A. Prat (Barcelona, Spain)

F. Brasó-Maristany (Barcelona, Spain)

16P - Understanding the biologic determinants of ribociclib efficacy in breast cancer

Abstract

Abstract

Background

Ribociclib improves survival in hormone receptor-positive (HR+)/HER2-negative (HER2-) advanced breast cancer (BC). Deeper understanding of the biology associated with ribociclib efficacy is needed, especially within the HER2-enriched (HER2-E) subtype given recent analysis of MONALEESA program. Here, we performed gene expression (GE) analysis with/without ribociclib monotherapy in BC patient-derived xenografts (PDX).

Methods

Eighteen PDXs representative of HR+/HER2- (n=11, 61%), HER2+ (n=6, 33%) and triple-negative (n=1, 6%) BC were treated with ribociclib monotherapy (75 mg/kg/day). The % change in tumor volume from baseline was calculated at day 35. RNA was obtained from flash-frozen tumors at baseline and day 12. PAM50 GE was analyzed by nCounter and associated with tumor response (as a continuous variable) using quantitative Statistical Analysis Microarrays (SAM). Differential GE during ribociclib treatment was identified using two-class paired SAM. All SAM used a false-discovery rate<5%.

Results

Baseline PAM50 subtype distribution was Luminal B (44%), HER2-E (33%) and Basal-like (B-L) (22%). HER2-E and Luminal B PDXs showed a statistically significant higher response to ribociclib (mean change in volume >40% and >140%), than B-L (>660%). Baseline GE analysis identified 6 genes highly expressed in responders (FOXA1, ERBB2, GRB7, MLPH, GPR160 and CXXC5), and 7 lower expressed genes (SFRP1, KRT17, MYC, CDH3, KRT5, MIA and KRT14). Paired GE analyses across PDXs identified 12 upregulated genes during treatment, including estrogen activation-related genes (ESR1, PGR, FOXA1, MAPT or BLVRA); and 12 downregulated genes, including proliferation-related genes (MKI67 or KIF2C) and HER2-E-related genes (ERBB2 or TMEM45B). Similar results were obtained with HR+/HER2- PDXs when analyzed separately.

Conclusions

In BC PDXs, B-L biology associates with lower response to ribociclib monotherapy than Luminal or HER2-E. Ribociclib induces a luminal phenotype with high GE of estrogen-regulated genes and low GE of proliferation genes, a biological switch that could explain the better efficacy of ribociclib in the endocrine therapy (ET)-resistant HER2-E subtype observed in clinical trials when combined with ET.

Legal entity responsible for the study

Institut d'Investigacions Biomèdiques August Pi i Sunyer.

Funding

Has not received any funding.

Disclosure

M. Oliveira: Honoraria (self): Roche, Novartis, Seattle Genetics; Advisory/Consultancy: Roche/Genentech, GlaxoSmithKline, Puma Biotechnology, AstraZeneca, Seattle Genetics; Research grant/Funding (institution): Philips Healthcare (Inst), Roche/Genentech (Inst), Novartis (Inst), AstraZeneca (Inst), Immunomedics (Inst), Seattle Genetics (Inst), Boehringer Ingelheim (Inst), GlaxoSmithKline (Inst), Cascadian Therapeutics (Inst), Sanofi (Inst), Celldex Therapeutics; Travel/Accommodation/Expenses: Roche, Novartis, Grünenthal Group, Pierre Fabre, GP Pharm, Eisai. N. Chic: Travel/Accommodation/Expenses: Novartis, Eisai, Pierre Fabre. R. Dienstmann: Advisory/Consultancy, Speaker Bureau/Expert testimony: Roche; Advisory/Consultancy: Boehringer Ingelheim; Speaker Bureau/Expert testimony: Ipsen; Speaker Bureau/Expert testimony: Amgen; Speaker Bureau/Expert testimony: Servier; Speaker Bureau/Expert testimony: Sanofi; Speaker Bureau/Expert testimony: Merck Sharp & Dohme; Research grant/Funding (self): Merck; Research grant/Funding (self): Pierre Fabre. C. Saura Manich: Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses: AstraZeneca, Daiichi Sankyo, Merck, Sharp and Dohme España SA, Novartis, Pfizer, Puma, Synthon; Advisory/Consultancy, Travel/Accommodation/Expenses: Celgene, Clovis Oncology, Eisai, F. Hoffmann-La Roche Ltd., Genomic Health, Odonate Therapeutics, Philips Healthwork, Pierre Fabre, prIME Oncology, Sanofi Aventis, Zymeworks; Research grant/Funding (institution): Eli Lilly and Company, Genentech, Immunomedics, Macrogenics, Piqur Therapeutics, Roche, Synthon. A. Prat: Advisory/Consultancy, Research grant/Funding (self): Novartis Farma, SA; Advisory/Consultancy: Lilly Spain; Advisory/Consultancy: Pfizer, SLU; Advisory/Consultancy, Research grant/Funding (self): Roche Farma, SA; Advisory/Consultancy: Bristol-Myers Squibb; Advisory/Consultancy: Amgen, SA; Advisory/Consultancy: Daiichi; Advisory/Consultancy: Oncolytics Bioteck; Research grant/Funding (self): Sysmex Europe GmbH; Research grant/Funding (self): Medica Scientia Inno, Research, SL; Research grant/Funding (self): Celgene, SLU; Research grant/Funding (self): Astellas Pharma, SA; Research grant/Funding (self): NanoString Technologies; Officer/Board of Directors, Member executive Board: Breast International Group (BIG).; Officer/Board of Directors, Member executive Board and Foundation: SOLTI; Research grant/Funding (self): Puma; Research grant/Funding (self): Incyte. V. Serra: Research grant/Funding (self): Novartis, Genentech. All other authors have declared no conflicts of interest.

