Barbara Pistilli (Villejuif, France)

Gustave Roussy - Cancer Campus

Author Of 6 Presentations

Proffered Paper session 2 (ID 8)

Invited Discussant 58O (ID 280)

Lecture Time
17:25 - 17:35
Room
Berlin Hall
Date
Wed, 04.05.2022
Time
16:45 - 18:15
Poster Display session (ID 9)

18P - Comparative genomic profiling of primary and locally recurrent luminal breast cancers (BC) (ID 36)

Abstract

Background

The late occurrence of isolated local recurrence (LR) of luminal BC calls into question whether these are true LR or new primaries. We evaluated the concordance of the mutation profiles between matched primary tumors (PT) and LR.

Methods

We collected data from women with LR of luminal BC treated at Gustave Roussy and Trieste University Hospital between 1992 and 2018. Following a quality control, targeted NGS was performed on the IonTorrent S5 NGS platform with the Oncomine Tumor Mutation Load Assay covering 409 critical oncogenes or tumor suppressor genes to analyze PT and LR samples. For the bioinformatic analysis, we retained the matched samples that passed quality check and had a total mean depth coverage ≥ 300X. Variants were filtered on their allele frequency ≥ 5% and a read count ≥ 5X, and on the basis of their genomic effect and annotation.

Results

Among the 131 eligible patients, 82 matched PT and LR were sequenced and analyzed. The table summarizes patient, PT and LR characteristics. Median time until LR was 6.0 years. After a median follow-up of 4.6 years following LR, median DDFS and OS were 8.1 and 8.7 years, respectively. In the PT, the main genes with more than 20% of variants were KMT2D, ATRX, MTOR, ATM and KMT2A. In the LR, the main genes with more than 10% of variants were KMT2D, NOTCH2, PIK3CA, and KMT2A. The main gene with recurrent mutation present in both PT and LR was PIK3CA (4.8%). This analysis showed that 17 cases (20%) shared the same variants between PT and LR.

Patient and tumor characteristics

PT LR
Age (years) Median 53 68
Invasive ductal carcinoma 56 (68.3%) 52 (63.4%)
Invasive lobular carcinoma 17 (20.7%) 18 (22.0%)
Other 9 (11.0%) 12 (14.6%)
Size (mm) Median 20 15
LN involvement 36 (43.9%) NA
Surgery of the breast Mastectomy 25 (30.5%) 47 (57.3%)
57 (69.5%) 30 (36.6%)
(Neo)adjuvant chemotherapy 36 (43.9%) 34 (41.5%)*
(Neo)adjuvant endocrine therapy 59 (72.0%) 64 (78.0%)*
Adjuvant radiotherapy 58 (70.7%) 17 (20.7%)

