ATEMPT 2.0: Adjuvant T-DM1 vs TH

Required: HER2 (ERBB2) amplification (HER2-positive by ASCO CAP 2018 guidelines, confirmed by central testing)

HER2-positive by ASCO CAP 2018 guidelines, confirmed by central testing. NOTE: HER-2 status must be confirmed to be positive by central review by NeoGenomics prior to patient starting protocol therapy.

Must have received: hormonal therapy (tamoxifen) — adjuvant

Patients may have received up to 4 weeks of tamoxifen therapy, or other hormonal therapy, for adjuvant therapy for this cancer.

Must have received: oophorectomy — cancer prevention

Prior oophorectomy for cancer prevention is allowed.

Must have received: partial breast radiation — prior to registration

Patients who have undergone partial breast radiation (duration ≤ 14 days) prior to registration are eligible. Partial breast radiation must be completed prior to 2 weeks before starting protocol therapy.

Must have received: investigational agent (window study) — prior to surgery for ≤ 2 weeks

Patients who have participated in a window study (treatment with an investigational agent prior to surgery for ≤ 2 weeks) are eligible. Patients must have discontinued the investigational agent at least 14 days before participation.

Cannot have received: chemotherapy

History of prior chemotherapy in the past 5 years.

Cannot have received: taxane (paclitaxel)

History of paclitaxel therapy

Cannot have received: whole breast radiation

Patients who have undergone whole breast radiation are not eligible.