Trial of a Vaccination With Tumor Antigen-loaded Dendritic Cell-derived Exosomes

Lung cancer is the worldwide leading cause of cancer death. In France, with 28,000 new cases per year, lung cancer is the 4th in terms of incidence but remains the leading cause of cancer death. The 5-year survival of lung cancer, all stages and all types, is very low, estimated at 12% among men and 16% among women in France. In advanced unresectable non small cell lung cancer, standard treatment relies on platinum-based induction chemotherapy. The median progression-free survival (PFS) in patients responding or stabilized after 4 chemotherapy cycles ranges from 2 to 2.8 months. Gustave Roussy and Curie institutes have developed an immunotherapy involving metronomic cyclophosphamide (mCTX) followed by vaccinations with tumor antigen-loaded dendritic cell-derived exosomes (Dex). mCTX inhibits Treg functions restoring T and NK cell effector functions and Dex are able to activate the innate and adaptive immunity. Phase I trials showed the safety and feasibility of Dex vaccines but no induction of T cells could be monitored in patients. Since 2007, we validated a new process for isolation of second generation Dex with improved immune stimulatory capacities. We propose a maintenance immunotherapy in 47 advanced unresectable NSCLC patients responding or stabilized after induction chemotherapy with Dex-based treatment to improve PFS rate at 4 months in these patients.