Abstract 241P
Background
MONARCH 2 (M2) demonstrated that the addition of continuously-dosed abemaciclib to fulvestrant significantly improved progression-free survival (PFS) and overall survival (OS) compared to placebo plus fulvestrant in women with HR+, HER2- advanced breast cancer (ABC) who had progressed on endocrine therapy (ET). Here we present the Objective Response Rate (ORR) from endocrine-naïve (EN) participants enrolled in MONARCH 2.
Methods
A small cohort of EN participants, with measurable disease at baseline, were initially enrolled in the M2 main study [excluded from the intent-to-treat (ITT) population] (N=20). Subsequently, 90 additional participants were enrolled under the EN addendum. The analysis population consist of a pooled EN cohort (N = 110). All participants were scheduled to receive abemaciclib (150mg or 200 mg Q12H) plus fulvestrant (500 mg, per label). Participants were not allowed to have had prior ET in any setting or prior chemotherapy in the metastatic setting. The primary endpoint was investigator-assessed confirmed ORR. The secondary endpoints were investigator-assessed PFS, duration of response (DoR), disease control rate (DCR), clinical benefit rate (CBR), and safety and tolerability.
Results
In the pooled EN cohort, confirmed ORR was 59.1% (95% CI 49.9-68.3). Median follow-up was 9.8 (0.03-73.05) months. PFS and DoR data are not mature at this time. No new safety signals were reported in the pooled EN cohort, and the safety profile was consistent with the previously reported MONARCH 2 population.
Conclusions
The primary analysis of confirmed ORR compares favorably with previously reported ORR for fulvestrant monotherapy in participants with a similar disease state. PFS and DoR data are not yet mature. The safety profile is similar to that previously reported in the primary MONARCH 2 main study.
Clinical trial identification
NCT02107703.
Editorial acknowledgement
Legal entity responsible for the study
Eli Lilly and Company.
Funding
Eli Lilly and Company.
Disclosure
J. Luis-Gonzalez Trujillo: Financial Interests, Personal and Institutional, Funding: Eli Lilly and Company; Financial Interests, Personal and Institutional, Funding: BMS; Financial Interests, Personal and Institutional, Funding: Roche; Financial Interests, Personal and Institutional, Funding: Pierre Fabre; Financial Interests, Personal, Advisory Board: BMS; Financial Interests, Personal, Advisory Board: MSL; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal and Institutional, Speaker’s Bureau: BMS; Financial Interests, Personal and Institutional, Speaker’s Bureau: Novartis. J.H. Sohn: Financial Interests, Institutional, Research Grant: MSD; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Eli Lilly and Company; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Institutional, Research Grant: Bayer; Financial Interests, Institutional, Research Grant: GSK; Financial Interests, Institutional, Research Grant: Contessa; Financial Interests, Institutional, Research Grant: Daiichi Sankyo. A. Llombart Cussac: Financial Interests, Personal, Leadership Role: Celgene; Financial Interests, Personal, Leadership Role: Eisai; Financial Interests, Personal, Leadership Role: Eli Lilly and Company; Financial Interests, Personal, Leadership Role: MSD; Financial Interests, Personal, Leadership Role: Novartis; Financial Interests, Personal, Leadership Role: Pfizer; Financial Interests, Personal, Leadership Role: Roche; Financial Interests, Personal, Stocks/Shares: Initia-Research; Financial Interests, Personal, Stocks/Shares: MedSIR; Financial Interests, Personal, Advisory Board: Genomic Health; Financial Interests, Personal, Advisory Board: GSK; Financial Interests, Personal, Advisory Board: Eli Lilly and Company; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Advisory Board: Pfizer; Financial Interests, Personal, Advisory Board: Pierre Fabre; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal and Institutional, Speaker’s Bureau: AstraZeneca; Financial Interests, Personal and Institutional, Speaker’s Bureau: Eli Lilly and Company; Financial Interests, Personal and Institutional, Speaker’s Bureau: MSD; Financial Interests, Personal and Institutional, Funding: Agendia; Financial Interests, Personal and Institutional, Funding: Foundation Medicine; Financial Interests, Personal and Institutional, Funding: Pierre Fabre; Financial Interests, Personal and Institutional, Funding: Roche; Financial Interests, Personal, Other, Travel: AstraZeneca; Financial Interests, Personal, Other, Travel: Eli Lilly and Company; Financial Interests, Personal, Other, Travel: Novartis; Financial Interests, Personal, Other, Travel: Pfizer; Financial Interests, Personal, Other, Travel: Rocher. W. Zhang: Financial Interests, Institutional, Full or part-time Employment: Eli Lilly and Company. N. Haddad: Financial Interests, Institutional, Full or part-time Employment: Eli Lilly and Company. H. Wasserstrom: Financial Interests, Institutional, Full or part-time Employment: Eli Lilly and Company. G. van Hal: Financial Interests, Institutional, Full or part-time Employment: Eli Lilly and Company. G.W. Sledge Jr: Financial Interests, Institutional, Stocks/Shares: Syndax; Financial Interests, Personal, Leadership Role: Syndax; Financial Interests, Personal, Invited Speaker: Symphony Evolution; Financial Interests, Personal, Advisory Role: Coherus Biosciences; Financial Interests, Personal, Advisory Role: Peregrine Pharmaceutical; Financial Interests, Personal, Advisory Role: Radius Health; Financial Interests, Personal, Advisory Role: Symphony Evolution; Financial Interests, Personal, Advisory Role: Taiho Pharmaceutical; Financial Interests, Personal and Institutional, Research Grant: Genentech/Roche; Financial Interests, Personal and Institutional, Other: Radius Health; Financial Interests, Personal and Institutional, Other: Taiho Pharmaceutical. All other authors have declared no conflicts of interest.