ShortStop-HER2: 12 Months vs. 6 Months of HER2-targeted Medications for People With HER2+ Breast Cancer Who Had a Pathologic Complete Response After Chemotherapy Plus Trastuzumab

Conditions

• Anatomic Stage I Breast Cancer AJCC v8
• Anatomic Stage II Breast Cancer AJCC v8
• Early Stage HER2+ Breast Cancer

Eligibility Criteria

Sex

ALL

Age

18 Years - N/A

Healthy Volunteers

Not accepted

Interventions

• Trastuzumab (Herceptin) — BIOLOGICAL
  Given IV or SC
• Pertuzumab — BIOLOGICAL
  Given IV or SC
• Echocardiography — PROCEDURE
  Undergo ECHO
• Multigated Acquisition Scan — PROCEDURE
  Undergo MUGA
• Mammography — PROCEDURE
  Undergo mammography
• Ultrasound — PROCEDURE
  Undergo ultrasound
• Magnetic Resonance Imaging — PROCEDURE
  Undergo MRI
• Biospecimen Collection — PROCEDURE
  Undergo blood and tissue sample collection
• Questionnaire Administration — OTHER
  Ancillary studies

Study Details

This phase III trial compares 6 months of human epidermal growth factor receptor 2 (HER2)-targeted therapy to 12 months of HER2-targeted therapy for the treatment of HER2-positive (+) breast cancer in patients that had a pathologic complete response (pCR) after preoperative (neoadjuvant) chemotherapy with trastuzumab. Trastuzumab and pertuzumab are monoclonal antibodies and forms of targeted therapy that attach to a receptor protein called HER2. HER2 is found on some cancer cells. When trastuzumab or pertuzumab attach to HER2, the signals that tell the cells to grow are blocked and the tumor cell may be marked for destruction by the body's immune system. Giving 6 months of HER2-targeted therapy may work better than giving 12 months for the treatment of HER2+ breast cancer in patients that had a pCR after neoadjuvant chemotherapy with trastuzumab.

Key Dates

Start date

Sep 17, 2025

Status verified

Jun 2026

Primary completion

Mar 13, 2028

Completion

Mar 13, 2037

Study Design

Enrollment

1,524 participants (estimated)

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Arms

• Active Comparator: Arm 1 (12-month adjuvant therapy)
  Patients receive trastuzumab IV or trastuzumab/hyaluronidase-oysk SC on day 1 of each cycle. Patients may also receive pertuzumab IV or hyaluronidase-zzxf/pertuzumab/trastuzumab SC, at the discretion of the treating investigator, on day 1 of each cycle. Cycles repeat every 21 days for up to 17 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo ECHO or MUGA as well as mammography, ultrasound, or MRI throughout the trial. Patients may also optionally undergo blood and tissue sample collection throughout the trial.
• Experimental: Arm 2 (6-month adjuvant therapy)
  Patients receive trastuzumab IV or trastuzumab/hyaluronidase-oysk SC on day 1 of each cycle. Patients may also receive pertuzumab IV or hyaluronidase-zzxf/pertuzumab/trastuzumab SC, at the discretion of the treating investigator, on day 1 of each cycle. Cycles repeat every 21 days for up to 9 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo ECHO or MUGA as well as mammography, ultrasound, or MRI throughout the trial. Patients may also optionally undergo blood and tissue sample collection throughout the trial.

Primary Outcome Measure

Recurrence-free survival (RFS) [ Time Frame: From randomization to invasive local, regional or distant breast cancer recurrence, or death from any cause prior to a documented disease recurrence, assessed up to 10 years ]

Central Contacts

• Jack Beranek
  773-702-9171
  [email protected]

Locations (652)