Dabrafenib and trametinib exposure-efficacy and tolerance in metastatic melanoma patients: a pharmacokinetic-pharmacodynamic real-life study.

PURPOSE: Dabrafenib plus trametinib combination has greatly improved survival in BRAFV600mut metastatic melanoma patients. However, data regarding the influence of pharmacokinetic markers in real-life patients are lacking. In this study, we aimed to explore dabrafenib and trametinib pharmacokinetic impact on progression-free survival (PFS), duration of response (DOR) or all grades treatment-related adverse events (ARAE) occurrence in routine care patients. METHODS: BRAFV600mut metastatic melanoma patients initiating standard doses of dabrafenib 150 mg BID plus trametinib 2 mg QD were included. Clinical data were collected via the French biobank MelBase, prospectively enrolling unresectable stage III or IV melanoma. Clinical response evaluation, ARAE reporting and dabrafenib and trametinib plasma quantification were performed. Association of individual Bayesian-estimated pharmacokinetic markers (AUC0-τ and Ctrough) and baseline clinical variables with DOR, PFS, clinical response, and ARAE was then assessed. RESULTS: Fifty patients (comprising 4 AJCC stage IIIc and 46 stage IV) were included. Median PFS reached 11.4 months, and overall response rate 70%. Fifty percent of patients experienced ARAE (G3 n = 10, G4 n = 0). In univariate analysis, median dabrafenib Ctrough within intermediate range was associated with a significantly higher PFS (HR [95% CI] = 0.41 [0.18; 0.91], p = 0.029) and DOR (HR [95% CI] = 0.39 [0.16; 0.94], p = 0.024), and association with DOR remained significant in multivariate analysis (HR [95% CI] = 0.34 [0.12; 0.95], p = 0.040). Trametinib pharmacokinetic markers were significantly higher in patients experiencing ARAE compared to patients without ARAE. CONCLUSION: In this study, exposure-efficacy and tolerance analysis highlighted the interest of therapeutic drug monitoring to optimize therapeutic management in BRAFV600mut metastatic melanoma patients based on trough concentrations of dabrafenib and trametinib.

Image-guided lymph node core-needle biopsy predicts survival in mycosis fungoides and Sézary syndrome.

BACKGROUND: The prognosis of Sézary syndrome (SS) and mycosis fungoides (MF) depends on lymph node (LN) involvement. The usefulness of LN image-guided core-needle biopsies (CNBs), instead of surgical sampling, has been poorly evaluated. OBJECTIVES: To determine the prognostic value of LN CNB in MF/SS. METHODS: A retrospective search was conducted to identify all LN biopsy specimens of MF/SS between 2008 and 2019. Biopsies were staged according to the International Society for Cutaneous Lymphomas/European Organisation for Research and Treatment of Cancer (ISCL/EORTC) criteria. We performed immunolabelling and determined the tumour clone frequency (TCF) by high-throughput sequencing of the T-cell receptor beta locus. RESULTS: We included 119 consecutive biopsies from 100 patients, 45 with MF and 55 with SS. N1, N2 and N3 stages were diagnosed in 34 (29%), 26 (22%) and 59 (49%) cases, respectively. The TCF, Ki67 index, and percentage of cells positive for thymocyte selection-associated high mobility group box protein (TOX), programmed cell death protein 1 (PD1), killer cell immunoglobulin-like receptor 3DL2 (KIR3DL2) and cluster of differentiation (CD)30 were all positively correlated with the N stage. Median overall survival (OS) for N1/N2 vs. N3 patients was 42 months (range 26-not reached) vs. 14 months (range 5-30), respectively (P < 0·001). In univariate analyses, an age > 75 years, LN short-axis diameter > 15 mm, N3 stage, presence of large-cell transformation, TOX > 60%, PD1 > 25%, Ki67 > 30%, KIR3DL2 > 15%, CD30 > 10% and TCF > 25% were identified as adverse prognostic factors. In multivariate analyses, only an age > 75 years and Ki67 index > 30% were associated with reduced OS. We developed a new prognostic index associating the N stage and the Ki67 index, which better discriminates N3 patients with poor prognosis. CONCLUSIONS: CNB allows an objective assessment of the LN involvement in MF/SS, relevant for staging and prognosis.

Mutagenicity assessment of environmental contaminations in a hospital centralized reconstitution unit.

