Patients with DLBCL, NOS who relapse or progress following first-line therapy have been treated wit "salvage regimens" consisting of high-dose (also termed high-intensity) chemotherapy conditioning drugs followed by autologous stem cell transplantation. This regimen has attained 3 year progression-free survival rates of 21–37%. Relapse following this treatment carries a very poor prognosis with median overall survival times of ~10 months. Patients who have failed or because of health issues are ineligible for autologous stem cell transplantation have been treated with low-dose (i.e. low-intensity) chemotherapy conditioning regimens followed by allogeneic stem cell transplantation. This regimen has achieved 3 year progression-free and overall survival rates of 41% and 52%, respectively. Further studies are underway to determine the best treatment regimens for these cases. Patients refractory to first-line therapy or who relapse within 12 months of receiving "salvage" therapy (including bone marrow transplant) for recurrent disease have had poor prognoses with median overall survival rates of 3.3 and 6.3 months, respectively. Thee prognosis of these patients appears to be improved by using CAR-T therapy.