Gaëlle Noé

Drug interactions with solid tumour-targeted therapies

Drug interactions are an on-going concern in the treatment of cancer, especially when targeted therapies, such as tyrosine kinase inhibitors (TKI) or mammalian target of rapamycin (mTOR) inhibitors, are being used. The emergence of elderly patients and/or patients with both cancer and other chronic co-morbidities leads to polypharmacy. Therefore, the risk of drug-drug interactions (DDI) becomes a clinically relevant issue, all the more so as TKIs and mTOR inhibitors are essentially metabolised by cytochrome P450 enzymes. These DDIs can result in variability in anticancer drug exposure, thus favouring the selection of resistant cellular clones or the occurrence of toxicity. This review provides a comprehensive overview of DDIs that involve targeted therapies approved by the FDA for the treatment of solid tumours for more than 3 years (sorafenib, sunitinib, erlotinib, gefitinib, imatinib, lapatinib, everolimus, temsirolimus) and medicinal herb or drugs. This review also provides some guidelines to help oncologists and pharmacists in their clinical practice.

Dimethyl fumarate controls the NRF2/DJ-1 axis in cancer cells: therapeutic applications.

The transcription factor NRF2 (NFE2L2), regulates important antioxidant and cytoprotective genes. It enhances cancer cell proliferation and promotes chemoresistance in several cancers. Dimethyl fumarate (DMF) is known to promote NRF2 activity in noncancer models. We combined in vitro and in vivo methods to examine the effect of DMF on cancer cell death and the activation of the NRF2 antioxidant pathway. We demonstrated that at lower concentrations (<25 μmol/L), DMF has a cytoprotective role through activation of the NRF2 antioxidant pathway. At higher concentrations, however (>25 μmol/L), DMF caused oxidative stress and subsequently cytotoxicity in several cancer cell lines. High DMF concentration decreases nuclear translocation of NRF2 and production of its downstream targets. The pro-oxidative and cytotoxic effects of high concentration of DMF were abrogated by overexpression of NRF2 in OVCAR3 cells, suggesting that DMF cytotoxicity is dependent of NRF2 depletion. High concentrations of DMF decreased the expression of DJ-1, a NRF2 protein stabilizer. Using DJ-1 siRNA and expression vector, we observed that the expression level of DJ-1 controls NRF2 activation, antioxidant defenses, and cell death in OVCAR3 cells. Finally, antitumoral effect of daily DMF (20 mg/kg) was also observed in vivo in two mice models of colon cancer. Taken together, these findings implicate the effect of DJ-1 on NRF2 in cancer development and identify DMF as a dose-dependent modulator of both NRF2 and DJ-1, which may be useful in exploiting the therapeutic potential of these endogenous antioxidants. Mol Cancer Ther; 16(3); 529–39. ©2017 AACR.

TGF-β2 induces Grb2 to recruit PI3-K to TGF-RII that activates JNK/AP-1-signaling and augments invasiveness of Theileria-transformed macrophages.

Theileria-infected macrophages display many features of cancer cells such as heightened invasive capacity; however, the tumor-like phenotype is reversible by killing the parasite. Moreover, virulent macrophages can be attenuated by multiple in vitro passages and so provide a powerful model to elucidate mechanisms related to transformed macrophage virulence. Here, we demonstrate that in two independent Theileria-transformed macrophage cell lines Grb2 expression is down-regulated concomitant with loss of tumor virulence. Using peptidimer-c to ablate SH2 and SH3 interactions of Grb2 we identify TGF-receptor II and the p85 subunit of PI3-K, as Grb2 partners in virulent macrophages. Ablation of Grb2 interactions reduces PI3-K recruitment to TGF-RII and decreases PIP3 production, and dampens JNK phosphorylation and AP-1-driven transcriptional activity down to levels characteristic of attenuated macrophages. Loss of TGF-R>PI3-K>JNK>AP-1 signaling negatively impacts on virulence traits such as reduced JAM-L/ITG4A and Fos-B/MMP9 expression that contribute to virulent macrophage adhesion and invasiveness.

Development and validation of a clinical HPLC method for the quantification of hydroxychloroquine and its metabolites in whole blood

Background: Therapeutic drug monitoring for hydroxychloroquine (HCQ) has been suggested to assess nonadherence and optimize treatment efficacy in systemic lupus erythematosus patients. Materials & methods: After protein precipitation, HCQ and its metabolites, desethylhydroxychloroquine and desethylchloroquine were separated on a phenyl column and monitored by fluorescence detection. The method was linear from 50 to 4000 ng/ml for HCQ. The intra-day and inter-day precision of HCQ, desethylhydroxychloroquine and desethylchloroquine ranged from 4.3 to 10.3%. LLOQ was 50 ng/ml for HCQ. Conclusion: The method is very practical and was applied to routinely monitor the steady state whole blood exposure of HCQ and its metabolites in systemic lupus erythematosus patients. It well correlated with our LC–MS/MS and another HPLC method.

