A Case Series of Post-Transplantation Cyclophosphamide in Unrelated Donor Hematopoietic Cell Transplantation for Aplastic Anemia.

Patients with severe aplastic anemia (SAA) who fail immunosuppressive therapy have a dismal prognosis. Hematopoietic stem cell transplantation (HSCT) from an unrelated donor (URD) is one of the most effective treatment options. Two institutions have independently adopted a post-transplantation cyclophosphamide (PTCy) approach for patients with SAA undergoing HSCT from a URD. Thirteen patients were included, 11 of whom had been treated with immunosuppressive therapy. Eight patients had a mismatched URD. All patients were conditioned with fludarabine, cyclophosphamide, and total body irradiation, in various dosage combinations. PTCy was given at a dose of 100 mg/kg. Two patients died, and overall survival was 85% at 2 years. All patients engrafted, but 1 patient developed secondary graft failure. Of the 11 patients alive after 2 years, 9 had complete donor chimerism. All surviving patients were transfusion-independent. Ten patients (77%) had cytomegalovirus reactivation, and 2 patients had more than 1 reactivation. No Epstein-Barr virus reactivation or post-transplantation lymphoproliferative disease was observed. Four patients had mild hemorrhagic cystitis. In summary, our findings show that PTCy is a promising treatment for patients with SAA undergoing URD HSCT.

Impact of Anti-CMV IgG Titers and CD34 Count Prior to Hematopoietic Stem Cell Transplantation from Alternative Donors on CMV reactivation.

Cytomegalovirus (CMV) reactivation remains one of the main infectious complications following hematopoietic stem cell transplantation (HSCT). In this study, we explored the role of anti-CMV antibody titers in HSCT from alternative donors and to compare the risk of CMV reactivation between posttransplant cyclophosphamide-based haploidentical HSCT and antithymocyte globulin-based unrelated donor (URD) HSCT. We included 98 CMV-positive patients, 30 undergoing haploidentical HSCT and 68 undergoing URD HSCT. The majority of patients had a malignant disease (84%), received a myeloablative conditioning regimen (78%), and received a bone marrow graft (90%). The median pretransplantation anti-CMV IgG level was 109 U/mL. With median follow-up of 2.2 years, a total of 72 CMV reactivations occurred in 50 patients. There was no difference in CMV reactivation pattern between haploidentical HSCT recipients and URD HSCT recipients. In multivariable analysis until the first event, the incidence of CMV reactivation was higher in patients with anti-CMV IgG levels >100 U/mL (hazard ratio [HR], 2.38; P = .005) and in patients diagnosed with grade II-IV acute graft-versus-host disease (GVHD) (HR, 10.8; P = .003) after day +50 and lower in patients who received higher doses of CD34 cells (HR, .44; P = .006). In multivariable analysis for recurring events, the incidence of CMV reactivation was higher in patients receiving reduced-intensity conditioning (HR, 1.69: P = .04) and in patients with acute GVHD (HR, 1.88; P = .02), and lower in those who received higher doses of CD34 cells (HR, .55; P = .01). In summary, we have shown that pretransplantation anti-CMV IgG titers are correlated with CMV reactivation risk. More studies are needed to assess how this information can be incorporated in HSCT. The use of high-dose cellular grafts, a modifiable risk factor, also protects against CMV reactivation.