Abstract 2616
Background
The identification of biomarkers to drive treatment is one of the most important objectives of precision medicine. During last years, the role of PIK3CA mutations have been related to clinical benefit deriving from treatment with PI3K, and mTOR inhibitors. In breast cancer (BC), PIK3CA mutations are widely present and the use, in clinical trials, of selective inhibitors improved clinical outcomes. The aim of this study is to assess the value of a monocentric genomic screening program to select patients for trials with experimental targeted agents.
Methods
We examined PIK3CA mutation in a cohort of 312 metastatic BC patients diagnosed at Hospital Clínico València-INCLIVA from Jan-13 to Apr-19. The sequencing of hotspot mutations was performed in primary (29.9%) and metastatic tissue (70.1%). We used two different technologies: MassARRAY technology (Sequenom MassARRAY, OncoCarta v1.0) and Iluminia MiSeq System (customised panel, OncoSpot v.1). Hotspots were selected according to databases already published. To be diagnosed as mutated, tumors needed to harbor at least 5% of mutant alleles. 7 clinical trials against PI3K pathway were available.
Results
PIK3CA analysis was performed in 312 paraffin embedded tumor samples, in which only 5.8% the analysis was not possible due to low quality of DNA. The distribution of BC subtypes were 77.6% Luminal, 13.9% HER2, and 8.5% triple negative (TN). PIK3CA mutations were detected in 96 patients (32.7%). In Luminal, PIK3CA mutations reached 36.8% while only 19.5% in HER2 and 16.0% in TN, respectively. A wide spectrum of PIK3CA mutations was found: H1047R (38.5%), E545K (30.2%), E542K (19.8%), R88Q (3.1%), M1043I (3.1%), N345K (2.1%), P539R (1.0%), K111E (1.0%), C420R (1.0%). One hundred and ninety (64.6%) patients were included in clinical trials, and 74 (38.9%) were treated with PI3K, AKT and mTOR inhibitors.
Conclusions
PIK3CA mutations were widely present among luminal BC, being actually a specific target for new drugs. PIK3CA mutational analysis was easily and successfully performed in our center. The identification of PIK3CA hotspots mutations lead to the access for our patient to novel drugs into clinical trials, achieving relevant clinical benefits in most of the cases.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
A. Lluch: Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Roche/Genentech; Advisory / Consultancy: Eisai; Advisory / Consultancy: Celgene. A. Cervantes: Advisory / Consultancy: Merk serono; Advisory / Consultancy: Roche; Advisory / Consultancy: Beigine; Advisory / Consultancy: Bayer; Advisory / Consultancy: Servier; Advisory / Consultancy: Lilly; Advisory / Consultancy: Novartis; Advisory / Consultancy: Takeda; Advisory / Consultancy: Astelas; Advisory / Consultancy: Pierre Fabre; Speaker Bureau / Expert testimony: Foundation Medicine. All other authors have declared no conflicts of interest.
Resources from the same session
2551 - Efficacy of dose-dense (DD) adjuvant chemotherapy (CT) in hormone receptor positive/HER2-negative early breast cancer (BC) patients (pts) according to immunohistochemically (IHC) defined luminal subtypes: an exploratory analysis of the GIM2 trial.
Presenter: Benedetta Conte
Session: Poster Display session 2
Resources:
Abstract
3426 - High dose Neo-adjuvant chemotherapy in Triple-Negative breast cancer with evidence of homologous recombination deficiency (HRD).
Presenter: Sonja Vliek
Session: Poster Display session 2
Resources:
Abstract
3792 - Risk factors for locoregional recurrence (LRR) after neoadjuvant chemotherapy: pooled analysis of prospective neoadjuvant breast cancer (BC) trials
Presenter: Gustavo Werutsky
Session: Poster Display session 2
Resources:
Abstract
4044 - Estimating radiotherapy-induced cardiovascular mortality in female breast cancer patients.
Presenter: Mark De Ridder
Session: Poster Display session 2
Resources:
Abstract
719 - 3-year follow-up of a phase III trial comparing the efficacy and safety of neoadjuvant and adjuvant trastuzumab and its biosimilar CT-P6 in HER2 positive early breast cancer (EBC)
Presenter: Justin Stebbing
Session: Poster Display session 2
Resources:
Abstract
3595 - Adjuvant chemotherapy in elderly breast cancer patients: pattern of use and impact on overall survival
Presenter: Axel Berthelot
Session: Poster Display session 2
Resources:
Abstract
3992 - Carboplatin-containing neoadjuvant chemotherapy for triple negative breast cancer (TNBC): a propensity score-matched study.
Presenter: Maria Vittoria Dieci
Session: Poster Display session 2
Resources:
Abstract
3477 - Impact of adjuvant trastuzumab emtansine (T-DM1) on incidence of metastatic breast cancer (mBC): an epidemiological model of patients with HER2-positive breast cancer (BC) who did not achieve pathological complete response (pCR) after neoadjuvant treatment (non-pCR)
Presenter: Mellissa Williamson
Session: Poster Display session 2
Resources:
Abstract
3928 - Chemotherapy (CT)-induced anaemia in patients (pts) treated with dose-dense regimen: Results of the prospectively randomised anaemia substudy from the neoadjuvant GeparOcto study
Presenter: Hans Tesch
Session: Poster Display session 2
Resources:
Abstract
2184 - The clinical impact of adjuvant dose-dense sequential chemotherapy (dds-CT) in patients with high-risk operable breast cancer (BC); pooled analysis of 6 clinical trials.
Presenter: Elena Fountzilas
Session: Poster Display session 2
Resources:
Abstract