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O. Martínez Saez (Barcelona, Spain)

23P - CDK4/6 inhibition and endocrine therapy (ET) in the HER2-enriched subtype (HER2-E) in hormone receptor-positive/HER2-negative (HR+/HER2-) advanced breast cancer (ABC): a retrospective analysis of real-world data

Abstract

Abstract

Background

The HER2-E subtype within HR+/HER2- ABC represents 10-25% and is characterized by poor prognosis. In the MONALEESA program, ribociclib + ET was found highly active in this subtype compared to ET. Here, we explored the prognostic and predictive value of HER2-E in patients (pts) treated with a CDK4/6 inhibitor (CDK4/6i) + ET in the real-world setting.

Methods

This is a retrospective study of 144 consecutive pts with HR+/HER2- ABC treated with a CDK4/6i + ET in the first line setting from 2014-2020 in Hospital 12 de Octubre (Madrid) and Clinic of Barcelona. Research-based PAM50 was performed in FFPE tumors collected before CDK4/6i (primary tumors or metastatic biopsies). Univariate and multivariable cox model progression-free survival (PFS) analyses were performed adjusting for the presence of visceral or “de novo” disease, menopausal status and performance status.

Results

114 pts (79%) had PAM50 data (50% primary/50% metastatic), and 47%/46%/7% received palbociclib/ribociclib/abemaciclib. Subtype distribution: Luminal A (33%), Luminal B (37%), HER2-E (19%), normal-like (8%) and Basal-like (5%). Median PFS for HER2-E disease was 7.4 months (mo) (95% confidence interval [CI] 5.0-22.0) and 21.1 mo (95% CI 16.6-31.3) for non-HER2-E disease (adjusted hazard ratio [aHRatio]=2.38, p=0.010). Median OS for HER2-E disease was 30.9 months (mo) (95% confidence interval [CI] 13.2-not reached [NR]) and NR (95% CI 47.2-NR) for non-HER2-E disease (aHRatio=4.39, p=0.021). Although exploratory and statistically non-significant, the PFS HRatio estimates of ribociclib vs palbociclib/abemaciclib in Luminal A, Luminal B and HER2-E subtype were 0.88, 0.90 and 0.44, respectively. Finally, the overall response rate of ribociclib in Luminal A/B and HER2-E disease was 40.5% and 42.9% vs 36.8% and 25.0% with palbociclib/abemaciclib.

Conclusions

In a real-world setting, we confirmed the poor prognosis of the HER2-E subtype in HR+/HER2- ABC. Despite the limitations, our results support the observation from the ML program where ribociclib in combination with ET was particularly active in the HER2-E subtype.

Legal entity responsible for the study

The authors.

Funding

Instituto de Salud Carlos III (PI19/01846) (to A.P.) Instituto 299 de Salud Carlos III (PI18/01408) (to E.C.) Breast Cancer Research Foundation (to 300 A.P.) PhD4MD (to N.C.) Fundació La Marató TV3 (to A.P) RESCUER Horizon 2020 301 (to A.P.) Save the Mama (to A.P.) Pas a Pas (to A.P.) Asociación Cáncer de Mama 302 Metastásico (to A.P.) Fundación Científica Asociación Española Contra el Cáncer (to 303 F.B.M.) Fundación SEOM (SEOM 2018 Grant: Fellowship for Training in 304 Research in Reference Centers) (to T.P.).

