Abstract P5-19-15: Prescribing preferences of US-based medical oncology physicians for patients with hormone receptor positive, HER2 negative metastatic breast cancer following prior endocrine therapies
Authors: Cianfrocca Mary E , Buettner Arden D , Britton Susan L , Lankford Maria L , Green Mark R 
Published: May 2015

Background: Non-steroidal aromatase inhibitors (NSAI) are a standard first-line therapy (Rx) for post-menopausal pts with hormone receptor positive (HR+), HER2 negative (HER2-) advanced and recurrent metastatic breast cancer (mBC). When studied in phase III clinical trials, combination hormonal Rx regimens have not consistently produced significant improvements in time to event measures compared to sequential single agents. However recent phase II and III studies combining hormonal and targeted agents have shown significant extensions in PFS and potential increases in OS. Due to the emergence of several targeted agents, standards of care for treatment after failure on a NSAI are evolving.

Methods: Prescribing preferences (PPrefs) of 187 U.S.-based medical oncology physicians (MOPs) were studied using a validated, proprietary, live, case-based market research tool (Challenging Cases®). Data were acquired using blinded, audience-response iPad technology and acquisition events took place in March and May 2014. A core case was constructed and PPrefs for three 1st, three 2nd, and one 3rd failure scenario were assessed. Core case: 60-year-old female; History of mild hypertension well-controlled by medication; diagnosed with stage 2B HR+, HER2-, grade 3, invasive ductal carcinoma; Primary Rx included lumpectomy+ sentinel node biopsy/axillary dissection, chemotherapy (CT) and radiotherapy (RT) followed by anastrozole with plans for 5 years (yrs) of Rx. Question posed: What systemic Rx would you recommend now?

Results:

Figure 1: PPrefs for Rx for first recurrent disease during or after 5 yrs of adjuvant anastrozoleScenarioEndocrine Rx Targeted StrategyCTOther Time to Recurrence(REC) Met sitesAnother NSAIFulvestrant (F)Exemestane (EXE)EXE + Everolimus (EVE)Single agent(SA)/ comboOther/ Clinical Trial (CLT)/Continue NSAI and add FS1a, N=18718 mths while on NSAI Non-Visceral (N-VIS) and Visceral (VIS)10%28%6%35%14%7%S1b, N=9718 mths while on NSAI N-VIS, Unproven VIS7%46%5%28%7%6%S2, N=1872 yrs post 5 yrs NSAI N-VIS25%35%18%17%3%5%

Figure 2: PPrefs for next Rx following adjuvant anastrozole and then letrozole (LET) at first failure.ScenarioEndocrine RxTSCTOther Time to REC after TX with LET Met sitesFEXEEXE + EVESA/ComboCLT/RT to rib + no Rx change, Continue current NSAI + add FS3, N=1875 mths N-VIS42%6%37%7%9%S4, N=18612 mths N-VIS46%6%36%5%9%S5, N=9418 mths N-VIS65%5%21%3%6% Time to REC on FFEXEEXE + EVESA/ComboOther/CLTS6, N= 1866 mths N-VIS, VISN/O3%40%55%2%N/O - not offered

Conclusion:

MOPs PPrefs for management of pts with ER+, HER2- mBC are dictated by time to REC, number of RECs, and presence/absence of VIS disease. EXE and EVE has substantial traction in all scenarios studied. Since these PPref data were acquired, OS findings from the BOLERO-2 trial of EXE alone or EXE + EVE have been presented. PPrefs using these case scenarios will be studied at 2 additional events prior to SABCS, allowing more robust data and insights into the early impact of the BOLERO-2 survival data on PPrefs to be available at the meeting.

Citation Format: Mary E Cianfrocca, Arden D Buettner, Susan L Britton, Maria L Lankford, Mark R Green. Prescribing preferences of US-based medical oncology physicians for patients with hormone receptor positive, HER2 negative metastatic breast cancer following prior endocrine therapies [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-19-15.