Audrey Thomas-Schoemann

Early Sorafenib-Induced Toxicity Is Associated with Drug Exposure and UGTIA9 Genetic Polymorphism in Patients with Solid Tumors: A Preliminary Study

Background Identifying predictive biomarkers of drug response is of key importance to improve therapy management and drug selection in cancer therapy. To date, the influence of drug exposure and pharmacogenetic variants on sorafenib-induced toxicity remains poorly documented. The aim of this pharmacokinetic/pharmacodynamic (PK/PD) study was to investigate the relationship between early toxicity and drug exposure or pharmacogenetic variants in unselected adult outpatients treated with single-agent sorafenib for advanced solid tumors. Methods Toxicity was recorded in 54 patients on days 15 and 30 after treatment initiation and sorafenib exposure was assessed in 51 patients. The influence of polymorphisms in CYP3A5, UGT1A9, ABCB1 and ABCG2 was examined in relation to sorafenib exposure and toxicity. Clinical characteristics, drug exposure and pharmacogenetic variants were tested univariately for association with toxicities. Candidate variables with p<0.1 were analyzed in a multivariate analysis. Results Gender was the sole parameter independently associated with sorafenib exposure (p = 0.0008). Multivariate analysis showed that increased cumulated sorafenib (AUCcum) was independently associated with any grade ≥3 toxicity (p = 0.037); UGT1A9 polymorphism (rs17868320) with grade ≥2 diarrhea (p = 0.015) and female gender with grade ≥2 hand-foot skin reaction (p = 0.018). Using ROC curve, the threshold AUCcum value of 3,161 mg/L.h was associated with the highest risk to develop any grade ≥3 toxicity (p = 0.018). Conclusion In this preliminary study, increased cumulated drug exposure and UGT1A9 polymorphism (rs17868320) identified patients at high risk for early sorafenib-induced severe toxicity. Further PK/PD studies on larger population are warranted to confirm these preliminary results.

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.

Arsenic Trioxide Exerts Antitumor Activity through Regulatory T Cell Depletion Mediated by Oxidative Stress in a Murine Model of Colon Cancer

Immunotherapy is a promising antitumor strategy that can successfully be combined with current anticancer treatment. In this study, arsenic trioxide (As2O3) was shown to increase the antitumor immune response in CT26 colon tumor-bearing mice through the modulation of regulatory T cell (Treg) numbers. As2O3 induced Treg-selective depletion in vitro. In vivo, tumor-bearing mice injected with 1 mg/kg As2O3 showed a significant decrease in the Treg/CD4 cell ratio and in absolute Treg count versus controls. As2O3 exerted antitumor effects only in immunocompetent mice and enhanced adoptive immunotherapy effects. Inhibition of As2O3-induced Treg depletion by the NO synthase inhibitor NG-nitro-l-arginine methyl ester and the superoxide dismutase mimic manganese [III] tetrakis-(5, 10, 15, 20)-benzoic acid porphyrin suggested that it was mediated by oxidative and nitrosative stress. The differential effect of As2O3 on Treg versus other CD4 cells may be related to differences in the cells’ redox status, as indicated by significant differences in 2′7′dichlorodihydrofluorescein diacetate and 4,5-diaminofluorescein diacetate fluorescence levels. In conclusion, these results show for the first time, to our knowledge, that low doses As2O3 can delay solid tumor growth by depleting Tregs through oxidative and nitrosative bursts, and suggest that As2O3 could be used to enhance the antitumor activity of adoptive immunotherapy strategies in human cancer.

An HPLC-UV method for the simultaneous quantification of vemurafenib and erlotinib in plasma from cancer patients.

Vemurafenib and erlotinib are two oral kinase inhibitors approved for the treatment of metastatic melanoma and advanced non-small cell lung cancer, respectively. In contrast with erlotinib, the single published method for analysis of vemurafenib in human plasma is based on mass spectrometry. The purpose of the present study was to develop an HPLC-UV method to simultaneously quantify these two drugs in plasma. Following liquid-liquid extraction, vemurafenib, erlotinib and sorafenib (internal standard) were separated isocratically on a C8 Xterra(®) MS using a mobile phase of glycine buffer (pH 9.0, 100mM)/acetonitrile (45:55, v/v). Samples were eluted at a flow rate of 0.9mL/min throughout the 12-min run. Dual UV wavelength mode was used, with vemurafenib and sorafenib monitored at 249nm, and erlotinib at 331nm. The calibration was linear in the range 1.25-100mg/L and 50-4000μg/L for vemurafenib and erlotinib, respectively. Inter- and intra-day precision was less than 6.7% and 6.6% for vemurafenib and erlotinib, respectively. This analytical method was successfully applied to assess the steady state plasma exposure of these drugs in cancer patients. This accurate method can be used in routine clinical practice to monitor vemurafenib or erlotinib concentrations in plasma from cancer patients.