A simple HPLC-UV method for quantification of enzalutamide and its active metabolite N-desmethyl enzalutamide in patients with metastatic castration-resistant prostate cancer

Enzalutamide is currently approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). To date, a single liquid chromatographic-tandem mass spectroscopy method is available to measure plasma enzalutamide concentrations in mCRPC patients. In this work, an accurate and sensitive HPLC-UV method has been developed for the simultaneous determination of enzalutamide and its active metabolite, N-desmethyl enzalutamide in plasma from mCRPC patients. Before precipitation of proteins with acetonitrile, samples were spiked with nilutamide (internal standard). Separation of analytes was achieved under isocratic elution on a C18 Kinetex column. The mobile phase consisted of a mixture of ammonium acetate buffer (pH=4.6, 20mM) and acetonitrile (60:40, v/v), and was delivered at a flow rate of 1.5mL/min throughout a 9-min run. UV detection was performed at 270nm. The method was linear over a concentration range of 0.50-50.0μg/mL for both analytes. Within- and between-day imprecision and accuracy were ≤10% at concentrations 0.75, 5.00, and 50.0μg/mL. This method has been implemented to assay steady-state trough plasma concentrations (n=30) of enzalutamide and N-desmethyl enzalutamide in 16 mCRPC patients. Overall, this HPLC-UV method is well-suited for routine application in clinical laboratories to perform therapeutic drug monitoring of enzalutamide in mCRPC patients.

Potential drug–drug interactions with abiraterone in metastatic castration-resistant prostate cancer patients: a prevalence study in France

PurposeAbiraterone acetate combined with prednisone improves survival in metastatic castration-resistant prostate cancer (mCRPC) patients. This oral anticancer agent may result in drug–drug interactions (DDI). We aimed to evaluate the prevalence of DDI with abiraterone and the possible determinants for the occurrence of these DDI.MethodsWe performed a single centre retrospective review from electronic medical records of mCRPC patients treated with abiraterone from 2011 to 2015. Potential DDI with abiraterone were identified using Micromedex and were categorized by a 4-point scale severity.ResultsSeventy-two out of ninety-five mCRPC pts (median age: 77 years [68–82]) had comorbidities. The median number of drugs used per patient was 7 [5–9]. 66 potential DDI with abiraterone were detected in 49 patients (52%): 39 and 61% were classified as major and moderate DDI, respectively. In the univariate analysis, pain (p < 0.0001), hypo-albuminemia (p = 0.032), and higher ECOG performance status (PS) (p = 0.013) were significantly associated with a higher risk of DDI with abiraterone. Pain (p < 0.0001) and PS (p = 0.018) remained significant in the multivariate analysis.ConclusionsPolypharmacy is an issue among mCRPC patients. In our study, half of the patients have potential DDI with abiraterone. Patients with pain and poor PS are at higher risk of DDI with abiraterone. A medication review by a pharmacist is of crucial importance to prevent DDI with abiraterone.

Development and validation of an ELISA method for the quantification of nivolumab in plasma from non-small-cell lung cancer patients

HIGHLIGHTSThis study describes a sensitive and accurate ELISA method for quantification of nivolumab in human plasma.Plasma concentration of nivolumab was assayed in non‐small‐cell lung cancer patients.The assay is applicable to investigate pharmacokinetics of nivolumab and its PK/PD relationship.Endogenous IgG level contributes to the interindvidual variability in nivolumab pharmacokinetics. ABSTRACT Nivolumab, an anti PD‐1 monoclonal antibody, has been approved for the treatment of previously treated advanced or metastatic non‐small‐cell lung cancer (NSCLC). The aim of this study was to develop and validate an ELISA method for the quantification of nivolumab in plasma from patients with NSCLC in order to perform future pharmacokinetic/pharmacodynamic (PK/PD) studies. A home‐made ELISA was developed and validated according to the general recommendations for the immunoassays. Then, the ELISA method was applied to quantify plasma trough levels (Cmin) of nivolumab (3 mg/kg every two weeks) in 27 NSCLC patients at days 14, 28 and 42 after start of treatment. Blood samples were collected just before the infusion on days 0 (baseline), 14, 28 and 42 after start of treatment. The dynamic calibration range for nivolumab assay was 5–100 &mgr;g/mL. Within‐ and between‐day imprecision for quality controls (5, 20 and 75 &mgr;g/mL) were less than 5 and 12%, respectively. The mean (± standard deviation) nivolumab Cmin was 17.3 ± 4.8 &mgr;g/mL (coefficient of variation, CV = 27.8%), 25.0 ± 9.7 &mgr;g/mL (CV = 38.8%) and 33.0 ± 12.9 &mgr;g/mL (CV = 39.1%) on days 14, 28 and 42, respectively. IgG (p = 0.002) and ALT (p = 0.041) were independently associated with plasma nivolumab Cmin at day 42. The present ELISA method for quantification of nivolumab in plasma from NSCLC patients is sensitive and accurate enough to be used for further PK/PD investigations.

Plasma vemurafenib exposure and pre-treatment hepatocyte growth factor level are two factors contributing to the early peripheral lymphocytes depletion in BRAF-mutated melanoma patients.

