Effect of the mixed bacterial vaccine on the immune response of patients with non-small cell lung cancer and refractory malignancies.

Since 1984, 13 patients were entered into our study and 12 patients have completed one or more cycles of treatment with mixed bacterial vaccine (MBV), a natural biologic response modifier derived from Streptococcus pyogenes and Serratia marcescens. Eight patients with refractory malignancy were treated with MBV only (0.1 ml intravenously [IV]) twice weekly for 3-16 weeks (colorectal cancer, pancreatic cancer, chronic lymphatic leukemia, hepatoma [two patients], sarcoma [three patients]). Four patients with advanced non-small cell lung cancer were treated with MBV in combination with low-dose cyclophosphamide, day 1; cisplatin, day 15; and MBV, 0.1 ml IV, days 5, 7, and 9. Two patients in this study received cyclophosphamide and cisplatin alone. The cycle was repeated every 28 days. Plasma interferon levels, interleukin-2 production by peripheral lymphocytes, and lymphocyte subpopulations were monitored. Interferon levels and interleukin-2 production showed increased or sustained values in general. In some patients, B-cells and helper T-cell populations increased, whereas T-suppressor cell numbers declined. With one exception, side effects were mild and consisted of fever greater than 37.8 degrees C (nine of 13), chills (11 of 13), increased respiratory rate (nine of 13), minor changes in blood pressure (seven of 13), and nausea (three of 13). One patient with non-small cell lung cancer had a partial response. Two patients with non-small cell lung cancer and one patient with refractory malignancy had stable disease and performance status at the end of 8 weeks of treatment; one patient with refractory malignancy was stable at the end of 4 weeks of treatment. In this pilot study, cancer patients treated with MBV showed objective evidence of immune stimulation with acceptable toxicity.