Abstract 4290
Background
The phosphatidylinositol 3-kinase (PI3K) pathway plays a central role in cell proliferation and survival in human cancer. Mutations in PIK3CA, the gene coding the p110α catalytic subunit of PI3K, are frequent in cancer and result in PI3K pathway activation. About 25% of HER2-positive breast cancers also carry PIK3CA mutations, known to confer resistance to anti-HER2 therapy. Here we report the preclinical characterization of MEN1611, a potent and selective orally available PI3K inhibitor, showing high activity against p110α mutant isoforms and sparing the δ isoform.
Methods
In vivo efficacy studies were evaluated through Tumour Volume Inhibition % (TVI%) and mRECIST criteria using cancer cell lines and patient-derived xenograft (PDX) models. Pathway activation and protein degradation analyses were performed by western blot and capillary electrophoresis immunoassay. Immune modulation was evaluated using murine macrophages differentiated in vitro.
Results
Consistent with its mechanism of action, MEN1611 down-modulates the PI3K/AKT signaling as well as selected downstream targets, both in vitro and in vivo. MEN1611 acts synergistically when combined with trastuzumab in several HER2-positive PIK3CA-mutated breast cancer cell lines and patient-derived xenograft models. The in vivo efficacy in trastuzumab-resistant models is supported by a long-lasting antitumor activity, paralleled by mechanistic down-regulation of pharmacodynamic biomarkers. Moreover, MEN1611 showed the ability to induce a dose-dependent alpha-isoform depletion, and to modulate the macrophage polarization towards a pro-inflammatory phenotype, consistent with its capability to co-inhibit P110γ.
Conclusions
Overall, these preclinical data support the progression in the development of MEN1611 in breast cancer and pave the way to the B-Precise-01 clinical study, a multicentre phase Ib study.
Clinical trial identification
NCT03767335.
Editorial acknowledgement
Legal entity responsible for the study
Menarini Ricerche S.p.A.
Funding
Menarini Ricerche S.p.A.
Disclosure
A. Fiascarelli: Full / Part-time employment: Menarini RIcerche S.p.A. G. Merlino: Full / Part-time employment: Menarini Ricerche S.p.A. S. Capano: Full / Part-time employment: Menarini Ricerche S.p.A. A. Paoli: Full / Part-time employment: Menarini Ricerche S.p.A.. A. Bressan: Full / Part-time employment: Menarini Ricerche. M. Bigioni: Full / Part-time employment: Menarini Ricerche S.p.A.. M. Scaltriti: Advisory / Consultancy: Memorial Sloan-Kettering Cancer Center. J. Arribas: Advisory / Consultancy: Vall d’Hebron Institute of Oncology. C. Bernadó Morales: Advisory / Consultancy: Vall d’Hebron Institute of Oncology. A. Pellacani: Leadership role, Full / Part-time employment: Menarini Ricerche S.p.A.. M. Salerno: Leadership role, Full / Part-time employment: Menarini Ricerche. M. Binaschi: Leadership role, Full / Part-time employment: Menarini Ricerche S.p.A.
Resources from the same session
2494 - CAR-T Nursing Education at a UK Specialist Cancer Hospital
Presenter: Rose Ellard
Session: Poster Display session 3
Resources:
Abstract
2438 - Professional Quality of Life, Perceived Stress and Psychological Resistance Levels of Oncology-Hematology Nurses and the Factors Affecting
Presenter: Tugba Pehlivan
Session: Poster Display session 3
Resources:
Abstract
3541 - Representation of cancer survivors’ preferences in policies for supportive care: Implications for oncology nursing
Presenter: Samantha Mayo
Session: Poster Display session 3
Resources:
Abstract
5093 - Vaginal moisturizing post PDR-Pulse Dose Rate Brachytherapy.
Presenter: Pilar Fernández
Session: Poster Display session 3
Resources:
Abstract
1066 - The stomized, chemo and radiotreated patient vs untreated patient: complications and comparison with data literature
Presenter: Cristoforo Ferrero
Session: Poster Display session 3
Resources:
Abstract
1724 - Evaluating the role of clinical nurse specialist
Presenter: Anita Zeneli
Session: Poster Display session 3
Resources:
Abstract
3753 - Role of the Advanced Practice Nurse (APN) in a Functional Unit for Lung cancer at the Catalan Institute of Oncology
Presenter: Isabel Brao
Session: Poster Display session 3
Resources:
Abstract
2676 - A bottom-up approach for prioritising the scientific activities of the Italian Association of Cancer Nurses (AIIAO): rationale and topic identification
Presenter: Valentina Biagioli
Session: Poster Display session 3
Resources:
Abstract
575 - Investigating quality of care for people with cancer and dementia
Presenter: Naomi Farrington
Session: Poster Display session 3
Resources:
Abstract
5578 - Two years of BRCA1 and BRCA2 somatic External Quality Assessment with Gen&tiss Tiss scheme in France
Presenter: Kelly Dufraing
Session: Poster Display session 3
Resources:
Abstract