Durvalumab With Trastuzumab and Pertuzumab in HER2-Enriched Breast Cancer

The purpose of this research study is to test the safety and effectiveness of using
durvalumab with trastuzumab and pertuzumab in participants with HER2-enriched breast cancer.
The standard or usual pre-surgery treatment for this type of disease are drugs called
trastuzumab and pertuzumab that target HER2. Studies have shown that trastuzumab and
pertuzumab treatment can stimulate the body's own immune system to attack cancer cells.
Durvalumab is a drug that also activates the immune system. The use of durvalumab together
with trastuzumab and pertuzumab treatment may allow the immune system to work harder to kill
cancer cells.

Inclusion Criteria:

1. Female aged >18 years at the time of study entry.

2. Histologically confirmed HER2-enriched (by BluePrint) and HER2-amplified (ERBB2 mRNA
>7.5-10) breast cancer.

3. Estrogen receptor and progesterone receptor negative.

4. Stage I or II disease.

5. Node-negative breast cancer according to the American Joint Committee on Cancer 7th
Edition.

6. T2 disease.

7. Bilateral breast cancers that individually meet eligibility criteria are allowed.

8. Eastern Cooperative Oncology Group performance status of 0 or 1.

9. Adequate organ and marrow function.

10. Baseline left ventricular ejection fraction greater than or equal to 50%, as measured
by multigated acquisition scan or echocardiogram.

11. Evidence of postmenopausal status or negative serum pregnancy test for premenopausal
patients. Negative serum beta-human chorionic gonadotropin pregnancy test within 7
days prior to the first dose of study treatment for premenopausal patients.

12. Willing to provide biopsy tissues as required by the study.

13. Willing and able to comply with the protocol for the duration of the study including
undergoing treatment and scheduled visits and examinations including follow-up.

Exclusion Criteria:

1. Participation in another clinical study with an investigational product within 28 days
prior to the first dose of study treatment.

2. Concurrent enrollment in another clinical study, unless it is an observational
(non-interventional) clinical study or during the follow-up period of an
interventional study.

3. Unresolved or unstable adverse events from prior administration of another
investigational drug.

4. Any concurrent chemotherapy, radiation therapy, immunotherapy, or biologic therapy for
cancer treatment.

5. Major surgical procedure (as defined by the investigator) within 28 days prior to the
first dose of study treatment.

6. History of allogenic organ transplantation.

7. Active or prior documented autoimmune or inflammatory disorders.

8. Uncontrolled intercurrent illness including but not limited to ongoing or active
infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable
angina pectoris, cardiac arrhythmia, interstitial lung disease, serious chronic
gastrointestinal conditions associated with diarrhea, or psychiatric illness/social
situations that would limit compliance with study requirements, substantially increase
the risk of incurring adverse events, or compromise the ability of the patient to give
written informed consent.

9. History of another primary malignancy except for: malignancy treated with curative
intent and with no known active disease for more than 5 years before the first dose of
study treatment and of low potential risk for recurrence.

10. History of active primary immunodeficiency.

11. Active infection including tuberculosis, hepatitis B, hepatitis C, or human
immunodeficiency virus.

12. Current or prior use of immunosuppressive medication within 14 days prior to the first
dose of study treatment.

13. Receipt of live attenuated vaccine within 30 days prior to the first dose of study
treatment.

14. Patients who are pregnant or breastfeeding or patients of reproductive potential who
are not willing to employ effective birth control from screening to 7 months after the
last dose of study treatment.

15. Known allergy or hypersensitivity to any of the study drugs or any of the study drug
excipients.