Treatment of an Nb-Pr-A.I.-3 (autonomous) tumor with combination chemotherapy.

The rat prostatic adenocarcinoma Nb-Pr-A.I.-3, an androgen-insensitive tumor, was evaluated with the following treatments: cyclophosphamide, cis-platinum, adriamycin, and the following combination therapies: cyclophosphamide and cis-platinum; adriamycin and cis-platinum; adriamycin, cis-platinum, and cyclophosphamide. Successful therapeutic combinations included cyclophosphamide alone (P Less Than 0.001) and the triple-drug combination (P Less Than 0.001). Significance was based on the final tumor volume at the termination of the experiment. Cyclophosphamide treatment alone was the only therapeutic regimen that resulted in complete tumor regression (16%) (2/12). Cyclophosphamide therapy also resulted in the lowest number of animals with metastasis (25%). On the basis of this study, the authors rate this animal model as a suitable one for trials of various chemotherapeutic combinations as well as for determining combination or single agents useful in preducing tumor regression and a decreased number of metastasis.