Improved GRFS after posttransplant cyclophosphamide-based vs ATG-based HLA-mismatched unrelated donor transplant

• Published in: Blood advances 2022-08, Vol.6 (15), p.4491-4500
• Main Authors: Jimenez Jimenez, Antonio, Komanduri, Krishna, Brown, Samantha, Wang, Trent, Pereira, Denise, Goodman, Mark, Beitinjaneh, Amer, Lekakis, Lazaros, Chinapen, Stephanie, Devlin, Sean, Ponce, Doris, Sauter, Craig, Perales, Miguel-Angel, Shaffer, Brian C.
• Format: Article
• Language: English
• Subjects: Transplantation
• ISSN: 2473-9529; 2473-9537
• DOI: 10.1182/bloodadvances.2022007596

A common method to prevent graft-versus-host disease after allogeneic hematopoietic cell transplantation (HCT) from an HLA-mismatched unrelated donor (MMUD) is tacrolimus, methotrexate, and antithymocyte globulin (ATG). The use of posttransplant cyclophosphamide (PTCy) showed promise in a prospective trial for MMUD HCT. We compared 1-year graft-versus-host disease–free, relapse-free survival (GRFS) in 128 recipients of prophylaxis based on tacrolimus/methotrexate/ATG (ATG group, n = 46) vs PTCy, mycophenolate mofetil, and tacrolimus or sirolimus (PTCy group, n = 82) after MMUD HCT. Patients receiving HCT from a MMUD mismatched at ≥1 locus among HLA-A, HLA-B, HLA-C, and HLA-DRB1 were included. The 2 groups were well matched for HCT indication, high-risk disease, and HCT comorbidity index, whereas more patients on PTCy received bone marrow (50% vs 26%; P = .01) and >1 locus HLA-mismatched (30.5% vs 2.2%; P = .001) grafts. The 1-year GRFS was 16% (95% confidence interval (CI): 8%-31%) vs 54% (95% CI: 44%-66%; P < .001) in the ATG and PTCy groups, respectively. The multivariable adjusted hazard ratio for GRFS was 0.34 (95% CI: 0.21-0.55; P < .001) with the use of PTCy. The 1-year overall survival in the ATG group was 45% (95% CI: 32%-62%) vs 75% (95% CI: 66%-85%) in the PTCy group (P < .001). Relapse incidence was similar. One-year nonrelapse mortality was greater after ATG-based prophylaxis: 38% (95% CI: 23%-52%) vs 16% (95 CI: 9%-25%), P < .001. In summary, PTCy-based prophylaxis resulted in superior GRFS and overall survival in recipients of MMUD. •PTCy improved GRFS compared with recipients of ATG-based prophylaxis after MMUD allogeneic HCT.•Allograft recipients of ATG-based prophylaxis had higher nonrelapse mortality and impaired humoral immune reconstitution. [Display omitted]