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
2743 - The Impact of Targeted Therapies and Immunotherapy in Melanoma Brain Metastases: a Systematic Review and Meta-Analysis
Presenter: Mario Mandala
Session: Poster Display session 3
Resources:
Abstract
5479 - Intracranial Anti-Tumor Activity in Melanoma Brain Metastases with Encorafenib Plus Binimetinib: A Multicenter, Retrospective Analysis
Presenter: Jose Lutzky
Session: Poster Display session 3
Resources:
Abstract
3560 - Outcomes of Patients with Melanoma Brain Metastases (MBM) Treated with Standard of Care Therapy After Being Excluded from MBM-Specific Clinical Trials
Presenter: Kourtney Holbrook
Session: Poster Display session 3
Resources:
Abstract
3175 - The analysis of current treatment outcomes in melanoma patients with brain metastases
Presenter: Joanna Placzke
Session: Poster Display session 3
Resources:
Abstract
4550 - A multivariate model to define prognostic groups among patients with melanoma brain metastases: a 10-year retrospective cohort study
Presenter: Giacomo Pelizzari
Session: Poster Display session 3
Resources:
Abstract
4191 - The immune landscape of melanoma significantly influences survival in patients with highly mutated tumors.
Presenter: Robert Ferguson
Session: Poster Display session 3
Resources:
Abstract
1625 - Final Results from Phase II of Combination with Canerpaturev (formerly HF10), an Oncolytic Viral Immunotherapy, and Ipilimumab in Unresectable or Metastatic Melanoma in 2nd-or later line treatment
Presenter: Kenji Yokota
Session: Poster Display session 3
Resources:
Abstract
5346 - Evaluating polygenic risk score prediction model for melanoma prognosis
Presenter: Miriam Potrony
Session: Poster Display session 3
Resources:
Abstract
5477 - Impact of sarcopenia in patients with metastatic melanoma treated with immunotherapy
Presenter: Maria Grazia Vitale
Session: Poster Display session 3
Resources:
Abstract
3469 - Ancillary evaluation of systemic immune antitumor response (SIAR) and tumor growth rate (TGR) of patients (pts) with metastatic melanoma (MM) treated with radiotherapy (RT) combined with ipilimumab (ipi) in the phase 1 study Mel-Ipi-Rx.
Presenter: Celine Boutros
Session: Poster Display session 3
Resources:
Abstract