A Window of Opportunity Study of Methionine Deprivation in Triple Negative Breast Cancer

Under the supervision of a registered dietitian, subjects will receive an individualized
dietary prescription that incorporates a methionine-free amino acid-modified medical food
(Hominex-2, Abbott Nutrition) supplemented with low-methionine foods. Hominex-2 contains a
mixture of L-amino acids but lacks methionine. Subjects will be instructed in the preparation
of Hominex-2 beverages (approximately 4-5 per day or per dietician recommendation) to deliver
100% of daily protein requirements (0.8 g/kg/day) and 40-45% of the caloric requirements. The
remaining calories will be met with low-methionine foods, including fruits, vegetables,
grains (e.g., specified cereal and bread), margarine and cooking oils. Subjects will be
provided with a list of foods that are low in methionine. Calories will not be restricted.
Subjects will be encouraged to follow their usual level of physical activity and instructed
to maintain a daily diet and exercise diary that will be reviewed weekly by the dietitian.

Inclusion Criteria:

- Participants must have histologically confirmed operable triple negative breast cancer

- ER (estrogen receptors) and PR (progesterone receptors) expression must be < 2%

- HER2 must negative as shown be either 0 or 1+ by immunohistochemistry (if 2+, in
situ hybridization method used to define HER2) OR by a HER2: 17 centromere signal
of <2.0 using a standard in situ hybridization method.

- No prior therapy for current breast cancer

- Operable breast cancer. Participants who are planned to undergo neo-adjuvant
chemotherapy are eligible as long as they consent to an additional breast biopsy
following the dietary intervention immediately prior to starting chemotherapy

- ECOG (Eastern Cooperative Oncology Group) performance status ≤1

- Ability to understand and the willingness to sign a written informed consent document

- Serum creatinine
- Non-pregnant. Women of childbearing potential must have a negative pregnancy test to
participate in this study

- Women of childbearing potential must agree to use effective contraceptives (as
discussed with their physician) while participating in this study

Exclusion Criteria:

- Patients who are receiving any other investigational agents

- Patients not able to swallow oral medications or with gastrointestinal conditions that
may impact absorption of oral medications

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements.