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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

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).

Hormone Receptor-Positive

Breast Cancer—Metastatic

2017 ASCO Annual Meeting

Abstract No:

J Clin Oncol 35, 2017 (suppl; abstr 1001)

Author(s): Richard S. Finn, John Crown, Istvan Lang, Katalin Boer, Igor Bondarenko, Sergey O. Kulyk, Johannes Ettl, Ravindranath Patel, Tamas Pinter, Marcus Schmidt, Yaroslav V. Shparyk, Anu Thummala, Nataliya L. Voytko, Camilla Fowst, Xin Huang, Sindy Kim, Dennis J. Slamon; David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA; Irish Cooperative Oncology Research Group, Dublin, Ireland; National Institute of Oncology, Budapest, Hungary; Szent Margit Korhaz, Onkologia, Budapest, Hungary; Dnepropetrovsk State Medical Center, Dnipropetrovsk, Ukraine; Municipal Treatment-and-Prophylactic Institution, Donetsk, Ukraine; Technical University of Munich, Munich, Germany; Comprehensive Blood and Cancer Center, Bakersfield, CA; Petz Aladar Megyei Oktato Korhaz, Gyor, Hungary; Johannes Gutenberg Universität, Mainz, Germany; Lviv State Oncological Regional Medical and Diagnostic Center, Lviv, Ukraine; Comprehensive Cancer Centers of Nevada, Las Vegas, NV; Kyiv City Clinical Oncology Center, Kyiv, Ukraine; Pfizer Italia Srl, Milan, Italy; Pfizer Inc., La Jolla, CA; Pfizer Inc., San Diego, CA

Abstract Disclosures


Background: Preclinical data identified a synergistic role for P and hormone blockade in blocking growth of ER+ breast cancer (BC) cell lines. PALOMA-1 was an open-label phase II trial comparing progression-free survival (PFS) in patients (pts) with advanced ER+/HER2– BC treated with P+L or L alone. Median PFS increased with addition of P to L to 20.2 mos (vs 10.2 mos with L alone; HR = 0.488), with an acceptable safety profile, leading to accelerated approval by the US FDA. These results were confirmed in the phase 3 PALOMA-2 trial. At the time of the final PFS analysis, overall survival (OS) data were immature with only 61 events in both arms and a median follow-up of < 30 mos with a trend in favor of P+L vs L (37.5 vs 33.3 mos; HR = 0.813; P= 0.211). Here we present final OS results. Methods: PALOMA-1 was a 2-part study evaluating P+L in ER+/HER2– advanced BC. Part 1 enrolled postmenopausal pts with this subtype using only ER+/HER2– while Part 2 enrolled pts of this subtype additionally screened for CCND1 amplification and/or loss of p16. The primary endpoint was investigator-assessed PFS. Secondary endpoints included objective response rate, OS, safety, and correlative biomarker studies. A total of 165 pts were randomized; 66 in Part 1 and 99 in Part 2. Baseline characteristics were balanced between treatment arms. In both parts, pts were randomized 1:1 to receive P+L or L alone. OS data were collected as well as post-study therapy. Results: As of Dec 2016, there were 116 OS events. Median OS was 37.5 mos (95% CI: 31.4, 47.8) with P+L vs 34.5 mos (95% CI: 27.4, 42.6) for L (HR = 0.897 [95% CI: 0.623, 1.294]; P= 0.281). Median OS was 37.5 vs 33.3 mos (HR = 0.837; P= 0.280) for Part 1 and 35.1 vs 35.7 mos (HR = 0.935; P= 0.388) for Part 2. 78.6% of pts in the P+L arm received post-study systemic therapy vs 86.4% in the L arm. More pts in the L arm received ≥3 lines of therapy (37% vs 18%). Further subgroup analyses and details on post-study therapies will be presented. Conclusions: In PALOMA-1, P+L provided a statistically non-significant trend towards an improvement in OS. Survival data from the phase III, PALOMA-2 study is awaited. Sponsor: Pfizer; Clinical trial information: NCT00721409

Other Abstracts in this Sub-Category:


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

Meeting: 2017 ASCO Annual Meeting Abstract No: 1000 First Author: George W. Sledge
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