Purpose: We investigated whether inhibition of interleukin 6 (IL-6) has therapeutic activity in ovarian cancer via abrogation of a tumor-promoting cytokine network.Experimental Design: We combined preclinical and in silico experiments with a phase 2 clinical trial of the anti-IL-6 antibody siltuximab in patients with platinum-resistant ovarian cancer.

Herein we report the use of next generation maleimides (NGMs) for the construction of a potent antibody-drug conjugate (ADC) via functional disulfide bridging. The linker has excellent stability in blood serum and the ADC, armed with monomethyl auristatin E (MMAE), shows excellent potency and cancer cell selectivity in vitro.

Delivering potent, stable, targeted and in vivo efficacious antibody–drug conjugates (ADCs) using pyridazinedione functional disulfide re-bridging reagents.

Tumor repopulation between cycles of chemotherapy likely has a negative effect on clinical outcome in ovarian cancer patients. Thus, avoiding treatment-free periods when tumor cells proliferate by providing sustained chemotherapy regimens may improve clinical response. We investigated the effect of sustained versus intermittent paclitaxel administration on tumor repopulation in ovarian cancer. Growth, clonogenic survival, and apoptosis were followed in SKOV3 and A2780 cells after equivalent exposure to intermittent and sustained levels of paclitaxel.

ABSTRACT:P-glycoprotein (PGP) encoded by the Mdr1 gene mediates the excretion of drugs in organs such as the liver and kidney. Inflammation has been shown to suppress the expression and activity of PGP in rodent liver, thus potentially altering the pharmacokinetics of drugs that are substrates of PGP. Here we examined the effect of endotoxin (lipopolysaccharide; LPS)-induced inflammation on the disposition of the PGP substrate doxorubicin (DOX) in the mouse. Male CD-1 mice received 5 mg/kg LPS intraperitoneally. DOX (5 mg/kg) was administered intravenously 24 h after LPS treatment. The time course of DOX levels in plasma, urine, bile, and tissues was analyzed by high performance liquid chromatography. PGP protein and mRNA expression in liver and kidney was measured using Western blots and reverse transcriptase polymerase chain reaction. As compared to controls, LPS-treated mice exhibited a significant decrease (50%) in biliary clearance and 3-fold increased renal clearance of DOX. These changes were associated with strongly reduced PGP protein levels (30% controls, p < 0.05) in the liver and increased PGP levels in the kidney (140% controls, p < 0.05). Hepatic mRNA levels of all Mdr isoforms were reduced in LPS-treated mice, whereas renal Mdr1b levels were increased. In LPS-treated mice, we also measured an increased area under the plasma concentration-time curve and reduced systemic clearance of DOX, as well as a 2-to 5-fold increase in the urinary excretion of the doxorubicin and doxorubicinol aglycones. Our data suggest that endotoxin-induced inflammation in mice causes differential regulation of PGP in liver and kidney, thereby altering the clearance profile of DOX.

We evaluated the pre-clinical efficacy of a novel intraperitoneal (i.p.) sustained-release paclitaxel formulation (PTX ePC ) using bioluminescent imaging (BLI) in the treatment of ovarian cancer. Human ovarian carcinoma cells stably expressing the firefly luciferase gene (SKOV3 Luc ) were injected i.p. into SCID mice. Tumour growth was evaluated during sustained or intermittent courses of i.p. treatment with paclitaxel (PTX). In vitro bioluminescence strongly correlated with cell survival and cytotoxicity. Bioluminescent imaging detected tumours before their macroscopic appearance and strongly correlated with tumour weight and survival. As compared with intermittent therapy with Taxol s , sustained PTX ePC therapy resulted in significant reduction of tumour proliferation, weight and BLI signal intensity, enhanced apoptosis and increased survival times. Our results demonstrate that BLI is a useful tool in the pre-clinical evaluation of therapeutic interventions for ovarian cancer. Moreover, these results provide evidence of enhanced therapeutic efficacy with the sustained PTX ePC implant system, which could potentially translate into successful clinical outcomes.

The novel PTX(ePC) formulation is a safer and better tolerated method for PTX administration, with significant increase in MTD and enhanced anti-tumour efficacy, suggesting improved therapeutic index with possible clinical implications in the treatment of ovarian tumours.

Herein we demonstrate that conjugation of a next generation maleimide (NGM) to engineered cysteines in a THIOMAB™ antibody delivers a THIOMAB™ antibody-drug conjugate (TDC) with a drug loading of ca. 2. This TDC is highly stable in blood serum conditions, selective and potent towards HER2 expressing cell lines and meets the current criteria for optimised antibody-drug conjugates (ADCs).Antibody-drug conjugates (ADCs) have emerged as targeted therapeutics against cancer by combining the selectivity of the antibody component with the potency of cytotoxic drugs. There are two FDA-approved ADCs already on the market (Adcetris™ and Kadcyla™) and over 40 additional ADCs currently undergoing clinical trials. 1-4Classical methods of conjugation for producing ADCs include lysine modication 5 and cysteine modication via reduction of solvent accessible disulde bonds followed by reaction with maleimides.6 It has been recognised that both methods generate heterogeneous mixtures of ADCs with different drug loadings and varied sites of attachment, resulting in sub-optimal therapeutic indices and higher clearance rates.7-13 Formation of higher drug-to-antibody ratio species (DAR > 4) have narrower therapeutic indices. 1,7,9,12,14 The latter method also results in the loss of structural disulde bonds which can lead to poor stability. 7,9,14The next generation of conjugation methods has aimed to reduce heterogeneity by focusing on site-selectivity. Chemoenzymatic methods have been used for ADC synthesis such as glycan modication, 15-17 glutamine amidation 18 and cysteine oxidation to aldehyde tags.19 Site-selective disulde modica-tion with small molecules has been achieved using nextgeneration maleimides (NGMs), 20-27 pyridazinediones (PDs)28-32 and bis-sulfones. 33,34 Site-specic reactivity has also been accomplished through incorporation of non-natural aminoacids into proteins for bioorthogonal conjugation. 10,35-39The THIOMAB™ antibody technology platform uses sitedirected mutagenesis to incorporate cysteines into the antibody. Conjugation to a classical maleimide bearing the drug of choice affords a THIOMAB™ antibody-drug conjugate (TDC) with full control over site reactivity and a precise drug-toantibody ratio (DAR).12,40-42 The technology also avoids issues with some chemoenzymatic methods that can result in over oxidation of aminoacids 43 and aldehyde tag conversion to unreactive gem-diols.44 TDCs have been demonstrated to improve therapeutic indices and pharmacodynamics over ADCs prepared by classical cysteine and lysine modication. 11,12,42Maleimides are rapid thiol-selective conjugation reagents.45,46 However, the succinimide conjugates thus formed can undergo retro-Michael reactions and scavenging with albumin, 47 resulting in premature drug release during blood circulation.10,41,48 N-Alkyl succinimide conjugates can be stabilised against retro-Michael reactions by hydrolysis to succinamic acid derivatives, 49-51 which resulted in ADCs with improved pharmacokinetics and in vivo efficacy. 41,51,52 Most Nalkyl t...