Tumor invasion induced by oxidative stress is dependent on membrane ADAM 9 protein and its secreted form

Oxidative stress plays a role in the regulation of cancer cell metastasis which involves cell invasion and adhesion that could be supported by ADAM proteins through the activities of their metalloprotease and disintegrin domains. We hypothesized that oxidative stress could act through the induction of ADAM9 protein in some cancer cells. Indeed, Western blot analysis for ADAM9 performed on A549 cells exposed to H2O2 reveals a dose‐dependent induction of two proteins (80 and 68 kDa) correlated with a sharp increase of the ADAM protease activity measured in supernatant while the activity measured on the cell layer was slightly affected. The 80kDa protein corresponds to the mature form of ADAM9. Immunoprecipitation analysis performed on concentrated supernatants revealed that the 68 kDa protein is a secreted form of ADAM9. When exposed to H2O2, A549 cells cocultured with confluent endothelial vascular cells resulted in a 5.5 fold (p < 0.001) increase in the number of adherent cells. Similarly, matrigel assay revealed a 3.25 fold (p < 0.01) increase in the number of invasive cells. The suppression of ADAM9 expression by specific small interfering RNA reduced oxidative stress‐induced invasiveness and adhesiveness. These functions could be mediated by an interaction between ADAM9 and β1 integrin because each of them were inhibited when the experiment is performed in presence of mAbs targeting ADAM9 ectodomain or β1‐integrin. These results emphasize the importance of oxidative stress in the regulation of cancer cell metastasis and suggest that ADAM9 and its secreted isoform can be important determinants in the ability of cancer cells to disseminate.

Effect of glucuronidation on transport and tissue accumulation of tyrosine kinase inhibitors: consequences for the clinical management of sorafenib and regorafenib

Introduction: UDP-glucuronosyltransferases (UGTs) are a multigenic family of enzymes responsible for the glucuronidation reaction. Many therapeutic classes of drugs used in solid tumors are UGT substrates, including cancer therapies. Areas covered: This article describes the tyrosine kinase inhibitors (TKIs) undergoing hepatic glucuronidation; its effect on transport and tissue accumulation and the clinical consequences of this particular metabolism. A PubMed search concerning the pharmacokinetics of the TKIs was performed. All are extensively metabolized by CYP450. Two TKIs, sorafenib and regorafenib, also have a major UGT-mediated metabolism and were therefore studied. Expert opinion: The prescription of the same dose of sorafenib and regorafenib for all patients may be inappropriate since at each enzymatic step of this multistep metabolism inter-individual fluctuations exist. Having a non-exclusive CYP-mediated route of metabolism may reduce the risk of variability in drug exposure when CYP3A4 substrates are concomitantly given. Several clinical consequences derive from this pharmacokinetic particularity of sorafenib and regorafenib. Since no clear difference distinguishes TKIs in efficacy in large randomized trials, the differences for the clinical management of their toxicity is a critical aspect.

Drug safety evaluation of sorafenib for treatment of solid tumors: consequences for the risk assessment and management of cancer patients

Introduction: Sorafenib is a multi-tyrosine kinase inhibitor (TKI). Considerable clinical experience has been accumulated since its first Phase III clinical trial in metastatic renal cancer patients in 2007. The management of its early acute toxicity in fit patients is well known. The management of prolonged treatment becomes the new challenge. Areas covered: Using sorafenib as a key word for PubMed search, we review preclinical and clinical data and discuss the pharmacokinetics and pharmacodynamics of sorafenib, its acute and cumulative toxicities and their consequences for patient management. Expert opinion: The systematic multi-disciplinary risk assessment of cancer patients prior to TKI initiation reduces the risks of acute and late toxicity, especially drug–drug interactions and arterial risks. Sarcopenia is now identified as a major risk of severe toxicity. The very diverse clinical pictures of cumulative toxicity must be known. The monitoring of sorafenib systemic exposure is helpful especially in elderly patients. Moreover, at disease progression, it allows distinguishing between underexposure to sorafenib and truly acquired resistance to the drug. The optimal use of sorafenib should allow improving the reported results of flat-dose. Finally, most of this knowledge could be used for the development and optimal use of the other TKIs.

