Pharmaceutical composition having enhanced antitumor activity and/or reduced side effects, containing an antitumor agent and an hydroximic acid derivative

A pharmaceutical composition having antitumor activity with reduced side effect(s) comprising an enhanced effective amount of a known active substance having antitumor effect selected from the group consisting of cisplatin and carboplatin or, optionally, a pharmaceutically suitable acid addition salt thereof and an effective amount of a hydroximic acid derivative of the formula I

• wherein,
• R1 represents a hydrogen atom or a C1-5 alkyl group,
• R2 stands for a hydrogen atom, a C1-5 alkyl group, a C3-8 cycloalkyl group or a phenyl group optionally substituted by a hydroxy or a phenyl group, or
• R1 and R2 together with the nitrogen atom they are attached to form a 5 to 8 membered ring optionally containing one or more further nitrogen, oxygen or sulfur atom(s) and said ring can be condensed with another alicyclic or heterocyclic ring, preferably a benzene, naphthalene, quinoline, isoquinoline, pyridine or pyrazoline ring, furthermore, optionally, the nitrogen and/or sulfur heteroatom(s) are present in the form of an oxide or dioxide,
• R3 means a hydrogen atom, a phenyl group, a naphthyl group or a pyridyl group wherein said groups can be substituted by one or more halo atom(s) or C1-4 alkoxy group(s),
• Y is a hydrogen atom, a hydroxy group, a C1-24 alkoxy group optionally substituted by an amino group, a C2-24 polyalkenyloxy group containing 1 to 6 double bond(s), a C1-25 alkanoyl group, a C3-9 alkenoyl group or a group of the formula R7—COO— wherein R7 represents a C2-30 polyalkenyl group containing 1 to 6 double bond(s),
• X stands for a halo atom, an amino group, a C1-4 alkoxy group, or
• X forms with B an oxygen atom, or
• X and Y together with the carbon atoms they are attached to and the —NR—O—CH2— group being between said carbon atoms form a ring of the formula a
• wherein
• Z represents an oxygen atom or a nitrogen atom,
• R stands for a hydrogen atom or
• R forms with B a chemical bond,
• A is a C1-4 alkylene group or a chemical bond or a group of the formula b,
• wherein
• R4 represents a hydrogen atom, a C1-5 alkyl group, a C3-8 cycloalkyl group or a phenyl group optionally substituted by a halo atom, a C1-4 alkoxy group or a C1-5 alkyl group,
• R5 stands for a hydrogen atom, a C1-4 alkyl group or a phenyl group,
• m has a value of 0, 1 or 2,
• n has a value of 0, 1 or 2,
• or a physiologically acceptable acid addition salt thereof in admixture with one or more conventional carrier(s),
• wherein the antitumor activity is against tumors sensitive to the combination.