Abstract P5-16-01: Implementation of routine genomic and proteomic profiling of metastatic breast cancer patients in a community cancer center
Authors: Williams CB , Krie A , De P , Dey N , Klein J , Williams KA , Hoogeveen M , Solomon B , Leyland-Jones B 
Published: May 2016

Background: The optimal treatment strategy for patients with metastatic breast cancer (MBC) is currently unknown. Resistance to standard therapies, including anthracyclines and taxanes, limit the number of treatment options in many patients to a small number of non-cross resistant regimens. Rational combination approaches that are selected based upon genomic and proteomic analysis represents a possible advance that warrants extensive exploration.

Methods: Single center analysis of 77 consecutive metastatic breast cancer patients seen over a 12 month period (June 2014 through May 2015). All patients were referred for sequencing and the metastatic disease was rebiopsied. All samples were sent for standard pathologic, genomic (FoundationOne), and proteomic (TheraLink) analysis.

Results: Genomic and proteomic analysis yielded actionable targets in a majority of cases (89%). The most common pathways involved were the following: PI3K/Akt/mTOR (73%), MAPK (46%), ErbB (36%), FGFR (25%), and Jak/STAT (11%). Over 100 unique molecular aberrations were identified in 40 evaluable patients. Current outcomes are summarized in Table 1. The overall response rate was 45%, with another 43% of patients with stable disease. Average number of prior therapies was over 4, with a range of 1-11.

Table 1ER+/HER2-CR = 3PR = 8SD = 15PD = 2NE = 20ER+/HER2+CR = 2PR = 2SD = 1PD = 0NE = 9ER-/HER2+CR = 0PR = 1SD = 1PD = 1NE = 2Triple NegativeCR = 0PR = 2SD = 0PD = 2NE = 6Total evaluable patients = 40Overall CR = 13%Overall PR = 33%Overall SD = 43%Overall PD = 13%Total Not Evaluable = 37 pts (48%)Overall Response Rate (ORR) = 45%     CR = complete response PR = partial response SD = stable disease PD = progressive disease NE = not evaluable

Conclusion: Since current literature suggests that an overall response rate of approximately 10% or less is expected for patients that have received greater than 4 previous lines of therapy, the ORR seen in this analysis is quite remarkable. Most patients in this analysis were treated with FDA approved drugs off label, which provided additional challenges and was the primary reason that many patients were not evaluable. Patients were only evaluable if they received the recommended therapy and were measured for outcome. Our initial data provides growing evidence that it is critical to incorporate genomic and proteomic analysis (preferably as early as possible in the disease course) to allow for the best chance of disease response.

Citation Format: Williams CB, Krie A, De P, Dey N, Klein J, Williams KA, Hoogeveen M, Solomon B, Leyland-Jones B. Implementation of routine genomic and proteomic profiling of metastatic breast cancer patients in a community cancer center. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-16-01.