Résumé
Abstract only TPS1101 Background: MEN1611 is a potent, selective class I inhibitor of PI3K, a key enzyme in the transduction of various extracellular growth factor signals essential for cell survival and apoptosis. The discovery in human cancers of frequent PIK3CA mutations, that have been linked to a worse outcome in advanced HER2-positive breast cancer, makes PI3K an attractive therapeutic target. Preclinical and clinical evidences support the development of MEN1611 in combination with other agents in the context of solid tumors. Methods: B-PRECISE-01 is an open-label, multicenter, phase Ib dose escalation study in patients with PIK3CA mutant tumors, HER2-positive advanced or metastatic breast cancer which has progressed after at least 2 lines of anti-HER2 based therapy. PIK3CA mutations are assessed centrally by real-time PCR assay in DNA derived from archived tumor samples. MEN1611 will be administered orally BID for continuous 28-day cycles until disease progression, in combination with weekly IV infusions of trastuzumab. In addition, HR-positive postmenopausal patients will also be treated with fulvestrant. After the completion of the dose escalation phase (Step 1), the study will continue in an expansion cohort (Step 2) testing the Recommended Phase 2 dose (RP2D) in a total of 15 patients in each of the treatment groups. The primary study objective is to assess combination safety and select RP2D. Secondary objectives include assessment of pharmacokinetics and pharmacodynamics, preliminary clinical activity of MEN1611 in combination with trastuzumab +/- fulvestrant, and correlation with PIK3CA mutations and other relevant cancer genes mutational status. Adverse events will be graded according to NCI CTCAE v4.03. Responses will be evaluated according to RECIST v1.1. Study variables will be presented by dose-cohort and overall using appropriate descriptive statistics. The enrollment began in July 2018 at European sites and US sites will shortly participate; up to date the first dose cohort level has been achieved. Clinical trial information: NCT03767335.