* Only adjuvant therapies

Conclusions

Although we found a wide range of molecular alterations in LR, a minority of patients had concordant mutational profiles between PT and LR. These findings, if confirmed in larger studies, may better guide the choice of therapy after LR excision.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Lacroix-Triki: Financial Interests, Advisory Board: Myriad genetics; Financial Interests, Advisory Board: Exact sciences; Financial Interests, Advisory Board: Rroche diagnostics; Financial Interests, Advisory Board: AstraZeneca; Financial Interests, Advisory Board: Daiichi Sankyo; Financial Interests, Advisory Board: MSD; Financial Interests, Advisory Board: Roche. E. Rouleau: Financial Interests, Invited Speaker: BMS; Financial Interests, Invited Speaker: AstraZeneca; Financial Interests, Invited Speaker: Roche; Financial Interests, Invited Speaker: Clovis; Financial Interests, Invited Speaker: GSK. L. Lacroix: Financial Interests, Advisory Role: Adept Field Solutions; Financial Interests, Advisory Role: AstraZeneca; Financial Interests, Advisory Role: Bayer; Financial Interests, Advisory Role: Boehringer; Financial Interests, Advisory Role: BMS; Financial Interests, Advisory Role: Lilly; Financial Interests, Advisory Role: Icomed; Financial Interests, Advisory Role: Genomic Health; Financial Interests, Advisory Role: Medimmune; Financial Interests, Advisory Role: Novartis; Financial Interests, Advisory Role: Pfizer; Financial Interests, Advisory Role: QualWorld; Financial Interests, Advisory Role: Taiho Oncology; Financial Interests, Advisory Role: Roche; Financial Interests, Advisory Role: Thermofisher; Financial Interests, Advisory Role: VelaDx; Financial Interests, Sponsor/Funding: Abbott; Financial Interests, Sponsor/Funding: Amgen; Financial Interests, Sponsor/Funding: AstraZeneca; Financial Interests, Sponsor/Funding: Beckman Coulter; Financial Interests, Sponsor/Funding: Bayer; Financial Interests, Sponsor/Funding: Boeringer; Financial Interests, Sponsor/Funding: BMS; Financial Interests, Sponsor/Funding: Illumina; Financial Interests, Sponsor/Funding: Genomic Health; Financial Interests, Sponsor/Funding: Guardant health; Financial Interests, Sponsor/Funding: Lilly; Financial Interests, Sponsor/Funding: Medimmune; Financial Interests, Sponsor/Funding: Myriad; Financial Interests, Sponsor/Funding: Novartis; Financial Interests, Sponsor/Funding: Pfizer; Financial Interests, Sponsor/Funding: Roche; Financial Interests, Sponsor/Funding: Siemens Healthineer; Financial Interests, Sponsor/Funding: Taiho Oncology; Financial Interests, Sponsor/Funding: Thermofisher; Financial Interests, Sponsor/Funding: VelaDx. F. André: Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Lilly; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Daiichi; Other, Founder: Pegacsy. B. Pistilli: Financial Interests, Institutional, Advisory Role: AstraZeneca; Financial Interests, Personal, Advisory Role: Myriad; Financial Interests, Personal, Advisory Role: Pierre Fabre; Financial Interests, Institutional, Advisory Role: Pfizer; Financial Interests, Institutional, Invited Speaker: Daiichi Sankyo; Financial Interests, Institutional, Invited Speaker: Novartis; Financial Interests, Institutional, Invited Speaker: Puma; Financial Interests, Personal, Sponsor/Funding: AstraZeneca; Financial Interests, Personal, Sponsor/Funding: Pierre Fabre; Financial Interests, Personal, Sponsor/Funding: MSD; Financial Interests, Institutional, Advisory Board: Novartis; Financial Interests, Institutional, Advisory Board: AstraZeneca; Financial Interests, Institutional, Advisory Board: Daiichi Sankyo. All other authors have declared no conflicts of interest.

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Poster Display session (ID 9)

73P - Effect of diarrheal prophylaxis or dose escalation on neratinib-associated diarrhea and tolerability in patients with HER2+ early-stage breast cancer: Final findings from the CONTROL trial (ID 88)

Abstract

Background

Neratinib (N), an irreversible pan-HER TKI, is approved in the EU for extended adjuvant treatment of early-stage HR+ HER2+ breast cancer (BC) after adjuvant trastuzumab (T)-based therapy. The CONTROL trial (NCT02400476) investigated pre-emptive antidiarrheal prophylaxis or dose escalation (DE) for prevention of diarrhea, the most frequent side effect of N.

Methods

CONTROL is an international, multi-cohort, open-label, phase 2 study. Patients (pts) ≥18y with stage I–IIIc HER2+ BC received oral N (240 mg/d for 1y) after T-based adjuvant therapy. Pts were enrolled sequentially into separate cohorts: 1) mandatory loperamide prophylaxis; 2) budesonide + loperamide; 3) colestipol + loperamide; 4) colestipol + loperamide PRN; 5) DE + loperamide PRN (2 cohorts). DE1 schedule: N 120 mg/d x w1, 160 mg/d x w2, then 240 mg/d from w3 to 12m. DE2 schedule: N 160 mg/d x w1&2, 200 mg/d x w3&4, then 240 mg/d from w5 to 12m. Primary endpoint: incidence of grade ≥3 diarrhea.

