, investigators have reported.
The rate of non-relapse mortality at one year was 21% in the retrospective analysis of 96 patients, recently reported in the journal.
Haploidentical allogeneic hematopoietic stem cell transplant (allo-HCT) is currently limited in use due to a high rate of relapse, but may hold potential promise for future applications, according to Firoozeh Sahebi, MD, a hematologist with the City of Hope Medical Center, Duarte, Calif., and colleagues. “Our results demonstrate that haploidentical allo-HCT can be safely performed in appropriate patients with MM who lack on HLA-matched sibling or unrelated donor.”
“The allo-HCT platform can be used in the context of other post-transplantation immune-based strategies, such as donor-derived chimeric antigen receptor T cells and natural killer cell infusions, newer immunomodulatory drugs or proteasome inhibitors, bispecific T cell engagers, and bispecific killer cell engagers, to further enhance antitumor effects and ultimately improve survival in an appropriate patient population,” Dr. Sahebi and colleagues said in their report.
The investigators reported results of a retrospective analysis including 96 patients with relapsed multiple myeloma who had failed at least one previous autologous HCT. They underwent haploidentical allo-HCT at European Society for Blood and Marrow Transplantation/Center for International Blood and Marrow Transplant Research centers between 2008 and 2016.
Median follow-up in the analysis was 24 months. Almost all patients (97%) achieved neutrophil engraftment by day 28, while 75% had recovery of platelets by day 60, Dr. Sahebi and co-investigators reported.
The 1-year nonrelapse mortality rate was 21%, but the cumulative risk of relapse and progression at 2 years was 56%, according to the study results. Two-year progression-free survival was reported to be 17%, while overall survival was 48%.
Acute graft-versus-host-disease (GVHD) of grades II-IV occurred in 39% by 100 days, while chronic GVHD was seen in 46% at 2 years, the report shows.
Factors linked to improved overall survival at 2 years included use of bone marrow as the source of stem cells, and the use of cyclophosphamide after transplantation, according to Dr. Sahebi and co-authors.
By contrast, factors that had no impact on overall survival, progression-free survival, or non-relapse mortality included disease status (ie, degree of response), gender, conditioning regimen intensity, presence of cytomegalovirus in the blood, or donor-recipient sex mismatch.
This analysis was conducted in part due to the limited availability of matched donors, along with the promising results of allo-HCT in other malignancies, according to investigators.
There were no conflicts of interest to report related to this research, Dr. Sahebi and colleagues reported in the journal.
SOURCE: Sahebi F, et al. . 2018 Sep 20. pii: S1083-8791(18)30575-5.