0000000000542405
AUTHOR
Michael C. Wei
A phase II study of the PI3K inhibitor taselisib (GDC-0032) combined with fulvestrant (F) in patients (pts) with HER2-negative (HER2-), hormone receptor-positive (HR+) advanced breast cancer (BC).
520Background: The PI3K pathway is activated in HR+ BC, often via gain-of-function mutations in PIK3CA that occur in ~40% of HR+ BC. Taselisib is a potent and selective PI3K inhibitor, with greater selectivity against mutant PI3Kα isoforms than wild type (WT) PI3Kα. Phase Ib data demonstrated good tolerability and preliminary efficacy for taselisib + F in HR+ BC. Methods: This Phase II, open-label, single-arm study enrolled post-menopausal pts with HER2-, HR+ locally advanced or metastatic BC (mBC) who had progression or non-response to ≥ 1 prior endocrine therapy in adjuvant or mBC settings. Pts received taselisib (6 mg capsule PO qd) plus F (500 mg IM on Cycle 1 Day 1, Cycle 1 Day 15, the…
Phase II Study of Taselisib (GDC-0032) in Combination with Fulvestrant in Patients with HER2-Negative, Hormone Receptor–Positive Advanced Breast Cancer
AbstractPurpose: This single-arm, open-label phase II study evaluated the safety and efficacy of taselisib (GDC-0032) plus fulvestrant in postmenopausal women with locally advanced or metastatic HER2-negative, hormone receptor (HR)-positive breast cancer.Patients and Methods: Patients received 6-mg oral taselisib capsules daily plus intramuscular fulvestrant (500 mg) until disease progression or unacceptable toxicity. Tumor tissue (if available) was centrally evaluated for PIK3CA mutations. Adverse events (AE) were recorded using NCI-CTCAE v4.0. Tumor response was investigator-determined using RECIST v1.1.Results: Median treatment duration was 4.6 (range: 0.9–40.5) months. All patients expe…
Abstract CT046: A phase I basket study of the PI3K inhibitor taselisib (GDC-0032) in PIK3CA-mutated locally advanced or metastatic solid tumors
Abstract Background: PIK3CA, a gene that encodes the α-isoform of the catalytic subunit of Class I PI3K (PI3Kα), is frequently mutated or amplified in solid tumors. Taselisib is an oral, potent, selective inhibitor of Class I PI3Kα, γ, and δ isoforms with enhanced activity against PIK3CA-mutated cancer models. Preclinical and clinical data demonstrated that single-agent taselisib has activity in multiple PIK3CA-mutated tumor types. Methods: This open-label phase I study (Cohort X of PMT4979g; NCT01296555) enrolled patients (pts) with PIK3CA-mutated tumors who had progressed after, or failed to respond to, at least one prior treatment regimen and were not candidates for regimens known to pro…