Anti-Thymocyte Globulin Prophylaxis in Patients With Hematological Malignancies Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: An Updated Meta-Analysis

Individualized dose of anti-thymocyte globulin based on weight and pre-transplantation lymphocyte counts in pediatric patients: a single center experience

Anti-thymocyte globulin (ATG) has become a standard in preventing GVHD in related and unrelated donor transplantation, but there is no consensus on the best administration schedule. The PARACHUTE trial reported excellent CD4 immune reconstitution (CD4 IR) using a dosing schedule based on the patient's weight and pre-conditioning absolute lymphocyte count (ALC). In 2015 we introduced the PARACHUTE dosing schedule for pediatric patients at our center. One hundred one patients were transplanted for malignant and non-malignant diseases. In this non-concurrent cohort CD4 IR+, defined by a single CD4 count >50/µL on day 90, was seen in 81% of patients. The incidence of grade II-IV and III to IV aGvHD was 26.6% and 15.3% and 5% for cGvHD with no severe cases. We found no difference in aGvHD between donor type and stem cell sources. Five-year EFS and OS were 77.5% and 83.5%. Grade III-IV GFRS was 75.2%. CD4 IR+ patients had better EFS (93.1% vs. 77.7%, p = 0.04) and lower non-relapse mortality (2.7% vs. 22.2%, p = 0.002). The PARACHUTE ATG dosing schedule individualized by weight and ALC results in good early immune reconstitution, low incidence of cGvHD, and favorable survival for patients with different disease groups, donor types, and stem cell sources.

Graft-versus-host disease: teaching old drugs new tricks at less cost

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). Currently, more patients can receive SCT. This is attributed to the use of reduced intensity regimens and the use of different GVHD prophylaxis that breaks the barrier of human leukocyte antigen, allowing an increase in the donor pool. Once an area with relatively few clinical trial options, there has been an increase in interest in GVHD prophylaxis and treatment, which has led to many US Food and Drug Administration (FDA) approvals. Although there is considerable excitement over novel therapies, many patients may not have access to them due to geographical or other resource constraints. In this review article, we summarize the latest evidence on how we can continue to repurpose drugs for GVHD prophylaxis and treatment. Drugs covered by our review include those that have been FDA approved for other uses for at least 15 years (since 2008); thus, they are likely to have generic equivalents available now or in the near future.

[Efficacy and safety of secondary allogeneic hematopoietic stem cell transplantation in 70 patients with recurrent hematologic malignancies after transplantation]

Objectives: To investigate the role of donor change in the second hematopoietic stem cell transplantation (HSCT2) for hematological relapse of malignant hematology after the first transplantation (HSCT1) . Methods: We retrospectively analyzed patients with relapsed hematological malignancies who received HSCT2 at our single center between Mar 1998 and Dec 2020. A total of 70 patients were enrolled[49 males and 21 females; median age, 31.5 (3-61) yr]. Results: Forty-nine male and 21 female patients were enrolled in the trial. At the time of HSCT2, the median age was 31.5 (3-61) years old. Thirty-one patients were diagnosed with acute myeloid leukemia, 23 patients with ALL, and 16 patients with MDS or other malignant hematology disease. Thirty patients had HSCT2 with donor change, and 40 patients underwent HSCT2 without donor change. The median relapse time after HSCT1 was 245.5 (26-2 905) days. After HSCT2, 70 patients had neutrophil engraftment, and 62 (88.6%) had platelet engraftment. The cumulative incidence of platelet engraftment was (93.1±4.7) % in patients with donor change and (86.0±5.7) % in patients without donor change (P=0.636). The cumulative incidence of CMV infection in patients with and without donor change was (64.0±10.3) % and (37.0±7.8) % (P=0.053), respectively. The cumulative incidence of grade Ⅱ-Ⅳ acute graft versus host disease was (19.4±7.9) % vs (31.3±7.5) %, respectively (P=0.227). The cumulative incidence of TRM 100-day post HSCT2 was (9.2±5.1) % vs (6.7±4.6) % (P=0.648), and the cumulative incidence of chronic graft versus host disease at 1-yr post-HSCT2 was (36.7±11.4) % versus (65.6±9.1) % (P=0.031). With a median follow-up of 767 (271-4 936) days, 38 patients had complete remission (CR), and three patients had persistent disease. The CR rate was 92.7%. The cumulative incidences of overall survival (OS) and disease-free survival (DFS) 2 yr after HSCT2 were 25.8% and 23.7%, respectively. The cumulative incidence of relapse, OS, and DFS was (52.6±11.6) % vs (62.4±11.3) % (P=0.423), (28.3±8.6) % vs (23.8±7.5) % (P=0.643), and (28.3±8.6) % vs (22.3±7.7) % (P=0.787), respectively, in patients with changed donor compared with patients with the original donor. Relapses within 6 months post-HSCT1 and with persistent disease before HSCT2 were risk factors for OS, DFS, and CIR. Disease status before HSCT2 and early relapse (within 6 months post-HSCT1) was an independent risk factor for OS, DFS, and CIR post-HSCT2. Conclusion: Our findings indicate that changing donors did not affect the clinical outcome of HSCT2.

Role of abatacept in the prevention of graft-versus-host disease: current perspectives

Administration of abatacept following transplantation has been reported to inhibit graft rejection and graft-versus-host-disease (GvHD) in mouse models associated with allogeneic hematopoietic stem cell transplant (HSCT). This strategy has recently been adopted in clinical practice for GvHD prevention in human allogeneic HSCT and offers a unique approach to optimizing GvHD prophylaxis following alternative donor HSCTs. When combined with calcineurin inhibitors and methotrexate, abatacept had shown to be safe and effective in preventing moderate to severe acute GvHD in myeloablative HSCT using human leukocyte antigen (HLA) unrelated donors. Equivalent results are being reported in recent studies using alternative donors, in reduced-intensity conditioning HSCT and nonmalignant disorders. These observations have led to hypothesizing that even in the setting of increasing donor HLA disparity, abatacept when given with traditional GvHD prophylaxis does not worsen general outcomes. In addition, in limited studies, abatacept have being protective against the development of chronic GvHD through extended dosing and in the treatment of steroid-refractory chronic GvHD. This review summarized all the limited reports of this novels approach in the HSCT setting.