Abstract 4694: Indices of actionability and clinical utility in a CLIA-enabled study of whole genome/exome/RNA sequencing in 33 cancer patients: Actionable vs. utility
Authors: Egan Jan B. , Bryce Alan H. , Champion Mia D. , Liang Winnie S. , Fonseca Rafael , McCullough Ann E. , Barrett Michael T. , Hunt Katherine , Condjella Rachel M. , McWilliams Robert R. , Mastrian Stephen D. , LoBello Janine , Hoff Daniel Von , Craig David W. , Stewart A. Keith , Carpten John D. , Borad Mitesh J. 
Published: May 2015

Background: Whole genome/exome/RNA sequencing has revolutionized the ability to assess the genomic landscape of cancer and is increasingly being utilized for clinical decision-making. Initial clinical applications have been constrained by specimen quantity, analyte quality and the time from sample acquisition to results report.

Methods: Patients with advanced cancers underwent surgical resection, excisional/core biopsies, or bone marrow biopsy. Samples were analyzed by whole genome or exome sequencing in addition to RNA sequencing, bioinformatics analysis, and therapeutic target prioritization by a multi-disciplinary Clinical Genomics Board. All prioritized targets were CLIA validated using Sanger sequencing, RT-qPCR, FISH, or IHC as appropriate. Treatment was delivered using off-label FDA approved drugs, clinical trials, or single patient INDs.

Results: We have enrolled 40 patients for whom sequencing data is available on 33. The initial 6 patients were evaluated in a non-CLIA pilot phase and 27 in a CLIA-enabled phase. Tumor types in the CLIA-enabled phase with the highest enrollment were pancreatic cancer (n=8) and cholangiocarcinoma (n=8). We sought to quantify the targets identified along with clinical benefit, defining these as the “Actionable Index” (AI) (proportion of patients with ≥ 1 putative drug target) and “Utility Index” (UI) (proportion of patients who derive clinical benefit). Putative therapeutic targets were identified in 7/8 (AI=0.88) cholangiocarcinoma (CC) patients and in 5/8 (AI=0.63) pancreatic cancer (PC) patients. All 3 CC patients who received target directed treatment achieved a partial response (UI=0.38). In contrast, none of the 4 PC patients who received target directed therapy had treatment response (UI=0.0). Interestingly no actionable targets were identified in 1 CC and in 2 PCs. One CC with an identified target was unable to access the drug and subsequently died. A CC patient and a PC patient, each with identified targets, expired prior to the initiation of therapy.

Conclusions: While whole genome/exome/RNA sequencing is providing unparalleled detail of tumor genomes, the application to the clinic must be carefully considered. Actionability of targets will eventually need to be defined in close relation to eventual clinical utility and appropriate refinements to disease-gene-drug databases implemented. Preliminary observations in pancreatic cancer and cholangiocarcinoma demonstrate disparity in correlation between utility indices and actionable indices. Application of these tools in larger cohorts and types of tumors will need to be conducted to ascertain more precise estimates. Additional measures that are organ-site agnostic but pertain to specific targets (e.g. BRAF) will also need to be developed in order to facilitate more judicious application of sequencing in the clinical setting.

Citation Format: Jan B. Egan, Alan H. Bryce, Mia D. Champion, Winnie S. Liang, Rafael Fonseca, Ann E. McCullough, Michael T. Barrett, Katherine Hunt, Rachel M. Condjella, Robert R. McWilliams, Stephen D. Mastrian, Janine LoBello, Daniel Von Hoff, David W. Craig, A. Keith Stewart, John D. Carpten, Mitesh J. Borad. Indices of actionability and clinical utility in a CLIA-enabled study of whole genome/exome/RNA sequencing in 33 cancer patients: Actionable vs. utility. [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 4694. doi:10.1158/1538-7445.AM2014-4694