Determinants of the interindividual variability in serum cytidine deaminase activity of patients with solid tumours.

AIMS: Cytidine deaminase (CDA) activity in cancer patients' serum has been proposed as a predictive biomarker for efficacy and toxicity of nucleoside analogues. However, discrepant results about its predictive value have been reported due to the high interindividual variability in CDA activity. This study aimed at identifying determinants of this interindividual variability. METHODS: From December 2014 to November 2015, 183 patients were prospectively included. Serum CDA activity, biological and clinical characteristics as well as five common single nucleotide polymorphisms (SNPs) in the CDA gene (c.-451C > T, c.-92A > G, c.-33_-31delC, c.79A > C, c.435 T > C) were analysed. Associations between clinical characteristics, pharmacogenetic variants and CDA activity were univariately tested. P < 0.1-candidate variables were analysed through a multivariate analysis. The association between CDA activity and toxicity was assessed for the 56 gemcitabine-treated patients. Intraindividual variability in CDA activity was explored in six pancreatic cancer patients treated with gemcitabine. RESULTS: Median CDA activity was 3.97 U mg-1 (range 1.53-15.49 U mg-1 ). A univariate analysis showed that CDA activity was statistically associated with Eastern Cooperative Oncology Group performance status, mild or severe malnutrition, inflammatory syndrome, leucocyte count, neutrophil count, albumin, C-reactive protein and -c.-33_-31delC single nucleotide polymorphism. A multivariate analysis identified that only neutrophil count (P < 0.0001) and severe malnutrition (P = 0.0278) were independently associated with CDA activity. Low CDA activity (<2 U mg-1 ) was not statistically associated with severe gemcitabine-related toxicities (P = 0.16). A decrease in CDA activity was observed during the longitudinal follow-up of six pancreatic cancer patients treated with gemcitabine (P = 0.03). CONCLUSIONS: These results suggest that neutrophil count and malnutrition should be considered for the interpretation of pretherapeutic CDA activity.

Role of the lean body mass and of pharmacogenetic variants on the pharmacokinetics and pharmacodynamics of sunitinib in cancer patients.

INTRODUCTION: Sunitinib is a multikinase inhibitor active in various cancers types including renal cancers and endocrine tumors. The study analyzed the influence of the lean body mass (LBM) and of pharmacogenetic variants on the exposure to sunitinib and its active metabolite, SU12662, and on sunitinib toxicity and clinical activity. MATERIALS AND METHODS: Exposure to sunitinib and SU12662 was assessed on days 10 and 21 during the first treatment cycle. Acute toxicity was graded using the NCI 4.0 CTCAE ver. 4.0. The LBM and 14 common single nucleotide polymorphisms in the CYP3A4/3A5, NR1I2, NR1I3, ABCB1, and ABCG2 genes were analyzed according to the drug exposure at day 10. Determinants (including sunitinib exposure and pharmacogenetic variants) for toxicities were assessed, as well as the relationship between drug exposure and survival in renal cancer patients. RESULTS: Ninety-two patients (60 % with renal cancer) were assessable for pharmacokinetics, toxicity and survival, and 66 for genetic analysis. The LBM (p < 0.0001) and a polymorphism in the ABCG2 transporter (421C>A) (p = 0.014) were two independent parameters accounting for the variability of composite (sunitinib + SU12662) exposure. Advanced age (OR = 1.47 [1.01-2.15], p = 0.048) and high sunitinib exposure (OR = 1.16 [1.05-1.28], p = 0.005) were independently associated with any grade ≥ 3 acute toxicity, and high SU12662 exposure was associated with grade ≥ 2 thrombocytopenia (OR = 1.27 [1.03-1.57], p = 0.028). A high composite area under the curve (AUC) >1,973 ng/mL∙h at day 21 was associated with a doubled survival (35.2 vs 16.7 months; log-rank p = 0.0051) in renal cancer patients. CONCLUSIONS: This study indicates that LBM and drug monitoring may be helpful in the management of sunitinib-treated patients.

Circulating Biomarkers in Patients With Locally Advanced or Metastatic Renal Cell Carcinoma Treated With Everolimus in the Pre-nephrectomy Setting.

