PHASE-II TRIAL OF INTRAVENOUS ENDOTOXIN IN PATIENTS WITH COLORECTAL AND NONSMALL CELL LUNG-CANCER

We report the immunological and clinical results of a phase II trial w ith intravenously administered highly purified endotoxin (Salmonella a bortus equi) in patients with advanced cancer. 15 patients with non-sm all cell lung cancer and 27 with colorectal cancer were entered into t he study. 37 evaluable patients received at least four injections of e ndotoxin (4 ng/kg body weight) and 1600 mg ibuprofen orally in 2-week intervals. Transient renal (WHO grade 0-1) and hepatic (WHO grade 0-4) toxicities occurred in several patients. Constitutional side-effects such as fever, chills and hypotension could not be prevented completel y by pretreatment with ibuprofen. 3 patients in the colorectal cancer group demonstrated objective responses (1 complete remission (CR), 2 p artial remission (PR)). The complete remission has been maintained for more than 3 years, while the partial remissions were stable for 7 and 8 months, respectively. Only marginal antitumour effects were seen in the lung cancer group. Tolerance of the macrophage system to the stim ulatory effect of endotoxin, as measured by human necrosis factor alph a (TNF-alpha) release into serum, built up after the first administrat ion and remained at a steady-state level after each subsequent injecti on. In contrast, rising CD4:CD8 ratio and release of tumour necrosis f actor beta (TNF-beta) indicated the continuing activation of the lymph ocyte system by repetitive injections of endotoxin. Copyright (C) 1996 Elsevier Science Ltd