Human pancreatic carcinoma xenograft models were developed from established MIA PaCa-2 and PANC-1 cell lines (ATCC, Rockville, MD). Tumors were maintained by serial trocar implantation in CD1 nu/nu mice, and attempts were made to test all drugs under optimal schedules at maximum tolerated doses. In both models, adriamycin, cisplatin, and 5-fluorouracil were inactive (< 60% inhibition of tumor weight), whereas gemcitabine (LY188011] produced modest activity (69% inhibition in MIA PaCa-2 and 76% inhibition in PANC-1. Major differences in tumor sensitivity were noted with diarylsulfonylureas (DSU) and taxol. The DSU (Sulofenur [LY186641] and LY295501) produced complete inhibition in the MIA PaCa-2 xenograft, but were inactive in PANC-1. Conversely, taxol produced 80% inhibition of PANC-1 tumor growth, but was inactive against MIA PaCa-2. In general, in vivo antitumor activity roughly correlated with in vitro tumor cytotoxicity with the exception of DSU. We have previously shown that DSU are extensively bound to albumin and that in vitro cytotoxic activity in serum-containing medium is not predictive of in vivo antitumor activity. The MIA PaCa-2 and PANC-1 xenograft models may be useful for selecting potential candidates for therapy of human pancreatic cancer.