Evaluation of the anti-angiogenic effect of bevacizumab on rat C6 glioma by spectral computed tomography

Biodistribution and pharmacokinetics of [89Zr]-anti-VEGF mAbs using PET in glioblastoma rat models

INTRODUCTION

Glioblastomas present intensive angiogenesis, thus anti-Vascular Endothelial Growth Factor (VEGF) antibodies (mAbs) have been proposed as promising therapies. However, the results of clinical trials reported moderate toxicity and limited effectiveness. This study evaluates the in vivo pharmacokinetics and biodistribution of these mAbs in a growing model of glioblastoma in rats using Positron Emission Tomography (PET).

MATERIAL

&Methods: mAbs were radiolabeled with zirconium-89. Four days after the model induction, animals were injected with 2.33 ± 1.3 MBq of [89Zr]-DFO-bevacizumab (n = 8) or 2.35 ± 0.26 MBq of [89Zr]-DFO-aflibercept (n = 6). PETs were performed at 0H, 48H, 168H, 240H, and 336H post-injection. Tumor induction was confirmed using [18F]-Fluorodeoxyglucose-PET and immunohistochemistry. Radiotracer uptake was estimated in all pre-defined Volumes-of-Interest.

RESULTS

Anti-VEGF mAbs showed 100 % Radiochemical-Purity. [89Zr]-DFO-bevacizumab showed a significantly higher bioavailability in whole-blood. A significant increase in the tumor uptake was detectable at 168H PET with [89Zr]-DFO-bevacizumab meanwhile with [89Zr]-DFO-aflibercept it was only detectable at 336H. [89Zr]-DFO-bevacizumab tumor uptake was significantly higher than that of [89Zr]-DFO-aflibercept in all the scans. Tumor induction was confirmed in all animal models.

CONCLUSION

MAbs detect VEGF-expression in glioblastoma models. Tumors were earlier targeted by Bevacizumab. The lower blood availability of aflibercept resulted in a lower tumor uptake than bevacizumab in all the scans.

Can angiogenesis inhibitor therapy cause changes in imaging features of hepatic hemangioma- Initial study

Background

To observe whether anti-angiogenesis therapy can induce changes in size and enhancement characteristics of hepatic hemangioma.

Method

133 patients with hepatic hemangioma lesions were analyzed and classified into a Bevacizumab group (n=65) and the control group (n=68). The parameters (Volume, CT enhancement ratio, enhancement patterns) of pre-and post-treatment in the bevacizumab and control groups independently calculated and compared by two radiologists. Correlation among the systolic blood pressure, diastolic blood pressure, heart rate with the hemangioma volume was evaluated using Pearson’s correlation analysis.

Results

The hepatic hemangioma volume was significantly decreased after treatment in the Bevacizumab group (8.6 ± 18.7mL vs.7.3 ± 16.3mL, P<0.05), and there was no significant change in the control group (15.1 ± 19.8mL vs.15.4 ± 20.7mL, P = 0.504). A significant difference in enhancement patterns of hepatic hemangiomas was observed after treatment with Bevacizumab (P<0.01). There was no significant difference in arterial phase (AP)enhancement rate and arterial phase-portal venous phase (AP-PVP) enhancement ratios after treatment in the Bevacizumab and control groups (Ps>0.05).The Pearson correlation results showed that blood pressure, heart rate, and hemangioma volume were unrelated or weakly related before and after bevacizumab treatment under the control of factors including weight, contrast injection scheme and CT scanning scheme.

Conclusions

Anti-angiogenesis therapy can cause changes in enhancement pattern and volume of hepatic hemangioma. Radiologists should pay more attention to the reexamination of tumor patients treated with anti-angiogenesis therapy.