There is a growing belief that angiogenesis inhibition represents a potentially promising, novel therapeutic approach to highly vascular solid tumors like malignant gliomas. Thalidomide and Peg-Intron (IFN - Interferon) are attractive drugs to use in combination to test the hypothesis of combination anti-angiogenesis therapy inhibition given their proven activity as single agents in patients with malignant gliomas and their spectrum of largely non-overlapping toxicities.