POSEIDON Trial Phase 1b Results: Safety, Efficacy and Circulating Tumor DNA Response of the Beta Isoform-Sparing PI3K Inhibitor Taselisib (GDC-0032) Combined with Tamoxifen in Hormone Receptor Positive Metastatic Breast Cancer Patients.
Richard D BairdAnnelot G J van RossumMafalda OliveiraKarin BeelenMeiling GaoMariette SchrierIngrid A M MandjesJavier Garcia-CorbachoAnne-Laure VallierGreig DougallErik D van WerkhovenConstanza LinossiSanjeev KumarHarm van TinterenMaurizio CallariEmma BeddowesJosé-Manuel Perez-GarciaHilde RosingElse PlattePetra M NederlofMargaret SchotAurelia de Vries SchultinkRené BernardsCristina SauraWilliam GallagherJavier CortesCarlos CaldasSabine C LinnPublished in: Clinical cancer research : an official journal of the American Association for Cancer Research (2019)
Taselisib can be safely combined with tamoxifen at the recommended phase 2 dose of 4 mg given once daily on a continuous schedule. Preliminary evidence of antitumor activity was seen in both PIK3CA mutant and wild-type cancers. The randomized phase 2 part of POSEIDON (testing tamoxifen plus taselisib or placebo) is currently recruiting.