Findings from a phase 3 trial may support the use of sorafenib as a maintenance therapy in patients with FLT3 internal tandem duplication (FLT3-ITD) acute myeloid leukemia (AML), following allogeneic hematopoietic stem cell transplantation (alloHSCT). The results of the trial were published in The Lancet Oncology.

In this open-label, multicenter study based in China (ClinicalTrials.gov Identifier: NCT02474290), patients with FLT3-ITD AML were randomly assigned (1:1) to receive sorafenib maintenance (100 patients), given as 400 mg twice per day, or to receive no maintenance (102 patients; control group). Eligible patients had received prior alloHSCT and were in composite complete remission with hematopoietic recovery. One-year cumulative incidence of relapse was the primary study endpoint, and this was measured from the intent-to-treat population.

Patients receiving sorafenib maintenance had a 1-year cumulative incidence of relapse of 7.0% (95% CI, 3.1-13.1) compared with 24.5% (95% CI, 16.6-33.2) in the control group (hazard ratio [HR], 0.25 [95% CI, 0.11-0.57]; P =.0010). The median follow-up time was 21.3 months following transplantation.

The 2-year cumulative incidence of relapse was 11.9% (95% CI, 6.2-19.6) with sorafenib and 31.6% (95% CI, 22.6-41.1) for the control group (HR, 0.29 [95% CI, 0.15-0.58]; P <.0001). The 2-year overall survival rate with sorafenib was 82.1% (95% CI, 72.6-88.5), and it was 68.0% (95% CI, 57.8-76.2) for the control group (HR, 0.48 [95% CI, 0.27-0.86]; P =.012).


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At 210 days following transplantation, grade 3 to 4 infections were reported among 25% of those in the sorafenib maintenance group and in 24% of the control. Rates of grade 3 to 4 acute or chronic graft-vs-host disease were similar between groups. Fatalities related to adverse events occurred in 4 patients in the sorafenib group and in 5 patients in the control arm, but no deaths were considered to be related to treatment.

Hematologic toxicity of grade 3 or 4 occurred in a larger number of patients in the sorafenib group (15%) than in the control group (7%). Skin-related grade 3 to 4 adverse events were reported in 7% of patients in the sorafenib group and 1% of patients in the control group.

The study investigators concluded that sorafenib maintenance after alloHSCT was associated with favorable outcomes for relapse and survival, and that it appeared well tolerated. “Sorafenib maintenance post-transplantation could be a therapeutic option for FLT3-ITD acute myeloid leukaemia,” wrote the investigators.

Reference

Xuan L, Wang Y, Huang F, et al. Sorafenib maintenance in patients with FLT3-ITD acute myeloid leukaemia undergoing allogeneic haematopoietic stem-cell transplantation: an open-label, multicentre, randomised phase 3 trial. Lancet Oncol. 2020;21(9):1201-1212. doi:10.1016/S1470-2045(20)30455-1