Disclosure

O. Martínez-Sáez: Advisory/Consultancy: Roche; Travel/Accommodation/Expenses: Roche; Speaker Bureau/Expert testimony: Eisai. P. Tolosa: Honoraria (institution), Speaker Bureau/Expert testimony: AstraZeneca; Speaker Bureau/Expert testimony: Amgen; Speaker Bureau/Expert testimony: Pfizer; Speaker Bureau/Expert testimony: Roche; Speaker Bureau/Expert testimony: MSD; Speaker Bureau/Expert testimony: Eisai. T. Pascual: Advisory/Consultancy: Roche; Advisory/Consultancy: Genentech. N. Chic: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Eisai; Travel/Accommodation/Expenses: Novartis; Travel/Accommodation/Expenses: Pierre Fabre. J.C. Laguna: Speaker Bureau/Expert testimony: Kyowa Kirin. M. Vidal: Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Honoraria (self), Advisory/Consultancy: Novartis; Honoraria (self): Daiichi Sankyo; Travel/Accommodation/Expenses: Pfizer. M. Muñoz: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Lilly; Speaker Bureau/Expert testimony: Pierre Fabre; Speaker Bureau/Expert testimony: Novartis; Speaker Bureau/Expert testimony: Eisai. A. Prat: Honoraria (self), Research grant/Funding (institution): Roche; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Novartis; Advisory/Consultancy: Amgen; Honoraria (self), Travel/Accommodation/Expenses: Daiichi Sankyo; Advisory/Consultancy: Bristol-Myers Squibb; Honoraria (self): MSD Oncology; Advisory/Consultancy: NanoString Technologies; Honoraria (self): Lilly; Advisory/Consultancy: Pfizer. E.M. Ciruelos: Advisory/Consultancy: MSD; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Novartis; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Advisory/Consultancy, Speaker Bureau/Expert testimony: Lilly; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Pfizer. All other authors have declared no conflicts of interest.

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G. Curigliano (Milan, Italy)

24P - Consensus on the utility of breast cancer multigene signatures in routine clinical practice among European Breast Cancer clinicians - The PROCURE project.

Abstract

Abstract

Background

Several genomic assays are available to profile early breast cancer (BC) that, according to current evidence, can provide reliable information including the risk of recurrence. However, little is known regarding their current use and the perception of utility across Europe. The PROCURE project aims to develop a consensus on the utility of breast cancer multigene signatures (BCMS) in treatment decision making for different eBC patient profiles based on the opinion of a panel of experts.

Methods

A Scientific Committee of 8 experts in BC from 8 European countries developed a Delphi questionnaire to be administered in two-waves to experienced clinicians across Europe, selected based on their experience in BC. The questionnaire includes 5 sections in order to characterize the participants and their expertise in BCMS, to understand the current clinical practice in eBC and the use of BCMS, to recall the participant’s opinion on the utility of the BCMS in eBC according to the patient profiles, to define recommendations on the use of BCMS in clinical practice and finally, to identify unmet needs and future applications of BCMS. 180 participants, including medical oncologists, surgeons, pathologists and gynaecologists, are expected to answer anonymously the online Delphi questionnaire. 70% agreement will be used to determine consensus on a topic.

Results

At the end of January 2021, 146 participants from 11 European countries (Austria, Denmark, France, Germany, Italy, Norway, Portugal, Spain, Sweden, Switzerland and the UK) registered to participate. 61 of them had already fully completed the 1^st wave Delphi questionnaire. Results from the 1^st wave will be presented to engage larger discussion with congress participants.

Conclusions

The PROCURE Project will provide useful information regarding how BCMS are currently used in clinical practice across Europe and will help to measure the utility attributed to the different BCMS by BC experts for their daily clinical practice, to establish recommendations on the use of BCMS to make treatment decision in different eBC patient profiles and to define current unmet needs and future applications of BCMS according to experts point of view.

Editorial acknowledgement

Adelphi Targis SL.

Legal entity responsible for the study

Veracyte Inc.

Funding

Veracyte Inc.

