Evaluation of PI3K-pathway–activation status in matched primary (P) and metastatic (M) ER+/HER2- breast cancer (BC) lesions according to PIK3CA-mutation status.

509 Background: The role of PI3Kp dysregulation as a predictor of sensitivity to PI3Kpi is unclear. We aimed to evaluate the efficacy of PI3Kpi in two cohorts of MBC pts with assessable PI3Kp status. Methods: MBC pts treated in ≥3rd line with PI3Kpi were reviewed. PI3Kp status: (a) No dysregulation: PIK3CA wt and PTEN normal; (b) PI3Kp dysregulation: PIK3CA mutation (PIK3CAmut) or PTEN low (HScore≤50). Cohort A: pts treated with single agent PI3Kpi. Cohort B: pts treated with PI3Kpi in combination with hormonal therapy (HT), chemotherapy (CT) and/or trastuzumab (T). Results: Out of 232 MBC pts screened for PI3Kp alterations from Sep09 to Sep11, 32 were treated with PI3Kpi. Cohort A (n=17): HR+/HER2- 88%, HER2+ 6%, triple negative 6%; median age 43, median MBC lines 4 (2-9); PIK3CAmut in 10/17 (58.8%; 6 exon9, 4 exon20), PTEN low 3/17 (17.6%), 1 pt both; PI3Kp dysregulation 12/17 pts. Cohort B (n=15): HR+/HER2- 40%, HER2+ 60%; median age 49, median MBC lines 4 (2-13); PIK3CAmut 3/13 assessable (23.1%; all exon20), PTEN low 6/15 (40%), 1 pt both; PI3Kp dysregulation 8/15 pts. Time to progression to PI3Kpi (TTP), overall survival from MBC diagnosis (OSMBC) and OS from PI3Kpi beginning (OSPI3Kpi), according to PIK3CA status and PI3Kp dysregulation, are shown. No differences were found according to PTEN status. Conclusions: These results suggest that the best outcomes with PI3Kpi in PIK3CAmut MBC pts occur when they are used in combination with HT/CT/T. Activity of non selective PI3Kpi used as single agents seems to be limited, making results from prospective trials with selective PI3Kα inhibitors and PI3Kpi in combinations eagerly awaited. [Table: see text]

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Impact of PIK3CA tumor mutation on the association of aspirin or NSAID use and time to breast cancer recurrence.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.1521 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. 1521-1521 ◽

Cited By ~ 2

Author(s):

Anne Marie McCarthy ◽

Wei He ◽

Susan Regan ◽

Andrew T. Chan ◽

Beverly Moy ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Patients ◽

Pik3ca Mutation ◽

Cancer Recurrence ◽

Primary Diagnosis ◽

Breast Cancer Recurrence ◽

Breast Cancer Patients ◽

Her2 Breast Cancer ◽

N Use ◽

Tumor Genotyping

1521 Background: Aspirin or NSAID (A/N) use post diagnosis is associated with lower risk of breast cancer recurrence and mortality in cohort studies. A potential mechanism is that A/Ns may suppress cell growth and induce apoptosis in tumors driven by phosphatidylinositol 3 kinase ( PIK3CA), the most common oncogene mutation in breast cancer. An interaction of A/Ns and PIK3CA mutation has been observed for colorectal cancer prognosis, but has not been studied in breast cancer. The objective was to assess time to breast cancer recurrence (TTR) with respect to A/N use and PIK3CAmutation. Methods: Patients with HR+/HER2- breast cancer treated at Massachusetts General Hospital in 2009-2014 who received tumor genotyping were included. PIK3CA mutations, including 8 common hotspot mutations, were assessed by a high-throughput tumor genotyping assay using DNA from formalin-fixed, paraffin-embedded tumor tissue. A/N use beginning 6 months post diagnosis through metastasis was extracted from electronic medical records using coded data and natural language processing. Patients with de novo metastatic disease or progressive disease within 6 months of primary diagnosis were excluded. TTR was estimated using Cox proportional hazards models. Results: Among breast cancer patients (N=212), 60 (28%) used A/Ns and 69 (33%) had PIK3CA mutation (see Table). After adjusting for age, stage, adjuvant endocrine therapy, radiation, and chemotherapy, A/N users had significantly longer TTR (HR=0.65 p=0.01). The association was similar for wild type (HR=0.58 p=0.01) and PIK3CA mutated tumors (HR=0.60 p=0.06), with no significant interaction of A/N use and PIK3CA (p=0.34). Conclusions: Among HR+ breast cancer patients, those who used A/Ns following primary diagnosis had longer TTR than non-users, regardless of tumor PIK3CA mutation status. The study provides a model for how tumor genomics could be integrated into secondary chemoprevention studies. [Table: see text]

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Use of alpelisib in the treatment of hormone receptor positive metastatic breast cancer: An institutional experience.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.e15216 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. e15216-e15216

Author(s):

Tsering G. Lama Tamang ◽

Daniel Kyung ◽

Lauren Eisenbud ◽

Tianyi Tang ◽

Ritesh Parajuli ◽

...

Keyword(s):

Breast Cancer ◽

Metastatic Breast Cancer ◽

Pik3ca Mutation ◽

Metastatic Breast ◽

Pi3k Pathway ◽

Real World Data ◽

Tumor Registry ◽

Hormone Receptor Positive ◽

Heavily Pretreated ◽

Institutional Experience

e15216 Background: Mutations in PI3K pathway is a known mechanism of resistance to endocrine therapy in breast cancer. Alpelisib is an alpha-specific PI3K inhibitor. Alpelisib with Fulvestrant is approved for treatment (Tx) of PIK3CA mutated HR+ metastatic breast cancer (MBC) that progress on hormonal therapy. Despite its approval by the FDA, real world data on the use of Alpelisib for the management of MBC is lacking. This abstract reviews the safety and efficacy of Alpelisib in the management of patients with MBC. Methods: A retrospective review of the tumor registry database at a single institution was conducted to identify patients with HR+ MBC. Detailed clinical and pathologic data of PIK3CA mutated patients treated with Alpelisib were obtained. Genomic profiling was done with Foundation One. Results: Table highlights the characteristics of the four patients. All were treated with Alpelisib and Fulvestrant after PIK3CA mutation was demonstrated. 3 patients were heavily pretreated with systemic Tx including CDK 4/6 inhibitors. All patients responded to Alpelisib and Fulvestrant despite treatment history. Mucositis, rash, hyperglycemia and pancytopenia were the observed adverse events (A/E). All A/E were adequately managed except in one patient that required discontinuation of Tx. None has clinically progressed. Conclusions: Our data suggests that Alpelisib and Fulvestrant is tolerated and improves outcomes in patients with HR+ MBC. Alpelisib and Fulvestrant could be an effective therapy in patients who have also progressed on systemic chemotherapy including CDK 4/6 inhibitors. Although our sample size is small, we hope that our experience could guide clinicians in the management of patients with HR+ MBC who harbor the PIK3CA mutation and are being treated with Alpelisib. [Table: see text]

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