Hematopoietic cell transplantation (HCT) is associated with a disease-free survival rate of 90 percent at five years in patients with beta-thalassemia, when the transplant is performed during childhood with a human leukocyte antigen-identical sibling. However, long-term data on toxicity and chronic complications following HCT are limited.
In a French retrospective study spanning 27 years and presented at the 22nd Congress of the European Hematology Association, Ilhem Rahal, from the HÃ´pital de la Timone in Marseille, France, and colleagues found that endocrinologic complications were frequent after allogeneic HCT (alloHCT). Fertility can be partially preserved, "but this result has to be re-evaluated with the more recent use of intravenous busulfan" as part of the conditioning regimen, they wrote.
The researchers identified 134 patients from a French national registry of patients with beta-thalassemia and the French Medical Society of Bone and Marrow Transplantation and Stem Cell Therapy. The analysis included 107 patients who received alloHCT between 1985 and 2012 and were alive at least two years following transplant.
The investigators assessed medical examination results, long-term treatments, and laboratory tests (including serum ferritin, hemoglobin, liver enzymes, creatinine, and thyroid evaluation) to determine long-term effects of alloHCT in 99 evaluable patients. Six patients were not evaluable, and two died of chronic graft-versus-host disease.
The median age at the time of alloHCT was 5.9 years (range = 8 months to 26 years). Most patients received bone marrow (85%) from a matched sibling donor (90%), and most underwent a conditioning regimen of busulfan and cyclophosphamide (85%, including oral busulfan in 52% of patients). The median age at last visit was 19 years (range not provided).
Following alloHCT, patients had a median hemoglobin value of 12.5 g/dL (range = 86-165 g/dL) at a mean of 18 years of age (range not provided). Age, donor sex, and the presence of donor thalassemia trait significantly influenced hemoglobin values, the authors reported.
Chronic complications occurred in 12 percent of patients, including hypothyroidism (n=7), diabetes (n=5), and heart failure (n=2). These were "similar to those observed in patients treated with transfusion and chelation therapy," the researchers noted. Two patients also experienced chronic respiratory failure related to transplant.
At the last evaluation, gonadal dysfunction was observed in 60 percent of women who were >13 years old; however, 12 of 27 women >20 years old experienced at least one successful pregnancy following alloHCT. At least half of patients were receiving a long-term hormonal treatment or antibiotic prophylaxis at the time of the last visit.
After two years, most patients (n=93) had stopped their immunosuppressive treatment, and 37 patients were being treated with iron chelation therapy and/or phlebotomies.
"A comprehensive and regular long-term follow-up should be established for all patients receiving alloHCT for beta-thalassemia major," the authors concluded.
The study's findings are limited by its retrospective design. Treatment developments for beta-thalassemia may also limit the study's implications.
The study authors report no relevant conflicts of interest.
Rahal I, Galambrun C, Bertrand Y, et al. Long-term health status after HSC transplantation for thalassemia: the French experience. Abstract #S131. Presented at the 22nd Congress of the European Hematology Association, June 23, 2017; Madrid, Spain.