Comparative study on ATG-thymoglobulin versus ATG-fresenius for the graft-versus-host disease (GVHD) prophylaxis in allogeneic stem cell transplantation from matched unrelated donor: a single-centre experience over the contemporary years

Comparing the Outcomes of Matched and Mismatched Unrelated Allogeneic Hematopoietic Stem Cell Transplantation with Different Anti-Thymocyte Globulin Formulations: A Retrospective, Double-Centre Experience on Behalf of the Polish Adult Leukemia Group

Despite notable advancements in immunotherapy in the past decades, allogeneic hematopoietic stem cell transplantation (allo-HCT) remains a promising, potentially curative treatment modality. Only a limited number of studies have performed a direct comparison of two prevalent rabbit anti-thymocyte globulin (r-ATG) formulations-specifically, Thymoglobuline (ATG-T, formerly Genzyme) and Grafalon (ATG-G, formerly Fresenius). The primary objective of our retrospective analysis was to compare the outcomes of adult patients undergoing matched or mismatched unrelated donor (MUD/MMUD) allo-HCT, with a graft-versus-host disease (GvHD) prophylaxis based on either ATG-T or ATG-G. A total of 87 patients who had undergone allo-HCT between 2012 and 2022 were included. We observed no significant differences between ATG-T and ATG-G concerning the occurrence of acute graft-versus-host disease (aGvHD), regardless of its severity. Conversely, chronic graft-versus-host disease (cGvHD) occurred less frequently in the ATG-T group compared to the ATG-G group (7.5% vs. 38.3%, p = 0.001). The negative impact of ATG-G on cGvHD was confirmed by multivariate analysis (HR 8.12, 95% CI 2.06-32.0, p = 0.003). Patients treated with ATG-T manifested a higher incidence of cytomegalovirus (CMV) reactivations (70% vs. 31.9%, p < 0.001), with a shorter time between transplant and CMV (<61 days, 77.8% vs. 33.3%, p = 0.008) and a higher median CMV copy number (1000 vs. 0, p = 0.004). Notably, despite a higher occurrence of CMV reactivations in the ATG-T cohort, most patients were asymptomatic compared to ATG-G (85.7% vs. 43.8%, p = 0.005). By multivariate analysis, only aGvHD had an influence on CMV reactivations (HR 0.18, 95% CI 0.04-0.75, p = 0.019). Finally, we observed no significant differences in terms of 5-year overall survival (OS) and 3-year relapse-free survival (RFS) while comparing ATG-T and ATG-G (32.0% vs. 40.3%, p = 0.423; 66.7% vs. 60.4%, p = 0.544, respectively).

Comparison of rabbit ATLG and ATG for GVHD prophylaxis in hematological malignancies with haploidentical hematopoietic stem cell transplantation

Rabbit anti-human T lymphocyte globulin (ATLG) and anti-thymocyte globulin (ATG) are commonly used for graft-versus-host disease (GVHD) prophylaxis in allogeneic hematopoietic stem cell transplantation (HSCT). Yet, their efficacy and safety have seldom been compared in hematological malignancies with haploidentical HSCT. A retrospective analysis with 28 ATLG (total dosage, 20-30 mg/kg) and 18 ATG (total dosage, 8-10 mg/kg) patients were performed. The cumulative incidences of chronic GVHD and relapse were comparable between both groups. ATLG showed a trend towards a lower acute GVHD incidence (28.6% vs. 44.4%, P = 0.242) and 3-year non-relapse mortality (10.7% vs. 27.8%, P = 0.160), and had a significantly higher 3-year overall survival (OS, 64.3% vs. 33.3%, P = 0.033) and GVHD-free and relapse-free survival (GRFS, 32.1% vs. 11.1%, P = 0.045) compared with ATG. Multivariate Cox regression analysis demonstrated ATLG was independently associated with a favorable OS (hazard ratio [HR] = 0.37, 95% confidence interval [CI]: 0.16-0.86, P = 0.020) and GRFS (HR = 0.51, 95%CI: 0.26-1.00, P = 0.051). Furthermore, ATLG had a lower risk of fever (25.0% vs. 61.1%, P = 0.014) and hemorrhage cystitis (7.1% vs. 38.9%, P = 0.008) than ATG-T. In conclusion, ATLG confers more survival benefit and a better safety profile than ATG and can be used in hematological malignancies with haploidentical HSCT. Prospective designed trials with a larger sample size are warranted to confirm the results in the future.

