Ex-vivo drug testing predicts chemosensitivity in acute myeloid leukemia

Abstract

The majority of acute myeloid leukemia (AML) patients will respond to standard chemotherapy, however, resistance is a prevalent problem contributing to incomplete responses, refractory disease, and ultimately patient death. Therefore, choosing more sensitive and effective chemotherapy regimens is of key clinical importance. In order to explore this issue, we investigated and optimized PharmaFlow, an automated flow cytometry method for evaluating the sensitivity of leukemia cells to multiple chemotherapeutic drugs ex vivo. We examined bone marrow samples from 38 Chinese AML patients and incubated them for 48 or 72 h with a panel of 7 single drugs and 6 combinations with cytarabine at different concentrations. Leukemic cell depletion was assessed by PharmaFlow and drug response parameter, called PharmaFlow score, was estimated using population pharmacodynamic models. We identified that most chemotherapeutic drugs and combinations could effectively eliminate pathological cells ex vivo. Estimated drug activities strongly correlated with the patients' duration to achieve clinical remission and PharmaFlow chemosensitivity measured ex vivo was highly predictive of the clinical outcome after chemotherapy. Applying a classification model, we determined a PharmaFlow score of 89.4 as the threshold to predict response to chemotherapy. Using this threshold, we found that in 84.2% of cases patient's cell response ex vivo predicted the observed clinical response and performed similarly or better than prognostic subgroups determined by cytogenetic characteristics. PharmaFlow has the potential to predict chemosensitivity for de novo, secondary and relapsed AML patients prior to treatment and may guide clinicians to tailor treatments and improve patient outcome. K E Y W O R D Sacute myeloid leukemia, chemosensitivity, PharmaFlow

Ex Vivo Chemosensitivity Profiling of Acute Myeloid Leukemia and Its Correlation With Clinical Response and Outcome to Chemotherapy

“…Recently, Lin et al used the PharmaFlow method to examine bone marrow samples from 38 Chinese AML patients with a panel of 7 single drugs and 6 combinations with cytarabine at different concentrations. Their data suggested that ex-vivo drug activity strongly corresponded to clinical efficacy in Chinese AML patients (17).…”

“…The in-vitro single-cell culture methods such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ATP assay cannot distinguish between tumor cells and non-tumor cells, or simulate the in-vivo microenvironment (8)(9)(10). Nowadays, high-throughput ex-vivo drug sensitivity screening test is used to detect pharmacological activity in the treatment of AML (11)(12)(13)(14)(15)(16)(17)(18). Herein, we tested the prediction value of the PharmaFlow platform using bone marrow samples of 104 AML patients.…”

Implementing a Functional Precision Medicine Tumor Board for Acute Myeloid Leukemia

“…We and others have utilized high-throughput ex vivo testing of AML cells to functionally identify drug response patterns (18)(19)(20)(21)(22)(23)(24). The Beat AML study reported on the functional testing of 122 small molecule inhibitors combined with genomic profiling in a cohort of 562 biobanked AML patient samples (23).…”

“…Snijder et al applied an image-based drug testing assay (pharmacoscopy) to demonstrate that the assay predicted clinical response to chemotherapy (21). Flow-cytometry has also been used to quantify responses in distinct cell subpopulations (19,(25)(26)(27). Nevertheless, many of these studies are retrospective and lack the integration of functional and molecular data.…”

Inhibitors of Chemoresistance Pathways in Combination with Ara-C to Overcome Multidrug Resistance in AML. A Mini Review

“…Knowing the different MOCs in each patient at each moment of their AML clinical history, that is, before, during and after treatment and relapse, would enable the use of personalized therapies with better results and less toxicity, which would result in a longer survival time. Some authors suggest that achieving this enterprise faces issues such as study costs and the technical limitations of molecular testing [ 45 ], others are more optimistic, recently a bone marrow mononuclear cell (BMMC) 3D culture model and an automated flow cytometry method, were tested to evaluating the sensitivity of leukemia cells to multiple chemotherapeutic drugs ex vivo and define resistance biomarkers of AML patient bone marrow samples in response to Ara-C treatment [ 46 , 47 ]. In silico analysis of highly prognostic human AML LSC gene expression signatures using existing datasets of drug-gene interactions have been used to identify compounds predicted to target LSC gene programs [ 48 ], the identification of a true genetic signature that predicts the response to cytarabine has been assayed in patients with AML through comprehensive multi-point analysis pharmacokinetic, pharmacodynamic (cytarabine-dependent) and clinical endings [ 49 ].…”