Results

563 pts were enrolled. All preventive strategies reduced grade 3 diarrhea vs ExteNET (historical control: 39%). Median cumulative duration of grade 3 diarrhea ranged from 2–3.5d in CONTROL (vs 5.0d for ExteNET). The proportion of pts discontinuing N because of diarrhea was decreased in CONTROL vs ExteNET. Key diarrhea outcomes in all CONTROL cohorts are presented in the table and will be fully detailed during the congress.

Patient disposition and diarrhea characteristics: All CONTROL cohorts

Loperamide (n=137) Budesonide+ loperamide (n=64) Colestipol+ loperamide (n=136) Colestipol + loperamide PRN (n=104) DE1 + loperamide PRN (n=60) DE2 + loperamide PRN (n=62)
Median duration of treatment, months (Q1–Q3) 11.6 (0.8–12.0) 12.0 (11.8–12.0) 11.9 (8.5–12.0) 12.0 (8.3–12.0) 12.0 (11.1–12.0) 11.9 (7.5–12.0)
Diarrhea, n (%)
Grade 3 42 (30.7) 18 (28.1) 28 (20.6) 34 (32.7) 8 (13.3) 17 (27.4)
Grade ≥4 0 0 0 0 0 0
Median cumulative duration of grade 3 diarrhea, days 3.0 3.0 3.5 2.0 2.5 2.0
Discontinuations due to diarrhea, n (%) 28 (20.4) 7 (10.9) 5 (3.7) 8 (7.7) 2 (3.3) 4 (6.5)
Dose reductions due to diarrhea, n (%) 10 (7.3) 2 (3.1) 10 (7.4) 10 (9.6) 2 (3.3) 7 (11.3)

Conclusions

These final findings from CONTROL show improved tolerability of N with all diarrhea prophylaxis strategies and suggest that DE1 with loperamide PRN allows pts to stay on treatm.ent longer and receive full benefit from N.

Clinical trial identification

NCT02400476.

Editorial acknowledgement

Editorial/writing assistance for this abstract was provided by Lee Miller (Miller Medical Communications Ltd.). This work was funded by the study sponsor (Puma Biotechnology Inc.).

Legal entity responsible for the study

Puma Biotechnology Inc.

Funding

Puma Biotechnology Inc.

Disclosure

A. Brufsky: Financial Interests, Personal, Advisory Role, Consulting fees: Puma Biotechnology Inc. A.J. Chien, R. Bose: Financial Interests, Institutional, Research Grant: Puma Biotechnology Inc. B. Pistilli: Financial Interests, Personal, Advisory Role, Consulting fees: Puma Biotechnology Inc.; Financial Interests, Personal, Advisory Role, Consulting fees: Pierre Fabre; Financial Interests, Institutional, Research Grant: Puma Biotechnology Inc. D. Diprimeo, N. Foruzan, L.M. McCulloch: Financial Interests, Personal, Full or part-time Employment: Puma Biotechnology Inc.; Financial Interests, Personal, Stocks/Shares: Puma Biotechnology Inc. All other authors have declared no conflicts of interest.

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Mini Oral session 2 (ID 2)

167MO - Association between ER, PR and HER2 levels and outcome under palbociclib (Pal) + aromatase inhibitors (AIs) as first-line therapy for ER+ HER2- metastatic breast cancer (MBC): An exploratory analysis of the PADA-1 trial (ID 15)

Abstract

Background

In 1st-line trials, the relative Progression Free Survival (PFS) benefit of adding CDK4/6 inhibitors to AI was consistent across all subgroups of patients (pts), including those with lower ER expression. However, little is known about the absolute PFS obtained under CDK4/6i and AI in pts with low ER expression and whether PR and HER2 expression impact PFS in this setting.

