Antitumor effect and peritumoral brain edema formation in relation to MX2, ACNU, and doxorubicin therapy: A comparative analysis using rodent models of gliomas

The potential antitumor effect of MX2, a new lipophilic morpholino anthracycline, was compared with those of ACNU or doxorubicin (DOX) using two different rodent glioma models. A mouse subcutaneous glioma model (203 glioma) was used to measure the effect of each drug on reducing the glioma size and a rat 9L intracerebral glioma model (9L glioma) was used to assess the antitumor effect on survival rate in a clinically similar fashion. Treatment with ACNU inhibited tumor growth by 94.6% (p < 0.0001) and complete regression of the tumor was observed in 3 of 25 (12.0%) of the ACNU-treated cases. Tumor growth was inhibited by 32.4% with DOX despite a tendency (p < 0.16) and by 59.4% with MX-2 (p < 0.001); neither of these drugs resulted in complete tumor regression. In the intracerebral glioma rats, only ACNU tended to ameliorate survival rate, but there was no statistical significance. These results suggest that ACNU has the most potent effect but MX2 can be an option for chemotherapy of malignant gliomas. Interestingly, all three drugs significantly elevated the brain water content on both the ipsilateral and contralateral sides of the tumor, although they did not induce brain edema in the normal rat brains. Careful management of brain edema might be required regardless of the drug used during chemotherapy to maximize the prognosis of glioma patients.