The physiologic role of cyclic adenosine monophosphate (cAMP) in the growth control of a spectrum of human cancer lines, including leukemic lines, and v-rasH oncogene-transformed NIH/3T3 cells is demonstrated by the use of site-selective cAMP analogs. These cAMP analogs, which can select either of the two known cAMP binding sites of the cAMP receptor protein, induce potent growth inhibition, phenotypic change, and differentiation (leukemic cells) of cancer cells at micromolar concentrations with no sign of cytotoxicity. The growth inhibition parallels selective modulation of cAMP-dependent protein kinase isozymes, type I versus type II, and suppression of cellular proto-oncogene expression. Site-selective cAMP analogs thus provide new biological tools for investigating cell proliferation and differentiation and also for the improved management of human cancers.

Summary Gemcitabine and 5-fluorouracil are the only two compounds with reproducible activity against advanced pancreatic cancer (APC). We have evaluated a novel combination of gemcitabine and 5-fluorouracil on the clinical benefit response (CBR) end point. Eleven consecutive patients with symptomatic APC were entered in a two-stage phase II trial. Gemcitabine was administered by intravenous (i.v.) bolus injection at the dose of 1000 mg m -2 on days 1, 8, 15 and 5-fluorouracil 500 mg m -2 was given by continuous i.v. infusion on days 1-5. Treatment was repeated every 28 days. A CBR was achieved in 7/11 patients. The mean time to loss of CBR was 26.5 weeks (range 14-18, median 22). Toxicity was mild and no APC patient experienced WHO grade 3 toxicity. The gemcitabine/5-fluorouracil combination is well tolerated and produces a symptomatic relief in the majority of APC patients.

A phase II clinical trial of subcutaneous recombinant Interleukin 2 (rIL-2) given by 5 days pulses followed by a 9 days rest has been performed in patients affected by renal cell carcinoma, malignant melanoma and colorectal cancer. A total of 25 patients entered the study, completed at least six courses of treatment, and were evaluable for toxicity and response to treatment. This schedule of subcutaneous rIL-2 was well tolerated and no World Health Organization grade 3 side effects were observed. A 33.3% response rate was recorded in patients affected by renal cell carcinoma, although no major responses were achieved in patients with malignant melanoma and colorectal cancer. A durable increase of natural killer activity retained by poeripheral blood mononuclear cells was demonstrated in these patients and was paralleled by increased serum levels of interferon gamma and tumor necrosis factor a without changes of circulating interleukin-1d. It is concluded that this schedule of pulse administration of subcutaneous rIL-2 has antitumor activity in renal cell carcinoma and produces durable biomodulatory effects.