Methods

PADA-1 is a phase III trial (NCT03079011) testing the clinical utility of ESR1mut detection in blood in ER ≥ 10% HER2- MBC pts receiving 1st- line Pal + AI. We investigated the association of locally-assessed ER (%), PR (%) and HER2 (0,1+,2+) IHC expression on the most recent tumor sample with PFS under Pal + AI.

Results

Of 1017 pts, 12 (1.2%), 34 (3.5%), 181 (18.5%) & 751 (76.8%) had an ER% expression of [10-20%], [21-50%], [51-80%] & [81-100%], respectively. N=249 pts (29.2%), 148 (17.3%), 186 (21.8%) & 270 (31.6%) had a PR% of [0-20%], [21-50%], [51-80%] & [81-100%], respectively (Allred scores will be presented). Available HER2 IHC scores were 0 & 1+/2+ in 357 (54.6%) & 296 (45.4%) pts, respectively. In univariate analysis, after a mFU of 28.1 months and 527 PFS events (51.8%) under Pal + AI, mPFS in pts with [10-50%], [51-80%] & [81-100%] ER IHC were 14.1, 21.6 & 30.1 months, respectively. mPFS in pts with [0-50%], [51-80%] & [81-100%] PR IHC were 20.6, 27.1 and 42.6 months, respectively. Longer PFS were observed in HER2(1/2+) vs (0) MBC (HR=0.79 [0.64;0.98]). In multivariate analysis, aside standard prognostic factors (PS, age, visceral disease, number of metastatic site, DMFI), both ER% and PR% had an independent prognostic impact: each +10% gain in ER% was associated with a reduced 10% risk of PFS event under Pal + AI (HR=0.90, 95%CI [0.84;0.96], p=0.002); each +10% gain in PR% was associated with a reduced 8% risk of PFS event under Pal + AI (HR=0.92, 95%CI [0.90;0.95], p<0.001).

Conclusions

ER and PR IHC % have significant, independent and similar impact on PFS achieved under 1st line by Pal + AI. The 14.1 months absolute mPFS obtained among pts with ER IHC <50% suggests that CDK4/6i + AI remains a good treatment option in this patient population.

Clinical trial identification

NCT03079011.

Legal entity responsible for the study

Unicancer & Arcagy-Gineco.

Funding

Pfizer.