Disclosure

G. Curigliano: Advisory/Consultancy: Novartis; Advisory/Consultancy: Roche; Advisory/Consultancy: Lilly; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: AstraZeneca; Honoraria (self), Advisory/Consultancy: Veracyte; Advisory/Consultancy: Genomic health; Advisory/Consultancy: Ellipsis. F. Cardoso: Honoraria (self): Amgen; Honoraria (self): Astellas/Medivation; Honoraria (self): AstraZeneca; Honoraria (self): Celgene; Honoraria (self): Daiichi Sankyo; Honoraria (self): GE Oncology; Honoraria (self): Genentech; Honoraria (self): GlaxoSmithKline; Honoraria (self): Macrogenics; Honoraria (self): Medscape; Honoraria (self): Merck-Sharp; Honoraria (self): Merus BV; Honoraria (self): Mylan; Honoraria (self): Mundipharma; Honoraria (self): Novartis; Honoraria (self): Pfizer; Honoraria (self): Pierre Fabre; Honoraria (self): priME Oncology; Honoraria (self): Roche; Honoraria (self): Samsung Bioepis; Honoraria (self): Eisai. M.I. Gnant: Honoraria (self): Veracyte; Honoraria (self): Amgen; Honoraria (self): Novartis; Honoraria (self): AstraZeneca; Honoraria (self): Eli Lilly; Honoraria (self): Daiichi Sankyo; Honoraria (self): Tolmar; Honoraria (self): LifeBrain. A-V. Lænkholm: Honoraria (self): Veracyte. F. Penault-Llorca: Honoraria (self), Research grant/Funding (self): Veracyte; Honoraria (self), Research grant/Funding (self): Exact science former Genomic Health; Honoraria (self): Agendia; Honoraria (self), Research grant/Funding (self): Myriad. A. Prat: Honoraria (self): Veracyte; Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Roche; Advisory/Consultancy: MSD Oncology; Advisory/Consultancy, Travel/Accommodation/Expenses: Daiichi Sankyo; Advisory/Consultancy: Amgen; Advisory/Consultancy: BMS; Advisory/Consultancy: Boehringer Ingelheim; Advisory/Consultancy, Research grant/Funding (institution): Puma Biotechnology; Advisory/Consultancy: Oncolytics Biotech; Advisory/Consultancy: AbbVie; Honoraria (institution): NanoString technologies; Research grant/Funding (institution): Incyte; Honoraria (self): Oncolytics; Honoraria (self), Research grant/Funding (self): Novartis; Advisory/Consultancy: Peptomyc; Honoraria (self), Advisory/Consultancy: Guardian health; Honoraria (self), Shareholder/Stockholder/Stock options: Reveal genomics; Advisory/Consultancy: AstraZeneca; Research grant/Funding (self): Incyte. All other authors have declared no conflicts of interest.

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M. Bellet Ezquerra (Barcelona, Spain)

40TiP - SOLTI-1802 ONAWA Trial: A Window of Opportunity Trial of Onapristone (ONA) in Postmenopausal Women with Estrogen and Progesterone Receptor-Positive/HER2-negative (ER+/PgR+/HER2-) Early Breast Cancer (EBC)

Abstract

Abstract

Background

PgR expression is a biomarker of ER functionality, cellular progression to malignancy, and response to endocrine therapy (ET) in HR+ BC. ONA, a type I antiprogestin showed activity in patients with metastatic BC, but early trials with its immediate release formulation showed liver toxicity and further studies were halted. The development of a new extended-release formulation (Context Therapeutics, PA, USA), which is associated with a lower liver toxicity (Cottu PH, PLOS ONE, 2018) has strongly supported the relaunching of ONA clinical development. ONA blocks Ser294 phosphorylation of PgR, a posttranslational event associated with elevated PgR transcriptional activity coupled to rapid PgR turnover and also, downregulates PgR gene targets both in tumor cells expressing a sumo-deficient/phospho-mimic activated (KR) and non-activated (WT) PgR phenotype, independent to the presence of progesterone. Considering BC heterogeneity and that PgR analysis by standard immunohistochemistry (IHC) does not perfectly correlate with PgR target gene expression, the identification of biomarkers allowing the selection of patients with PgR-driven tumors that may benefit from antiprogestins treatment is currently an unmet need.

