A phase I schedule dependency study of the aurora kinase inhibitor MSC1992371A in combination with gemcitabine in patients with solid tumors.

INTRODUCTION: MSC1992371A is an aurora kinase inhibitor with potential antitumor activity. METHODS: This trial established the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of oral MSC1992371A given before or after gemcitabine (1,000 mg/m(2)) in a 21-day cycle in patients with advanced malignancies. In schedule 1 (n = 31), gemcitabine was administered on days 1 and 8 followed by escalating doses of MSC1992371A on days 2 and 9. In schedule 2 (n = 35), MSC1992371A was given on days 1 and 8 followed by gemcitabine on days 2 and 9. Patients had a range of solid tumors, the most frequent of which was colorectal (n = 19). RESULTS: In both schedules, the 37 mg/m(2) dose level was defined as the MTD. The main DLT was grade 4 neutropenia. Adverse events consisted of neutropenia, thrombocytopenia, asthenia, fatigue, nausea, vomiting, anorexia, and diarrhea. Administration of MSC1992371A prior to gemcitabine had no effect on the metabolism or elimination of gemcitabine. Time to reach maximum plasma concentration and area under the plasma concentration-time curve for MSC1992371A increased proportionally with dose. Exploration of drug-target-related and tumor biomarkers did not identify predictors of biologic activity or response. Two patients (1 with lung carcinoma and 1 with hepatocellular carcinoma) had durable partial responses in schedule 2, and 5 patients had stable disease (SD) lasting 6 - 14 months. CONCLUSION: Oral MSC1992371A can be administered at a MTD of 37 mg/m(2) in combination with the standard 1,000 mg/m(2) dose of gemcitabine, but hematologic toxicity requires careful monitoring. Preliminary signs of efficacy were indicated by durable responses and SD.

A phase l study of three different dosing schedules of the oral aurora kinase inhibitor MSC1992371A in patients with solid tumors.

Aurora kinase inhibitors (AKIs) are a class of antimitotic, small-molecule anticancer agents. MSC1992371A is an AKI being evaluated for the treatment of patients with solid tumors. This phase I, open-label, dose-escalation study determined the maximum tolerated dose (MTD) of MSC1992371A in different dosing schedules in patients with locally advanced or metastatic solid tumors. MSC1992371A was administered on days 1 and 8 (schedule 1) or on days 1, 2, and 3 (schedule 2) of a 21-day cycle. The study was expanded with a third schedule (study drug on days 1-3 and 8-10). Adverse events were monitored throughout the study. Antitumor efficacy, drug pharmacokinetics, and pharmacodynamics were evaluated. Ninety-two patients were enrolled. MSC1992371A was dosed over eight levels in schedules 1 and 2, and the MTD was determined as 74 mg/m(2) per cycle for both schedules and as 60 mg/m(2) in schedule 3, albeit only in three patients due to discontinuation of the study. Overall, the most common grade 3 or 4 treatment-emergent adverse events were neutropenia, febrile neutropenia, thrombocytopenia, anemia, and fatigue. The most frequent dose-limiting toxicity over all schedules was neutropenia. MSC1992371A plasma concentrations tended to increase with increasing dose levels. Although no complete or partial responses were seen, stable disease ≥3 months was observed in 11 patients. Analysis for markers of target modulation and pharmacodynamics effects was unsuccessful. MSC1992371A was generally well tolerated in patients, with mainly transient hematologic toxicities apparent at an MTD of 60-74 mg/m(2)/21-day cycle, independent of dosing frequency.

In vivo type 2 cannabinoid receptor-targeted tumor optical imaging using a near infrared fluorescent probe.

The type 2 cannabinoid receptor (CB2R) plays a vital role in carcinogenesis and progression and is emerging as a therapeutic target for cancers. However, the exact role of CB2R in cancer progression and therapy remains unclear. This has driven the increasing efforts to study CB2R and cancers using molecular imaging tools. In addition, many types of cancers overexpress CB2R, and the expression levels of CB2R appear to be associated with tumor aggressiveness. Such upregulation of the receptor in cancer cells provides opportunities for CB2R-targeted imaging with high contrast and for therapy with low side effects. In the present study, we report the first in vivo tumor-targeted optical imaging using a novel CB2R-targeted near-infrared probe. In vitro cell fluorescent imaging and a competitive binding assay indicated specific binding of NIR760-mbc94 to CB2R in CB2-mid delayed brain tumor (DBT) cells. NIR760-mbc94 also preferentially labeled CB2-mid DBT tumors in vivo, with a 3.7-fold tumor-to-normal contrast enhancement at 72 h postinjection, whereas the fluorescence signal from the tumors of the mice treated with NIR760 free dye was nearly at the background level at the same time point. SR144528, a CB2R competitor, significantly inhibited tumor uptake of NIR760-mbc94, indicating that NIR760-mbc94 binds to CB2R specifically. In summary, NIR760-mbc94 specifically binds to CB2R in vitro and in vivo and appears to be a promising molecular tool that may have great potential for use in diagnostic imaging of CB2R-positive cancers and therapeutic monitoring as well as in elucidating the role of CB2R in cancer progression and therapy.