Imaging the Met Receptor Tyrosine Kinase (Met) and Assessing Tumor Responses to a Met Tyrosine Kinase Inhibitor in Human Xenograft Mouse Models with a [ 99m

Developing an imaging agent targeting the hepatocyte growth factor receptor protein (Met) status of cancerous lesions would aid in the diagnosis and monitoring of Met-targeted tyrosine kinase inhibitors (TKIS). A peptide targeting Met labeled with [ 99m Tc] had high affinity in vitro (K d = 3.3 nM) and detected relative changes in Met in human cancer cell lines. In vivo [ 99m Tc]-Met peptide (AH-113018) was retained in Met-expressing tumors, and high-expressing Met tumors (MKN-45) were easily visualized and quantitated using singlephoton emission computed tomography or optical imaging. In further studies, MKN-45 mouse xenografts treated with PHA 665752 (Met TKI) or vehicle were monitored weekly for tumor responses by [ 99m Tc]-Met peptide imaging and measurement of tumor volumes. Tumor uptake of [“ m Tc]-Met peptide was significantly decreased as early as 1 week after PHA 665752 treatment, corresponding to decreases in tumor volumes. These results were comparable to Cy5**-Met peptide (AH-112543) fluorescence imaging using the same treatment model. [ 99m Tc] or Cy5**-Met peptide tumor uptake was further validated by histologic (necrosis, apoptosis) and immunoassay (total Met, p Met, and plasma shed Met) assessments in imaged and nonimaged cohorts. These data suggest that [ 99m Tc] or Cy5**-Met peptide imaging may have clinical diagnostic, prognostic, and therapeutic monitoring applications

A phase I/II multicenter study of single-agent foretinib as first-line therapy in patients with advanced hepatocellular carcinoma

Purpose: This phase I/II single-arm study evaluated the safety, pharmacokinetics, pharmacodynamics, and activity of foretinib, an oral multikinase inhibitor of MET, ROS, RON, AXL, TIE-2, and VEGFR2, in the first-line setting in advanced hepatocellular carcinoma patients. Experimental Design: In the phase I part, advanced hepatocellular carcinoma patients were dose escalated on foretinib (30-60 mg) every day using the standard 3+3 design. Once the maximum tolerated dose (MTD) was determined, an additional 32 patients were dosed at the MTD in the phase II expansion cohort for assessment of efficacy and safety. Exploratory analyses were conducted to assess potential biomarkers that might correlate with clinical efficacy and survival. Results: The MTD of foretinib was established as 30 mg every day. The most frequent adverse events were hypertension, decreased appetite, ascites, and pyrexia. When dosed at 30 mg every day in the first-line setting, foretinib demonstrated promising antitumor activity. According to the modified mRECIST, the objective response rate was 22.9%, the disease stabilization rate 82.9%, and the median duration of response 7.6 months. The median time to progression was 4.2 months and the median overall survival (OS) was 15.7 months. Fifteen candidate biomarkers whose levels in the circulation were significantly altered in response to foretinib treatment were elucidated. Multivariate analyses identified IL6 and IL8 as independent predictors of OS. Conclusions: Foretinib demonstrated promising antitumor activity and good tolerability in the first-line setting in Asian advanced hepatocellular carcinoma patients. Baseline plasma levels of IL6 or IL8 might predict the response to foretinib