Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation as Immunotherapy for Pancreatic Cancer

Objective: Advanced unresectable pancreatic cancer has an extremely poor prognosis despite intensive chemotherapy. As a new therapeutic modality, we investigated nonmyeloablative allogeneic hematopoietic stem cell transplantation from a related donor. Methods: Five patients with chemotherapy-resistant pancreatic cancer received allogeneic peripheral blood stem cell transplantation after a conditioning regimen consisting of low-dose total body irradiation and fludarabine. The prophylaxis for graft-versus-host disease consisted of mycophenolate mofetil and cyclosporine. Results: The median age of the 5 patients was 54 years, and the median duration from diagnosis to nonmyeloablative allogeneic hematopoietic stem cell transplantation was 10 months. Three of the 5 patients achieved complete donor chimerism of peripheral T cells, at a median time of day 42. Acute graft-versus-host disease developed in 3 patients: grade 2 in 2 patients and grade 1 in 1. Tumor reduction was observed in 2 patients: 1 patient showed disappearance of the pancreatic tumor, and the other patient showed approximately 20% reduction of the tumor. Marked elevation of tumor necrosis factor alpha was observed as the tumor regressed. Conclusions: Although advanced pancreatic cancer progresses rapidly, some graft-versus-tumor effects and pivotal role of tumor necrosis factor alpha were suggested. To obtain the durable response, patient selection and new strategies become important.