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Best abstracts

42O - Biomarker analysis from KAITLIN, a randomised phase III study of adjuvant trastuzumab emtansine (TDM-1; K) plus pertuzumab (P) versus trastuzumab (H) plus taxane (T) plus P after anthracyclines (AC) for high-risk HER2-positive early breast cancer (EBC)


07 May 2021


Best abstracts


Otto Metzger


Annals of Oncology (2021) 32 (suppl_2): S37-S47. 10.1016/annonc/annonc504


O. Metzger1, C. Lambertini2, I. Krop3, G. Lewis Phillips4, C.M. Perou5, F. Symmans6, I. Melero7, N. Harbeck8, E.P. Winer9, S. Im10, C.H. Barrios11, H. Bonnefoi12, J.R. Gralow13, P.A. Ellis14, L. Gianni15, M. Toi16, S.M. Swain17, T. Boulet2, C. Song18, S. de Haas19

Author affiliations

  • 1 Boston/US
  • 2 F. Hoffmann-La Roche Ltd., Basel/CH
  • 3 Dana-Farber Cancer Institute, Boston/US
  • 4 Genentech, Inc., South San Francisco/US
  • 5 Lineberger Comprehensive Cancer Center, University of North Carolina, 27599 - Chapel Hill/US
  • 6 University of Texas MD Anderson Cancer Center, 77030-4095 - Houston/US
  • 7 Clinica Universitaria de Navarra, 31008 - Pamplona/ES
  • 8 Ludwig Maximilians University - Grosshadern, 81377 - Munich/DE
  • 9 Dana-Farber Cancer Institute, Harvard Medical School, 2115 - Boston/US
  • 10 SNUH-Seoul National University Hospital, 3080 - Seoul/KR
  • 11 Oncoclínicas, HSL, PUCRS, 90570-080 - Porto Alegre/BR
  • 12 Institut Bergonié Unicancer and Bordeaux University, 33076 - Bordeaux/FR
  • 13 University of Washington Seattle Cancer Care Alliance, 98109-4405 - Seattle/US
  • 14 Guy’s Hospital and Sarah Cannon Research Institute, SE1 9RT - London/GB
  • 15 Fondazione Michelangelo, 20154 - Milano/IT
  • 16 Kyoto University-Graduate school of medicine, 606-8507 - Kyoto/JP
  • 17 Georgetown University Medical Center, 20057 - Washington/US
  • 18 Genentech, Inc., 94080 - South San Francisco/US
  • 19 F. Hoffmann-La Roche Ltd., 4070 - Basel/CH


Abstract 42O


KAITLIN (NCT01966471) compared adjuvant AC-KP versus AC-THP in patients with HER2-positive, high-risk EBC. A preplanned exploratory analysis assessed the relationship between invasive disease-free survival (IDFS) and biomarkers (BMs) potentially related to response.


Baseline tumor samples were used for central assessment of HER2 and pre-specified BMs including HER2 mRNA expression and PTEN IHC expression by median (med) cutoff, and activating PIK3CA hotspot mutations. The effect of treatment and BMs on IDFS was assessed via descriptive analyses.


BMs were well balanced between treatment arms. No BM subgroup showed more benefit from AC-KP than AC-THP. A trend for reduced benefit with AC-KP vs AC-THP was seen in the HER2 <30% expression and 4 to <6 gene copy number subgroups (Table). No clear prognostic relationships were identified in pooled arms (PIK3CA mut vs non-mut HR=1.27 [0.92–1.74]; HER2 IHC3+ vs IHC2+ HR=0.82 [0.55–1.23]; HER2 mRNA ≥ vs < med HR=0.76 [0.56–1.03]). Table: 42O

AC-THP (n=918) AC-KP (n=928) HR (95% CI)
BM* n 3-yr IDFS, % n 3-yr IDFS, %
HER2 IHC 2+ 3+ 130781 95.294.1 127791 93.593.2 1.34 (0.65–2.80)0.89 (0.64–1.24)
HER2 gene ratio 2 to <4 ≥4 200693 95.994.1 186714 92.893.1 1.29 (0.71–2.35)0.91 (0.64–1.30)
HER2 gene copy number 4 to <6 ≥6 78809 97.494.2 86811 87.093.8 2.77 (1.08–7.09)0.85 (0.61–1.18)
HER2 mRNA 446436 94.594.6 442454 91.794.3 1.18 (0.79–1.77)0.86 (0.54–1.36)
HER2 IHC Expression <30% Expression ≥30% 67851 97.094.0 70858 91.193.2 3.41 (1.10–10.60)0.87 (0.63–1.18)
PIK3CA Mut Not mut 276606 95.993.7 249645 89.794.1 1.31 (0.78–2.20)0.91 (0.62–1.32)
PTEN 329479 95.794.4 348468 91.494.7 1.39 (0.87–2.22)0.84 (0.53–1.34)

*HER2 IHC0/1+ (n=14), HER2 gene copy number <4 (n=20) and gene ratio <2 (n=11) excluded.


