Lenalidomide combined with mismatched microtransplantation for acute myeloid leukemia

Expert consensus on microtransplant for acute myeloid leukemia in elderly patients -report from the international microtransplant interest group

Recent studies have shown that microtransplant (MST) could improve outcome of patients with elderly acute myeloid leukemia (EAML). To further standardize the MST therapy and improve outcomes in EAML patients, based on analysis of the literature on MST, especially MST with EAML from January 1st, 2011 to November 30th, 2022, the International Microtransplant Interest Group provides recommendations and considerations for MST in the treatment of EAML. Four major issues related to MST for treating EAML were addressed: therapeutic principle of MST (1), candidates for MST (2), induction chemotherapy regimens (3), and post-remission therapy based on MST (4). Others included donor screening, infusion of donor cells, laboratory examinations, and complications of treatment.

Comparative study of micro-transplantation from HLA fully mismatched unrelated and partly matched related donors in acute myeloid leukemia

Micro-transplantation (MST) by chemotherapy, combined with granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (GPBSC) infusion, from an HLA partial matched related donor has shown some encouraging effective therapy for acute myeloid leukemia (AML). However, the outcome of human leukocyte antigen (HLA) fully mismatched unrelated donor-derived MST in such patients is still unknown. In the present study, we compared the efficacy of HLA fully mismatched unrelated donor-derived MST, and partly matched related donor-derived MST, in AML of 126 patients from two centers in China, These patients, aged 16 to 65 years, were given three or four courses of MST, which consisted of a high dosage cytarabine followed by GPBSC from unrelated donor or related donor. There was a statistically significant difference in 3-year leukemia-free survival (LFS) and 3-year overall survival (OS) between the unrelated and the related group. The non-treatment-related mortality (NRM) rates of patients, and other adverse complications, were no different in the two groups. In conclusion, unrelated donor-derived MST is believed to be a safe treatment, with efficacy similar to or higher than related donor-derived MST. This result provides support for the potential of MST for expanding the donor selection. However, the specific mechanism of action needs further study.

Current state of nonengrafting donor leukocyte infusion (focus on microtransplantation for acute myeloid leukemia)

PURPOSE OF REVIEW

Microtransplantation (or micro-stem cell transplantation, MST) is one permutation of alloreactive immunotherapy increasingly studied in clinical trials. It is most commonly applied to patients with myeloid malignancies who are not suitable candidates for allogeneic hematopoietic cell transplantation. This review highlights the past 2 years of work on stem/progenitor cell products in the field of nonengrafting donor leukocyte infusion (NE-DLI), with a focus on applications of MST in acute myeloid leukemia (AML).

RECENT FINDINGS

Assessing the utility of MST is hampered by lack of randomized controlled trials and by variability in donor selection algorithms, treatment timing, and unknown factors. The inherent complexity of the bidirectional alloreactive reactions, implicating many cell types, makes it challenging to move beyond correlative, population-level biology toward mechanistic explanations for MST's actions in any given patient-donor pair. Yet there are indicators that by stimulating a recipient-vs.-tumor effect, MST might substantially improve complete remission rates in AML and that it might find a role in postremission therapy.

SUMMARY

The mechanistic underpinnings of MST are gradually being disentangled and its clinical development remains in early stages.