Page 274 - Personalised medicine of fluoropyrimidines using DPYD pharmacogenetics Carin Lunenburg
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Chapter 10
Supplementary Table 2. Comparison of phenotyping assays in performance for prediction of severe fluoropyrimidine-induced toxicity
Clinical validity parameters for the prediction of severe fluoropyrimidine-induced toxicity are shown for the 2-13C-uracil breath test and uracil loading assay. DPYD variant allele carriers were excluded, since DPYD variant allele carriers received an initial dose reduction based on their genotype, and therefore bias could develop in the onset of severe fluoropyrimidine-induced toxicity.
Assay
2-13C-uracil breath test
Oral uracil loading dose
N of patients
74 82
Median (IQR)
DOB50: 161 (145.6-186.3) ‰
U/DHU ratio at 120 min: 0.58 (0.31-1.09)
Cut-off for DPD deficiency
DOB50 ≤128.9 ‰8,9
U/DHU-ratio at 120 min ≥2.46
Sensitivity Specificity NPV PPV F1-scorea
(%) (%)
27 89 7 97
(%) (%) (%)
88 30 29
82 33 11
a The F1-score represents the harmonic mean of sensitivity and PPV.
Supplementary Figure 1. Endogenous uracil levels and endogenous DHU/U ratio plotted against the time between the blood draw and last food intake Abbreviations: DHU: dihydrouracil; U: uracil; vs: versus.
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