Disclosure

T. De La Motte Rouge: Financial Interests, Personal, Financial Interests, Advisory Board: AstraZeneca; Financial Interests, Personal, Financial Interests, Advisory Board: Clovis Oncology; Financial Interests, Personal, Financial Interests, Advisory Board: GSK; Financial Interests, Institutional, Financial Interests, Advisory Board: MSD; Financial Interests, Personal, Financial Interests, Advisory Board: Mylan; Financial Interests, Personal, Financial Interests, Advisory Board: Pfizer; Financial Interests, Personal, Financial Interests, Advisory Board: Roche; Financial Interests, Personal, Financial Interests, Advisory Board: Tesaro; Financial Interests, Institutional, Financial Interests, Local PI: AstraZeneca; Financial Interests, Institutional, Financial Interests, Local PI: GSK; Financial Interests, Institutional, Financial Interests, Research Grant,: MSD; Financial Interests, Institutional, Financial Interests, Local PI: MSD; Financial Interests, Institutional, Financial Interests, Local PI: Netris Pharma; Financial Interests, Institutional, Financial Interests, Research Grant: Novartis; Financial Interests, Institutional, Financial Interests, Research Grant: Pfizer; Non-Financial Interests, Institutional, Non-Financial Interests, Local PI: Pfizer; Financial Interests, Institutional, Financial Interests, Local PI: Roche; Non-Financial Interests, Institutional, Non-Financial Interests, Principal Investigator: Arcagy; Non-Financial Interests, Non-Financial Interests, Advisory Role: French National Cancer Institute; Non-Financial Interests, Non-Financial Interests, Advisory Role: Unicancer. J. Frenel: Financial Interests, Personal, Other, Consulting fees: Novartis; Financial Interests, Personal, Other, Consulting fees: AstraZeneca; Financial Interests, Personal, Other, Consulting fees: Pfizer; Financial Interests, Personal, Other, Consulting fees: Lilly; Financial Interests, Personal, Other, Consulting fees: Clovis Oncology; Financial Interests, Personal, Other, Consulting fees: GSK; Financial Interests, Personal, Other, Consulting fees: Gilead; Financial Interests, Personal, Other, Consulting fees: Daiichi Sankyo; Financial Interests, Personal, Other, Consulting fees: Seagen; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Novartis; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: AstraZeneca; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Pfizer; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Lilly; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Clovis Oncology; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: GSK; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Gilead; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Daiichi Sankyo; Financial Interests, Institutional, Other, Support for attending meetings and/or travel: Seagen. A. Hardy-Bessard: Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Pfizer; Financial Interests, Personal, Advisory Role: AstraZeneca; Financial Interests, Personal, Advisory Role: Clovis; Financial Interests, Personal, Advisory Role: MSD; Financial Interests, Personal, Advisory Role: Seagen; Financial Interests, Personal, Advisory Role: GSK; Non-Financial Interests, Personal, Advisory Role, Travel/Accommodation/Expenses: Roche. T. Bachelot: Non-Financial Interests, Personal, Non-Financial Interests, Advisory board, travel: Roche; Non-Financial Interests, Personal, Non-Financial Interests, Advisory board, travel: AstraZeneca; Non-Financial Interests, Personal, Non-Financial Interests, Advisory board, travel: Pfizer; Non-Financial Interests, Personal, Financial Interests, Advisory board: Seattle Genetics; Non-Financial Interests, Personal, Non-Financial Interests, Advisory board, travel: Novartis. B. Pistilli: Financial Interests, Personal, Advisory Role: Puma Biotechnology; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Myriad Genetics; Financial Interests, Personal, Advisory Role: Pierre Fabre; Financial Interests, Institutional, Funding: Daiichi; Financial Interests, Institutional, Funding: Puma Biotechnology; Financial Interests, Institutional, Funding: Novartis; Financial Interests, Institutional, Funding: Merus; Financial Interests, Institutional, Funding: Pfizer; Financial Interests, Institutional, Funding: AstraZeneca; Financial Interests, Institutional, Funding: Sanofi. S. Delaloge: Financial Interests, Institutional, Advisory Board: AstraZeneca; Financial Interests, Institutional, Invited Speaker: AstraZeneca; Financial Interests, Institutional, Advisory Board: Cellectis; Financial Interests, Institutional, Invited Speaker: Exact Sciences; Financial Interests, Institutional, Advisory Board: Isis/servier; Financial Interests, Institutional, Invited Speaker: Lilly; Financial Interests, Institutional, Invited Speaker: MSD; Financial Interests, Institutional, Advisory Board: Novartis; Financial Interests, Institutional, Advisory Board: Orion; Financial Interests, Institutional, Invited Speaker: Pfizer; Financial Interests, Institutional, Advisory Board: Pierre fabre; Financial Interests, Institutional, Advisory Board: Rappta; Financial Interests, Institutional, Advisory Board: Sanofi; Financial Interests, Institutional, Invited Speaker: Seagen; Financial Interests, Institutional, Other, Steering Committee Member: AstraZeneca; Financial Interests, Institutional, Other, Steering Committee Member: BMS; Financial Interests, Institutional, Funding: GE; Financial Interests, Institutional, Other, Local PI: Orion; Financial Interests, Institutional, Other, Steering Committee Member: Pfizer; Financial Interests, Institutional, Other, Steering Committee Member: Puma; Financial Interests, Institutional, Other, Steering Committee Member: Roche; Financial Interests, Institutional, Other, Steering Committee Member: Sanofi; Financial Interests, Institutional, Other, Coordinating PI: Taiho; Financial Interests, Institutional, Member of the Board of Directors: SFSPM. L. Deiana: Financial Interests, Personal, Other, board and travel: AstraZeneca; Financial Interests, Personal, Other, board and travel: Pfizer; Financial Interests, Personal, Other, board and travel: Lilly; Financial Interests, Personal, Other, board and travel: Novartis. F. Del Piano: Financial Interests, Institutional, Other: Novartis; Financial Interests, Institutional, Other: Daiichi Sankyo. D. Genet: Personal, Other: Pfizer. C.B. Levache: Financial Interests, Institutional, Other, Material disposal: Amgen. F.C. Bidard: Financial Interests, Personal and Institutional, Invited Speaker, and advisory board, research grant, principal investigator: AstraZeneca; Financial Interests, Personal, Advisory Board: BioNTech; Financial Interests, Personal, Invited Speaker, and advisory board: Lilly; Financial Interests, Personal, Advisory Board, and advisory board, research grant, principal investigator: Menarini; Financial Interests, Personal and Institutional, Invited Speaker: Novartis; Financial Interests, Personal and Institutional, Invited Speaker, advisory board, research grant, principal investigator: Pfizer; Non-Financial Interests, Institutional, Advisory Board, and principal investigator: Prolynx; Financial Interests, Personal, Advisory Board, and principal investigator: Radius; Financial Interests, Personal and Institutional, Invited Speaker, and advisory board, research grant: Roche; Financial Interests, Institutional, Invited Speaker, and principal investigator: Sanofi. All other authors have declared no conflicts of interest.

