Phenotyping in oncology

Selection of patients who will likely respond or will develop relevant side effects has the potential to improve anticancer therapy. Considering the many contributing factors in drug disposition, we hypothesized that variability in drug disposition could be better explained by phenotype, rather than by the genotype alone. In this thesis, phenotype tests in oncology were studied, with a focus on phenotype breath tests and CYP2D6 metabolism in breast cancer patients using tamoxifen. A review is given of phenotype studies published before 2011 addressing drug metabolizing enzymes in relation to anticancer drugs. The 13C-dextromethorphan-breath test was related to CYP2D6 genotype and serum concentrations of endoxifen, the active metabolite of tamoxifen. A 13C-dextromethorphan breath test was equally predictive of endoxifen levels as compared to the CYP2D6 genotype. We showed that there was no difference in CYP2D6 phenotype between metastasized patients and early breast cancer patients. Because endoxifen levels did not significantly differ between the two groups as well, our findings do not have clinical implications thus far.UBL - phd migration 201

Feasibility and effectiveness of trifluridine/tipiracil in metastatic colorectal cancer: real-life data from The Netherlands

Background: The RECOURSE trial showed clinical efficacy for trifluridine/tipiracil for refractory metastatic colorectal cancer patients. We assessed the feasibility and effectiveness of trifluridine/tipiracil in daily clinical practice in The Netherlands. Methods: Medical records of patients from 17 centers treated in the trifluridine/tipiracil compassionate use program were reviewed and checked for RECOURSE eligibility criteria. Baseline characteristics, safety, and survival times were compared, and prespecified baseline characteristics were tested in multivariate analyses for prognostic significance on overall survival (OS). Results: A total of 136 patients with a median age of 62 years were analyzed. Forty-three patients (32%) did not meet the RECOURSE eligibility criteria for not having received all prior standard treatments (n = 35, 26%) and/or ECOG performance status (PS) 2 (n = 12, 9%). The most common grade ≥3 toxicities were neutropenia (n = 44, 32%), leukopenia (n = 8, 6%), anemia (n = 7, 5%), and fatigue (n = 7, 5%). Median progression-free survival (PFS) and median OS were 2.1 (95% CI, 1.8–2.3) and 5.4 months (95% CI, 4.0–6.9), respectively. Patients with ECOG PS 2 had a worse median OS (3.2 months) compared to patients with ECOG PS 0–1 (5.9 months). ECOG PS, KRAS-mutation status, white blood cell count, serum lactate dehydrogenase, and alkaline phosphatase were prognostic factors for OS. Conclusions: Our data show that treatment with trifluridine/tipiracil in daily clinical practice is feasible and safe. Differences in patient characteristics between our population and the RECOURSE study population should be taken into account in the interpretation of survival data. Our results argue against the use of trifluridine/tipiracil in patients with ECOG PS 2. Funding: Johannes J.M. Kwakman received an unrestricted research grant from Servier

Phenotyping drug disposition in oncology

Personalised Therapeutic

Cholinesterase inhibitor treatment in patients with delirium

Pathophysiology, epidemiology and therapy of agein

SNPs and Haplotypes in DPYD and Outcome of Capecitabine-Letter

Experimentele farmacotherapi

Lapatinib for Advanced or Metastatic Breast Cancer

Personalised Therapeutic

Breath Tests to Phenotype Drug Disposition in Oncology

Experimentele farmacotherapi

Failing hormones

Afdeling Klinische Chemie en Laboratoriumgeneeskunde (AKCL