First-in-Human Study in Healthy Subjects with the Noncytotoxic Monoclonal Antibody OSE-127, a Strict Antagonist of IL-7Rα.

OSE-127 is a humanized mAb targeting the IL-7Rα-chain (CD127), under development for inflammatory and autoimmune disease treatment. It is a strict antagonist of the IL-7R pathway, is not internalized by target cells, and is noncytotoxic. In this work, a first-in-human, phase I, randomized, double-blind, placebo-controlled, single-center study was carried out to determine the safety, pharmacokinetics, pharmacodynamics, and immunogenicity of OSE-127 administration. Sixty-three healthy subjects were randomly assigned to nine groups: six single ascending dose groups with i.v. administration (0.002-10 mg/kg), a single s.c. treatment group (1 mg/kg), and two double i.v. injection groups (6 or 10 mg/kg). Subjects were followed during <146 d. OSE-127's pharmacokinetic half-life after a single dose increased from 4.6 (1 mg/kg) to 11.7 d (10 mg/kg) and, after a second dose, from 12.5 (6 mg/kg) to 16.25 d (10 mg/kg). Receptor occupancy was ≥95% at doses ≥0.02 mg/kg, and this saturation level was maintained >100 d after two i.v. infusions at 10 mg/kg. IL-7 consumption was inhibited by OSE-127 administration, as demonstrated by a decreased IL-7 pathway gene signature in peripheral blood cells and by ex vivo T lymphocyte restimulation experiments. OSE-127 was well tolerated, with no evidence of cytokine-release syndrome and no significant alteration of blood lymphocyte counts or subset populations. Altogether, the observed lack of significant lymphopenia or serious adverse events, concomitant with the dose-dependent inhibition of IL-7 consumption by target cells, highlights that OSE-127 may show clinical activity in IL-7R pathway-involved diseases.

Enhanced cytotoxicity and nuclear accumulation of doxorubicin-loaded nanospheres in human breast cancer MCF7 cells expressing MRP1.

Previous studies have demonstrated that doxorubicin (DOX) encapsulated in polyisohexylcyano-acrylate nanospheres (NS-DOX) circumvented the resistance of breast cancer cells overexpressing P-glycoprotein (Pgp). Another protein is involved in multidrug resistance phenotype, the multidrug resistance associated protein (MRP1). We report that NS-DOX overcomes multidrug resistance in breast cancer cells overexpressing MRP1. Taking into account that anthracyclines are conjugated to or co-transported with glutathione by MRP1, these data suggest that probably due to ion pair formation (NS-DOX), MRP1 could not transport the anthracycline. Pgp is probably able to transport the ion pair drug complex and the mechanisms of drug resistance reversion in Pgp expressing cells need to be further elucidated.

Quantification of the expression of multidrug resistance-related genes in human tumour cell lines grown with free doxorubicin or doxorubicin encapsulated in polyisohexylcyanoacrylate nanospheres.

Doxorubicin (dox) encapsulated in polyisohexylcyanoacrylate nanospheres (PIHCA-dox) can circumvent P-glycoprotein-mediated multidrug resistance (MDR). In order to investigate whether this drug formulation is able to select MDR cells in culture in the same way as free doxorubicin does, two human tumour cell lines, K562 and MCF7, were grown with increasing concentrations of either free dox or PIHCA-dox. For both drug formulations and for each selection level, the cell lines were more resistant to free dox than to PIHCA-dox. The MCF7 sublines selected with PIHCA-dox exhibited a higher level of resistance to both doxorubicin formulations than those selected with free doxorubicin. Different levels of overexpression of several genes involved in drug resistance (MDR1, MRP1, BCRP and TOP2alpha) occurred in the resistant variants. MDR1 gene overexpression was consistently higher in free dox-selected cells than in PIHCA-dox-selected cells, while this was the reverse for the BCRP gene. Overexpression of the MRP1 and TOP2alpha genes was also observed in the selected variants. Our results show that several mechanisms may be involved in the acquisition of drug resistance and that drug encapsulation markedly alters or delays these processes.

Increase of doxorubicin sensitivity by doxorubicin-loading into nanoparticles for hepatocellular carcinoma cells in vitro and in vivo.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is known to be chemoresistant to anticancer drugs due to the multidrug resistant (MDR) transporters expression. Here, we compared in vitro and in vivo the anti-tumor efficacy of doxorubicin-loaded polyisohexylcyanoacrylate nanoparticles (PIHCA-Dox) versus free doxorubicin (Dox). These nanoparticles are known to overcome the MDR phenotype. METHODS: We first determined in vitro the 50% inhibition concentration (IC(50)) of these drugs on different human hepatoma cell lines. Secondly, the efficacy of the drugs in vivo was determined on the X/myc transgenic murine model of HCC by histological counting of apoptotic tumorous hepatocytes and by TUNEL labeling. We characterized by semi-quantitative RT-PCR the MDR-related gene (mdr1, mdr3, mrp1) expression pattern in this model. RESULTS: In vitro, IC(50) was reduced with PIHCA-Dox versus Dox for Huh7 (1.7-fold reduction; P<0.001), HepaRG (4.5-fold reduction; P<0.01), HepG2 (1.5-fold reduction; P<0.001), and HepG2.2.15 (1.5-fold reduction; P=0.059). In vivo, HCC in transgenic mice overexpressed the mdr1 and mdr3 genes and the antitumor drugs efficacy was greatly enhanced after injection of PIHCA-Dox (9.0+/-5.0%; n=15) versus Dox (4.6+/-3.3%; n=13; P=0.01) for apoptotic bodies count. CONCLUSIONS: These promising data showing a higher anti-tumor efficacy on HCC of PIHCA-Dox versus Dox, warrant further studies in both animals and humans.