A study to look at whether atezolizumab taken with trastuzumab emtansine works in people with early breast cancer who have already had chemotherapy and surgery and how safe this medicine is

A PHASE III, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED CLINICAL TRIAL TO EVALUATE THE EFFICACY AND SAFETY OF ADJUVANT ATEZOLIZUMAB OR PLACEBO AND TRASTUZUMAB EMTANSINE FOR HER2-POSITIVE BREAST CANCER AT HIGH RISK OF RECURRENCE FOLLOWING PREOPERATIVE THERAPY.

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

CTRI

Registry ID

CTRI/2021/08/035911

Enrollment

1150

Registered

2021-08-25

Start date

Unknown

Completion date

Unknown

Last updated

2026-01-12

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Health Condition 1: C509- Malignant neoplasm of breast of unspecified site

Interventions

Intervention1: Atezolizumab 1200 mg: IV Q3W for 14 cycles Intervention2: Trastuzumab emtansine 3.6 mg/kg: IV Q3W for 14 cycles Control Intervention1: Atezolizumab placebo 1200 mg: IV Q3W for 14 cycles

Eligibility

Inclusion criteria

Inclusion criteria: Signed Informed Consent Form Histologically confirmed invasive breast carcinoma Diagnosis of HER2-positive breast cancer with assessment of hormone receptor and PD-L1 status Clinical Stage cT4/anyN/M0, any cT/N2–3/M0, or cT1-3/N0-1/M0 Patients with cT1 3/N0 1/M0 disease at presentation (patients with cT1mi/T1a/T1b/N0 are not eligible) must have pathologic evidence of residual invasive carcinoma in axillary lymph node(s) at surgery (with or without residual invasive disease in the breast) positive axillary nodal residual disease (ypN0-1) is only mandatory in patients with cT1 3/N0 1/M0 disease. Randomization may be performed within 7 days of the 12 weeks in case of delay to meet eligibility criteria. Non-hormonal contraceptive methods with a failure rate of

Exclusion criteria

Exclusion criteria: Stage IV (metastatic) breast cancer Inadequate excision Prior treatment with trastuzumab emtansine or atezolizumab Active tuberculosis

Design outcomes

Primary

Measure	Time frame
IDFS, evaluate the efficacy of atezolizumab when given in combination with trastuzumab emtansine compared with placebo and trastuzumab emtansine in the Full Analysis Set (FAS) IDFSTimepoint: 63 months from FPI	—

Secondary

Measure	Time frame
IDFS including second primary non-breast invasive cancer, efficacy of atezolizumab when given in combination with trastuzumab emtansine compared with placebo & trastuzumab emtansineTimepoint: 63 months from FPI	—

Countries

Australia, Austria, Belgium, Brazil, Bulgaria, China, Czech Republic, Denmark, France, Germany, Greece, Hong Kong, Hungary, India, Italy, Mexico, New Zealand, Poland, Portugal, Republic of Korea, Romania, Russian Federation, Singapore, Spain, Taiwan, Thailand, Turkey, Ukraine, United Kingdom, United States of America

Contacts

Public ContactRashmin Shukla

Roche Products (India) Pvt. Ltd.

jyotii.poddaar@roche.com9136064373

Outcome results

None listed

Source: CTRI (via WHO ICTRP) · Data processed: Feb 4, 2026