Dynamic gadobutrol-enhanced MRI predicts early response to antivascular but not to antiproliferation therapy in a mouse xenograft model.

PURPOSE: Dynamic contrast-enhanced magnetic resonance imaging has been described as a method to assess tumor vascularity and, therefore, is discussed as a noninvasive biomarker for drug response prediction in tumor therapies. Because antiangiogenic and antiproliferative drugs are frequently combined for therapy, the aim was to investigate (1) the early response predictability and (2) the extent to which these therapy types influence dynamic contrast-enhanced magnetic resonance imaging with gadobutrol soon after therapy initiation. METHODS: Mice bearing a KPL-4 tumor were treated with either bevacizumab as an antiangiogenic drug or trastuzumab as a cytotoxic anti-tumor drug. The gadobutrol-contrast agent exposure of the tumor was recorded before and at several time points after therapy initiation to examine the response prediction by dynamic contrast-enhanced magnetic resonance imaging. RESULTS: Both therapies resulted in significant tumor growth attenuation over 30 days of therapy, but the individual response to each therapy was different. Specifically, bevacizumab affected the dynamic gadobutrol-enhanced MRI-derived area under the curve at early time points (≤8 days), while trastuzumab did not. CONCLUSION: The area under the curve obtained from dynamic gadobutrol-enhanced MRI predicted early tumor response to the antiangiogenic drug bevacizumab, but not to the anti-tumor cell drug trastuzumab. This indicates that the area under the curve may be useful for assessing early antiangiogenic but not antiproliferative drug effects.

Impact of lung morphology on clinical outcomes with riociguat in patients with pulmonary hypertension and idiopathic interstitial pneumonia: A post hoc subgroup analysis of the RISE-IIP study.

BACKGROUND: Riociguat in Patients with Symptomatic Pulmonary Hypertension associated with Idiopathic Interstitial Pneumonias (RISE-IIP), a randomized, controlled, phase 2b trial of riociguat for pulmonary hypertension associated with idiopathic interstitial pneumonia, was terminated early due to increased mortality in riociguat-treated patients. Baseline characteristics of enrolled patients demonstrated a low diffusing capacity of the lung for carbon monoxide (DLCO) with preserved lung volumes at baseline, suggesting the presence of combined pulmonary fibrosis and emphysema (CPFE) in some patients. This post hoc analysis of RISE-IIP was undertaken to explore lung morphology, assessed by high-resolution computed tomography, and associated clinical outcomes. METHODS: Available baseline/pre-baseline high-resolution computed tomography scans were reviewed centrally by 2 radiologists. The extent of emphysema and fibrosis was retrospectively scored and combined to provide the total CPFE score. RESULTS: Data were available for 65/147 patients (44%), including 15/27 fatal cases (56%). Of these, 41/65 patients (63%) had CPFE. Mortality was higher in patients with CPFE (12/41; 29%) than those without (3/24; 13%). Fourteen patients with CPFE had emphysema > fibrosis (4 died). No relationship was observed between CPFE score, survival status, and treatment assignment. A low DLCO, short 6-min walking distance, and high forced vital capacity:DLCO ratio at baseline also appeared to be risk factors for mortality. CONCLUSIONS: High parenchymal lung disease burden and the presence of more emphysema than fibrosis might have predisposed patients with pulmonary hypertension associated with idiopathic interstitial pneumonia to poor outcomes in RISE-IIP. Future studies of therapy for group 3 pulmonary hypertension should include centrally adjudicated imaging for morphologic phenotyping and disease burden evaluation during screening.

Anetumab ravtansine: a novel mesothelin-targeting antibody-drug conjugate cures tumors with heterogeneous target expression favored by bystander effect.

Mesothelin is a tumor differentiation antigen frequently overexpressed in tumors such as mesothelioma, ovarian, pancreatic, and lung adenocarcinomas while showing limited expression in nonmalignant tissues. Mesothelin is therefore an attractive target for cancer therapy using antibody-drug conjugates (ADC). This study describes the detailed characterization of anetumab ravtansine, here referred to as BAY 94-9343, a novel ADC consisting of a human anti-mesothelin antibody conjugated to the maytansinoid tubulin inhibitor DM4 via a disulfide-containing linker. Binding properties of the anti-mesothelin antibody were analyzed using surface plasmon resonance, immunohistochemistry, flow cytometry, and fluorescence microscopy. Effects of BAY 94-9343 on cell proliferation were first studied in vitro and subsequently in vivo using subcutaneous, orthotopic, and patient-derived xenograft tumor models. The antibody binds to human mesothelin with high affinity and selectivity, thereby inducing efficient antigen internalization. In vitro, BAY 94-9343 demonstrated potent and selective cytotoxicity of mesothelin-expressing cells with an IC(50) of 0.72 nmol/L, without affecting mesothelin-negative or nonproliferating cells. In vivo, BAY 94-9343 localized specifically to mesothelin-positive tumors and inhibited tumor growth in both subcutaneous and orthotopic xenograft models. In addition, BAY 94-9343 was able to induce a bystander effect on neighboring mesothelin-negative tumor cells. Antitumor efficacy of BAY 94-9343 correlated with the amount of mesothelin expressed and was generally superior to that of standard-of-care regimen resulting in complete tumor eradication in most of the models. BAY 94-9343 is a selective and highly potent ADC, and our data support its development for the treatment of patients with mesothelin-expressing tumors.

Monitoring therapeutical intervention with ezetimibe using targeted near-infrared fluorescence imaging in experimental atherosclerosis.

Ezetimibe (EZE), an inhibitor of cholesterol absorption, reduces atherosclerosis in apolipoprotein E-deficient (apoE(-/-)) mice. The matrix protein ED-B fibronectin (ED-B) is upregulated in atherosclerotic lesions. Using a novel conjugate for near-infrared fluorescence (NIRF) imaging targeting ED-B, we studied the effect of EZE on plaque lesion formation in apoE(-/-) mice. ApoE(-/-) mice received EZE (5 mug/kg/d) or chow up to the age of 4, 6, and 8 months. NIRF imaging of aortic lesions was performed 24 hours after intravenous application ex vivo and in vivo. Plaque lesion formation was analyzed by histology and immunohistochemistry. Aortic lesion formation detected by Sudan staining and NIRF imaging was significantly reduced at 6 and 8 months (p < .001). Plaque areas determined by NIRF imaging significantly correlated with Sudan staining (p < .001). EZE treatment resulted in a significant reduction in plaque macrophage and ED-B immunoreactivity (both p < .05) in brachiocephalic lesions. There was a significant reduction in plaque size in brachiocephalic arteries in 8-month-old mice treated with EZE compared with mice during short-term treatment (p < .05), indicating EZE plaque regression. Targeted NIRF imaging showed a correlation to histologic lesion extension during therapeutical intervention in experimental atherosclerosis.

Comparison of two tricarbocyanine-based dyes for fluorescence optical imaging.

Optical technologies are evolving in many biomedical areas including the biomedical imaging disciplines. Regarding the absorption properties of physiological molecules in living tissue, the optical window ranging from 700 to 900 nm allows to use fluorescent dyes for novel diagnostic solutions. Here we investigate the potential of two different carbocyanine-based dyes fluorescent in the near infrared as contrast agents for in vivo imaging of subcutaneously grown tumours in laboratory animals. The primary aim was to modify the physicochemical properties of the previously synthesized dye SIDAG to investigate the effect on the in vivo imaging properties.