Outcomes of Autologous Transplantation for Treatment-Related AML and MDS in Previously Treated Multiple Myeloma Patients (pts)

Introduction:

Therapy related myelodysplastic syndrome (t-MDS) and acute myeloid leukemia (t-AML) are significant long-term complications of MM treatment. We have treated pts on standard therapy protocols including TT2, TT3, TT4 and TT5. These protocols include an induction, tandem melphalan-based ASCT and consolidation, followed by three years of maintenance. As a part of the protocols, multiple bone marrow examinations including metaphase cytogenetics are performed at regular intervals, giving us the unique opportunity to examine the development of t-MDS/t-AML and understand the efficacy of subsequent treatment. Here we investigate the outcome of t-AML and t-MDS treated with autologous stem cell transplantation (ASCT) in MM patients.

Materials and Methods, Results:

During the period between 1998 to 2015, a total of 1558 pts were treated for MM with standard therapy protocols. We identified 68 pts out of 1558 who developed t-AML + t-MDS. Thirty-one had a confirmed diagnosis of t-AML, and thirty-seven had a diagnosis of t-MDS. The median age at diagnosis was 60 years (range 45-76). The median time from diagnosis MM of t-AML and t-MDS was 66 months (range, 9.6-155.4) and 63 months (range, 8-130), respectively. Baseline cytogenetics were as follows: complex cytogenetics in 34 pts out of 68, del(7) in 24 pts, del(5) in 17 pts, and del(17p) in 5 pts.

Eighteen out of thirty-one t-AML pts were treated with ASCT. The remaining 13 pts did not receive ASCT. The treatment related mortality (TRM) at day100 (D100) in the ASCT group was 33% (6/18 pts). Neutrophil and platelet engraftment was achieved in all 18 pts by D21. Complete remission was achieved in 50% (9 out of 18) of pts. When we compared pts who received ASCT to those who were treated with chemotherapy only, the median overall survival (OS) was 11.28 months after ASCT vs 1.32 months without ASCT (p < 0.05). Nineteen out of thirty seven t-MDS pts were treated with ASCT. When we compared pts who received ASCT to chemotherapy only for t-MDS, there was no difference in survival between the groups. A mortality rate of 47% (9/19) was recorded at D200 after transplantation due to severe infections and lack of engraftment.

Conclusion:

t-AML and t-MDS treatment is a significant therapeutic challenge for the elderly, who often have poor risk cytogenetic markers, significant comorbidities and a compromised performance status. In our case series of post MM therapy t-AML, ASCT prolonged survival. In contrast, there was no change in survival of t-MDS pts, most likely due to high rate of infectious complications seen in this group. To our knowledge, this is the first analysis suggesting a survival benefit from ASCT in treating t-AML. Although the numbers in our study are small, we recommend that ASCT can be safely considered for t-AML patients who are physically fit, have autologous stem cells in storage and are overseen by a good supportive care team. These results need to be validated in large prospective studies.