Consistent with the primary study results, AC-KP did not reduce the risk of an IDFS event compared to AC-THP in any BM subgroup. HP + chemotherapy remains the standard of care for those with high-risk HER2-positive EBC. No BMs had prognostic value in the pooled arm analyses.

Clinical trial identification


Editorial acknowledgement

Support for third-party writing assistance was provided by Tracy McNally, PhD and Holly Strausbaugh, PhD (Twist Medical, Burlingame, CA, USA), funded by F. Hoffmann-La Roche.

Legal entity responsible for the study

F. Hoffmann-La Roche.


F. Hoffmann-La Roche.


O. Metzger: Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses: AbbVie; Advisory/Consultancy, Research grant/Funding (institution): G1 Therapeutics; Research grant/Funding (institution): Roche; Research grant/Funding (institution), Non-remunerated activity/ies, Co-chair Advisory Board: Pfizer. C. Lambertini: Full/Part-time employment: F. Hoffmann - La Roche Ltd. I.E. Krop: Honoraria (self), Research grant/Funding (institution): Genentech/Roche; Research grant/Funding (institution): Pfizer; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Daiichi Sankyo; Honoraria (self): Macrogenics; Honoraria (self): Seattle Genetics; Honoraria (self): Celltrion; Honoraria (self): Merck; Honoraria (self): Novartis; Honoraria (self): AstraZeneca; Honoraria (self): Context Therapeutics. G. Lewis Phillips: Full/Part-time employment: Genentech, Inc; Shareholder/Stockholder/Stock options: F. Hoffmann - La Roche Ltd. C.M. Perou: Advisory/Consultancy, Leadership role, Shareholder/Stockholder/Stock options, Licensing/Royalties: Bioclassifier LLC; Advisory/Consultancy, Shareholder/Stockholder/Stock options, Licensing/Royalties, Officer/Board of Directors: GeneCentric Therapeutics. F. Symmans: Shareholder/Stockholder/Stock options, Licensing/Royalties, Founder shares, licensed intellectual property: Delphi Diagnostics; Shareholder/Stockholder/Stock options: IONIS Pharmaceuticals; Shareholder/Stockholder/Stock options: Eiger Pharmaceuticals. I. Melero: Honoraria (self), Research grant/Funding (institution): Roche/Genentech; Honoraria (self), Research grant/Funding (institution): BMS; Honoraria (self), Research grant/Funding (institution): AstraZeneca; Honoraria (self): Alligator Bioscience; Honoraria (self): Bayer; Honoraria (self): Tusk Therapeutics; Honoraria (self): Gossamer Bio; Honoraria (self): Amunix; Honoraria (self): Replimune; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Medincell; Honoraria (self): Monopteros Therapeutics; Honoraria (self): Molecular Partners; Honoraria (self): Biontech; Honoraria (self): PharmaMar. N. Harbeck: Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony: Pierre Fabre; Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony: Roche. E.P. Winer: Research grant/Funding (institution): AstraZeneca; Honoraria (self), Advisory/Consultancy: Carrick Therapeutics; Honoraria (self), Advisory/Consultancy: G1 Therapeutics; Honoraria (self), Research grant/Funding (institution): Genentech/Roche; Honoraria (self), Advisory/Consultancy: Genomic Health; Honoraria (self), Advisory/Consultancy: GSK; Honoraria (self), Advisory/Consultancy: Jounce; Honoraria (self), Advisory/Consultancy: Leap; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy: Novartis; Honoraria (self), Advisory/Consultancy: Seattle Genetics; Honoraria (self), Advisory/Consultancy: Syros; Honoraria (self), Advisory/Consultancy: Zymeworks. S-A. Im: Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: AstraZeneca; Honoraria (self), Advisory/Consultancy: Amgen; Honoraria (self), Advisory/Consultancy: Eisai; Honoraria (self), Advisory/Consultancy: Hanmi; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Novartis; Advisory/Consultancy: MSD; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Pfizer; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Roche; Non-remunerated activity/ies, Investigational agent for trial: Dae Woong. C.H. Barrios: Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Pfizer; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Novartis; Research grant/Funding (institution): Amgen; Honoraria (self), Advisory/Consultancy, Research grant/Funding (self): AstraZeneca; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Boehringer