The therapeutic response to vemurafenib, a BRAF serine-threonine kinase inhibitor, exhibits large variations between patients. Evaluation of factors predicting the clinical efficacy of vemurafenib may help to identify patients at high risk of non-response in the early phase of treatment. The aim of this study was to analyze the pharmacokinetics of vemurafenib by a population approach and to evaluate the relationship between plasma drug exposure and pre-treatment plasma hepatocyte growth factor (HGF) levels with clinical effects (progression-free survival (PFS), peripheral lymphocytes depletion) in patients with metastatic BRAFV600 mutated melanoma treated with single agent vemurafenib. Concentration-time data (n=332) obtained in 44 patients were analyzed using the NONMEM program. Pre-treatment plasma levels of HGF (n=36) were assayed by ELISA method. A Cox model was used to identify prognostic factors associated with progression-free survival (PFS), and a linear regression to identify factors contributing to the depletion of peripheral lymphocytes at day 15. Steady-state pharmacokinetics of vemurafenib was described by a one compartment model with first order absorption and first order elimination. None of the tested covariates explained the inter-patient variability in CL/F. A significant decrease in total lymphocytes count was observed within the first 15days (median ratio Day15/Day0=0.66, p<0.0001). Patients with Day15/Day0 ratio below 0.66 had longer PFS (14 vs 4 months, HR=0.41, CI95%=[0.15-0.77], p=0.0095). In the multivariate Cox model analysis, ECOG PS was the only parameter independently associated with PFS (grade 1 vs 0, HR=3.26, CI95%=[1.29-8.22], p=0.01 and grade ≥2 vs 0, HR=4.77, CI95%=[1.52-14.95], p=0.007). Plasma vemurafenib exposure (p=0.046) and pre-treatment HGF levels (p=0.003) were independently associated with the total lymphocyte ratio Day15/Day0. These findings show that plasma vemurafenib exposure and pre-treatment HGF levels are two factors contributing to the early peripheral lymphocytes depletion which itself is associated with PFS.

Soluble VEGFR‐1: A new biomarker of sorafenib‐related hypertension

Dear Editor, In a recent issue of The Journal of Clinical Pharmacology, we read with interest the paper by Thomeas et al which evaluated the biological reproducibility and estimated relevant covariates for candidate circulating biomarkers of angiogenesis. The study examined VEGF-A, soluble VEGFR2, and angiopoietin 2 after exposure to sorafenib (Nexavar, a pan-VEGFR tyrosine kinase inhibitor, VEGFR-TKI). The authors concluded that technical considerations in the measurement of these circulating biomarkers by ELISA can significantly affect results and limit their use in clinical practice. The measurement of soluble VEGFR-1 (sVEGFR1), another biomarker of angiogenesis, is now available with an automated method allowing one to assay plasma sVEFGR-1 levels in “real time,” and with reproducible results. We observed that sVEGFR1 could be an interesting biomarker in a cohort of patients with advanced solid tumors treated with sorafenib, as it was related to grade 2 hypertension. The present population represents a subgroup of a clinical study previously published. A longitudinal follow-up including assessment of plasma sVEGFR-1 and sorafenib concentrations was conducted. Blood samples were collected on days (D) 0, 15, 30, and 60 after sorafenib initiation, meanwhile hypertension was prospectively graded according to the European Society of Hypertension (ESH) guidelines. Sorafenib and sVEGFR-1 concentrations in plasma were assessed by using liquid chromatography and an automated chemiluminescent immunoassay (Roche, Elecsys, and Cobas, Switzerland), respectively. Forty-one adult patients (30men and 11women)with a median age of 60 years (interquartile range 50–73) were explored. Sixteen patients (39%) experienced grade 2 hypertension during the follow-up period. Between D0 and D15 after sorafenib initiation, mean sVEGFR-1 concentrations decreased by 25% (80.7 30.4 ng/mL vs. 55.8 14.6 ng/mL, P1⁄4 .03). No significant variation in sVEGFR-1 concentrations was observed thereafter. Baseline sVEGFR1 levels were not predictive for developing grade 2 hypertension (P1⁄4 .42). A lower plasma sVEGFR-1 concentration during the follow-up period was associated with grade 2 hypertension The Journal of Clinical Pharmacology 2015, 55(4) 478–479

Lithium effects on serine-threonine kinases activity: High throughput kinomic profiling of lymphoblastoid cell lines from excellent-responders and non-responders bipolar patients

Abstract Objectives: Lithium is the leading mood stabiliser for maintenance treatment in bipolar disorder (BD). However, response to lithium is heterogeneous with more than 60% of patients experiencing partial or no response. In vitro and in vivo molecular studies have reported the implication of kinases in the pathophysiology of BD. Methods: Since kinases are putative targets for lithium therapeutic action, we conducted the first pilot study using kinase array technology to evaluate the global serine/threonine kinases (STK) profiles in cell lines from BD I subtype patients classified as lithium excellent-responders (ER) and non-responder (NR) to lithium treatment. Results: We found significant differences in the basal STK profiles between ER and NR to lithium. We also tested lithium influence on the global STK profile and found no significant difference between ER vs NR cell lines. Conclusions: The results obtained in this exploratory study suggest that multiplex kinase activity profiling could provide a complementary approach in the study of biomarkers of therapeutic response in BD.