OnCo
Congress digests· May 2026 · Munich

ESMO Breast Cancer 2026

Oral SERDs and PROTACs consolidated their place in ESR1-mutant disease, T-DXd de-escalation strategies matured in HER2+ early breast cancer, and the limits of giving one ADC straight after another became clearer.

  1. 01

    VERITAC-2 and the first PROTAC approval

    Vepdegestrant improved progression-free survival versus fulvestrant in ESR1-mutant ER+/HER2- advanced breast cancer, with no benefit in ESR1-wild-type disease; the FDA approved it in Q2 2026, the first PROTAC degrader to reach market.

    VERITAC-2VepdegestrantPROTACs & molecular glues (targeted protein degradation)Estrogen receptor (ERα)
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  2. 02

    PHERGain and neoCARHP: response-guided de-escalation in HER2+ disease

    Imaging- and pCR-guided strategies allow selected HER2+ patients to receive less chemotherapy; T-DXd-based de-escalation was a central discussion.

    Trastuzumab deruxtecanHER2-positive breast cancerPathologic complete response (pCR)DESTINY-Breast11
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  3. 03

    SATEEN / BRE-354: a second TOP1-payload ADC after the first is less effective

    Retrospective series showed limited efficacy when a second ADC was given immediately after progression on a prior ADC, prompting discussion of interposing chemotherapy between ADC courses.

    ADC sequencingCaution: TOP1 ADC immediately after TOP1 ADCPayload-class switching as the rule for ADC sequencingTrastuzumab deruxtecanSacituzumab govitecan
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  4. 04

    TROPION-Breast02 in frontline PD-L1-negative TNBC

    Datopotamab deruxtecan showed efficacy versus chemotherapy in first-line PD-L1-negative TNBC; the choice between Dato-DXd and sacituzumab govitecan was framed as patient-dependent (stomatitis and ocular events versus neutropenia and diarrhoea).

    TROPION-Breast02Datopotamab deruxtecanSacituzumab govitecanTriple-negative breast cancer (TNBC)
    Source
  5. 05

    HERTHENA-BC: HER3-DXd active across breast cancer subtypes

    Dose-expansion data for patritumab deruxtecan showed activity in HR+/HER2-, HER2+, and triple-negative breast cancer.

    Patritumab deruxtecanHER3Triple-negative breast cancer (TNBC)HR-positive / HER2-negative breast cancer
    Source
  6. 06

    PREcoopERA: ovarian suppression still needed with oral SERDs

    In premenopausal HR+ early breast cancer, ovarian function suppression remained essential even as oral endocrine agents advance.

    Endocrine therapy (SERMs, AIs, SERDs)HR-positive / HER2-negative breast cancer
    Source