In the 2B3-101 single Agent dose-escalation phase, female and male patients with solid tumors and brain metastases or recurrent malignant glioma will be enrolled. Patients will be assigned to a dose level cohort. - The starting dose will be 5 mg/m2, which is equal to 1/10 of the human equivalent dose of the LD10 of 2B3-101 in rats. A "3+3" dose-escalation design will be used. The study will investigate sequential cohorts consisting of 3-6 patients to be enrolled and treated at the applicable dose level. Planned dose levels for subsequent cohorts are 10, 20, 30, mg/m2 and steps of 10 mg/m2 thereafter. For more information on the dose escalation design and the increments, please see the dose escalation criteria section.