A conditioning regimen of clofarabine plus total body irradiation prior to allogeneic hematopoietic stem-cell transplantation (HSCT) led to a graft-versus-host disease (GVHD) relapse-free survival rate of 22% in patients with high-risk acute leukemia, according to research presented at the Tenth Annual Meeting of the Society of Hematologic Oncology.
Ali Atoui, MD, of the American University of Beirut in Lebanon, and colleagues conducted the observational retrospective study at the American University of Beirut Medical Center and Saint-Antoine Hospital in Paris, France.
The researchers wanted to determine the outcomes of patients who received a conditioning regimen of total body irradiation and clofarabine, an immunosuppressive purine analog, before receiving HSCT from a matched or haploidentical donor.
“The addition of total body irradiation to conditioning regimens has been widely investigated. However, the use of single-agent clofarabine in combination with higher doses of [total body irradiation] ranging from 4 to 8 Gy has not been studied,” Dr. Atoui and colleagues wrote.
The study included 23 patients, most of whom were male (61%), with a median patient age of 43 years (range, 21-78). Half of the patients had acute myeloid leukemia, while half had acute lymphoblastic leukemia. Most patients (61%) were in complete remission at the type of transplant, while 35% had refractory disease. See the Table for information on the donor types.
Table. Donor Types for Patients Undergoing a Conditioning Regimen of Clofarabine Plus Total Body Irradiation Prior to Allogeneic HSCT
| Donor type | Percentage of patients receiving |
| Matched related donor | 39% |
| Matched unrelated donor | 17% |
| Haploidentical related donor | 35% |
| Unrelated cord blood donor | 9% |
All patients received clofarabine and most (87%) received 4 Gy total body irradiation, while 13% received 8 Gy. Most patients received antithymocyte globulin (65%).
The GVHD relapse-free survival rate was 22% at 1 year after transplant. The 2-year progression-free survival rate was 48%, with a 2-year overall survival rate of 43% at a median follow-up of 22.4 months. The transplant-related mortality rate was 4% at 100 days after transplant and 13% at 1 year after transplant.
“The use of clofarabine in combination with [total body irradiation] as a conditioning regimen for allogeneic stem-cell transplant in high-risk acute leukemia confers disease control with low transplant-related mortality,” Dr. Atoui and colleagues concluded.
Atoui A, Dulery R, Terro K, et al. Clofarabine and total body irradiation as a conditioning regimen for allogeneic stem cell transplantation in high-risk acute leukemia. Poster CT-028. Presented at the Tenth Annual Meeting of the Society of Hematologic Oncology; September 28-October 1, 2022; Houston, TX.
