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2017 ASCO Annual Meeting!

Session: Breast Cancer—Metastatic

Type: Oral Abstract Session

Time: Saturday June 3, 1:15 PM to 4:15 PM

Location: Hall D1

MONARCH 2: Abemaciclib in combination with fulvestrant in patients with HR+/HER2- advanced breast cancer who progressed on endocrine therapy

Hormone Receptor-Positive

Breast Cancer—Metastatic

2017 ASCO Annual Meeting

Abstract No:

J Clin Oncol 35, 2017 (suppl; abstr 1000)

Author(s): George W. Sledge, Masakazu Toi, Patrick Neven, Joohyuk Sohn, Kenichi Inoue, Xavier B. Pivot, Olga Nikolaevna Burdaeva, Meena Okera, Norikazu Masuda, Peter A. Kaufman, Han A. Koh, Eva-Maria Grischke, Martin Frenzel, Yong Lin, Susana Barriga, Ian C. Smith, Nawel Bourayou, Antonio Llombart-Cussac; Stanford University School of Medicine, Stanford, CA; Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Hospital Gasthuisberg, Leuven, Belgium; Yonsei Cancer Center, Seoul, Republic of Korea; Saitama Cancer Center, Saitama, Japan; CHU Jean Minjoz, Besançon, France; Arkhangelsk Regional Clinical Oncology Dispensary, Arkhangelsk, Russia; Adelaide Cancer Centre, Adelaide, Australia; Department of Surgery, Breast Oncology, NHO Osaka National Hospital, Osaka, Japan; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH; Kaiser Permanente, Bellflower, CA; Universitӓts-Frauenklinik Tubingen, Eberhard Karls University, Tubingen, Germany; Eli Lilly and Company, Indianapolis, IN; Eli Lilly and Company, Madrid, Spain; AstraZeneca, Congleton, United Kingdom; Eli Lilly and Company, Paris, France; Hospital Arnau de Vilanova, Valencia, Spain

Abstract Disclosures


Background: Abemaciclib, an oral, selective inhibitor of CDK4 & 6, dosed on a continuous schedule, demonstrated clinical activity as monotherapy in patients (pts) with treatment refractory hormone receptor positive (HR+) metastatic breast cancer (MBC). The tolerability and activity of abemaciclib + fulvestrant (F) supported Phase 3 evaluation. Methods: MONARCH 2 is a double-blind Phase 3 trial of abemaciclib + F vs placebo (P) + F in women with HR+/HER2- advanced breast cancer. Women who progressed on (neo)adjuvant endocrine therapy (ET), ≤12 months from end of adjuvant ET, or on first line ET for MBC and who had not received chemotherapy for metastatic disease were eligible. Pts were randomized 2:1 to receive abemaciclib at 150 mg Q12H (or 200 mg prior to amendment) or P plus F (500 mg, per label) and stratified by metastatic site (visceral, bone only, or other) and resistance to prior ET (primary vs secondary). Pre/perimenopausal pts received a gonadotropin-releasing hormone agonist. The primary objective was investigator-assessed progression-free survival (PFS). Secondary endpoints included objective response rate (ORR) and other efficacy and safety endpoints. Assuming a hazard ratio (HR) of 0.703 in favor of abemaciclib + F, 378 events were needed for 90% power at one sided α=.025. Results: 669 pts were randomized to abemaciclib + F (N=446) and to P + F (N=223). 56% of pts had visceral disease, 72% had measurable disease, 25% had primary ET resistance, and 82% were postmenopausal. In the ITT population 379 PFS events were observed with a median PFS of 16.4 m for abemaciclib + F and 9.3 m for P + F (HR: 0.553; 95% CI: 0.449, 0.681, P<.0000001 by log-rank test). In pts with measurable disease, the ORR was 48.1% (3.5% complete response [CR]) for abemaciclib + F and 21.3% (0% CR) for P + F. The most frequent treatment emergent adverse events for abemaciclib + F vs P + F were diarrhea (86.4% vs 24.7%), neutropenia (46.0% vs 4.0%), nausea (45.1% vs 22.9%), and fatigue (39.9% vs 26.9%). Conclusions: Abemaciclib + fulvestrant was an effective treatment in patients with HR+/HER2- advanced breast cancer who progressed on endocrine therapy with significantly improved PFS and ORR. Clinical trial information: NCT02107703

Other Abstracts in this Sub-Category:


1. Overall survival results from the randomized phase II study of palbociclib (P) in combination with letrozole (L) vs letrozole alone for frontline treatment of ER+/HER2– advanced breast cancer (PALOMA-1; TRIO-18).

Meeting: 2017 ASCO Annual Meeting Abstract No: 1001 First Author: Richard S. Finn
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive


2. A phase II trial of the CDK4/6 inhibitor palbociclib (P) as single agent or in combination with the same endocrine therapy (ET) received prior to disease progression, in patients (pts) with hormone receptor positive (HR+) HER2 negative (HER2−) metastatic breast cancer (mBC) (TREnd trial).

Meeting: 2017 ASCO Annual Meeting Abstract No: 1002 First Author: Luca Malorni
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive


3. Everolimus (EVE) plus endocrine therapy in patients with estrogen receptor–positive (ER+), human epidermal growth factor receptor 2–negative (HER2) advanced breast cancer (BC): First- and second-line data from the BOLERO-4 study.

Meeting: 2017 ASCO Annual Meeting Abstract No: 1010 First Author: Fatima Cardoso
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive