Dr Jimenez Jimenez on PBSC from HLA-Mismatched Donors in Hematological Malignancies

Antonio Martin Jimenez Jimenez, MD, discusses conditioning therapy, PBSC from HLA-MMUD, and PTCy for GVHD prophylaxis in hematological malignancies.

Antonio Martin Jimenez Jimenez, MD, associate professor, medicine, the University of Miami Sylvester Comprehensive Cancer Center, discusses findings from the phase 2 ACCESS study (NCT04904588), which evaluated reduced-intensity conditioning therapy, mobilized peripheral blood stem cells (PBSC) from HLA-mismatched unrelated donors (MMUD) and post-transplant cyclophosphamide (PTCy) for graft-vs-host disease (GVHD) prophylaxis in adult patients with hematological malignancies. This study builds on previous data from the multicenter phase 2 15-MMUD trial (NCT02793544).

The primary aim of ACCESS was to determine whether the 1-year overall survival (OS) rate with mobilized PBSC would be comparable with that observed with bone marrow grafts, Jimenez Jimenez says. The results demonstrated an OS rate of 79% (95% CI, 68%-87%) at 1 year post-HCT, which is comparable with the OS rates seen in patients receiving fully matched grafts and consistent with the outcomes in the PTCy arm of the phase 3 BMT CTN 1703 study (NCT03959241), Jimenez Jimenez notes. This OS rate highlights the efficacy of using PBSC from MMUD in the reduced-intensity conditioning setting with PTCy-based GVHD prophylaxis.

Other key outcomes included a GVHD relapse-free survival rate of 51% (95% CI, 39%-62%) at 1 year, indicating that over half of the patients were alive, disease free, and without significant GVHD-related complications at that time point, Jimenez Jimenez explains. This outcome is particularly noteworthy given the use of mismatched grafts, Jimenez Jimenez emphasizes. Additionally, the non-relapse mortality rate with mobilized PBSC was deemed acceptable, reinforcing the safety profile of this approach, according to Jimenez Jimenez.

The estimated incidence of grade 3/4 acute GVHD at 6 months was 9% (95% CI, 3%-16%), and severe chronic GVHD was reported in an estimated 9% (3%-17%) of patients at 1 year. This low rate of severe GVHD underscores the effectiveness of PTCy-based prophylaxis in managing GVHD in this patient population, Jimenez Jimenez states.

In a presentation given at the 2024 ASCO Annual Meeting, Jimenez Jimenez emphasized that these findings indicate that mobilized PBSC from MMUD, combined with PTCy-based GVHD prophylaxis, offers a viable alternative to bone marrow grafts, providing comparable survival outcomes and a favorable safety profile. The ACCESS study supports the use of mobilized PBSC in this setting, potentially expanding the donor pool for patients requiring allogeneic stem cell transplantation.

Related Videos
Joseph Franses, MD, PhD
Shipra Gandhi, MD
Chih-Yi Liao, MD
Mazyar Shadman, MD, MPH
Sheldon M. Feldman, MD
Rita Mukhtar, MD
Lajos Pusztai, MD, DPhil
Hope S. Rugo, MD
Marc Machaalani, MD
Craig Eckfeldt, MD, PhD, assistant professor, medicine, faculty, Microbiology, Immunology, and Cancer Biology PhD Graduate Program, Division of Hematology, Oncology, and Transplantation, the University of Minnesota Medical School