Prospective feasibility of a minimal BH3 profiling assay in acute myeloid leukemia

BH3 profiling can assess global mitochondrial priming and dependence of leukemic cells on specific BH3 anti-apoptotic proteins such as BCL-2. In acute myeloid leukemia (AML), proof-of-concept prognostic studies have been performed on archived samples variably accounting for molecular genetics. We undertook a single-center feasibility study of a simplified flow-based assay to determine the absolute mitochondrial priming and BCL-2 dependence in consecutive AML patients. When possible, results on the leukemic fraction were normalized to the cognate lymphocyte population (relative priming and BCL-2 dependence). Samples from 97 (89.8%) of the 108 referred patients were successfully processed. Relative priming and BCL-2 dependence could be determined in 62 (67.4%) and 67 (62.0%) samples, respectively. Absolute mitochondrial priming was lower in patients having previously failed intensive chemotherapy compared to chemotherapy-naïve patients (p = 0.01), but its prognostic impact was limited. Conversely, relative BCL-2 independence tended to predict worse EFS (HR = 2.51, p = 0.07) and OS (HR = 2.79, p = 0.10) independently of adverse genetic risk. Our results show that simplified BH3 profiling can be prospectively assessed in AML patients but that its prognostic use may require internal normalization. Future studies should compare its relevance with other functional assays such as ex vivo drug testing or BH3 protein expression.