Predicting steady-state endoxifen plasma concentrations in breast cancer patients by CYP2D6 genotyping or phenotyping. Which approach is more reliable?

In previous studies, steady-state Z-endoxifen plasma concentrations (ENDOss) correlated with relapse-free survival in women on tamoxifen (TAM) treatment for breast cancer. ENDOss also correlated significantly with CYP2D6 genotype (activity score) and CYP2D6 phenotype (dextromethorphan test). Our aim was to ascertain which method for assessing CYP2D6 activity is more reliable in predicting ENDOss. The study concerned 203 Caucasian women on tamoxifen-adjuvant therapy (20 mg q.d.). Before starting treatment, CYP2D6 was genotyped (and activity scores computed), and the urinary log(dextromethorphan/dextrorphan) ratio [log(DM/DX)] was calculated after 15 mg of oral dextromethorphan. Plasma concentrations of TAM, N-desmethyl-tamoxifen (ND-TAM), Z-4OH-tamoxifen (4OH-TAM) and ENDO were assayed 1, 4, and 8 months after first administering TAM. Multivariable regression analysis was used to identify the clinical and laboratory variables predicting log-transformed ENDOss (log-ENDOss). Genotype-derived CYP2D6 phenotypes (PM, IM, NM, EM) and log(DM/DX) correlated independently with log-ENDOss. Genotype-phenotype concordance was almost complete only for poor metabolizers, whereas it emerged that 34% of intermediate, normal, and ultrarapid metabolizers were classified differently based on log(DM/DX). Multivariable regression analysis selected log(DM/DX) as the best predictor, with patients' age, weak inhibitor use, and CYP2D6 phenotype decreasingly important: log-ENDOss = 0.162 - log(DM/DX) × 0.170 + age × 0.0063 - weak inhibitor use × 0.250 + IM × 0.105 + (NM + UM) × 0.210; (R2  = 0.51). In conclusion, log(DM/DX) seems superior to genotype-derived CYP2D6 phenotype in predicting ENDOss.

Clinical features of seronegative, but CSF antibody-positive, anti-NMDA receptor encephalitis.

OBJECTIVE: To determine the frequency of anti-NMDA receptor encephalitis without detectable serum NMDAR antibodies and to compare the clinical features of these patients with those with NMDAR antibodies in serum and CSF. METHODS: This is a retrospective assessment of serum antibody status and clinical features of 489 patients with anti-NMDAR encephalitis, defined by the presence of NMDAR antibodies in the CSF, and available paired serum/CSF samples examined at Hospital Clínic-Institut d'Investigacions Biomèdiques August Pi I Sunyer, Barcelona, between January 2007 and December 2017. NMDAR antibodies were determined with rat brain immunostaining, in-house cell-based assay (CBA), and a commercial CBA. Patients were considered seronegative if NMDAR antibodies were undetectable with the 3 indicated techniques. RESULTS: Serum NMDAR antibodies were not detected in 75 of 489 (15%) patients. Compared with the 414 seropositive patients, the seronegative were older (23.5 years [interquartile range (IQR): 17-43] vs 20.5 [IQR: 14-31]; p < 0.0001) and less frequently women (39 [52%] vs 313 [76%]; p < 0.001) and had less tumors (6 [9%] vs 128 [32%]; p < 0.001). In multivariate analysis, older age at diagnosis (odds ratio [OR]: 1.35 [per decade]; 95% confidence interval [CI]: 1.10-1.67), absence of tumor (OR: 0.14; 95% CI: 0.05-0.43), and less need for intensive care unit admission (OR: 0.35; 95% CI: 0.18-0.69) were independent variables associated with the absence of serum NMDAR antibodies. Time to diagnosis, treatment with immunotherapy, relapses, and outcome were similar in seronegative and seropositive patients. CONCLUSIONS: NMDAR antibodies are not detected in the serum of 15% of the patients with anti-NMDAR encephalitis. These patients appear to be older and have milder neurologic symptoms with less frequency of tumors.

Oral maintenance metronomic vinorelbine versus best supportive care in advanced non-small-cell lung cancer after platinum-based chemotherapy: The MA.NI.LA. multicenter, randomized, controlled, phase II trial.

BACKGROUND: Oral vinorelbine administered at the maximum tolerated dose has already showed activity and a good safety profile in advanced non-small-cell lung cancer (NSCLC). The MA.NI.LA study was a phase II, multicenter, randomized, controlled trial that aimed to assess the effects of a 'switched maintenance' regimen with oral metronomic vinorelbine (OMV) in patients with NSCLC who had not progressed after first-line platinum-based chemotherapy. PATIENTS AND METHODS: Patients were randomly assigned in a 1:1 ratio to either OMV (50 mg three-times weekly) as maintenance treatment or best supportive care (BSC). The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective disease control rate (DCR, CR + PR + SD), safety and quality of life. RESULTS: In total, 61 and 59 patients were assigned to OMV and BSC, respectively. At a median follow-up of 23.9 (IQR 10.2-38.2) months, patients treated with OMV reported a significantly lower progression rate compared to patient in the BSC arm (89% [54/61] vs 96% [56/58]; HR 0.73; 90% CI 0.53-0.999, p = 0.049). Median PFS for patients treated with vinorelbine was 4.3 months (95% CI 2.8-5.6) vs 2.8 months (95% CI 1.9-4.5) for patients receiving BSC. This benefit was specifically evident in patients aged ≥70 years, in current smokers, and in those who reported disease stabilization as best response to induction chemotherapy. OS and response rate and quality of life were similar in the two arms. Drop-out rate for major toxicity with OMV was unexpectedly high (25%, 14/61) mainly due to grade 3-4 neutropenia (11%, 7/61). Conclusions In patients with unselected NSCLC achieving disease control after platinum-based chemotherapy switch maintenance therapy with OMV prolonged PFS compared to BSC; however, the optimal dose of OMV requires further investigation.