Ingelheim; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): GlaxoSmithKline; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution): Roche/Genentech; Research grant/Funding (institution): Lilly; Research grant/Funding (institution): Sanofi; Research grant/Funding (institution): Taiho Pharmaceutical; Research grant/Funding (institution): Mylan; Research grant/Funding (institution): Merrimack; Honoraria (self), Advisory/Consultancy: MSD; Honoraria (self), Advisory/Consultancy: Bayer; Research grant/Funding (institution): Astellas Pharma; Honoraria (self), Advisory/Consultancy: Eisai; Research grant/Funding (institution): Bristol-Myers Squibb; Research grant/Funding (institution): Daiichi Sankyo; Research grant/Funding (institution): Abraxis Biosciences, BioMarin, LEO Pharma, AbbVie, Merck, and Millennium; Research grant/Funding (institution): AB Science, Asana Biosciences, Medivation, Exelixis, and Imclone Systems. H. Bonnefoi: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Non-remunerated activity/ies: Daiichi. J.R. Gralow: Honoraria (self): Genentech/Roche; Honoraria (self): Pfizer; Honoraria (self): Puma; Honoraria (self): AstraZeneca; Honoraria (self): Immunomedics; Honoraria (self): Genomic Health; Honoraria (self): Novartis; Honoraria (self): Sandoz/Hexal; Honoraria (self): Radius; Honoraria (self): Inbiomotion. L. Gianni: Advisory/Consultancy: Hexal Sandoz; Advisory/Consultancy: Seattle Genomics; Advisory/Consultancy: Synthon; Honoraria (self), Advisory/Consultancy: Zymeworks; Advisory/Consultancy: Sanofi-Aventis; Advisory/Consultancy: Forty Seven (CD47); Advisory/Consultancy: Genenta; Advisory/Consultancy: METIS Precision Medicine; Advisory/Consultancy: Novartis; Advisory/Consultancy: Odonate Therapeutics; Honoraria (self), Advisory/Consultancy: Revolution Medicine; Advisory/Consultancy: Synaffix; Advisory/Consultancy: Menarini Ricerche; Advisory/Consultancy: Amgen; Advisory/Consultancy: Biomedical Insights Inc.; Honoraria (self): Daiichi Sankyo; Licensing/Royalties, Co-inventor of European Patent Application N. 12195182.6 and 12196177.5 titled \"PDL-1 expression in anti-HER2 therapy\": Roche. M. Toi: Honoraria (self), Speaker Bureau/Expert testimony, Research grant/Funding (institution): Chugai, Takeda, Pfizer, Taiho, Eisai, AstraZeneca, Shimadzo, Yakult, Nippon Kayaku; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (self): Kyowa-Kirin, Daiichi Sankyo; Research grant/Funding (institution): Astellas, AFI Technologies, JBCRG Association, Astehnologies, Luxonos, Shionogi, GL Science; Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony: Eli Lilly; Honoraria (self), Speaker Bureau/Expert testimony: MSD, Exact Science, Novartis; Honoraria (self), Advisory/Consultancy: Konica Minolta, BMS; Advisory/Consultancy: Athenex Oncology, Bertis, Terumo, Kansai Medical Net. S.M. Swain: Honoraria (self), Advisory/Consultancy: AstraZeneca; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Daiichi Sankyo; Honoraria (self), Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses, support for third party medical writing: Roche/Genentech; Honoraria (self), Advisory/Consultancy: Exact Sciences (Genomic Health); Honoraria (self), Advisory/Consultancy: Molecular Templates; Honoraria (self), Advisory/Consultancy: Silverback Therapeutics; Honoraria (self), Advisory/Consultancy: Tocagen; Honoraria (self), Advisory/Consultancy, Travel/Accommodation/Expenses: Eli Lilly; Honoraria (self), Advisory/Consultancy: Natera; Honoraria (self), Advisory/Consultancy: Athenex; Honoraria (self), Advisory/Consultancy: Bejing Medical Foundation; Research grant/Funding (institution): Kailos Genetics; Travel/Accommodation/Expenses: Bristol-Myers Squibb; Travel/Accommodation/Expenses: Caris Life Sciences; Advisory/Consultancy, Scientific Advisory Board: Inivata. T. Boulet: Full/Part-time employment, Employee from Parexel International GmbH contracted by Roche for Statistical services: F. Hoffmann-La Roche Ltd. C. Song: Shareholder/Stockholder/Stock options, Full/Part-time employment: Roche/Genentech. S. de Haas: Shareholder/Stockholder/Stock options, Full/Part-time employment: F. Hoffmann-La Roche Ltd. All other authors have declared no conflicts of interest.

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