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
4596 - A Phase 2, Open-Label, Randomized, Multicenter Trial of Encorafenib + Binimetinib Evaluating a Standard-dose and a High-dose Regimen in Patients With BRAFV600-Mutant Melanoma Brain Metastasis (MBM) (POLARIS)
Presenter: Michael Davies
Session: Poster Display session 3
Resources:
Abstract
1891 - Continuation of annual screening mammograms and breast-cancer mortality in women over 70
Presenter: Xabier Garcia De Albeniz
Session: Poster Display session 3
Resources:
Abstract
5587 - Introducing standardized medical procedure and dynamic decision support program in precision oncology for the community of practice
Presenter: Istvan Petak
Session: Poster Display session 3
Resources:
Abstract
4757 - Effectively using primary care givers in oncology care through capacity building, task sharing and techno-mentoring.
Presenter: Dinesh Pendharkar
Session: Poster Display session 3
Resources:
Abstract
4497 - A single institution review of capecitabine related acute admissions and cost analysis
Presenter: Gemma Dart
Session: Poster Display session 3
Resources:
Abstract
2187 - Health status of middle-aged and older cancer survivors in China: results from the China Health and Retirement Longitudinal Study (CHARLS)
Presenter: Jiarui Li
Session: Poster Display session 3
Resources:
Abstract
5101 - Crossed looks on lung cancer perception and knowledge from general public and physicians in France: results of a two-fold survey
Presenter: Céline Mascaux
Session: Poster Display session 3
Resources:
Abstract
4354 - Knowledge and perception of clinical trials (CTs) and attitude towards participation among Polish oncological patients - A pilot survey
Presenter: Artur Kotowski
Session: Poster Display session 3
Resources:
Abstract
3499 - Achieving best possible cancer treatment outcomes in care pathways through benchmarking; ABC-Benchmarking
Presenter: Anke Wind
Session: Poster Display session 3
Resources:
Abstract
2270 - Impact of 10-day Fulbright Specialist Program (FSP) and Project Pink Blue (PPB) Education Sessions on Medical Oncology knowledge among Doctors that treat cancer in Nigeria
Presenter: Mike Martin
Session: Poster Display session 3
Resources:
Abstract