Many drugs are available in renal cell carcinoma (RCC), yet clinicians are still looking for predictive biomarkers of disease recurrence or progression supporting more personalised treatments. An assessment of circulating biomarkers over time was carried out in this French, open-label, single-arm, multicentre trial conducted in 25 patients with either locally advanced (n = 14) or metastatic RCC (n = 11) who received everolimus (10 mg daily) for 6 weeks prior to nephrectomy (NEORAD, NCT01715935). Circulating biomarkers, including circulating tumour cells, haematopoietic and endothelial cells, plasma angiogenesis and inflammatory markers were quantified at baseline, upon everolimus and post-nephrectomy. We assessed tumour burden, objective response rate upon RECIST1.1, disease-free survival (DFS) and progression-free survival (PFS). The correlation between circulating biomarkers was evaluated with multiple factor analysis and biomarker association with DFS/PFS by Cox regression. No objective response rate was obtained before nephrectomy. Upon everolimus, neutrophils, platelets and sVEGFR2 significantly decreased. We did not find any association between circulating biomarkers and DFS/PFS, but patients with the highest tumour burden at baseline had significantly higher plasma levels of interleukin-6, an inflammatory circulating biomarker, and lower levels of sVEGFR2, related to angiogenesis. Further understanding of the link between these circulating biomarkers could help to optimise drug combinations in RCC.

Efficacy of venlafaxine for the prevention and relief of oxaliplatin-induced acute neurotoxicity: results of EFFOX, a randomized, double-blind, placebo-controlled phase III trial.

BACKGROUND: Oxaliplatin neurosensory toxicity is dose limiting and may present as acute symptoms and/or cumulative peripheral neuropathy. PATIENTS AND METHODS: From October 2005 to May 2008, patients with oxaliplatin-induced acute neurotoxicity were randomized into a double-blind study, to receive either venlafaxine 50 mg 1 h prior oxaliplatin infusion and venlafaxine extended release 37.5 mg b.i.d. from day 2 to day 11 or placebo. Neurotoxicity was evaluated using numeric rating scale (NRS) for pain intensity and experienced relief under treatment, the Neuropathic Pain Symptom Inventory and the oxaliplatin-specific neurotoxicity scale. The primary end point was the percentage of patients with a 100% relief under treatment. RESULTS: Forty-eight patients were included (27 males, median age: 67.6 years). Most patients had colorectal cancer (72.9%). Median number of cycles administered at inclusion was 4.5 (mean cumulative oxaliplatin dose: 684.6 mg). Twenty out of 24 patients in arm A (venlafaxine) and 22 out of 24 patients in arm B (placebo) were assessable for neurotoxicity. Based on the NRS, full relief was more frequent in the venlafaxine arm: 31.3% versus 5.3% (P=0.03). Venlafaxine side-effects included grade 1-2 nausea (43.1%) and asthenia (39.2%) without grade 3-4 events. CONCLUSION: Venlafaxine has clinical activity against oxaliplatin-induced acute neurosensory toxicity.

Relation between plasma trough concentration of abiraterone and prostate-specific antigen response in metastatic castration-resistant prostate cancer patients.

BACKGROUND: Abiraterone (ABI) is a major oral agent for the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients but its systemic exposure is subject to a large inter-individual variability. We aimed to explore the relationship between ABI trough plasma concentration and prostate-specific antigen (PSA) response in mCRPC patients and to identify the critical determinants for its activity. PATIENTS AND METHODS: This is a monocentric prospective observational study in mCRPC patients treated with ABI. The plasmatic concentration of ABI at steady state was measured using liquid chromatography with fluorescence detection. The primary objective was to study the relationship between mean ABI plasma exposure (ABI Cmin) and 3-month PSA response. RESULTS: From 2012 to 2016, 61 mCRPC patients were eligible for pharmacokinetic/pharmacodynamic assessment. Thirty-eight patients experienced PSA response (62%, [confidence interval {CI} 95% 50-78]). In univariate analysis, ABI Cmin was 1.5-fold higher in responders: 12.0 ng/mL (CI 95% 9.4-15.6) versus 8.0 ng/mL (CI 95% 5.8-11.6; P = 0.0015). In multivariate analysis, only ABI Cmin was independently associated with PSA response (odds ratio = 1.12 [CI 95% 1.01-1.25], P = 0.004). By receiver operating characteristic analysis, the optimal threshold for ABI Cmin was 8.4 ng/mL. Progression-free survival (PFS) was significantly higher in patients with ABI Cmin above 8.4 ng/mL (hazard ratio 0.55, [CI 95% 0.31-0.99], 12.2 [CI 95% 9.2-19.5] versus 7.4 [CI 95% 5.5-14.7] months otherwise, P = 0.044). CONCLUSIONS: We showed that ABI trough concentration correlates with PSA response and PFS. Moreover, we could determine a cut-off value of plasmatic concentration for PSA response. Altogether, ABI concentration monitoring appears as a new approach to improve clinical outcome in mCPRC patients.