Phase I single-dose study of intracavitary-administered Nimotuzumab labeled with 188 Re in adult recurrent high-grade glioma.

Radioimmunotherapy (RIT) may improve the management of malignant gliomas. A Phase I clinical trial was performed to evaluate, for the first time, the toxicity and clinical effect of an intracavitary administration of a single dose of Nimotuzumab (h-R3) labeled wit (188)Re. Nimotuzumab is a humanized monoclonal antibody directed against epidermal growth factor receptors. Three patients with anaplastic astrocytoma (AA) and 8 with glioblastoma multiforme (GBM) were intended to be treated with 3 mg of mAb labelled with 10 or 15 mCi of (188)Re. In patients treated with 10 mCi (n=6) transitory worsening of pre-existing neurological symptoms were observed. Two patients treated with 15 mCi (n=4) developed early severe neurological symptoms and one also developed late severe toxicity (radionecrosis). In the group treated with 10 mCi, 1 GBM patient died in progression 6 months after the treatment, 2 patients (1 GBM and 1 AA) developed stable disease during 3 months. One GBM patient had partial response for more than 1 year and 2 patients (1 GBM and 1 AA) were asymptomatic and in complete response after 3 years of treatment. Maximal tolerated dose of the radioimmunoconjugate (188)Re-Nimotuzumab was 3 mg of the h-R3 labelled with 10 mCi of (188)Re. The radioimmunoconjugate showed a high retention in the surgical created resection cavity and the brain adjacent tissues with a mean value of 85.5 % of the injected dose one hour post-administration. This radioimmunoconjugate may be relatively safe and a promising therapeutic approach for treating high grade gliomas.

Systemic and skin toxicity in Cercopithecus aethiops sabaeus monkeys treated during 26 weeks with a high intravenous dose of the anti- epidermal growth factor receptor monoclonal antibody Nimotuzumab.

Nimotuzumab (h-R3) is a humanized anti-epidermal growth factor receptor monoclonal antibody (mAb) registered for treating head and neck tumours. The present study was designed to evaluate the systemic and skin toxicity of chronic intravenous administration of the h-R3 in a relevant species demonstrated by comparing the h-R3 binding affinity constants (Kd) in microsomal placental fractions from Homo sapiens and Cercopithecus aethiops monkeys using an EGF-Receptor radioligand competition assay. The Kd obtained for Nimotuzumab were 9.1 x 10(-8) M for monkeys and 4.5 x 10(-8) M for humans. Monkeys (n = 18) were distributed into 3 groups with 3 animals of each sex in each group. Group I received saline; group II received 2.85 mg/kg of h-R3; and group III received 28.57 mg/kg of the h-R3, which represent 1 and 10 times the human dose, and they were weekly intravenously treated during 26 weeks. During the study there were no deaths. Electroneurophysiological, sanguine chemistry and haematological results did not evidence alterations. Areas of haematomas, probably related with the administration procedure, were observed at the administration zones of all animals. The electrocardiography study showed at the end of the study a slight increase in the cardiac frequency of four treated animals without other signs. Unexpectedly, skin biopsies and a detailed clinical inspection of the animals did not detect the presence of cutaneous rash or any other skin toxicity sign reported for the majority of the anti-EGF-R monoclonal antibodies. It is concluded that doses up to 28.5 mg/kg of h-R3, intravenously administered during 26 weeks to Cercopithecus aethiops monkeys, do not produce considerable toxic effects.