Trial design

ONAWA is an open-label, single arm, multicenter window of opportunity clinical trial of ONA (50 mg extended-release tablets BID for 21 days) for postmenopausal women with EBC amenable to receive a short course of ET before surgery. Ten patients with ER+/PgR+/HER2- and ki67 ≥ 15% BC will be enrolled at 4 sites of the SOLTI network. The primary objective is to evaluate the biological activity of ONA by the rate of Complete Cell Cycle Arrest determined by Ki67 (≤2.7%). Secondary endpoints include safety and correlating biological activity with IHC of tumor expression (ER, PgR, Ser294-PgR, CD24, CD44, ALDH1, Ki67), estradiol, and progesterone blood levels, and gene expression profile (NanoString nCounter® Breast 360^TM panel). The study was approved in July 2020 and recruitment started in November 2020. Seven patients have been enrolled at the time of this submission.

Clinical trial identification

NCT04142892; EudraCT Number: 2019-001433-13.

Legal entity responsible for the study

SOLTI Breast Cancer Research Group.

Funding

Context Therapeutics.

Disclosure

X. González-Farré: Honoraria (self), Non-remunerated activity/ies: Roche; Honoraria (self): Eisai; Honoraria (self): SOLTI. P. Villagrasa: Speaker Bureau/Expert testimony: NanoString. A. Prat: Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Novartis; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Roche; Honoraria (self), Advisory/Consultancy: MSD; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Daiichi Sankyo; Advisory/Consultancy, Research grant/Funding (self): NanoString; Advisory/Consultancy: Oncolytics Biotech; Advisory/Consultancy: Amgen; Advisory/Consultancy: Puma. C. Saura Manich: Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: AstraZeneca; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Celgene; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Daiichi Sankyo; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Eisai; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Hoffman-La Roche; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Genomic Health; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Sharp and Dhome España SA; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Pfizer; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Philips Healthwork; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Pierre Fabre; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: prIME Oncology; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Puma; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Synthon; Advisory/Consultancy, Research grant/Funding (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Sanofi Aventis. All other authors have declared no conflicts of interest.

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E. Ciruelos (Madrid, Spain)

73TiP - SOLTI1710 PROMETEO II: Palbociclib in combination with letrozole in Hormone Receptor-positive (HR+)/HER2-negative residual disease after standard neoadjuvant chemotherapy (NAC)

Abstract

Abstract

Background

The combination of cyclin-dependent kinase inhibitors (CDK4/6i) with first or second-line endocrine therapy are the standard of care for HR+/HER2-negative metastatic breast cancer (BC); its role in the early-setting is being evaluated in several studies with discordant results. In HR+/HER2-negative BC, pathologic complete response (pCR) rates after NAC are around 15%. Additional therapeutic strategies to eradicate these residual tumor cells are needed. To characterize the biological effect of CDK4/6i in residual disease (RD) after NAC, could help to better understand their role in early BC.

Trial design

SOLTI-1710 PROMETEO II is an open-label, multicenter window of opportunity trial of Palbociclib and letrozole tested in patients with HR+/HER-negative RD after completing anthracycline/taxane-based NAC. PROMETEO II will include 22 patients. Invasive RD must be confirmed by core-biopsy and have a diameter ≥ 10mm measured by ultrasound. Adequate organ function and ECOG PS 0-1 are required. A short course of Palbociclib is administered at a dose of 125 mg/day for 21 days and letrozole 2.5 mg/day continuously until surgery. BC surgery is carried out 1 week after the last dose of palbociclib. The primary objective of the trial is to evaluate the antitumor activity by the Complete Cell Cycle Arrest (CCCA) rate determined by Ki67 ≤2.7%, centrally assessed at surgery. Secondary endpoints include pCR rate, RCB and safety. To date, 12 patients have been included at 8 sites in Spain.

Clinical trial identification

NCT04130152.

Legal entity responsible for the study

SOLTI.

Funding

Pfizer.

Disclosure

E. Ciruelos: Advisory/Consultancy, Non-remunerated activity/ies: Pfizer; Advisory/Consultancy: Roche; Advisory/Consultancy: Lilly; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Novartis; Advisory/Consultancy: MSD. X. González-Farré: Advisory/Consultancy: SOLTI Breast Cancer Group; Advisory/Consultancy, Non-remunerated activity/ies: Roche; Advisory/Consultancy: Eisai. P. Villagrasa: Honoraria (self): NanoString. A. Prat: Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Roche; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Novartis; Honoraria (self), Advisory/Consultancy: MSD Oncology; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Daiichi Sankyo; Research grant/Funding (self): NanoString Technologies; Advisory/Consultancy: Oncolytics Biotech; Advisory/Consultancy: Amgen; Advisory/Consultancy: PUMA. S. Pernas Simon: Advisory/Consultancy, Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: Polyphor; Advisory/Consultancy: Seattle Genetics; Advisory/Consultancy: Roche. All other authors have declared no conflicts of interest.

