Use of pyrimido[5,4-d]pyrimidines for preventing primary and secondary resistance in chemotherapy and pharmaceuticals containing these compounds

摘要

The invention relates to pharmaceuticals containing a pyrimido[5,4-d]pyrimidine of the formula <IMAGE> in which R2 is a dialkanolamino group, R4 and R8, which can be identical or different, are a dialkylamino group or a pyrrolidino or piperidino group which is optionally substituted by a methyl group and R6 is a hydrogen atom or an alkyl group, or its physiologically tolerated acid addition salts with an inorganic or organic acid and at least one chemotherapeutic agent from the series of natural products, and to the use of the above pyrimido[5,4-d]pyrimidines for sensitising tumours in chemotherapy with the abovementioned chemotherapeutic agents.