Comparison of Different Rabbit Anti-Thymocyte Globulin Formulations in the Prophylaxis of Graft-Versus-Host Disease: A Systematic Review

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a potentially curative treatment modality, frequently used for patients suffering from haematological malignancies. In the last two decades, there have been multiple randomised controlled trials (RCTs), review articles, and meta-analyses addressing the efficacy of rabbit anti-thymocyte globulin (r-ATG) as a graft-versus-host disease (GvHD) prophylaxis. Nevertheless, only a few aimed to compare the effectiveness of different r-ATG formulations. Since the last article we retrieved comparing different r-ATGs in GvHD prophylaxis dates back to 2017, we performed a systematic literature review of articles published since 2017 to this day, utilising PubMed, Scopus, Cochrane, and MEDLINE, with the main endpoints being prophylaxis of acute GvHD (aGvHD) and chronic GvHD (cGvHD). We subjected to scrutiny a total of five studies, of which four compared the differences between Thymoglobulin (ATG-T) and Grafalon (ATG-G), and one discussed the impact of ATG-T dose. Overall, cGvHD, aGvHD grades II-IV, TRM, OS, NRM, LFS, relapse, overall infections, and EBV reactivation do not seem to be affected by the type of utilised rATG. However, data on aGvHD grades III-IV, GRFS, moderate-severe cGvHD, and CMV reactivation is conflicting. Through our research, we sought to summarise the most recent findings concerning r-ATGs in allo-HCT, and provide insight into the differences between the targets and origin of various ATG formulations.

Outcomes of patients with hematological malignancies who undergo unrelated donor hematopoietic stem cell transplantation with ATG-Fresenius versus ATG-Genzyme

To compare the outcomes of patients with hematological malignancies who received ATG-Fresenius (ATG-F) 20 mg/kg versus those who received ATG-Genzyme (ATG-G) 10 mg/kg in an unrelated donor hematopoietic stem cell transplantation (HSCT) procedure, a total of 186 patients who underwent their first allogeneic HSCT with an unrelated donor were retrospectively analyzed. One hundred and seven patients received ATG-F, and seventy-nine patients received ATG-G. Multivariate analysis showed that the type of ATG preparation had no effect on neutrophil engraftment (P = 0.61), cumulative incidence of relapse (P = 0.092), nonrelapse mortality (P = 0.44), grade II-IV acute graft-versus-host disease (GVHD) (P = 0.47), chronic GVHD (P = 0.29), overall survival (P = 0.795), recurrence-free survival (P = 0.945) or GVHD-free relapse-free survival (P = 0.082). ATG-G was associated with a lower risk of extensive chronic GVHD and a higher risk of cytomegaloviremia (P = 0.01 and HR = 0.41, P < 0.001 and HR = 4.244, respectively). The results of this study suggest that the preparation of rabbit ATG used for unrelated HSCT should be selected based on the incidence of extensive chronic GVHD of each center, and the posttransplant management strategy should be adjusted according to the ATG preparation.

GITMO Registry Study on Allogeneic Transplantation in Patients Aged ≥60 Years from 2000 to 2017: Improvements and Criticisms

Today, allogeneic stem cell transplantation (allo-SCT) can be offered to patients up to age 70 to 72 years and represents one of the most effective curative treatments for many hematologic malignancies. The primary objective of the study was to collect data from the allo-SCTs performed in Italy between 2000 and 2017 in patients aged ≥60 years to evaluate the changes in safety and efficacy outcomes, as well as their distribution and characteristics over time. The Italian Group for Bone Marrow Transplantation, Hematopoietic Stem Cells and Cell Therapy (GITMO) AlloEld study (ClinicalTrials.gov identifier NCT04469985) is a retrospective analysis of allo-SCTs performed at 30 Italian transplantation centers in older patients (age ≥60 years) between 2000 and 2017 (n = 1996). For the purpose of this analysis, patients were grouped into 3 time periods: time A, 2000 to 2005 (n = 256; 12%); time B, 2006 to 2011 (n = 584; 29%); and time C, 2012 to 2017 (n = 1156; 59%). After a median follow-up of 5.6 years, the 5-year nonrelapse mortality (NRM) remained stable (time A, 32.8%; time B, 36.2%; and time C, 35.0%; P = .5), overall survival improved (time A, 28.4%; time B, 31.8%; and time C, 37.3%; P = .012), and the cumulative incidence of relapse was reduced (time A, 45.3%; time B, 38.2%; time C, 30.0%; P < .0001). The 2-year incidence of extensive chronic graft-versus-host disease was reduced significantly (time A, 17.2%; time B, 15.8%; time C, 12.2%; P = .004). Considering times A and B together (2000 to 2011), the 2-year NRM was positively correlated with the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) score; NRM was 25.2% in patients with an HCT-CI score of 0, 33.9% in those with a score of 1 or 2, and 36.1% in those with a score of 3 (P < .001). However, after 2012, the HCT-CI score was not significantly predictive of NRM. This study shows that the transplantation procedure in elderly patients became more effective over time. Relapse incidence remains the major problem, and strategies to prevent it are currently under investigation (eg, post-transplantation maintenance). The selection of patients aged ≥60 could be improved by combining HCT-CI and frailty assessment to better predict NRM.

