Young Adult Patients with Post -HCT Relapse of AML May Benefit from Aggressive Salvage and 2^nd Cellular Therapy

A Significant Proportion of Young Adult Patients with Post -HCT Relapse Of AML Benefit From Aggressive Salvage And 2^nd Cellular Therapy.

INTRODUCTION:

There is currently no standard of care for patients with AML who relapse following hematopoietic cell transplantation (HCT), and outcomes in these patients are generally poor.

Given this fact, there is great variability in practice, and many patients may be palliated in the absence of suitable clinical trials, especially following early relapses. We sought to analyse long-term survival of young adults with AML based on whether or not they received a second cellular therapy (CT) (second transplant or donor lymphocyte infusion [DLI]) following post-HCT relapse.

METHODS:

We retrospectively analysed data on patients who had received a HCT between 2000 and 2012 and had a post HCT relapse. The patients were stratified by whether or not they had 2^nd CT with or without prior chemotherapy. Baseline characteristics and outcomes were compared.

RESULTS:

Ninety four patients were identified who had relapsed AML following HCT.

The median age at transplant for the patients was 27.5 (range 14-58y) years for the whole cohort; 50% were females.

Of these, 30 patients received 2^nd CT either in the form of DLI (80% for available CT data) or a 2^nd HCT.

Median in age for both groups was 24 years and there was no significant difference between the 2 groups in good or poor risk cytogenetics.

Median time to relapse was significantly lower in the group that did not receive 2^nd CT vs the group that did (5.9 vs 18.2 months, p<0.001).

For the 64 patients that did not receive 2^nd CT, reasons included early relapse (28 cases), presence of GVHD (15 cases), refractory to salvage (8 cases), poor performance (9 cases), and patient choice (4).

The OS for patients who did not receive 2^nd CT was 4.5 months ± 2.6% vs 36% ± 11% for patients who did receive 2^nd CT (Fig.1). Of the 6 patients in the 2^nd CT group who relapsed in <6 months, only 1 survived long term (16%).

Conclusion: The management of post BMT relapse remains challenging, and a number of factors may preclude intensive therapy post-HCT relapse. However, our experience confirms that a proportion of patients do benefit from long-term survival from a strategy of aggressive salvage followed either by DLI or a second HCT; in addition to disease biology, a treatment bias where early relapses are less likely to be treated aggressively partly explains the difference in outcome in the groups. This strategy should be considered in young fit patients and may lead to long-term survival in a significant proportion of young adults; patients with later relapses beyond 6 months appear to derive a greater benefit. Prospective clinical trials are required incorporating novel therapies in patients who relapse early post HCT.

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