Clinical trialNCT06876714RecruitingPhase 3Interventional

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

SponsorAlliance for Clinical Trials in OncologyEnrollment1,524Anatomic Stage I Breast Cancer AJCC v8Anatomic Stage II Breast Cancer AJCC v8Early Stage HER2+ Breast Cancer

View the registry record on ClinicalTrials.gov

Summary

The lay summary the sponsor registered on ClinicalTrials.gov.

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.

clinicaltrials.gov ↗

Investigators

The overall officials registered on this study. Names that resolve to a findmyKOL profile link to it; the rest are shown as registered.

Adrienne Waks, MD
Alliance for Clinical Trials in Oncology
Study Chair
clinicaltrials.gov ↗

A profile link is shown only when the registered name resolves to a person record with a confident, namesake-checked match; ambiguous names stay unlinked.

Sites

684 registered facilities, with the per-site recruitment status where the registry publishes one. ClinicalTrials.gov does not publish per-site enrollment counts.

Puerto Rico

Doctors Cancer Center
Manati, Puerto Rico
Luis J. Santos Reyes
Recruiting
Centro Comprensivo de Cancer de Upr
San Juan, Puerto Rico
Luis J. Santos Reyes
Recruiting
Proncology
San Juan, Puerto Rico
Luis J. Santos Reyes
Recruiting
San Juan City Hospital
San Juan, Puerto Rico
Luis J. Santos Reyes
Recruiting

United States

Cancer Center at Saint Joseph'S
Phoenix, Arizona, United States
Suspended
Mayo Clinic Hospital in Arizona
Phoenix, Arizona, United States
Saranya Chumsri
Recruiting
Mercy Hospital Fort Smith
Fort Smith, Arkansas, United States
Suspended
Nea Baptist Memorial Hospital and Fowler Family Cancer Center - Jonesboro
Jonesboro, Arkansas, United States
Elizabeth John
Recruiting
Carti Cancer Center
Little Rock, Arkansas, United States
Suspended
Mission Hope Medical Oncology - Arroyo Grande
Arroyo Grande, California, United States
Suspended
Tower Cancer Research Foundation
Beverly Hills, California, United States
Karissa Britten
Recruiting
Mercy Cancer Center - Carmichael
Carmichael, California, United States
Shahzad Siddique
Recruiting
Mercy San Juan Medical Center
Carmichael, California, United States
Shahzad Siddique
Recruiting
Enloe Medical Center
Chico, California, United States
Helen K. Chew
Recruiting
Kaiser Permanente Dublin
Dublin, California, United States
Alice T. Kengla
Recruiting
Mercy Cancer Center - Elk Grove
Elk Grove, California, United States
Shahzad Siddique
Recruiting
Stanford Cancer Center Emeryville
Emeryville, California, United States
Amina Chaudhry
Recruiting
Kaiser Permanente-Fremont
Fremont, California, United States
Alice T. Kengla
Recruiting
Washington Health
Fremont, California, United States
Bogdan S. Eftimie
Recruiting
Kaiser Permanente Fresno Orchard Plaza
Fresno, California, United States
Alice T. Kengla
Recruiting
Uci Health - Chao Family Comprehensive Cancer Center and Ambulatory Care
Irvine, California, United States
Sayeh M. Lavasani
Recruiting
Uc San Diego Moores Cancer Center
La Jolla, California, United States
Kay T. Yeung
Recruiting
Loma Linda University Medical Center
Loma Linda, California, United States
Gayathri Nagaraj
Recruiting
Fremont - Rideout Cancer Center
Marysville, California, United States
Helen K. Chew
Recruiting
Mercy Cancer Center
Merced, California, United States
Suspended
Kaiser Permanente- Modesto Mob Ii
Modesto, California, United States
Alice T. Kengla
Recruiting
Kaiser Permanente-Modesto
Modesto, California, United States
Alice T. Kengla
Recruiting
Kaiser Permanente-Oakland
Oakland, California, United States
Alice T. Kengla
Recruiting
Uc Irvine Health/chao Family Comprehensive Cancer Center
Orange, California, United States
Sayeh M. Lavasani
Recruiting
Stanford Cancer Institute Palo Alto
Palo Alto, California, United States
Amina Chaudhry
Recruiting
Huntington Memorial Hospital
Pasadena, California, United States
Karissa Britten
Recruiting
Eisenhower Medical Center
Rancho Mirage, California, United States
Manasa Vulchi
Recruiting
Mercy Cancer Center - Rocklin
Rocklin, California, United States
Shahzad Siddique
Recruiting
Kaiser Permanente-Roseville
Roseville, California, United States
Alice T. Kengla
Recruiting
Kaiser Permanente Downtown Commons
Sacramento, California, United States
Alice T. Kengla
Recruiting
Kaiser Permanente-South Sacramento
Sacramento, California, United States
Alice T. Kengla
Recruiting
Mercy Cancer Center - Sacramento
Sacramento, California, United States
Shahzad Siddique
Recruiting
University of California Davis Comprehensive Cancer Center
Sacramento, California, United States
Helen K. Chew
Recruiting
Uc San Diego Medical Center - Hillcrest
San Diego, California, United States
Kay T. Yeung
Recruiting
Kaiser Permanente-San Francisco
San Francisco, California, United States
Alice T. Kengla
Recruiting

644 more sites on the registry record.ClinicalTrials.gov ↗

Site investigator names are published by ClinicalTrials.gov only while a study recruits, so completed studies list sites without them.

Drugs studied

The drug and biological interventions registered on this study, normalized to their RxNorm ingredient where possible.

Pertuzumab →Trastuzumab →

Linked drugs open the directory filtered to KOLs working with them.clinicaltrials.gov ↗

Registration & key dates

Registry attributes as recorded on the ClinicalTrials.gov study record.

Start: 17 Sept 2025
Primary completion: 13 Mar 2028
Completion: 13 Mar 2037
Last update posted: 5 Aug 2026
Registered enrollment: 1,524
Registry id: NCT06876714

clinicaltrials.gov ↗

Source: ClinicalTrials.gov, via the CTTI AACT database, data as of 24 Aug 2026. Registry facts are shown as registered by the study sponsor; findmyKOL does not interpret them.