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Poster Display session (ID 9)

225P - Impact of potential drug-drug interactions (PDDI) on adherence to endocrine therapy (ET) among patients with breast cancer (BC) in the Health Improvement Network (THIN) (ID 235)

Abstract

Background

ET represents a cornerstone in the treatment of early and late hormone receptors-positive (HR+) BC. However, adherence to ET is a major issue that can substantially impact survival outcomes. We explored whether PDDI with ET impact adherence.

Methods

We scanned the French version of the THIN™ database for women who had a reported diagnosis of BC and received ET (tamoxifen [tam] or aromatase inhibitor [AI]) between 1994 and 2021. Adherence was measured annually and defined by a medication possession ratio (MPR) ≥ 80% over 1-year prescription period. PDDI was classified using the Claude Bernard Drug Database into absent, minor (combination to take into account), moderate (combination requiring precautions for use), major (combination not recommended) and contraindicated. We used repeated-measure regression models to estimate odds ratios (OR) for the correlation between MPR ≥ 80% and age, baseline comorbidities, PDDI, and MPR during the previous year. Among patients with multiple PDDI, the worse PDDI category by patient was retained and included in the multivariable model.

Results

Among the 10,863 eligible pts, polypharmacy ≥ 5 drugs was reported in 33.7% and 47.8% of the tam and AI cohorts. PDDI occurrence is summarized in the table. PDDI were mostly moderate in the tam (60.4-80.6%) and AI (94.7%-99.3%) cohorts; contraindicated combinations were below 1%. In the tam cohort, annual MPR ≥ 80% was 79.3% (n = 2,824) at year 1 and 89.5% (n = 426) at year 5. The association between MPR ≥ 80% and presence of PDDI was not statistically significant neither in the tam (OR 0.991, 95% CI 0.0.914-1.075) nor AI (OR 1.046, 95% CI 0.954-1.147) cohorts.

