Abstract LB-96: A novel blood preservation system to study oncogenic signaling pathway biomarkers by flow cytometry in leukemia/lymphoma clinical trials

Propelled by the advent of new technologies and an evolving regulatory landscape, the desire to personalize cancer treatments has never been greater. There is a critical need to reliably evaluate target inhibition and pharmacodynamic activity of investigational drugs in biologically relevant compartments. However, the ability to fulfill such a task in global clinical trials is complicated by varying technical expertise available at clinical sites and considerations about specimen stability for centralized laboratory analysis. We developed a novel formalin-based preservation method that enables specimen stabilization in a single step, requiring less than 20 minutes, without the need for specialized training or instrumentation. Stabilized specimens can be frozen for shipping and batched analysis at a later time point, in a specialized laboratory. Using this preservation method, we developed a flow assay enabling identification of multiple cell-types, and quantification of intracellular biomarkers in target cellular compartments, in both the peripheral blood (PB) and bone marrow (BM). We present pharmacodynamic (PD) data for a novel anticancer investigational agent intended for acute myeloid leukemia and multiple myeloma and its effect on multiple target biomarkers of the PI3K signaling pathway, including phosphorylation of the S6 ribosomal protein (S6). Our novel fixation method allowed detection of pS6 modulation in a dose dependent manner in both tumor cells and PB or BM in response to the novel investigational agent. Assay sensitivity and concordance were evaluated by comparing flow assay with western blot analysis, with each assay performed at a different site using the same batched frozen samples; exceptional preservation of phosphorylated proteins for more than 72 hours could be observed, when frozen immediately following fixation. In conclusion, our novel preservation method enables reliable quantification of signaling biomarkers in centralized laboratories at different time points post sample (PB or BM) acquisition requiring minimal processing at collection sites. Citation Format: Anil Pahuja, Abdel Saci, Shyam Sarikonda, Armin Graber, Benjamin Lee, Jelveh Lameh, Shabnam Tangri, Naveen Dakappagari. A novel blood preservation system to study oncogenic signaling pathway biomarkers by flow cytometry in leukemia/lymphoma clinical trials. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-96. doi:10.1158/1538-7445.AM2014-LB-96