The use of decitabine was linked to improved platelet counts and survival rates in patients with refractory prolonged isolated thrombocytopenia (RPIT), which can be a complication of allogeneic hematopoietic cell transplantation (HCT), according to the results of a study recently published in Blood Advances.
“Isolated thrombocytopenia is a frequent and severe complication of HCT that is associated with worse outcomes,” the study investigators explained in their report. According to the investigators, RPIT has been thought to relate to such factors as disease recurrence, treatment history, factors related to the transplant donor, and other transplantation complications. However, they suggested that the absence of a consistent definition for prolonged isolated thrombocytopenia has hindered understanding of its patterns.
This prospective, phase 3 clinical trial (ClinicalTrials.gov Identifier: NCT02487563) included patients who had undergone allogeneic HCT and developed RPIT and who were treated at any of 6 participating hematology centers in China.
Patients were randomly assigned across 3 treatment arms: low-dose decitabine with recombinant human thrombopoietin (arm A), decitabine only (arm B), or conventional treatment (arm C). Platelet response at 28 days following treatment was the primary study endpoint, and this was defined as a sustained increase of 30 x 109/L or more, independent of transfusion for 3 days.
Across the participating centers, 2616 allogeneic HCT recipients were identified, of whom 256 had developed thrombocytopenia for more than 60 days following transplantation, and 97 met criteria for study inclusion. A total of 91 patients were evaluated for response.
The response rate for arm A was 66.7%, for arm B it was 73.3%, and for arm C it was 19.4%. Arms A and B were not statistically different for response (P =.779), while the response rate for arm C was statistically lower than the others (P <.001).
At a median follow-up of 11 months, the estimated 1-year survival rates were 64.4% for arm A and 73.4% for arm B, which were both greater than in arm C (41.0%). When the decitabine arms were combined, the survival rate was 68.2%, which was significantly higher than 1-year survival in arm C (P =.008).
The treatment arms receiving decitabine also showed significantly elevated total megakaryocyte counts, platelet-shedding megakaryocytes, and megakaryocyte polyploidy, while arm C did not. This suggested there are improvements in megakaryocyte proliferation and maturation with decitabine, according to the investigators.
“In conclusion, this multicenter randomized study demonstrates the efficacy and safety of decitabine for patients with RPIT after HCT, with improved response and prolonged survival,” the study investigators wrote in their report.
Tang Y, Chen J, Liu Q, et al. Low-dose decitabine for refractory prolonged isolated thrombocytopenia after HCT: a randomized multicenter trial. Blood Adv. 2021;5(5):1250-1258. doi:10.1182/bloodadvances.2020002790