Bystander effect of vinorelbine alters antitumor immune response.

The bystander effect (BE) is the ability of malignant cells affected by an anticancer agent to induce damage in neighboring cancer cells. In this study, we showed that it could also affect immune cells surrounding the tumor and interfere with the antitumor immune response. We observed that the exposure of human lung cancer cells A549 to vinorelbine induced a BE on neighboring human peripheral blood mononuclear cells (PBMCs) in vitro and on mice splenocytes in vivo. In vitro, the number of PBMCs killed because of their coculture with vinorelbine‐pretreated A549 cells was 33% higher than those killed by A549 control cells (p = 0.003). In addition, we showed that when vinorelbine‐pretreated A549 cells were injected into immunocompetent mice, splenocyte proliferation ex vivo toward tumor cells decreased by 27% compared with that seen in mice injected with untreated A549 cells (p = 0.03). Finally, in vivo experiment in A549 tumor bearing nude mice showed that adoptive transfer of A549 immune splenocytes was not able to delay tumor growth when vinorelbine‐pretreated A549 cells were used for immunization. Inhibition of the BE by the nitric oxide synthase inhibitor, N(G)‐nitro‐L‐arginine methyl ester, and the superoxide dismutase mimic, mangafodipir, suggested that it was mediated by oxidative and nitrosative stress. In conclusion, exposure of cancer cells to vinorelbine alters the antitumor immune response through a BE mediated by cellular oxidative and nitrosative stress. Our results offer new prospects for using oxidative stress modulators to restore the antitumor immune response in patients treated with anticancer agents.

Prise d’antioxydants et d’autres thérapies complémentaires par les patients sous chimiothérapie antitumorale : étude prospective

Use of complementary and alternative medicine (CAM) has been reported to be more and more frequent among cancer patients in USA. The aim of this study was to analyze among French cancer patients the prevalence of CAM use, focusing on antioxidants (AO) that could interfere with antitumor agents. Seventy-nine patients, treated by antitumor chemotherapy in oncology day care unit, participated to an interview (medium age  =  60 years old). CAM use was reported by 42% of patients: mostly AO (24%) (selenium, green tea and vitamins ACE, more specifically), but also relaxation, acupuncture, hypnosis (19%) and homeopathy (15%). Among patients using CAM, 66% of them indicated that their physicians were not aware of this use and 47% of them thought that CAM use was safe. Nevertheless, for seven patients who have taken AO, previous in vitro and preclinical studies suggested interactions with antitumor chemotherapy. Therefore, CAM use and, more specifically, AO use is common among cancer patients treated by antitumor chemotherapy in France. Nevertheless, AO could generate interactions with conventional treatment. Clinical studies are warranted to evaluate these interactions, and adequate communication with patients is needed.

Clinical and kinomic analysis identifies peripheral blood mononuclear cells as a potential pharmacodynamic biomarker in metastatic renal cell carcinoma patients treated with sunitinib.

Background Sunitinib is a protein tyrosine kinase (PTK) inhibitor that has immune-modulating properties. In this context, peripheral blood mononuclear cells (PBMC), mainly constituted by lymphocytes, could be a perfect surrogate tissue for identifying and assaying pharmacodynamic biomarkers of sunitinib. In this study, we investigated the changes in lymphocytes count as pharmacodynamic biomarker in metastatic renal cell carcinoma (mRCC) patients under sunitinib therapy. Thereafter, we studied the ex vivo effect of sunitinib and SU12262 (active metabolite) on PBMC from naïve mRCC patients using a high throughput kinomic profiling method. Methods The prognostic value of total lymphocytes count between Day 0 and Day 21 (expressed as a ratio D21/D0) was retrospectively investigated in 88 mRCC patients under sunitinib therapy. PTK PamChip® microarrays were used to explore prospectively the ex vivo effect of sunitinib and SU12662 on PTK activity in PBMC from 21 naïve mRCC patients. Results In this retrospective study, D21/D0 lymphocytes ratio (Hazard Ratio, 1.83; CI95%, 1.24-2.71; p=0.0023) was independently associated with PFS. Interestingly, kinomic analysis showed that D21/D0 lymphocytes ratio and Heng prognostic model was statistically associated with the ex vivo sunitinib and SU12662 effect in PBMC. Conclusion The present study highlights that D21/D0 total lymphocytes ratio could be a promising pharmacodynamic biomarker in mRCC patients treated with sunitinib. Additionally, it paves the way to investigate the kinomic profile in PBMC as a prognostic factor in a larger cohort of mRCC patients under sunitinib therapy.