INTRODUCTION: Cytotoxic drug exposure of hospital staff preparing intravenous chemotherapy is a major issue and related mutagenic risks should be more explored. The aim of this study was to assess the mutagenicity of several cytotoxic mixtures prepared at fixed concentrations, and the mutagenicity of environmental samples collected in a hospital centralized reconstitution unit. In parallel cytotoxic exposure in environmental samples was quantified. METHODS: Environmental samples were performed by wiping method using swabs in five critical production unit areas. Mutagenicity was assessed with a liquid microplate AMES test using two salmonella typhimurium strains (TA98 and TA100), in prepared cytotoxic mixtures containing 14 cytotoxic drugs (cyclophosphamide, cytarabine, dacarbazine, docetaxel, doxorubicin, epirubicin, etoposide, 5-fluorouracil, gemcitabine, ifosfamide, irinotecan, methotrexate, paclitaxel and pemetrexed) according a dichotomous strategy and in environmental samples. Cytotoxic drugs were quantified in samples using liquid chromatography coupled to mass tandem spectrometry. RESULTS: Mutagenesis was observed for the mix of 14 cytotoxic drugs with TA98 strain ±â€¯S9 fraction but not TA100 strain. After dichotomous approach, only doxorubicin and epirubicin exposure were associated to mutagenesis. The mutagenesis observed was expressed at lower concentrations with the mix of the 14 drugs than with anthracyclins alone, assuming a synergistic effect. Despite measurable level of cytotoxic contamination in environmental samples, no mutagenesis was highlighted in Ames tests performed on these environmental samples. CONCLUSIONS: The analyses carried out show the conservation of the mutagenicity of cytotoxic drugs found in very low quantities in the environment. The traces of cytotoxic drugs found in our unit regularly exceed the limits given by some authors. This approach may be considered as a new tool to monitor environmental contamination by cytotoxic drugs.

PDE4D promotes FAK-mediated cell invasion in BRAF-mutated melanoma.

The cyclic AMP (cAMP) signaling pathway is critical in melanocyte biology for regulating differentiation. It is downregulated by phosphodiesterase (PDE) enzymes, which degrade cAMP itself. In melanoma evidence suggests that inhibition of the cAMP pathway by PDE type 4 (PDE4) favors tumor progression. For example, in melanomas harboring RAS mutations, the overexpression of PDE4 is crucial for MAPK pathway activation and proliferation induced by oncogenic RAS. Here we showed that PDE4D is overexpressed in BRAF-mutated melanoma cell lines, constitutively disrupting the cAMP pathway activation. PDE4D promoted melanoma invasion by interacting with focal adhesion kinase (FAK) through the scaffolding protein RACK1. Inhibition of PDE4 activity or inhibition of PDE4D interaction with FAK reduced invasion. PDE4D expression is increased in patients with advanced melanoma and PDE4D-FAK interaction is detectable in situ in metastatic melanoma. Our study establishes the role of PDE4D in BRAF-mutated melanoma as regulator of cell invasion, and suggests its potential as a target for preventing metastatic dissemination.

Determination of rifampicin in human plasma by high-performance liquid chromatography coupled with ultraviolet detection after automatized solid-liquid extraction.

A precise and accurate high-performance liquid chromatography (HPLC) quantification method of rifampicin in human plasma was developed and validated using ultraviolet detection after an automatized solid-phase extraction. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision, accuracy, lower limit of quantification and stability. Chromatographic separation was performed on a Chromolith RP8 column using a mixture of 0.05 m acetate buffer pH 5.7-acetonitrile (35:65, v/v) as mobile phase. The compounds were detected at a wavelength of 335 nm with a lower limit of quantification of 0.05 mg/L in human plasma. Retention times for rifampicin and 6,7-dimethyl-2,3-di(2-pyridyl) quinoxaline used as internal standard were respectively 3.77 and 4.81 min. This robust and exact method was successfully applied in routine for therapeutic drug monitoring in patients treated with rifampicin.

Imbalance of MMP-2 and MMP-9 expression versus TIMP-1 and TIMP-2 reflects increased invasiveness of human testicular germ cell tumours.

