS microsamples of capillary blood, showing acceptable accuracy, precision, and 28-day stability at -21°C, with results comparable to venous plasma in 194 samples from patients with solid tumours. This enables therapeutic drug monitoring using microsamples in oncology practice.

HPLC-MS Quantification of Multiple Tyrosine Kinase Inhibitors in Patients with Solid Tumors: Method Validation and Clinical Application — Staudinger et al., Pharmaceutics (paywalled) · source ↗

• blood
• dried
• capillary
• vams
• neoteryx-mitra
• validation
• tdm
• oncology

A review of 39 studies found that dried blood spot and volumetric absorptive microsampling show promising results for therapeutic drug monitoring of oral targeted anticancer drugs. The authors state that external validation remains crucial to confirm reliability, citing haematocrit effects and sample stability as key challenges.

Advancing Therapeutic Drug Monitoring for Oral Targeted Anticancer Drugs: From Hospital-Based Towards Home-Sampling — Meertens et al., Biomedical Chromatography · source ↗

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

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