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J. Laguna Montes (Barcelona, Spain)

109P - Subsequent therapies after progressing to CDK4/6 inhibition (CDK4/6i) in hormone receptor positive/HER2 negative (HR+/HER2-) advanced breast cancer (ABC)

Abstract

Abstract

Background

There is limited data in the real world setting regarding the effectiveness of subsequent lines of treatment after progressing to CDK4/6i. The optimal therapeutic sequence is still unknown and predictors are needed.

Methods

This is a retrospective single-center study of 99 consecutive patients (pts) with HR+/HER2- ABC who progressed to CDK4/6i + endocrine therapy (ET) in the 1^st or 2nd line setting between 05/2015-01/2021. Research-based PAM50 subtyping using the nCounter platform was performed in tumor samples collected before CDK4/6i. Median progression free survival (mPFS) and overall survival (mOS) were calculated using the Kaplan Meier method.

Results

mPFS with CDK4/6i in 1st line (59%) was 10.4 months (m) and 11.7m in 2nd line (41%). At the time of the analysis, 71% of patients had progressed to the subsequent line. mPFS and mOS after CDK4/6i were 5.3 and 19.6m, respectively. No correlation was observed between previous PFS on CDK4/6i and mPFS (p=0.74). mPFS with chemotherapy (CT) (45%) was 6.4m; with ET alone (18%), 2.9m; with ET + everolimus (eve) (10%), 5.1m; with PIK3CA inhibitors + ET (9%), 5.4m; and with other CDK4/6i + ET (3%), 9.1m. Fourteen percent of pts did not receive any subsequent treatment. Responses were only observed with CT (12/44), eve + ET (1/10) and CDK4/6i re-treatment (2/3). PAM50 data was available for 75 pts (75%). Luminal A (30%) showed a mPFS of 6.4m and mOS was not reached; Luminal B (33%), 7.6 and 42.1m; HER2-enriched (19%), 1.8 and 11.6m; Basal-like (10%), 7.9 and 11.5m. Luminal vs. non-luminal disease with ET had a mPFS of 2.9 and 3.7m (p=0.99); with target therapies + ET, 13.8 and 1.7m (p=0.026) and with ET 7.0 and 6.1m (p=0.094). Pts who showed progression to CDK4/6i as the best response (n=19) had a mPFS of 1.7m when treated with ET combinations (n=4) and 8.1m with CT (n=15).

Conclusions

Our exploratory results show limited benefit with post-CDK4/6i therapies, independently from previous PFS. PAM50 subtype remains prognostic in this context. Primary CDK4/6i refractory tumors might benefit more from CT than ET.

Legal entity responsible for the study

Hospital Clinic y Provincial of Barcelona.

Funding

Instituto de Salud Carlos III (PI19/01846) (to A.P.) Breast Cancer Research Foundation (to 300 A.P.) PhD4MD (to N.C.) Fundació La Marató TV3 (to A.P) RESCUER Horizon 2020 301 (to A.P.) Save the Mama (to A.P.) Pas a Pas (to A.P.) Asociación Cáncer de Mama 302 Metastásico (to A.P.) Fundación Científica Asociación Española Contra el Cáncer (to 303 F.B.M.) Fundación SEOM (SEOM 2018 Grant: Fellowship for Training in 304 Research in Reference Centers) (to T.P.).