Prevalence of PDDI with ET at baseline and during follow up

Tam AI
PDDI at baseline 13.5% 8.0%
PDDI at year 1 42.4% 31.8%
PDDI at year 2 40.9% 31.4%
PDDI at year 3 40.9% 32.8%
PDDI at year 4 35.5% 32.8%
PDDI at year 5 33.9% 32.5%

Conclusions

Adherence to ET was not associated with PDDI in patients with HR+ BC treated with tam or AI.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

A. Bardet: Financial Interests, Personal, Other: Roche SAS. O. Bougacha, L. Gantzer, B. Lekens: Financial Interests, Full or part-time Employment: Cegedim R&D. I.V. Luis: Financial Interests, Institutional, Invited Speaker: Amgen; Financial Interests, Institutional, Invited Speaker: Pfizer/Edimark; Financial Interests, Institutional, Invited Speaker: Pfizer/Edimark; Financial Interests, Institutional, Invited Speaker: AstraZeneca. S. Delaloge: Financial Interests, Institutional, Advisory Board: AstraZeneca, Novartis, Pierre Fabre, Orion, Sanofi, Rappta, Cellectis, Isis/Servier; Financial Interests, Institutional, Invited Speaker: Exact Sciences, Pfizer, Seagen, Lilly, AstraZeneca, MSD, Roche Genentech, BMS, Puma, Orion, Sanofi; Financial Interests, Institutional, Advisory Board, Ad Board: Besins Healthcare; Financial Interests, Institutional, Funding: GE; Financial Interests, Institutional, Invited Speaker, Clinical Research Funding to my Institution: Taiho; Non-Financial Interests, Invited Speaker, Société Française de Sénologie et Pathologie Mammaire: SFSPM. F. André: Financial Interests, Institutional, Research Grant: AstraZeneca, Lilly, Novartis, Pfizer, Roche, Daiichi; Other, Founder: Pegacsy. S. Michiels: Financial Interests, Personal, Other, Statistical advice: IDDI, Amaris, Roche; Financial Interests, Personal, Other, DSMB member: Sensorion, Servier, Biophytis, Yuhan. B. Pistilli: Financial Interests, Institutional, Advisory Role: AstraZeneca, Pfizer, Novartis, AstraZeneca, Daiichi Sankyo; Financial Interests, Personal, Advisory Role: Myriad, Pierre Fabre; Financial Interests, Institutional, Invited Speaker: Daiichi Sankyo, Novartis, Puma; Financial Interests, Personal, Sponsor/Funding: AstraZeneca, Pierre Fabre, MSD. All other authors have declared no conflicts of interest.

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Proffered Paper session 2 (ID 8)

LBA1 - Unraveling the mechanism of action and resistance to Trastuzumab deruxtecan (T-DXd): biomarker analyses from patients from DAISY trial (ID 281)

Abstract

Background

T-DXd is an anti-HER2 antibody-drug conjugate that has demonstrated high antitumor activity in HER2-positive and HER2-low metastatic breast cancer (mBC). We aimed to unravel the mechanism of action and resistance to T-DXd in patients from DAISY trial.

Methods

DAISY is a phase II clinical trial (NCT04132960) that assessed T-DXd efficacy in mBC according to HER2-expression (HER2-positive, HER2-low, and HER2-negative). Bystander effect and T-DXd uptake were analyzed by immunohistochemistry (IHC) (HER2, gH2AX, and T-DXd) on tumor biopsies at baseline and on-treatment (n=10 patients). T-DXd immune effects were explored by multiplex immunofluorescence (CD3, CD4, CD8, CD68, FoxP3, PD-1, PD-L1, CK/SOX10 antibodies) on tumor biopsies at baseline and on-treatment (Day 22 or 43, n=31 patients). Mechanisms of resistance were analyzed on tumor samples at baseline (n=118) and at progression by whole exome sequencing (n=24) and IHC (n=25). The predictive value of HER2 spatial distribution was investigated by artificial intelligence (AI) using weakly supervised and clustering algorithms on HER2-positive slides images at baseline (n=61).

Results

Molecular analyses showed that cancer cells expressing low levels of HER2, but not HER2-null cells, uptake T-DXd (p=0.053). In the whole population (n=31), a decrease of PDL1-positive cells was associated with a best objective response (BOR) (p=0.008). No modulation of T cells and macrophages was observed (p=0.6 and p=0.9 respectively). A decrease of PDL1 expression was detected in HER2-positive mBC (n=18; p=0.02). Clustering algorithms identified a cluster associated with a lower BOR (p=0.007), whose features identified by AI included a high percentage of HER2-negative cells currently under investigation. At progression, a decrease of HER2 expression was observed in 13/25 (52%) patients (p=0.07). DNA sequencing and final AI results will be available at the meeting.

