Background

The goal of our study was to find predictors for the development of secondary myelodysplastic syndrome or acute myelogenous leukemia (s-MDS/AML) in patients with relapsed or refractory lymphoma who received high-dose chemotherapy and autologous stem cell transplantation (ASCT).

Study design and methods

We conducted a retrospective review of 295 patients with relapsed or refractory lymphoma who had undergone their first stem cell collection and ASCT. Patient, disease, and treatment characteristics were collected. The primary goal of this study was to analyze the association between the number of apheresis days needed to collect the requisite stem cell dose in addition to the previously described factors such as age, sex, number and type of prior chemotherapeutic regimens, disease type and status, and the risk of developing s-MDS/AML.

Results

Twenty-two patients of 295 were diagnosed with s-MDS/AML after a median follow-up of 62 months. Multivariate analysis using a classification and regression tree showed that the incidence of s-MDS/AML was lowest in patients who were not more than 55 years old at transplantation and in whom the target cell dose was collected in fewer than two apheresis sessions (5-year cumulative incidence, 1%), whereas incidence was highest in patients who were more than 55 years old at transplantation and who received a transplant more than 21 months after their initial lymphoma diagnosis (5-year cumulative incidence, 20%).

Conclusion

Our study defines a subset of relapsed or refractory lymphoma patients who should be closely monitored for development of s-MDS/AML after high-dose chemotherapy and ASCT.

Background

High-dose, post-transplantation cyclophosphamide (PTCy) to prevent graft-versus-host disease (GVHD) has improved outcomes in haploidentical (HAPLO) stem cell transplantation (SCT). However, it remains unclear whether this strategy is effective in SCT from 1-antigen human leukocyte antigen (HLA)-mismatched unrelated donors (9/10 MUD) and how the outcomes of these patients compare with those of haploidentical transplantation recipients.

Methods

A parallel, 2-arm, nonrandomized phase 2 clinical trial was conducted of melphalan-based reduced-intensity conditioning with PTCy, tacrolimus, and mycophenolate mofetil to prevent GVHD in patients with high-risk hematologic malignancies who underwent HAPLO (n = 60) or 9/10 MUD (n = 46) SCT.

Results

The 1-year overall and progression-free survival rates were 70% and 60%, respectively, in the HAPLO arm and 60% and 47%, respectively, in the 9/10 MUD arm. The day +100 cumulative incidence of grade II to IV acute GVHD and grade III to IV acute GVHD was 28% and 3%, respectively, in the HAPLO arm and 33% and 13%, respectively, in the 9/10 MUD arm. The 2-year cumulative incidence of chronic GVHD was 24% in the HAPLO arm and 19% in the 9/10 MUD arm. The 1-year cumulative incidence of nonrelapse mortality was 21% in the HAPLO arm and 31% in the 9/10 MUD arm, and the 1-year relapse rate was 19% in the HAPLO arm and 25% in the 9/10 MUD arm.

Conclusions

Although this was a nonrandomized study and could not serve as a direct comparison between the 2 groups, the authors conclude that PTCy-based GVHD prophylaxis is effective for both HAPLO and 9/10 MUD SCTs. Prospective randomized trials will be required to compare the efficacies of alternative donor options for patients lacking HLA-matched donors. Cancer 2016;122:3316-3326. © 2016 American Cancer Society.