A retrospective study suggests that allogeneic hematopoietic stem cell transplantation (HCT) may support disease-free survival for patients with certain therapy-related hematologic malignancies following treatment for multiple myeloma (MM). The study results were published in the European Journal of Haematology.

The study investigators explained in their report that life expectancy has increased over time for patients with MM, but with a higher risk of secondary malignancies, including therapy-related malignancies. The researchers also explained that their heavily pretreated condition, in addition to other factors, can contribute to worse outcomes for patients with therapy-related hematologic malignancies following MM. However, they noted, there has been limited research involving allogeneic HCT outcomes in these patients.

The analysis included patients treated at Princess Margaret Cancer Center at the University of Toronto in Toronto, Canada. Patients had been previously treated for MM and subsequently developed therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML), therapy-related acute lymphoblastic leukemia (t-ALL), or therapy-related chronic myelomonocytic leukemia (t-CMML). Patients received allogeneic HCT for these therapy-related malignancies and were evaluated for survival outcomes, clinical and laboratory characteristics, and features related to MM and its treatment.


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The analysis included 20 patients, 13 of whom had developed t-MDS/AML, 6 of whom had t-ALL, and 1 of whom had t-CMML. Patients had a median age at the time of allogeneic HCT of 62.5 years (range, 49-73). There was a median time from the MM diagnosis to the hematologic malignancy diagnosis of 6.0 years. Nearly one-third (30%) of evaluable patients had a complex/monosomal karyotype, which was the most common cytogenetic abnormality observed in patients with available cytogenetic data. Allogeneic HCT involved human leukocyte antigen-matched siblings in 30% of transplants, unrelated donors in 60%, and haploidentical donors in 10%.

The 2-year overall survival (OS) rate was 53.1%, and the 2-year relapse-free survival rate was 47.2%. The 2-year cumulative incidence of relapse (CIR) was 15.0%, and the 2-year nonrelapse mortality rate was 35.0%. For patients surviving more than 100 days after allogeneic HCT, the median follow-up time was 33 months.

A nonsignificant trend was observed of a better 2-year OS rate for patients with t-ALL (66.7%) than for patients with t-MDS/AML (42.7%; P =.36), with these patient groups showing a similar pattern for 2-year CIR (0% vs 15.4%, respectively; P =.33). Multivariate analyses did not reveal factors that appeared to be predictors of poor survival outcomes in patients with t-MDS/AML or t-ALL.

“Allogeneic HCT should be offered to patients with therapy-related acute leukemias after MM who are in remission and have a good performance status,” the study investigators concluded in their report.

Reference

Vasudevan Nampoothiri V, Pasic I, Law AD, et al. Allogeneic hematopoietic stem cell transplantation in patients with therapy-related hematologic malignancies developing after multiple myeloma. Eur J Haematol. Published online January 31, 2022. doi:10.1111/ejh.13750