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
2927 - Singapore Caregiver Quality Of Life Scale (SCQOLS): Turkish Validity and Reliability Study
Presenter: Nur Basak
Session: Poster Display session 3
Resources:
Abstract
5066 - Screening for Psicosocial Distress in recently diagnosed cancer patients
Presenter: Eva Baillès
Session: Poster Display session 3
Resources:
Abstract
6074 - Socio-demographic characteristics and quality of life analysis of cancer survivors followed at a Primary Care Center.
Presenter: Begona Grana Suarez
Session: Poster Display session 3
Resources:
Abstract
5129 - The adhesion in the screening measures in carrying patients of breast cancer and ovary hereditary and the relationship with the psychological aspects
Presenter: Melinda Concepcion
Session: Poster Display session 3
Resources:
Abstract
5635 - Assessment of emotional discomfort of oncological patients in the first nursing visit at Donostia University Hospital
Presenter: Elena Uranga
Session: Poster Display session 3
Resources:
Abstract
858 - A systematic review and meta-analysis of the distress thermometer for the screening of distress in Chinese patients with cancer
Presenter: Hui Hui Sun
Session: Poster Display session 3
Resources:
Abstract
4475 - Pharmacist and Nurse (PN) Led Melanoma Immunotherapy Clinic: Patient Experience Survey
Presenter: Dharmisha Chauhan
Session: Poster Display session 3
Resources:
Abstract
1871 - Phone Triage & Acute Review Clinics: The emerging role of the Oncology Specialist Nurse
Presenter: Fiona Barrett
Session: Poster Display session 3
Resources:
Abstract
5193 - Patient reported outcomes during immunotherapy: symptom burden in daily clinical practice
Presenter: José Koldenhof
Session: Poster Display session 3
Resources:
Abstract
2453 - Factors related to hospital length of stay, re-admissions and unplanned care for patients with cancer, an on-going study
Presenter: Helena Ullgren
Session: Poster Display session 3
Resources:
Abstract