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2018 ASCO Annual Meeting!

Session: Breast Cancer—Metastatic

Type: Oral Abstract Session

Time: Sunday June 3, 8:00 AM to 11:00 AM

Location: Hall D2

Phase III study of taselisib (GDC-0032) + fulvestrant (FULV) v FULV in patients (pts) with estrogen receptor (ER)-positive, PIK3CA-mutant (MUT), locally advanced or metastatic breast cancer (MBC): Primary analysis from SANDPIPER.

Hormone Receptor-Positive

Breast Cancer—Metastatic

2018 ASCO Annual Meeting

Abstract No:

J Clin Oncol 36, 2018 (suppl; abstr LBA1006)

Author(s): Jose Baselga, Susan Faye Dent, Javier Cortés, Young-Hyuck Im, Véronique Diéras, Nadia Harbeck, Ian E. Krop, Sunil Verma, Timothy R. Wilson, Huan Jin, Lijia Wang, Frauke Schimmoller, Jerry Y. Hsu, Jing He, Michelino DeLaurentiis, Pamela Drullinsky, William Jacot; Memorial Sloan Kettering Cancer Center, New York, NY; The Ottawa Hospital Cancer Centre, Ottawa, ON, Canada; Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain, and Ramón y Cajal University Hospital, Madrid, Spain; Samsung Medical Center, Seoul, Korea, Republic of (South); Institut Curie, Paris, and Centre Eugène Marquis, Rennes, France; Brustzentrum der Universität München (LMU), Munich, Germany; Dana-Farber Cancer Institute, Boston, MA; Tom Baker Cancer Centre, Department of Oncology, University of Calgary, Calgary, AB, Canada; Genentech Inc., South San Francisco, CA; Istituto Nazionale Tumori Fondazione G. Pascale, Naples, Italy; Institut du Cancer de Montpellier, Montpellier, France

Abstract Disclosures


Background: Taselisib, a potent, selective PI3K inhibitor, has enhanced activity in PIK3CA-MUT BC cell lines and confirmed partial responses in PIK3CA-MUT BC as a single-agent or with FULV. We assessed taselisib + FULV in pts with ER-positive, HER2-negative, PIK3CA-MUT locally advanced or MBC. Methods: SANDPIPER (NCT02340221) is a double-blind, placebo (PBO)-controlled, randomized, phase III study. Postmenopausal pts with disease recurrence or progression during or after an aromatase inhibitor were randomized 2:1 to receive taselisib (4 mg oral, qd) or PBO + FULV (500 mg). Stratification factors were: visceral disease, endocrine sensitivity, and geographic region. Pts with PIK3CA-MUT tumors, assessed by central cobas PIK3CA Mutation Test, were randomized separately from non-MUT tumors. The primary endpoint was investigator-assessed progression-free survival (INV-PFS) in pts with PIK3CA-MUT tumors. Secondary endpoints included objective response rate (ORR), overall survival (OS), clinical benefit rate (CBR), duration of objective response (DoR), PFS by blinded independent central review (BICR-PFS), and safety. Results: 516 pts were randomized in the PIK3CA-MUT intention-to-treat (ITT) population. Efficacy is shown in the Table. Taselisib + FULV significantly improved INV-PFS (hazard ratio [HR] 0.70) as confirmed by BICR-PFS (HR 0.66). OS is immature. The most common grade ≥3 adverse events (AEs; preferred terms) in the taselisib + FULV arm in safety-evaluable pts who received ≥ 1 dose of treatment were diarrhea (12%), hyperglycemia (10%), colitis (3%), and stomatitis (2%). AEs led to more taselisib discontinuations (17% v 2%) and dose reductions (37% v 2%), v PBO. Conclusions: Taselisib + FULV significantly improved INV-PFS, v PBO + FULV, in pts with ER-positive, HER2-negative, PIK3CA-MUT locally advanced or MBC. The safety profile is largely consistent with previous studies. Clinical trial information: NCT02340221

Median INV-PFS, moN=176
HR0.70 (p=.0037)
Baseline measurable diseasen=134n=264
ORR, %11.928.0
CBR, %37.351.5
DoR, mon=16

Other Abstracts in this Sub-Category:


1. Ribociclib (RIB) + fulvestrant (FUL) in postmenopausal women with hormone receptor-positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC): Results from MONALEESA-3.

Meeting: 2018 ASCO Annual Meeting Abstract No: 1000 First Author: Dennis J. Slamon
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive


2. Genetic landscape of resistance to CDK4/6 inhibition in circulating tumor DNA (ctDNA) analysis of the PALOMA3 trial of palbociclib and fulvestrant versus placebo and fulvestrant.

Meeting: 2018 ASCO Annual Meeting Abstract No: 1001 First Author: Nicholas C. Turner
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive


3. Abemaciclib for pre/perimenopausal women with HR+, HER2- advanced breast cancer.

Meeting: 2018 ASCO Annual Meeting Abstract No: 1002 First Author: Patrick Neven
Category: Breast Cancer—Metastatic - Hormone Receptor-Positive