Experimental studies of new anthracyclines: aclacinomycin, THP-adriamycin and ditrisarubicins.

Aclacinomycin is a member of naturally occurring anthracyclines having three sugar moieties in the molecule. It showed antitumour activity on various mouse and rat tumours. Combination therapy with AraC etc. gave remarkable clinical results on acute myeloid leukaemia. Aclacinomycin strongly inhibits RNA synthesis of the tumour cells. It has lower cardiac toxicity than adriamycin and no mutagenicity. THP-Adriamycin is a derivative of adriamycin designed from the structure of baumycins. It showed stronger effects than adriamycin in inhibiting many mouse tumours such as L1210 and P388 leukaemia, B16 melanoma and colon 38 adenocarcinoma. THP-Adriamycin is rapidly taken up by both adriamycin-sensitive and resistant leukaemic cells. Its level of cardiac toxicity is as low as that of aclacinomycin. Ditrisarubicins are new naturally occurring anthracyclines isolated from Streptomyces having six sugar moieties in the molecule. Ditrisarubicin has a potent cytostatic and antitumour activities on adriamycin resistant mouse leukaemia. Its binding constant to DNA is extremely high compared with other anthracyclines.