Clinical validation study of dried blood spot for determining everolimus concentration in patients with cancer

A. E.C.A.B. Willemsen, L. M. Knapen, Y. M. de Beer, R. J.M. Brüggemann, S. Croes, C. M.L. van Herpen, N. P. van Erp

Onderzoeksoutput: Bijdrage aan tijdschriftArtikelpeer review

19 Citaten (Scopus)


Purpose: Everolimus treatment is seriously hampered by its toxicity profile. As a relationship between everolimus exposure and effectiveness and toxicity has been established, early and ongoing concentration measurement can be key to individualize the dose and optimize treatment outcomes. Dried blood spot (DBS) facilitates sampling at a patients’ home and thereby eases dose individualization. The aim of this study is to determine the agreement and predictive performance of DBS compared to whole blood (WB) to measure everolimus concentrations in cancer patients. Methods: Paired DBS and WB samples were collected in 22 cancer patients treated with everolimus and analyzed using UPLC-MS/MS. Bland-Altman and Passing-Bablok analysis were used to determine method agreement. Limits of clinical relevance were set at a difference of ± 25%, as this would lead to a different dosing advice. Using DBS concentration and Passing-Bablok regression analysis, WB concentrations were predicted. Results: Samples of 20 patients were suitable for analysis. Bland-Altman analysis showed a mean ratio of everolimus WB to DBS concentrations of 0.90, with 95% of data points within limits of clinical relevance. Passing-Bablok regression of DBS compared to WB revealed no constant bias (intercept 0.02; 95% CI 0.93–1.35) and a small proportional bias (slope 0.89; 95% CI 0.76–0.99). Predicted concentrations showed low bias and imprecision and 90% of samples had an absolute percentage prediction error of < 20%. Conclusions: DBS is a valid method to determine everolimus concentrations in cancer patients. This can especially be of value for early recognition of over- or underexposure to enable dose adaptations.

Originele taal-2Engels
Pagina's (van-tot)465-471
Aantal pagina's7
TijdschriftEuropean Journal of Clinical Pharmacology
Nummer van het tijdschrift4
StatusGepubliceerd - 1 apr. 2018
Extern gepubliceerdJa


Duik in de onderzoeksthema's van 'Clinical validation study of dried blood spot for determining everolimus concentration in patients with cancer'. Samen vormen ze een unieke vingerafdruk.

Citeer dit