Patients with acute leukemia or myelodysplastic syndrome (MDS) who received fractionated total body irradiation plus fludarabine as a pre-transplant conditioning regimen had a two-year overall survival (OS) rate of 80%.
Researchers investigated the use of this conditioning regimen in patients undergoing mismatched related or unrelated donor hematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide. Most patients had acute lymphoblastic leukemia (46.5%) or acute myeloid leukemia (36.1%), while other patients had MDS.
Amrita Desai MD, MPH, of the City of Hope in Duarte, California, and colleagues conducted the research and presented their findings at the 10th Annual Meeting of the Society of Hematologic Oncology.
The retrospective, single-center study included 155 patients with hematologic malignancies who received a radiation dose of 1200 centigray with fludarabine and post-transplant cyclophosphamide 50 mg/kg on post-transplant days three and four, mycophenolate mofetil on days five to 35, and started tacrolimus or sirolimus on day five.
The median patient age was 38 years (range, 9-60 years), and most patients were male (56.8%). The median donor age was 31 years. Most patients (67.1%) had haploidentical donors, while the remainder (32.9%) had mismatched-unrelated donors. Nearly all patients (97.5%) had a Karnofsky performance status of ≥80.
The two-year overall survival rate was 80.1%, with a disease-free survival rate of 76.9% at a median follow-up of 24 months (range, three to 81 months). The 100-day non-relapse mortality rate was 1.9%, while the two-year relapse rate was 11.8%.
The fractionated total body irradiation plus fludarabine conditioning regimen was a “well-tolerated [myeloablative conditioning] regimen in mismatched donors with leukemia and MDS with low transplant-related mortality and good outcomes,” Dr. Desai and colleagues wrote.
The regimen is “promising” but “needs to be studied in future prospective randomized trials” the researchers concluded.
Reference
Desai A, Yang D, Blackmon A, et al. Fractionated total body irradiation and fludarabine based conditioning regimen with post-transplant cyclophosphamide (PTCy) for mismatched related and unrelated donors HCT for acute leukemia and MDS. Abstract CT-505. Presented at the 10th Annual Meeting of the Society of Hematologic Oncology, September 28-October 1, 2022.