Long survival of patients with small cell lung cancer after adjuvant treatment with the anti-idiotypic antibody BEC2 plus Bacillus Calmette-Guerin

Despite active therapies for small cell lung cancer (SCLC), most patients r elapse and die of the disease. The present study evaluates immunization usi ng the anti-idiotypic antibody BEC2, which mimics the ganglioside GD3 expre ssed on the surface of most SCLC tumors, combined with Bacillus Calmette-Gu erin (BCG) as an immune adjuvant, We hypothesized that active immunization could alter the natural history of the disease, Fifteen patients who had co mpleted standard therapy for SCLC received a series of five intradermal imm unizations consisting of 2.5 mg of BEC2 plus BCG over a 10-week period. Blo od was collected for serological analysis, and outcome was monitored, All p atients developed anti-BEC2 antibodies, despite having received chemotherap y with or without thoracic radiation. We detected anti-GD3 antibodies in fi ve patients, including those with the longest relapse-free survival. The me dian relapse-free survival for patients with extensive stage disease is II months and has not been reached for patients with limited stage disease (>4 7 months), with only one of seven patients having relapsed after a median f ollow-up of 47 months. Immunization of patients with SCLC after standard th erapy using BEC2 plus BCG can induce anti-GD3 antibodies and is safe. The s urvival and relapse-free survival in this group of patients are substantial ly better than those observed in a prior group of similar patients. A Phase III trial is being conducted to evaluate BEC2 plus BCG as adjuvant therapy after chemotherapy and irradiation.