Clinical outcomes of oral metronomic vinorelbine in advanced non-small cell lung cancer: correlations with pharmacokinetics and MDR1 polymorphisms.

PURPOSE: This study investigated correlations of the clinical outcomes of oral metronomic vinorelbine (VNR) with VNR pharmacokinetics and MDR1 polymorphisms. METHODS: Eighty-two patients with metastatic non-small cell lung cancer (NSCLC) unfit for standard chemotherapy were treated with VNR at the oral doses of 20-30 mg every other day or 50 mg three times a week. They had a performance status (PS) ≤ 3, were > 70-year-old and drug-naïve or cisplatin-pretreated. MDR1 2677G > T and 3435C > T polymorphisms were analysed and blood concentrations of VNR and desacetyl-VNR (dVNR: active metabolite) assayed. Overall survival (OS), treatment duration and drug-related toxicity were the main endpoints. RESULTS: Median OS and treatment duration were 27 weeks (range 1.3-183) and 15 weeks (range 1.3-144), respectively. OS was directly correlated with the duration of VNR treatment and number of therapy lines after VNR treatment (multiple linear regression: adjusted r2 = 0.71; p < 0.00001). Neither MDR1 genotypes nor VNR/dVNR concentrations predicted OS. VNR blood levels were positively correlated with platelet counts (r2 = 0.12; p = 0.0036). Patients who had long-term benefit (treated for ≥ 6 month without toxicity) showed lower VNR concentrations than those who had not. Twelve patients stopped therapy due to grade 3-4 toxicity. Toxicity was associated with blood concentrations of VNR ≥ 1.57 ng/mL and dVNR ≥ 3.04 ng/mL, but not with MDR1 polymorphisms. CONCLUSIONS: Neither pharmacokinetic nor pharmacogenetic monitoring seem useful to predict OS. On the other hand, high VNR and dVNR blood levels were associated with severe toxicity.

Oral Metronomic Vinorelbine (OMV) in elderly or pretreated patients with advanced non small cell lung cancer: outcome and pharmacokinetics in the real world.

Background Oral metronomic therapy (OMV) is particularly suitable for palliative care, and schedules adapted for unfit patients are advisable. This study investigated the effects of oral vinorelbine given every other day without interruption and its pharmacokinetic profile in patients with advanced lung cancer. Materials and Methods Ninety-two patients received OMV at doses of 20, 30 or 50 mg. Toxic events, clinical benefit and overall survival were analysed. Blood pharmacokinetics were evaluated in 82 patients. Results Median treatment duration and overall survival were 15 (range 1.3-144) and 32.3 weeks, respectively; fourty-eight (60%) patients experienced clinical benefit. Outcomes were unrelated to previous therapies, age, histology or comorbidities. Toxicity was associated with higher blood concentrations of the drug. Pharmacokinetics were stable for up to two years, and were not influenced by treatment line or age. Conclusions OMV produced non-negligible survival in patients and also showed stable long-term blood concentrations. The schedule of 20-30 mg every other day without interruption gave good tolerability and clinical benefit.

Targeted therapies for advanced and metastatic adenocarcinoma of the gastroesophageal junction: is there something new?

Despite improvements in systemic chemotherapy (CT), the prognosis of metastatic adenocarcinoma of the gastroesophageal junction remains poor. Over the years, new targeting agents have become available and were tested, with or without CT, in first or subsequent lines of therapy. The epidermal growth factor receptor family was targeted with monoclonal antibodies (MoAbs) (trastuzumab, cetuximab, panitumumab) and tyrosin kinase inhibitors (TKIs) (lapatinib, erlotinib, gefitinib). Only trastuzumab, in combination with cisplatin and fluoropyrimidines, significantly improved overall survival (OS) in first-line therapy (13.8 vs. 11.1 months). Angiogenesis also was targeted with MoAbs (bevacizumab and ramucirumab); ramucirumab, a vascular endothelial growth factor-receptor 2 antagonist, enhanced OS in two phase III studies in the first (9.6 vs. 7.4 months) and subsequent lines of treatment (5.2 vs. 3.8 months), while the bevacizumab study was negative. TKIs (sunitinib, sorafenib, regorafenib, apatinib) were tested in this setting in phase II studies in the second/third line, only showing modest antitumor activity. The hepatocyte growth factor receptor (MET) was targeted in untreated patients in a phase III trial with MoAb rilotumumab, with or without CT, but the study was stopped because of mortality excess in the rilotumumab arm. Mammalian target of rapamycin (MTOR) pathway inhibition with everolimus was tested in pretreated patients in a placebo-controlled phase III trial who failed to improve OS (5.4 vs. 4.3 months). In conclusion, considering the modest survival gain obtained overall, the high cost of these therapies and the quality of life issue must be primarily considered in treating these patients.

