Phase I trial of human lymphoblastoid interferon with whole body hyperthermia in advanced cancer

Laboratory studies have shown a potentiation of the biological effects of interferons (IFN) by elevated temperatures (39.5-40.5 degrees C). Based on such observations a Phase I clinical trial involving 17 cancer patients was conducted to assess the toxicity and biological effects of combining whole body hyperthermia (WBH) (40.5 degrees C for 75 min) and IFN. The study design incorporated a treatment schedule which allowed comparisons of WBH alone, to IFN administered i.m., to combinations of the two modalities. Human lymphoblastoid IFN was given for 6 days in weeks, 2, 4, and 6. At least 4 patients were entered at each of three IFN dose levels (1 x 10(6) units/m2; 3 x 10(6) units/m2; 10 x 10(6) units/m2). WBH was delivered on day 1 of week 1, day 6 of week 4, and days 4 and 6 of week 6. IFN was administered 1 h prior to WBH. The schedule used allowed for the development of tachyphylaxis to IFN-induced fever. Maximum temperatures were not significantly higher 24 h post-IFN/WBH than after a comparable number of days of human lymphoblastoid IFN alone. There was no statistically significant difference in toxicity assessments, hematological and hepatic blood parameters, serum IFN levels, or biological response modulation (i.e., 2',5'-oligoadenylate synthetase activity; beta 2-microglobulin levels; natural killer cell cytotoxicity, using K562 target cells and Chang cells) 24 h posttreatment between human lymphoblastoid IFN alone or combined modality therapy. No cumulative toxicity was observed in 6 patients receiving maintenance therapy for up to 1 year. Prior preclinical observations, together with the clinical safety reported in this study, encourage further investigation into the interactions between IFNs and hyperthermia.