Preclinical evaluation of several cisplatinum analogs against human esophageal carcinoma by subrenal capsule assay

The antitumor activities of CDDP analogs (CBD-CA, NK-121, 254-S) were evaluated preclinically by subrenal capsule assay (SRCA) with cyclophosphamide pretreatment. In the fundamental study, the antitumor activities against serially transplanted human esophageal cancer xenograft (IMEs-1) were compared with subcutaneous transplantation assay in nude mice and SRCA. The antitumor activities in SRCA were similar to those of in nude mice assay system (CBDCA greater than CDDP greater than 254-S greater than NK-121). Thus SRCA was considered to be useful for the evaluation of the activities of these agents. The activities were also tested against 10 human esophageal tumors obtained clinically. The sensitivity rate of these agents were 50% in CDDP, 30% in CBDCA, 30% in NK-121, and 30% in 254-S, respectively. These analogs seemed to be less effective than CDDP. However, in two cases, analogs were active though CDDP were inactive. The results suggest that these analogs are useful for the cases in which CDDP can not be given due to the toxicities and also for outpatient use.