C. Stoffregen (Bad Homburg vor der Hoehe, Germany)
Lilly Deustchland GmbHAuthor Of 1 Presentation
104P - Clinical characteristics of patients (pts) with complete response (CR) to abemaciclib-based endocrine therapy (ET) in MONARCH 2 (M2) and MONARCH 3 (M3)
Abstract
Background
Abemaciclib is an oral cyclin-dependent kinase 4 & 6 inhibitor, dosed on a continuous schedule, approved for the treatment of hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) combined with ET. In this pt population, CR is rarely seen with ET alone. Pt/disease characteristics may correlate with response to a specific treatment. In this post-hoc exploratory analysis, we report characteristics of pts with CR to abemaciclib+ET in M2 and M3.
Methods
M2 (NCT02107703) and M3 (NCT02246621) were double-blind, phase III studies in which women with HR+, HER2- ABC were randomised to receive abemaciclib/placebo+ET (M2: fulvestrant; M3: aromatase inhibitor). M2 included pts with progression during or ≤1 year of (neo)adjuvant ET or on first ET for ABC. M3 included pts who had not received prior systemic therapy for ABC. Disease characteristics were described in pts who achieved CR (RECIST v1.1) across the two studies, focusing on parameters reported to be associated with poor prognosis. Data are from the final progression-free survival analyses.
Results
Of 774 pts randomised to receive abemaciclib in M2 and M3, a total of 23 achieved CR: 14/446 in M2 and 9/328 in M3 (corresponding data in M2 and M3 pts receiving placebo+ET: 1/223 and 1/165 pts, respectively). A total of 3/14 M2 and 6/9 M3 abemaciclib pts had Eastern Cooperative Oncology Group (ECOG) status 1 (remainder: ECOG 0); 2/14 M2 and 0/9 M3 pts were progesterone receptor negative; 4/14 M2 and 3/9 M3 pts had a high-grade tumour; 10/14 M2 and 9/9 M3 pts had no bone-only disease, and 2/14 M2 and 0/9 M3 pts had liver metastases at baseline. Treatment-free interval was <3 years for 3/4 M3 pts with recurrent metastatic disease who had received adjuvant ET. 10/14 M2 pts and 5/9 M3 pts achieved CR <3 months after starting treatment; 7/14 M2 and 6/9 M3 pts had duration of response >15 months.
Conclusions
A small proportion of pts with recurrent ABC treated with abemaciclib in M2 and M3 achieved CR, including some pts with disease characteristics reported to be associated with poor prognosis. Those responses had a short time to onset and were relatively durable.
Editorial acknowledgement
Medical writing assistance was provided by Gill Gummer and Caroline Spencer (Rx Communications, Mold, UK).
Legal entity responsible for the study
Eli Lilly and Company.
Funding
Funded by Eli Lilly and Company.
Disclosure
J. Huober: Honoraria (self), Advisory/Consultancy, Research grant/Funding (self), Travel/Accommodation/Expenses: Celgene; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self), Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy, Research grant/Funding (self): Hexal; Honoraria (self), Advisory/Consultancy: Eli Lilly and Company; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Pfizer; Travel/Accommodation/Expenses: Daiichi; Honoraria (self), Advisory/Consultancy: AstraZeneca; Honoraria (self), Advisory/Consultancy: MSD; Honoraria (self): Eisai; Honoraria (self), Advisory/Consultancy: AbbVie. N. Chouaki, C. Stoffregen, A. Korfel: Full/Part-time employment: Eli Lilly and Company. F. Lerebours: Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: AstraZeneca; Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Eisai; Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony: Eli Lilly and Company; Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Novartis; Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Pierre Fabre; Honoraria (self), Advisory/Consultancy: Genomic Health; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Pfizer. All other authors have declared no conflicts of interest.