[Models of preclinical studies of anthracyclines]

Since the first discovery of antitumor properties of daunorubicin in 1962, several hundreds of anthracyclines have been evaluated. In 1969, the primary screening on L1210 leukemia allowed to detect doxorubicin which is more active than daunorubicin and has been found clinically active on several human solid tumors. Therefore, L1210 leukemia appeared to be a useful model for evaluating experimental antitumor activity of anthracyclines, indicating a possible correlation between this model and the clinic. Analogs which are equally or more active than doxorubicin in the primary screening are tested in the secondary screening, then eventually in models of cardiotoxicity in order to evaluate their therapeutic index. The secondary screening includes murine solid tumors (B16 melanoma, Lewis lung carcinoma, mammary adenocarcinomas, colon adenocarcinomas 26 and 38) and human tumor xenografts into nude mice or under the renal capsule of normal mice (LX1, lung - CX1, colon - MX1, breast). Various tumor localizations (i.p., i.v., s.c., i.m., i.c.), various routes of administration (mainly i.v. and p.o.), various schedules of treatment (early or delayed, repeated or intermittent) and models of polychemotherapy are used to obtain a better evaluation of the compound. P388 leukemia resistant to doxorubicin is useful to test cross resistance in vivo and also to screen compounds able to reverse this phenomenon. Until now, 17 new anthracyclines have been introduced into clinical trials. Aclacinomycin has a different mechanism of action from that of doxorubicin (induction of tumor cell differentiation, inhibition of B and T suppressor lymphocytes); it is less myelotoxic and it is not mutagenic in vitro. THP-doxorubicin is more active than doxorubicin against L1210 leukemia and some solid tumors; it seems less cardiotoxic.(ABSTRACT TRUNCATED AT 250 WORDS)