Dose Intensity And Efficacy Of The Combination Of Everolimus And Exemestane (Eve/Exe) In A Real World Population Of Hormone Receptor Positive Advanced Breast Cancer: A Multicenter Italian Experience

BACKGROUND: Everolimus, an mTOR inhibitor, in combination with exemestane is approved for hormone receptor (HR) positive advanced breast cancer (ABC), after failure of treatment with non-steroidal aromatase inhibitor (NSAI). We assessed the toxicity of the combination and the correlation between dose intensity and response to therapy, in a real world population of ABC from 11 Italian centers. Moreover, we evaluated OS of the whole population, RR and PFS according to line of treatment (from 1rd to 3th and from 4th on). METHODS: 154 pts were treated with combination of everolimus 10 mg and exemestane 25 mg daily from 05/2011 today. Median age was 62 (47-82). Median time to metastatic disease was 49 months (0-269). Median number of metastatic sites was 2 (55.2% of pts visceral versus 44.8% non visceral disease). N=117 (75.9%) pretreated with HT as adjuvant; N=126 pts (81.8%) treated with HT for advanced disease prior to EVE/EXE, with a median of one line (0-5). N=102 pts (66.2%) treated with chemotherapy for metastatic disease, with a median of one line (0-6) before everolimus treatment. RESULTS: Sixteen pts received EVE/EXE as 1st line (10.4%), 39 as 2nd (25.3%), 37 as 3rd (24%), 62 as 4th or more (40,3%). Response was evaluable in 127 out of 154 pts; CR/PR/SD respectively 5/27/56 pts. RR according to line (from 1st to 3rd vs ≥ 4th) was respectively 22.8% vs 26.4% (p=0,864). The median PFS for all population (150 pts) was 38 weeks (95% CI: 33-42). The PFS according to line (1st- 3rd vs ≥ 4th) was 38 wks in both subgroups, p=0.73. OS (126/154 pts) was 28 mths (95% CI: 31-38). The most frequent adverse events were collected in the table. Median duration of treatment with everolimus 10 mg and 5 mg was respectively 180 (9-854) and 129 days (3-738). Fifty-eight pts (37,6%) never stopped treatment with everolimus 10 mg; 16 pts (10,4%) definitively stopped everolimus for toxicity; 80 pts (52,0%) temporarily interrupted the treatment, resuming at dose level 10 mg (31 pts) or reducing at 5 mg (49 pts). Main reason for discontinuation/interruption was stomatitis G2-G3. RR and PFS evaluated according to dose intensity, 10 mg vs 5 mg, were respectively 25.9% vs 30% p=0.779, 38 wks (27-44) vs 40 wks (31-48) P=0.614 CONCLUSIONS: efficacy in terms of RR and PFS of the combination EVE/EXE is not related to dose intensity (10 mg vs 5 mg), the discontinuation of the treatment is high with the starting dose of 10 mg, the toxicity is consistent with previous phase II-III studies although we collected some different toxicities. Citation Format: Forcignano R, Petrucelli L, Cazzaniga ME, Lupo LI, Chiuri VE, Cairo G, De Matteis E, Febbraro A, Giordano G, Campidoglio S, Fabi A, Giampaglia M, Bilancia D, La Verde N, Maiello E, Morritti M, Giotta F, Lorusso V, Scavelli C, Romito S, Cusmai A, Palmiotti G, Tornesello A, Ciccarese M. Dose intensity and efficacy of the combination of everolimus and exemestane (EVE/EXE) in a real world population of hormone receptor positive advanced breast cancer: A multicenter Italian experience. [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 P4-13-15.