Disclosure

J.C. Laguna: Speaker Bureau/Expert testimony: Kyowa Kirin. T. Pascual: Advisory/Consultancy: Roche; Advisory/Consultancy: Genentech. N. Chic: Travel/Accommodation/Expenses: Eisai; Travel/Accommodation/Expenses: Novartis; Speaker Bureau/Expert testimony: Eisai; Travel/Accommodation/Expenses: Pier Fabre. M. Vidal: Honoraria (self): Pfizer; Honoraria (self): Novartis; Honoraria (self): Roche; Honoraria (self): Daiichi Sankyo; Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Pfizer; Advisory/Consultancy: Roche; Advisory/Consultancy: Novartis. R. Moreno: Speaker Bureau/Expert testimony: Eisai. A. Prat: Honoraria (self): Novartis; Honoraria (self): Pfizer; Honoraria (self): Roche; Honoraria (self): MSD Oncology; Honoraria (self): Lilly; Honoraria (self): Daiichi Sankyo; Travel/Accommodation/Expenses: Daiichi Sankyo; Research grant/Funding (self): Roche; Research grant/Funding (self): Novartis; Advisory/Consultancy: NanoString Technologies; Advisory/Consultancy: Amgen; Advisory/Consultancy: Roche; Advisory/Consultancy: Novartis; Advisory/Consultancy: Pfizer; Advisory/Consultancy: Bristol-Myers Squibb. M. Muñoz: Honoraria (self): Roche; Honoraria (self): Novartis; Honoraria (self): Pierre Fabre; Honoraria (self): Eisai; Advisory/Consultancy: Roche; Advisory/Consultancy: Novartis; Advisory/Consultancy: Pierre Fabre; Advisory/Consultancy: Eisai; Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Lilly. O. Martínez-Sáez: Travel/Accommodation/Expenses: Roche; Advisory/Consultancy: Roche; Speaker Bureau/Expert testimony: Eisai. All other authors have declared no conflicts of interest.

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E. Ciruelos (Madrid, Spain)

130TiP - SOLTI-1303 PATRICIA II randomized phase II trial of palbociclib plus trastuzumab and endocrine therapy (ET) versus treatment of physician's choice (TPC) in metastatic HER2-positive and hormone receptor-positive (HER2+/HR+) breast cancer (BC) with PAM50 luminal intrinsic subtype

Abstract

Abstract

Background

PATRICIA phase II trial showed that Palbociclib in combination with trastuzumab is safe and exhibits promising survival outcomes in trastuzumab pretreated HER2+/HR+ advanced breast cancer with a PAM50 Luminal A or B subtype (Ciruelos E. et al, CCR 2020). Based on these results, PATRICIA II was designed to include only patients with HER2+/HR+, PAM50 Luminal A/B tumors to receive palbociclib, trastuzumab and ET versus treatment of physician’s choice (TPC).

Trial design

PATRICIA II is a randomized open-label, adaptive design, phase II study. Patients must have centrally confirmed HER2+/HR+ and PAM50 Luminal A or B tumors and have received at least 1 (and no more than 4) prior lines of anti-HER2 regimens for locally advanced or metastatic BC. Patients are randomized 1:1 to receive trastuzumab plus palbociclib at a standard dose of 125 mg/day orally 3 weeks on/ 1 week off and ET (Cohort C1) or TPC (cohort C2). ET options in cohort 1 are either an aromatase inhibitor, fulvestrant or tamoxifen +/- ovarian suppression. TPC options in cohort C2 are T-DM1 or chemotherapy (gemcitabine, vinorelbine, capecitabine, eribulin, paclitaxel or docetaxel) plus trastuzumab. Stratification factors include number of previous regimens for advanced or metastatic BC (1-2 vs 3-4) and the presence of visceral disease (yes vs no). Primary endpoint is to compare the progression-free survival between two arms. The study has an 80% power with two-sided alpha=0.05 to detect a HR of 0.62 in favor of the palbociclib cohort. Secondary endpoints include response rate, overall survival, safety, and quality of life. Tumor tissue and blood samples will be collected for biomarker analyses. An estimated total of 516 patients will be screened to include 232 patients with HER2+/HR+ PAM50 Luminal A or B tumors. The recruitment is ongoing in 20 sites in Spain and as of February 3^rd, 2021, 107 patients were screened and 30 were enrolled in the trial.

Clinical trial identification

NCT02448420.

Legal entity responsible for the study

SOLTI.

Funding

Pfizer.

