In vivo T-cell depletion with antithymocyte globulins improves overall survival after myeloablative allogeneic stem cell transplantation in patients with hematologic disorders

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

Background

Anti-thymocyte globulin (ATG) prophylaxis reduces graft-versus-host disease (GVHD) incidence. This meta-analysis aimed to explore the long-term efficacy of ATG and the influencing factors in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods

PubMed, Embase, and Cochrane databases were searched for the relevant studies published up to August 2020. Data from randomized controlled trials (RCTs) on ATG prophylaxis for GVHD prevention in allo-HSCT patients were extracted.

Results

A total of eight relevant RCTs (1,348 patients) were included. ATG significantly reduced the incidence of grade III–IV aGVHD (P = 0.001) and cGVHD (P < 0.001). ATG significantly improved the GVHD relapse-free survival (GRFS) (P < 0.001). The immunosuppressive regimen (number and dose of immunosuppressants) was significantly reduced when using ATG (P = 0.005). Epstein-Barr virus (EBV) reactivation was high in patients receiving ATG (P = 0.003). No significant differences were detected in relapses, overall survival (OS), relapse-free survival (RFS), and non-relapse mortality (NRM) between the ATG and no ATG groups. Subgroup analyses revealed that the donor type and ATG formulation might be the possible sources of heterogeneity among the included studies. Meta-regression analysis showed that the cumulative dose of ATG did not affect GVHD, OS, relapse, RFS, and NRM.

Conclusion

Although ATG had no significant effect on relapse, RFS, and NRM, it significantly reduced the occurrence and severity of GVHD, improved the GRFS, and reduced the number and dose of immunosuppressants in patients undergoing allo-HSCT.

Low-dose anti-thymocyte globulin reduce severe acute and chronic graft-versus-host disease after allogeneic stem cell transplantation

BACKGROUND

Anti-thymocyte globulin (ATG) administered at 5-10 mg/kg can prevent graft-versus-host disease (GVHD). We sought to investigate the potential for lower doses of ATG to decrease non-relapse mortality (NRM).

METHODS

We consecutively compared the outcomes of patients with hematological diseases who received allogeneic stem cell transplants from allogeneic related or unrelated donors before February 2010 and were not administered ATG (reference arm), with those administered 2.5 mg/kg ATG after March 2010 (treatment arm).

RESULTS

We recruited 19 patients into each arm (median age 49 years, range 19-64). 16 patients received myeloablative preparation regimens and 22 patients received toxicity-reduced preparation regimens. All but one patient achieved engraftment, and one secondary graft failure was observed. Overall incidence of acute and chronic GVHD were 63.2 and 15.8%, respectively, in the ATG arm (21.1% grade II to IV, and 0.0% grade III/IV acute GVHD), and 57.9 and 47.4%, respectively, in the reference arm (31.6% grade II to IV, and 21.1% grade III/IV acute GVHD). The estimated probability of overall survival (OS) at 6 years and relapse rate 3 years after transplantation were 49.2 and 26.3% for the ATG arm, respectively, and 54.2 and 21.1% for the reference arm, respectively. The rate of NRM was 10.5% in the ATG arm and 26.3% in the reference arm. No patients died as a result of acute or chronic GVHD.

CONCLUSIONS

Low-dose ATG may suppress severe acute GVHD and chronic GVHD without increasing NRM, and can be used safely for Japanese patients receiving transplants from HLA-matched donors.

Efficacy of antithymocyte globulin for allogeneic hematopoietic cell transplantation: a systematic review and meta-analysis

The efficacy of rabbit antithymocyte globulin (ATG) for the prevention of graft-versus-host disease (GVHD) has been evaluated in several randomized control trials, but the results show some discrepancies. Therefore, we performed a systematic review and meta-analysis covering the latest RCTs including six trials (total 845 patients). The incidence of acute and chronic GVHD was significantly lower in the ATG arms (risk ratio, 0.75 and 0.54, respectively). No significant differences were found regarding overall survival, the incidence of relapse, and non-relapse mortality; however, the incidence of cytomegalovirus and Epstein-Barr virus reactivation increased (risk ratio, 1.25 and 1.33), and neutrophil engraftment was significantly delayed (median, 2.66 days). In conclusion, rabbit ATG should be beneficial as a GVHD prophylaxis in addition to conventional regimens, with close monitoring of virus reactivation and enough attention to delayed engraftment. Studies comparing the timing and dosage of ATG are essential to determine the suitable prophylactic regimens.

The efficacy and safety of rabbit anti-thymocyte globulin vs rabbit anti-T-lymphocyte globulin in peripheral blood stem cell transplantation from unrelated donors

The comparative efficacy and safety of antithymocyte globulin (ATG) at fixed doses in patients undergoing allogeneic peripheral blood stem cell transplantation from unrelated donors (UR-PBSCT) has not been evaluated. In this study, the records of 56 patients and 54 patients who received pre-transplant ATG-Thymoglobulin (ATG-T) at a total dose of 10 mg/kg and ATG- Fresenius (ATG-F) at a total dose of 20 mg/kg, respectively, were retrospectively analyzed. ATG-F patients had a significantly lower probability of developing chronic graft-vs-host disease (cGVHD) than those treated with ATG-T (p = 0.04). ATG-F was associated with a non-significant trend towards lower relapse rates and higher survival at 3- and 5-years of follow-up compared with ATG-T. A significantly greater proportion of ATG-T patients experienced chills and high fever than ATG-F patients (p < 0.01). The current findings suggest that ATG-F may more effectively and safely prevent cGVHD without increasing relapse rates in patients undergoing UR-PBSCT.

Outcomes of peripheral blood stem cell transplantation patients from HLA-mismatched unrelated donor with antithymocyte globulin (ATG)-Thymoglobulin versus ATG-Fresenius: a single-center study

Although antithymocyte globulin (ATG) had been widely used in hematopoietic stem cell transplantation from unrelated donor due to its ability to prevent acute and chronic graft-versus-host disease (GVHD), the comparative efficacy and safety of ATG-Thymoglobulin (ATG-T) and ATG-Fresenius (ATG-F) in patients undergoing HLA-mismatched allogeneic peripheral blood stem cell transplantation from unrelated donors (UR-PBSCT) has not been evaluated. Retrospective analysis of patients who underwent HLA-mismatched UR-PBSCT between January 2003 and December 2013 and received pre-transplant ATG-T at a total dose of 10 mg/kg or ATG-F at a total dose of 20 mg/kg was performed. Patients who received ATG-T (n = 23) or ATG-F (n = 28) had similar baseline demographic, disease, and transplant characteristics. There were no significant between-groups differences in the probability of acute GVHD (P = 0.721) and chronic GVHD (P = 0.439). ATG-F was associated with nonsignificant trends toward higher disease-free survival at 3-year follow-up compared with ATG-T (45.7 ± 11.1 vs 61.3 ± 9.7 %, respectively, P = 0.07). A significantly greater proportion of ATG-T patients experienced high fever than ATG-F patients (P < 0.01) during ATG infusion. There was no difference in the rate of infection between the two treatment groups. There were less adverse effects comparing ATG-F with ATG-T. ATG-T at a total dose of 10 mg/kg and ATG-F at a total dose of 20 mg/kg had a similar clinical outcome in the setting of HLA-mismatched UR-PBSCT.