Survival following relapse after allogeneic hematopoietic cell transplantation for acute leukemia and myelodysplastic syndromes in the contemporary era.

OBJECTIVE/BACKGROUND: Relapse is the most common cause of treatment failure after allogeneic hematopoietic cell transplantation (alloHCT). No standard of care exists, and a wide range of treatments are used for post-alloHCT relapse. In the recent era, several novel therapies including targeted agents are available for acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS).

METHODS

We reviewed outcomes after alloHCT relapse, with or without use of these newer agents for ALL, AML, and MDS. In total, 115 adults with relapsed or refractory ALL (n = 17), AML (n = 67), and MDS (n = 31) at median 5 (range, 1-64) months after their first alloHCT in 2010-2018 were included.

RESULTS

Median follow-up was 19 (range, 6-80) months after relapse from alloHCT. Targeted agents were given to 29 (25%) patients. In multivariable analysis, use of targeted agent at any time point after relapse was not associated with survival. Matched unrelated (vs. matched sibling; hazard ratio [HR] 1.70; p = .027) or haploidentical donor grafts (vs. matched sibling; HR 2.69; p = .003), presence of grade II-IV acute graft-versus-host disease before relapse (HR 2.46; p < .001), and less than 12 months from HCT to relapse (<6 vs. > 12 months; HR 6.34; p < .001; 6-12 vs. > 12 months; HR 3.16; p = .005) were adverse prognostic factors for post-relapse survival.

CONCLUSION

Outcomes after alloHCT relapse remain poor regardless of the novel agent use. Innovative treatment strategies are needed to improve outcomes after relapse post-alloHCT.