The histological classification of testicular germ cell tumours (TGCTs) to seminoma or non-seminomatous germ cell tumours is at present the main criterion for the clinical outcome and selection of the treatment strategy. In view of the need to identify novel prognostic biomarkers for TGCTs, we investigated the expression of the matrix metalloproteinases MMP-2 and MMP-9 in testicular tumour tissues and cell lines of both seminoma and non-seminoma origin. Immunohistochemistry and zymography analysis of tumoural tissues showed significantly higher levels of MMP-2 and MMP-9 compared with normal testis with the active forms detected only in the tumour tissues. Three cell lines representative of the different tumour types, JKT-1 seminoma, NCCIT teratocarcinoma and NTERA2/D1 embryonal carcinoma were also evaluated for their expression of these MMPs using qPCR and zymography and for their invasive properties. The more invasive non-seminomatous teratocarcinoma and embryonal cells expressed considerably more MMP-2 and MMP-9 compared with seminoma cells exhibiting lower invasiveness. Furthermore, an inverse relation was observed between invasiveness and the expression of endogenous inhibitors TIMP-1 and TIMP-2. The MMP inhibitor Marimastat inhibited invasion in all cell lines, the highest inhibition was observed in the more invasive NTERA2/D1 and NCCIT cells, which presented the highest ratio of MMP-2 and MMP-9 vs. TIMP-1 and TIMP-2. These results highlight the importance of MMP-2 and MMP-9 in the invasiveness of testicular tumours and suggest that their levels, vs. those of TIMP-1 and TIMP-2, may represent potential biomarkers for testicular malignancy.

Antisense inhibition of amphiregulin expression reduces EGFR phosphorylation in transformed human breast epithelial cells.

The activation of epidermal growth factor receptor (EGFR) by its ligands constitutes an important step in the metastatic process but the clinical response to its inhibition in breast cancer patients has so far been very low. In this work, we investigated the role of the EGFR ligand amphiregulin (AR) in modulating EGFR activation. For this, transformed epithelial mammary tumor cells NS2T2A1 were used in which AR or EGFR expression was down-regulated by antisense cDNA technique. This down-regulation was associated with a significant inhibition of matrix metalloproteinase-9 production as well as cell proliferation, but this inhibition was only minimally reversed by exogenously added AR or EGF. EGFR protein levels were not affected but EGFR-tyrosine phosphorylation in response to EGF was markedly reduced. Thus, the inhibition of AR expression, which impairs EGFR response to its exogenously available ligands, may represent an alternative anti-EGFR therapeutic strategy in breast cancer.

Telomerase targeting by retinoids in cells from patients with myeloid leukemias of various subtypes, not only APL.

Numerous strategies have been proposed to specifically inhibit telomerase (human telomerase reverse transcriptase (hTERT)) but to date only a few are clinically relevant in anticancer therapy. Recently, we have shown that long-term treatment with all-trans retinoic acid (ATRA), a compound clinically approved for differentiation therapy of acute promyelocytic leukemia (APL), represses hTERT in differentiation-resistant APL cell lines leading to telomere shortening and death. This signaling requires the co-activation of the retinoic acid receptor alpha (RARalpha) and the retinoic X receptor (RXR). In contrast to differentiation-therapy, which is only successful in this subtype of leukemia, the telomerase-targeted pathway could also be of use in non-APL. Here, we demonstrate that repression of hTERT occurs in fresh blasts cells from patients with myeloid leukemias of various subtypes exposed ex vivo to ATRA or synthetic retinoids. These results support the idea that, by hTERT targeting, retinoids can induce telomere shortening and cell death and their integration in therapy protocols for myeloid leukemias refractory to maturation should be considered.

Regulation of the vascular endothelial growth factor (VEGF) receptor Flk-1/KDR by estradiol through VEGF in uterus.

The induction of vascular endothelial growth factor (VEGF) expression by 17beta-estradiol (E(2)) in many target cells, including epithelial cells, fibroblasts and smooth muscle cells, suggests a role for this hormone in the modulation of angiogenesis and vascular permeability. We have already described a cyclic increase in Flk-1/KDR-expressing capillaries in the human endometrium during the proliferative and mid-secretory phases, strongly suggestive of an E(2) effect on Flk-1/KDR expression in the endometrial capillaries. However, it is unclear whether these processes are due to a direct effect of E(2) on endothelial cells. Using immunohistochemistry, we report an increase in Flk-1/KDR expression in endometrial capillaries of ovariectomized mice treated with E(2), or both E(2) and progesterone. This process is mediated through estrogen receptor (ER) activation. In vitro experiments using quantitative RT-PCR analysis demonstrate that Flk-1/KDR expression was not regulated by E(2) in human endothelial cells from the microcirculation (HMEC-1) or macrocirculation (HUVEC), even in endothelial cells overexpressing ERalpha or ERbeta after ER-mediated adenovirus infection. In contrast, Flk-1/KDR expression was up-regulated by VEGF itself, in a time- and dose-dependent manner, with the maximal response at 10 ng/ml. Thus, we suggest that E(2) up-regulates Flk-1/KDR expression in vivo in endothelial cells mainly through the modulation of VEGF by a paracrine mechanism. It is currently unknown whether or not the endothelial origin might account for differences in the E(2)-modulation of VEGF receptor expression, particularly in relation to the vascular bed of sex steroid-responsive tissues.