Preclinical studies to predict efficacy of vascular changes induced by combretastatin a-4 disodium phosphate in patients.
OBJECTIVE
To determine how combretastatin A-4 disodium phosphate (CA4DP) dose-dependent changes in radiation response of a C3H mouse mammary carcinoma relate to measurements of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters and how those mouse DCE-MRI results compare with published clinical DCE-MRI data.


METHODS
C3H mammary carcinomas grown in female CDF(1) mice were treated when at 200 mm(3) in size. Groups of mice were given graded radiation doses, either alone or followed 30 min later by an intraperitoneal injection of CA4DP, administered at doses of 10-250 mg/kg. The radiation dose producing local tumor control in 50% of treated animals at 90 days (TCD(50)) was calculated for each CA4DP dose. DCE-MRI was performed before and 3 h after CA4DP administration, and parameters describing vascularity and interstitial volume were estimated.


RESULTS
TCD(50) showed a dose-dependent decrease reaching significance at 25 mg/kg. At greater doses of 50 and 100 mg/kg, the TCD(50) increased slightly and was not significantly different from that of controls. TCD(50) significantly decreased again at 250 mg/kg. The drug dose-response curves for all post-treatment vascular DCE-MRI parameters showed a shape similar to that of the TCD(50) curve. A similar dose dependency was seen with previously published clinical data.


CONCLUSIONS
Our preclinical DCE-MRI data could predict the CA4DP enhancement of the tumor radiation response and suggest the clinical CA4DP doses necessary to improve the radiation response in patients.
Nielsen
Thomas
T
Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark. thomas@oncology.dk
Murata
Rumi
R
Maxwell
Ross J
RJ
Stødkilde-Jørgensen
Hans
H
Ostergaard
Leif
L
Horsman
Michael R
MR
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D003287:Contrast Media; D004307:Dose-Response Relationship, Radiation; D004354:Drug Screening Assays, Antitumor; D005260:Female; D008279:Magnetic Resonance Imaging; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply* / Q000188:drug therapy / Q000532:radiotherapy*; D051379:Mice; D008815:Mice, Inbred Strains; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000473:pathology; D013267:Stilbenes / Q000627:therapeutic use*; D047368:Tumor Burden
D000972:Antineoplastic Agents, Phytogenic; D003287:Contrast Media; D013267:Stilbenes; C058728:fosbretabulin