Disclosure

E.M. Ciruelos: Advisory/Consultancy, Non-remunerated activity/ies: Pfizer; Advisory/Consultancy: Roche; Advisory/Consultancy: Lilly; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Novartis; Advisory/Consultancy: MSD. S. Pernas Simon: Advisory/Consultancy, Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: Polyphor; Advisory/Consultancy: Seattle Genetics; Advisory/Consultancy: Roche. M. Oliveira: Advisory/Consultancy, Research grant/Funding (institution): AstraZeneca; Research grant/Funding (institution): Philips Healthcare; Advisory/Consultancy, Research grant/Funding (institution): Genentech; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses: Roche; Research grant/Funding (institution): Immunomedics; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Seattle Genetics; Advisory/Consultancy, Research grant/Funding (institution): GSK; Research grant/Funding (institution): Boehringer Ingelheim; Research grant/Funding (institution): Puma Biotechnology; Research grant/Funding (institution): Zenith Epigenetics; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy: Puma Biotechnology; Travel/Accommodation/Expenses: Pierre Fabre; Travel/Accommodation/Expenses: Eisai. B. Bermejo De Las Heras: Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Advisory/Consultancy: Palex; Advisory/Consultancy: MSD; Advisory/Consultancy: Novartis; Advisory/Consultancy: Pfizer. X. González-Farré: Advisory/Consultancy: SOLTI Breast Cancer Group; Advisory/Consultancy, Non-remunerated activity/ies: Roche; Advisory/Consultancy: Eisai. P. Villagrasa: Honoraria (self): NanoString. A. Prat: Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Novartis; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): Roche; Honoraria (self), Advisory/Consultancy: MSD Oncology; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Daiichi Sankyo; Advisory/Consultancy, Research grant/Funding (self): NanoString Technologies; Advisory/Consultancy: Oncolytics Biotech; Advisory/Consultancy: Amgen; Advisory/Consultancy: Puma. All other authors have declared no conflicts of interest.

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M. Guillén (Barcelona, Spain)

177P - COVID-19 pandemic impact in newly diagnosed breast cancer patients BCP at a 3rd level hospital

Abstract

Abstract

Background

On March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. Worldwide, health authorities recommended limiting elective surgeries, diagnostic procedures and non-urgent face-to-face consultations. The full range of consequences of these restrictive measures in cancer diagnosis has not yet been well documented in Spain. Here, we report the impact of these disruptions in the diagnosis of breast cancer at our institution.

Methods

We performed a retrospective study comparing new breast cancer diagnosis at the medical oncology department in a tertiary center in 2019 and 2020. Data corresponding to clinical-pathological features at diagnosis was collected from clinical records. Categorical variables were compared using the Fisher’s exact test and chi-square. Normally-distributed continuous variables were compared using two sample-t-tests. P values of < 0.05 were considered statistically significant.

Results

In 2020, there were 210 new BCP, which represent a 26% decrease compared to 2019 (n=285). The overall number of screening mamograms (SM) decreased from 13041 in 2019 to 8239 in 2020 (37%), resulting in 46% fewer new diagnosis in this group (57 in 2019 vs 31 in 2020). Diagnoses made after referral from other hospital services were also reduced (40 in 2019 vs 23 in 2020, 42% reduction). Smaller reductions were observed in new breast cancer patients referred from other hospitals (19%) and from primary care centers (13%). Diagnoses at stage I, were significantly reduced by 47% (n=135 in 2019 vs n=71 in 2020) and in stage II by 18% (n=108 in 2019 vs n=89 in 2020). Stage III diagnoses were increased by 30% (n=23 in 2019 vs n=30 in 2020) and in stage IV by 11%, although the absolute number of patients was similar in both subgroups (n=18 in 2019 vs n=20 in 2020) (p=0.0068).

Conclusions

Suspension of SM and limited outpatient consultations have contributed to diagnostic delays. Accordingly, higher proportion of patients presented with locally advanced disease. These delays are expected to have an impact in breast cancer specific survival in the coming years. Therefore, our findings should bring awareness about the importance of defining measures to prevent COVID pandemic impact on other diseases.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Vidal: Honoraria (self), Travel/Accommodation/Expenses: Pfizer; Honoraria (self), Advisory/Consultancy: Novartis; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Honoraria (self): Daiichi Sankyo. N. Chic: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Eisai; Travel/Accommodation/Expenses: Novartis; Travel/Accommodation/Expenses: Pierre Fabre. O. Martínez-Sáez: Speaker Bureau/Expert testimony: Eisai; Advisory/Consultancy, Travel/Accommodation/Expenses: Roche. R. Moreno: Speaker Bureau/Expert testimony: Eisai. A. Prat: Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Travel/Accommodation/Expenses: Daiichi Sankyo; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Roche; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Novartis; Honoraria (self): MSD Oncology; Honoraria (self): Lilly; Advisory/Consultancy: NanoString Technologies; Advisory/Consultancy: Amgen; Advisory/Consultancy: Bristol-Meyers Squib. M. Muñoz: Honoraria (self), Travel/Accommodation/Expenses: Roche; Honoraria (self): Novartis; Honoraria (self): Pierre Fabre; Honoraria (self): Eisai; Travel/Accommodation/Expenses: Lilly. All other authors have declared no conflicts of interest.

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