Conclusions

A correlation between HER2 expression and T-DXd uptake in cancer cells was observed in on-treatment biopsies. T-DXd did not modulate intratumoral lymphocytes but decreased PDL1 expression. WES analyses at baseline and progression samples will be presented on-site.

Legal entity responsible for the study

The authors

Funding

Unicancer and Daiichi Sankyo

Disclosure

V. Dieras: Financial Interests, Personal, Advisory Board, Travel Expenses: Roche, Novartis, Lilly, Pfizer, AstraZeneca, MSD, Daiichi Sankyo, Seagen, Gilead; Financial Interests, Personal, Invited Speaker, Travel Expenses: Lilly, Pfizer, AstraZeneca, MSD, Daiichi Sankyo, Seagen, Gilead; Financial Interests, Personal, Principal Investigator, Travel Expenses: Pfizer, Daiichi Sankyo, Seagen; Financial Interests, Personal, Advisory Board: AbbVie; Financial Interests, Personal, Principal Investigator: AbbVie; Non-Financial Interests, Personal, Advisory Board: Eisai, Pierre Fabre Oncologie. E. Deluche: Financial Interests, Personal, Advisory Board: Novartis, Pfizer, Fresenius Kabi, Lilly; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Other, scientific events: Lilly, GSK; Financial Interests, Personal, Other, funding for conference travel: AstraZeneca-Daiichi, Roche, Amgen. B. Pistilli: Financial Interests, Institutional, Other, Consulting Fees: AstraZeneca, Pfizer; Financial Interests, Personal, Other, Consulting Fees: Myriad, Pierre Fabre; Financial Interests, Institutional, Speaker’s Bureau: Daiichi Sankyo, Novartis, Puma; Financial Interests, Institutional, Writing Engagements: Daiichi Sankyo, Novartis, Puma; Financial Interests, Personal, Other, Attending Meetings and/or Travel: AstraZeneca, Pierre Fabre, MSD; Financial Interests, Institutional, Advisory Board: Novartis, AstraZeneca, Daiichi Sankyo. T. Bachelot: Financial Interests, Personal, Advisory Board: Roche, Novartis, AstraZeneca, Pfizer, Seagen; Financial Interests, Institutional, Research Grant: Novartis, Roche, AstraZeneca, Seagen, Pfizer; Financial Interests, Personal, Invited Speaker: Roche. D. Tran: Non-Financial Interests, Institutional, Full or part-time Employment, Full-time: DIEP T. N. TRAN. N. Droin: Non-Financial Interests, Institutional, Full or part-time Employment, Part-time: Nathalie Droin. M. Kobayashi, T. Kakegawa: Other, Personal, Full or part-time Employment, Employee of Daiichi Sankyo RD Novare, which belongs to Daiichi Sankyo Group. Daiichi Sankyo Group is developing T-DXd: Daiichi Sankyo RD Novare. M. Lacroix-Triki: Financial Interests, Personal, Invited Speaker: AstraZeneca, Daiichi Sankyo; Financial Interests, Personal, Other, Consulting Fees: AstraZeneca, Daiichi Sankyo. F. André: Financial Interests, Institutional, Research Grant: AstraZeneca, Lilly, Novartis, Pfizer, Roche, Daiichi; Other, Founder: Pegacsy. All other authors have declared no conflicts of interest.

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Presenter Of 1 Presentation

Proffered Paper session 2 (ID 8)

Invited Discussant 58O (ID 280)

Lecture Time
17:25 - 17:35
Room
Berlin Hall
Date
Wed, 04.05.2022
Time
16:45 - 18:15