The Ludwig Lung Cancer Study Group aims to investigate the role of immunotherapy as adjuvant treatment modality in operable non-small cell bronchial carcinoma. The participants are 12 european clinics and institutes. With a proven accrual of 350 patients per year the group offers a sharp tool in clinical oncology with regards to bronchial carcinoma. The accrual phase of the first trial was closed on February 2, 1979 with 475 patients, starting a new protocol on February 5, 1979. The ongoing randomized clinical trial aims to determine if intrapleural administration of corynebacterium parvum (c. p.) can increase the tumor recurrence-free interval or increase survival. Furthermore the study aims to identify high and low risk patient subgroups after biological and immunological investigations. The possibility of giving c. p. intrapleurally in humans was investigated in a phase-I-toxicity study. A dose of 7 mg has been adopted for the clinical trial since this dose combines a measureable systemic effect (increase of leucocyte and monocyte counts) with acceptable toxicity. The main morbidity was fever, flu-like symptoms and chest pain.