Breast Cancer—Local/Regional/Adjuvant

Oncoletter provides you with quotes from the abstract's conclusions. To see more, go the ASCO Meeting Library while clicking on the link of the study-titles (to see videos and slides needs a payable registration)

500 Primary analysis of KAITLIN: A phase III study of trastuzumab emtansine (T-DM1) + pertuzumab versus trastuzumab + pertuzumab + taxane, after anthracyclines as adjuvant therapy for high-risk HER2-positive early breast cancer (EBC).

Nadia Harbeck, Seock-Ah Im, Carlos H. Barrios, et al.

The abstract concludes: Replacing adjuvant taxane and trastuzumab with T-DM1 did not result in significantly improved efficacy or overall safety. Nonetheless, in this high-risk population, a favorable IDFS outcome was achieved in both study arms. HP + chemotherapy remains the standard of care for patients with high-risk HER2-positive EBC. Clinical trial information: NCT01966471.

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501 Three-year follow-up of neoadjuvant chemotherapy with or without anthracyclines in the presence of dual HER2-blockade for HER2-positive breast cancer (TRAIN-2): A randomized phase III trial.

Anna van der Voort, Mette S. van Ramshorst, Erik D. van Werkhoven, et al

The abstract concludes: The 3-year follow-up of the TRAIN-2 study confirms the results of the primary outcome that anthracylines do not improve efficacy and are associated with clinically relevant toxicity. A neoadjuvant carboplatin-taxane based regimen with dual HER2-blockade can be considered in all stage II-III breast cancer patients, regardless of hormone receptor and nodal status. Clinical trial information: NCT01996267.

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502 Biomarker data from KATHERINE: A phase III study of adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab (H) in patients with residual invasive disease after neoadjuvant therapy for HER2-positive breast cancer.

Carsten Denkert, Chiara Lambertini, Peter A. Fasching, et al.

The abstract concludes: These exploratory analyses provide the first data on the relationship between biomarker expression in residual disease after HER2-targeted therapy and outcomes. PIK3CA mut status did not influence outcomes with H or T-DM1. T-DM1 benefit appeared to be independent of all biomarkers assessed. Clinical trial information: NCT01772472.

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503 Chemotherapy (CT) de-escalation using an FDG-PET/CT (F-PET) and pathological response-adapted strategy in HER2[+] early breast cancer (EBC): PHERGain Trial.

Javier Cortes, Geraldine Gebhart, Manuel Ruiz Borrego, et al.

The abstract concludes: F-PET identify pts with HER2[+] EBC who are more likely to benefit from CT-free dual HER2-blockade with HP. Follow-up is ongoing for iDFS endpoint. Depending on the results of this second co-primary endpoint, this strategy could select a group of HER2[+] EBC pts who would not need CT. Clinical trial information: NCT03161353.

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504 ALTERNATE:  Neoadjuvant endocrine treatment (NET) approaches for clinical stage II or III estrogen receptor-positive HER2-negative breast cancer (ER+ HER2- BC) in postmenopausal (PM) women: Alliance A011106.

Cynthia X. Ma, Vera J. Suman, A. Marilyn Leitch, et al.

The abstract concludes: Neither F nor F+A significantly improved ESDR compared to A alone in PM pts with locally advanced ER+ HER2- BC. RFS data are awaited. Support: U10CA180821, U10CA180882, U24CA196171, https://acknowledgments.alliancefound.org; NCI BIQSFP, BCRF, Genentech, AstraZeneca. Clinical trial information: NCT01953588.

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505 Letrozole + ribociclib versus letrozole + placebo as neoadjuvant therapy for ER+ breast cancer (FELINE trial).

Qamar J. Khan, Anne O'Dea, Aditya Bardia, et al.

The abstract concludes: Addition of R to L as NET did not result in more women with a PEPI score of 0. At D14C1 twice as many women on L+R had CCCA compared to L+P (92% vs 52%). However, significantly more women on L+R had increased proliferation between D14C1 and surgery, resulting in similar CCCA at surgery. Correlative studies are being performed to determine mechanisms of on-therapy acquired resistance to ribociclib. Continuous and intermittent doses of R have similar efficacy, toxicity. Clinical trial information: NCT02712723.

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506 MINDACT: Long-term results of the large prospective trial testing the 70-gene signature MammaPrint as guidance for adjuvant chemotherapy in breast cancer patients.

Fatima Cardoso, Laura van 't Veer, Coralie Poncet, et al.

The abstract concludes: The primary DMFS endpoint at 5 years continues to be met in CT untreated C-High / G-Low risk women, confirming MINDACT as a positive de-escalation study. With longer follow-up and in line with the natural history of luminal breast cancer, more distant relapses do occur but the estimated gain of 2.6% for CT administration in C-High / G-Low patients remains small in light of CT harmful effects. The level IA evidence for the clinical utility of the 70-gene signature for adjuvant CT decision making is maintained. Clinical trial information: NCT00433589.

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507 Phase III trial of metronomic capecitabine maintenance after standard treatment in operable triple-negative breast cancer (SYSUCC-001).

XI Wang, Shu-Sen Wang, Heng Huang, et al.

The abstract concludes: Maintenance therapy with metronomic capecitabine for one year following standard treatment significantly improved DFS in operable TNBC, which was safe and well tolerated. (SYSUCC-001, Clinical trial information: NCT01112826.

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508 Primary results of NRG Oncology / NSABP B-43: Phase III trial comparing concurrent trastuzumab (T) and radiation therapy (RT) with RT alone for women with HER2-positive ductal carcinoma in situ (DCIS) after lumpectomy.

Melody A. Cobleigh, Stewart J. Anderson, Kalliopi P. Siziopikou, et al.

The abstract concludes: The addition of T to RT did not achieve the protocol objective of 36% reduction in the IBTR rate but did achieve a modest, statistically non-significant reduction of 19%. Support: U10-180868, -180822, UG1-189867; Genentech. The authors thank Elaina Harper and Marlon Jones for data management. Clinical trial information: NCT00769379.