Editor's Note: The 66th Annual Meeting of the American Society of Hematology (ASH) took place from December 7–10, 2024, in San Diego, USA. As one of the largest and most prestigious international conferences in the field of hematology, ASH highlighted groundbreaking advancements and new drug development data, showcasing the highest levels of academic research globally. Platelet delay or engraftment failure is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Strategies to accelerate platelet engraftment remain a critical clinical challenge. At this year’s ASH meeting, Dr. Erlie Jiang and his team from the Institute of Hematology & Blood Diseases Hospital (Chinese Academy of Medical Sciences) presented findings from their study (Abstract #266) investigating the effects of elevated recombinant human thrombopoietin (rhTPO) dosing on platelet engraftment in allo-HSCT. Hematology Frontier interviewed Prof. Jiang to explore the research findings and their implications.

01. Hematology Frontier: Could you elaborate on the factors and mechanisms behind delayed or failed platelet engraftment following allo-HSCT?

Dr. Erlie Jiang: The exact mechanisms underlying poor platelet engraftment after allo-HSCT are not fully understood, but several factors may contribute:

1. Insufficient Hematopoietic Stem Cell Numbers: A low stem cell dose can slow or impair platelet engraftment, potentially leading to graft rejection.
2. Poor Bone Marrow Microenvironment: Patients who have undergone intensive chemotherapy or those with advanced idiopathic myelofibrosis (PMF) may have an inadequate bone marrow microenvironment to support normal hematopoiesis.
3. Immune Factors: Ineffective immune clearance in the recipient or excessive donor immune activity can also disrupt platelet engraftment.

02. Hematology Frontier: Could you summarize your ASH 2024 study on elevated rhTPO dosing for allo-HSCT patients?

Dr. Erlie Jiang: Building on previous cohort studies, we conducted a prospective, dosage-exploration controlled clinical trial to assess the efficacy and safety of high-dose rhTPO (22,500 U, approximately 300 U/kg) versus low-dose rhTPO (15,000 U) in adult allo-HSCT recipients. Administered daily from day 1 post-transplant, the high-dose rhTPO significantly shortened platelet engraftment time by one day and neutrophil engraftment time by 1.5 days. Platelet counts of ≥30×10⁹/L were achieved over three days earlier in the high-dose group. Moreover, the incidence of poor platelet engraftment was lower in the high-dose group.

A particularly noteworthy finding was the significantly lower rate of moderate-to-severe aGVHD in the high-dose group, underscoring the potential benefits of elevated rhTPO dosing in reducing this complication.

03. Hematology Frontier: The optimal rhTPO dosing for promoting platelet engraftment post-allo-HSCT is still unclear. How do you determine the dosage in clinical practice, and are there plans for further research?

Dr. Erlie Jiang: While the optimal dose has not been definitively established, increasing the rhTPO dose may further improve platelet engraftment. However, safety considerations must be addressed carefully. Weight-based dosing might provide the best therapeutic outcomes. Larger-scale studies are necessary to confirm the optimal dose.

Additionally, understanding the relationship between rhTPO dosing and the incidence of moderate-to-severe aGVHD remains a critical area of interest. Several experts at this year’s ASH conference discussed this issue, emphasizing the need for basic research to elucidate underlying mechanisms and clinical trials to validate therapeutic benefits.

Dr. Erlie Jiang

• Institute of Hematology & Blood Diseases Hospital (Chinese Academy of Medical Sciences) Director of the Stem Cell Transplantation Center
• Academic Titles: MD, PhD, and doctoral advisor Chair of the Hematopoietic Stem Cell Transplantation Committee, Chinese Primary Health Care Foundation Head of the Leukemia Autologous Transplant Collaboration Group, China Hematology Specialty Alliance Deputy Chair, Hematopoietic Stem Cell Application Committee, Chinese Society of Hematology Executive Member, Hematologic Oncology Committee, Chinese Anti-Cancer Association Editorial Board Member of Chinese Journal of Hematology and Leukemia & Lymphoma

Research Focus:

Specializes in hematopoietic stem cell transplantation and related complications, including platelet engraftment and aGVHD management.

Achievements: Recipient of multiple Tianjin Science and Technology Progress Awards and principal investigator for over 10 national and provincial key projects. Author of 50+ SCI-indexed publications in journals such as Blood and Haematologica.