An imidazotetrazine that is 3,4-dihydroimidazo[5,1-d][1,2,3,5]tetrazine which is substituted at positions 3, 4, and 8 by methyl, oxo, and carboxamide groups, respectively. A prodrug for MTIC (5-(3-methyltriaz-1-en-1-yl)-1H-imidazole-4-carboxamide, formed by spontaneous hydrolysis of temozolomide in the body), it is used as an oral alkylating agent for the treatment of newly diagnosed malignant glioblastoma multiforme (concomitantly with radiotherapy) and malignant melanoma.