Germ line polymorphisms as predictive markers for pre-surgical radiochemotherapy in locally advanced rectal cancer: a 5-year literature update and critical review.

PURPOSE: Locally advanced rectal cancer is currently treated with pre-surgical radiotherapy and chemotherapy. Approximately one-half of patients obtain a relevant shrinkage/disappearance of tumour, with major clinical advantages. The remaining patients, in contrast, show no benefit and possibly need alternative treatment. To provide the best therapeutic option for each individual patient, predictive markers have been widely researched. This review was undertaken to evaluate recent progress made in this field. METHODS: A systematic literature search was performed using PubMed and Scopus database, focused on germ line gene polymorphisms as biomarkers and response and toxicity as outcomes. Because an exhaustive previous review was available describing findings up to 2008, we restricted our analysis to the last 5 years. RESULTS: Ten original research articles were found, reporting promising results for some candidate genes in drug metabolism (TYMS, MTHFR), DNA repair (XRCC1, OGG1, CCND1) and inflammation (SOD2, TGFB1)/immunity (IL13) pathways, but with no firm conclusion. All the studies had small sample size and were defined as exploratory. This review highlights pivotal molecular, clinical, genetic and statistical issues in the investigation of genetic polymorphisms as outcome predictors for rectal cancer and offers suggestions for future development. CONCLUSIONS: What emerges is a clear need for new proposals, especially in view of the increasing evidence for tumour-host and gene-gene interactions during anticancer treatment, together with stronger adherence to proper methodological requirements.

Age affects pegylated liposomal doxorubicin elimination and tolerability in patients over 70 years old.

PURPOSE: Pegylated liposomal doxorubicin (PLD) is often used in elderly people, due to its improved tolerability. However, clinical and pharmacological data in the subset of patients over 70 are scanty. METHODS: PLD safety was evaluated in 35 patients (aged ≥70 years) who were treated with PLD as a single agent for 165 cycles. Doxorubicin plasma levels, leukocyte DNA breaks and monocyte count variations were measured as markers of drug exposure, DNA repair capability and reticuloendothelial system activation, respectively. A correlation between these markers and age was sought. RESULTS: Treatment was generally well tolerated. Skin erythrodysesthesia was the most frequent side effect, and no severe (G4) toxicity occurred. PLD plasma half-life generally correlated with age (P < 0.001) and was particularly prolonged in octogenarians (P = 0.005). Doxorubicin clearance significantly declined up to 70 % at cycle 7. DNA breaks increased over the first two cycles (P = 0.007) and were inversely correlated with age (P = 0.007) and directly with clearance (P = 0.006). Pre-treatment monocyte counts increased over cycles (P < 0.001) and were associated with an increase in clearance at cycle 3 (P = 0.015). The hand-foot-skin syndrome was significantly more severe in patients of advanced age or longer PLD half-life. CONCLUSIONS: This study showed (1) increased systemic drug exposure over subsequent cycles; (2) association of age with increased drug exposure, reduced DNA repair capability and worse skin toxicity; (3) a relation between monocyte count and drug clearance.

Equilibrative nucleoside transporter 1 genotype, cytidine deaminase activity and age predict gemcitabine plasma clearance in patients with solid tumours.

AIM: Gemcitabine (GEM) enters normal and tumour cells via concentrative (CNT) and equilibrative nucleoside transporters (ENT) and is subsequently deaminated to the inactive difluorodeoxyurine (dFdU) by cytidine deaminase (CDA). The aim of our study was to ascertain whether the nucleoside transporter genotype and the CDA activity phenotype can predict total GEM plasma clearance. METHODS: Forty-seven patients received GEM 1000-1250mgm(-2) i.v. over 30min. Plasma concentrations of GEM and dFdU were measured and individual pharmacokinetic profiles were determined. CDA activity was measured ex vivo in plasma samples. The two most common hENT1 and hCNT1 polymorphisms were determined from genomic DNA. RESULTS: Multivariate analysis revealed that GEM plasma clearance (CL) was positively correlated with the end of infusion dFdU : GEM ratio (P < 0.0001), which is a marker of in vivo CDA activity. The ENT1 genotype characterized by high transport capacity (G/G) and age were inversely correlated with CL (P= 0.027 and 0.048, respectively). A strong correlation was found between end of infusion GEM concentration and area under the concentration-time curve from time 0 to infinity (AUC(0,∞)) (r(2) = 0.77). CONCLUSIONS: Our results confirm the role of CDA and age on the interindividual variability of GEM CL and show the contribution of the hENT1 genotype for the first time.