Abstract P4-13-09: Clinical effectiveness of everolimus and exemestane in advanced breast cancer patients from Asia and Africa: First efficacy and updated safety results from the phase IIIb EVEREXES study

Background

BOLERO-2 phase III trial established the efficacy of everolimus (EVE) plus exemestane (EXE) for the treatment of postmenopausal patients with hormone receptor (HR)-positive, HER2-negative, advanced breast cancer (aBC). However, in this study only a minority (<10%) of patients were recruited from African and Asia Pacific countries. Considering the potential effects of ethnic and cultural differences on treatment effectiveness, it remains compelling to confirm the safety and efficacy profile of EVE+EXE in these populations.

Methods

EVEREXES is an open-label phase IIIb, single arm, multi-center trial, which from March 2013 to October 2014 enrolled 232 post-menopausal, HR-positive and HER2-negative, aBC patients previously treated with aromatase inhibitors, across 13 countries in Asia Pacific, Middle East, North and South Africa, with a significant majority of patients being of Asian ethnicity (196, 84.5%). Its primary objective was to investigate the safety and tolerability profile of EVE+EXE. Secondary objectives were the evaluation of efficacy (assessed by PFS, ORR, and CBR based on RECIST 1.1 criteria) and change in ECOG performance status.

Results

At data cut off of 31st of January 2015, at a median follow up of 11.7 months, median PFS for the ITT population was 9.5 months [9.2-11.6 months], based on local assessment, with the observation of 1 (0.4%) CR and 35 (15.4%) PR. Regarding safety and tolerability, a majority (81.1%) of grade (G) 1/2 adverse events (AEs) was reported. In particular, the following pattern was observed in terms of % of patients who developed G1/G2/G3 mTOR-inhibition induced AEs: stomatitis (36.1, 13.7, 10.6), rash (21.6/6.2/0), fatigue (10.6, 4.4, 2.2), hyperglycemia (6.2, 11.5, 7.0), weight decrease (7.5, 7, 0.9), pneumonitis (5.7, 7, 0.9). No Grade 4 AEs related to EVE+EXE treatment were observed, with exception of one case of non infectious pneumonitis (0.4%). Median dose intensity of everolimus was 9.2 mg/day.

Conclusions

Efficacy and safety results from EVEREXES trial further confirm the role of EVE+EXE for the treatment of HR+/Her2- advanced BC patients in Eastern countries. Results were consistent with data previously reported in BOLERO-2 trial.

Citation Format: Im Y-H, Uslu R, Lee KS, Nagarkar R, Sohn J, Sevinc A, Altundag K, Chang Y-C, Abdel-Razeq H, Im S-A, Jeong J, Park HY, Arpornwirat W, Bastick P, Le TH, Ocak Arikan O, Xue HL, Canatar A, Valenti R, Kim S-B. Clinical effectiveness of everolimus and exemestane in advanced breast cancer patients from Asia and Africa: First efficacy and updated safety results from the phase IIIb EVEREXES study. [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 P4-13-09.

Endoxifen for breast cancer: Multiple-dose, dose-escalation study characterizing pharmacokinetics and safety in metastatic breast cancer patients

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Background: Endoxifen is an active metabolite of tamoxifen, a drug used in the treatment of breast cancer. To be clinically effective, tamoxifen must be converted to endoxifen by CYP2D6. Direct administration of endoxifen would not be subject to pharmacogenetic variations or drug-drug interactions. Our preclinical studies (Breast Cancer Treat 122, 579-584, 2010) have validated the concept of using endoxifen for the treatment of breast cancer. In human (Clin. Pharmacol. Ther. 88, 814-817, 2010), the single oral doses tested up to 4 mg of endoxifen were safe, well tolerated and bioavailable. Methods: A multiple-dose escalating study was conducted in 3 cohorts and each cohort had 6 patients (18 metastatic breast cancer patients). Endoxifen at 3 dose levels (2, 4, or 8 mg) was given once daily for 28 days. Routine laboratory tests, vital signs and electrocardiograms were measured throughout the study. Blood samples for PK analysis were collected after 28 days post dose. Endoxifen in plasma samples was determined using LC-MS/MS. Results: Endoxifen was found to be safe up to 8.0 mg. At steady state, it displays dose-proportional PK with respect to Cmax and AUC ( see Table below). Conclusions: Multiple daily endoxifen doses of 4.0-8.0 mg resulted in endoxifen exposures that would be sufficient for effective therapy. The favorable safety and multiple-dose PK profile of endoxifen warrants further evaluation of safety and efficacy of endoxifen in breast cancer patients. [Table: see text]