Maytansinoids, pharmaceutical compositions thereof and method of use thereof

An antitumor composition which comprises as an active ingredient an amount effective to inhibit the growth of tumors of a compound of the formula:

• ##STR8## wherein X is H or Cl, and
• R is C.sub.1-8 alkyl, phenyl, phenyl-C.sub.1-4 alkyl or 5- or 6-membered azaheterocyclic group containing one to four of N, of the class consisting of pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazinyl, piperidyl, piperazinyl, imidazolyl, pyrazolyl triazolyl, tetrazolyl, pyrrolinyl, pyrazolinyl, imidazolinyl, pyrrolidinyl, pyrazolidinyl, imidazolidinyl and triazolidinyl,
• said R group having one or two substituents selected from the group consisting of carboxyl, sulfo, an amino group which is substituted or mono-substituted by C.sub.1-4 alkyl, C.sub.3-4 alkenyl, benzyl, phenyl, C.sub.1-4 alkylsulfonyl, benzenesulfonyl and p-toluenesulfonyl, and
• a quaternary ammonio group of the formula:
• ##STR9## wherein each of R.sup.2, R.sup.3 and R.sup.4 is independently C.sub.1-4 alkyl, allyl or benzyl, or the quaternary ammonio group if formed at the ring N of a pyridinio, pyrazinio, pyrimidinio, pyridazinio, imidazolio, pyrazolio, pyrrolinio, triazolio, tetrazolio, piperidinio, piperazinio, pyrrolidinio, pyrrolinio, imidazolinio, imidazolidinio, pyrazolinio and pyrazolidinio group.

A method of inhibiting the growth of tumor cells and prolonging the survival time of a tumor-bearing warm blooded animal, which comprises administering to said animal an amount effective to inhibit the growth of tumors of a compound of the formula:

• ##STR10## wherein X is H or Cl, and
• R is C.sub.1-8 alkyl, phenyl, phenyl-C.sub.1-4 alkyl or 5- or 6-membered azaheterocyclic group containing one to four of N, of the class consisting of pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazinyl, piperidyl, piperazinyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, pyrrolinyl, pyrazolinyl, imidazolinyl, pyrrolidinyl, pyrazolidinyl, imidazolidinyl and triazolidinyl,
• said R group having one or two substituents selected from the class consisting of carboxyl, sulfo, an amino group which is unsubstituted or mono-substituted by C.sub.1-4 alkyl, C.sub.3-4 alkenyl, benzyl, phenyl, C.sub.1-4 alkylsulfonyl, benzenesulfonyl and p-toluenesulfonyl, and a quaternary ammonio group of the formula:
• ##STR11## wherein each of R.sup.2, R.sup.3 and R.sup.4 is independently C.sub.1-4 alkyl, allyl or benzyl, or the quaternary ammonio group is formed at the ring N or a pyridinio, pyrazinio, pyrimidinio, pyridazinio, imidazolio, pyrazolio, pyrrolinio, trazolio, tetrazolio, piperidinio, piperazinio, pyrrolidinio, pyrrolinio, imidazolinio, imidazolidinio, pyrazolinio and pyrazolidinio group.