EX-VIVO RAS PEPTIDE VACCINATION IN PATIENTS WITH ADVANCED PANCREATIC-CANCER - RESULTS OF A PHASE I II STUDY/

In a pilot phase I/II study we have tested synthetic ras peptides used as a cancer vaccine in 5 patients with advanced pancreatic carcinoma. The treatment principle used was based on loading professional antige n-presenting cells (APCs) from peripheral blood with a synthetic ras p eptide corresponding to the ros mutation found in tumour tissue from t he patient. Peptide loading was performed ex vivo and the next day APC s were re-injected into the patients after washing to remove unbound p eptide. Patients were vaccinated in the first and second week and ther eafter every 4-6 weeks. In 2 of the 5 patients treated, an immune resp onse against the immunising ras peptide could be induced. None of the patients showed evidence of a T-cell response against any of the ras p eptides before vaccination. The treatment was well tolerated and could be repeated multiple times in the same patient. Side effects were not observed even if an immunological response against the ras peptide wa s evident. We conclude that ras peptide vaccination according to the p resent protocol is safe and may result in a potentially beneficial imm une response even in patients with advanced malignant disease. (C) 199 6 Wiley-Liss, Inc.