A comparative study of porcine antihuman lymphocyte globulin versus antithymocyte globulin-fresenius in an allogeneic hematopoietic cell transplantation conditioning regimen for severe aplastic anemia

OBJECTIVES

To compare the outcomes of antihuman T lymphocyte globulin (ATG-F) and porcine antihuman lymphocyte globulin (p-ALG) as part of a conditioning regimen in hematopoietic stem cell transplantation (HSCT) for severe aplastic anemia (SAA).

METHODS

we performed a retrospective analysis, evaluating the outcome of patients with SAA who received ATG-F based conditioning (n = 26) with those receiving p-ALG conditioning (n = 34).

RESULTS

The median time to neutrophil engraftment was 11 days (range, 8 - 38) and 11 days (range, 9 - 24) in the p-ALG and ATG-F groups (P = 0.857); the median platelet engraftment time was 15 (range, 9 - 330) days and 13 (range, 10 - 56) days (P = 0.155). There were no significant differences in grades II - IV acute graft-versus-host disease (aGVHD), grades III - IV aGVHD, chronic GVHD (cGVHD), and the moderate-severe cGVHD between the ATG-F and p-ALG groups (P>0.05).

DISCUSSION

Patients in the ATG-F group functioned significantly better on role-physical (P = 0.006), general health (P = 0.029), and physical component summary (P = 0.009). The estimated overall survival and failure free survival rates at 5 years were 88.5% ± 6.3% vs. 82.4% ± 6.5% (P = 0.515), 84.6% ± 7.1% vs. 79.4% ± 6.9%, respectively (P = 0.579). The infection rates were 61.53% and 47.05%, respectively (P = 0.265).

CONCLUSION

As part of the conditioning regimen, p-ALG achieved a similar efficacy as ATG-F without increasing the incidence of transplantation complications in SAA patients.

Comparison of 2 Different Rabbit Anti-Thymocyte Globulin (r-ATG) Preparations: Thymocyte r-ATG versus T Lymphoblast Cell Line r-ATG in Allogeneic Hematopoietic Stem Cell Transplantation for Acquired Severe Aplastic Anemia: Propensity Score-Matched Analysis

We retrospectively analyzed the outcomes of 214 patients with severe aplastic anemia (SAA) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) with rabbit anti-thymocyte globulin (r-ATG) or ATG-Fresenius (ATG-F). Using propensity score matching, we performed a case-control study comparing 44 and 23 patients in the r-ATG and ATG-F groups, respectively. The median time was 11 versus 11 days (P = .368) for myeloid engraftment and 11 versus 13 days (P = .030) for platelet engraftment in the r-ATG and ATG-F groups, respectively. The r-ATG group showed a lower incidence of grade III to IV acute graft-versus-host disease (GVHD) than the ATG-F group (2.27% versus 17.39%, P = .026). Similar outcomes were observed between the r-ATG and ATG-F groups for infection rate (59.09% versus 56.52%, P = .840), grade II to IV acute GVHD (20.45% versus 21.74%, P = .948), overall incidence of chronic GVHD (26.83% versus 22.73%, P = .704), moderate to severe chronic GVHD (9.76% versus 13.64%, P = .648), and transplantation-related mortality (11.36% versus 4.35%, P = .614). There was no statistical difference in 5-year overall survival (86.40% versus 95.7%, P = .245); GVHD-free, failure-free survival (77.30% versus 78.30%, P = .986); or health-related quality of life (P > .05) between r-ATG and ATG-F.

Differential Elimination of Anti-Thymocyte Globulin of Fresenius and Genzyme Impacts T-Cell Reconstitution After Hematopoietic Stem Cell Transplantation

Anti-thymocyte globulin (ATG) is a lymphocyte depleting agent applied in hematopoietic stem cell transplantation (HSCT) to prevent rejection and Graft-vs.-Host Disease (GvHD). In this study, we compared two rabbit ATG products, ATG-Genzyme (ATG-GENZ), and ATG-Fresenius (ATG-FRES), with respect to dosing, clearance of the active lymphocyte binding component, post-HSCT immune reconstitution and clinical outcome. Fifty-eigth pediatric acute leukemia patients (n = 42 ATG-GENZ, n = 16 ATG-FRES), who received a non-depleted bone marrow or peripheral blood stem cell graft from an unrelated donor were included. ATG-GENZ was given at a dosage of 6-10 mg/kg; ATG-FRES at 45-60 mg/kg. The active component of ATG from both products was cleared at different rates. Within the ATG-FRES dose range no differences were found in clearance of active ATG or T-cell re-appearance. However, the high dosage of ATG-GENZ (10 mg/kg), in contrast to the low dosage (6-8 mg/kg), correlated with prolonged persistence of active ATG and delayed T-cell reconstitution. Occurrence of serious acute GvHD (grade III-IV) was highest in the ATG-GENZ-low dosage group. These results imply that dosing of ATG-GENZ is more critical than dosing of ATG-FRES due to the difference in clearance of active ATG. This should be taken into account when designing clinical protocols.