Abstract CT-01: BYL719, a next generation PI3K alpha specific inhibitor: Preliminary safety, PK, and efficacy results from the first-in-human study

Abstract Purpose Somatic alteration of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) is a crucial therapeutic target in breast cancer (BC) and PI3Kα-specific inhibitor Alpelisib has been used in clinics. This study investigates the PIK3CA alterations in Chinese and Caucasians BC patients for the purpose of selecting anti-PI3K therapy. Methods The molecular profile of the PIK3CA gene was analyzed in 412 Chinese patients with untreated invasive BC using a 540 gene next-generation sequencing panel. The results were compared with data of the Caucasian BC patients in The Cancer Genome Atlas (TCGA-white). Results PIK3CA alterations were frequently found in BC of estrogen receptor (ER) positive (49.3%, p = 0.024), low ki67 proliferation index (58.3%, p = 0.007) and low pathological grade (grade I/II/III 80%, 53.4%, 35.9%, p < 0.001). Compared to TCGA-white, Chinese BC patients had a higher alteration frequency (45.6% vs. 34.7%, p < 0.001) with larger proportion of p.H1047R mutation among three common mutation sites (p.E545K, p.E542K and p.H1047R) (66.1% vs. 43.7%, p = 0.01). Across four molecular subtypes, ER + /human epidermal growth factor receptor 2 positive (HER2 +) tumors harbored the most PIK3CA alterations (51.6%), while ER-/HER2- harbored the least alteration (30.0%) but the most copy number amplification (19.05%). Conclusion PIK3CA alterations prevail in Chinese BC patients and have different molecular features compared to that of Caucasians. The results provide precise annotations of PIK3CA genomic alterations of Chinese in the context of application of PIK3CA inhibitor.

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Pharmacodynamic (PD) evaluation of LY2181308 in patients with metastatic malignancies

Journal of Clinical Oncology ◽

10.1200/jco.2009.27.15_suppl.3507 ◽

2009 ◽

Vol 27 (15_suppl) ◽

pp. 3507-3507 ◽

Cited By ~ 2

Author(s):

D. C. Talbot ◽

J. Davies ◽

A. Olsen ◽

V. Andre ◽

M. Lahn ◽

...

Keyword(s):

Gene Expression ◽

Tumor Cells ◽

Tumor Tissue ◽

Human Study ◽

Specific Inhibitor ◽

Survivin Expression ◽

Biopsy Material ◽

Ct Guided ◽

Survivin Protein ◽

Phase Ii Studies

3507 Background: Survivin is an inhibitor of apoptosis and its overexpression in cancer has been associated with poor survival. LY2181308 (LY), a novel modified antisense oligonucleotide is a specific inhibitor of survivin. The safety and PK profile of LY from this first-in-human study was presented at ASCO 2008. We now present the PD data from this trial. Methods: Patients with advanced or metastatic malignancies who had failed previous anti-tumor treatments were enrolled. Three consecutive IV loading doses given over 3 hours were followed by weekly maintenance doses. Pre- and post-dosing biopsies were mandated to test for evidence of modification of the target at doses where a PD effect was expected. Biopsies were taken 48 hours after the last loading dose by CT-guided fine needle biopsy. Tumor tissue was paraffin-embedded for immunohistochemistry (IHC) and survivin gene expression. Given the finite amount of biopsy material, the quantification of survivin protein was prioritized. In addition, at one site, pre- and post-dosing endobronchial sampling was conducted in NSCLC patients, with the aim of quantifying levels of native survivin protein, and assessing changes in cell cycle profile in freshly isolated tumor cells using FACS analysis. Results: Out of the 34 patients enrolled, 22 patients had a pre- and posttreatment biopsy. Results from IHC indicated that survivin expression was reduced in the nucleus and cytoplasm in 11/17 and 5/14 evaluable pairs, respectively. LY was detected in neoplastic and non-neoplastic tumor cells in 5/16 and 15/16 evaluable pairs respectively. Gene expression analysis indicated a reduction in survivin expression by 20% to 50% in 11/15 evaluable pairs. Analysis of the fresh tumor material from endobronchial sampling revealed that 2 out of 3 patients with NSCLC had a near-complete elimination of survivin-positive cells accompanied by an increase in the fraction of cells with a sub-G1 DNA content, consistent with cell death. Conclusions: In this study, we were able to demonstrate the presence of the ASO in tumor tissue and confirm a reduction in survivin protein and gene expression. These findings demonstrate the proof of principle of antitumor activity of LY and provide the rationale for phase II studies. [Table: see text]

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