EndoPredict® Extended Endocrine Trial (EXET)

The EndoPredict® molecular test is validated to predict late distant recurrence after 5

years of endocrine therapy in women with estrogen receptor-positive (ER+), human

epidermal growth factor receptor 2-negative (HER2-) early stage breast cancer, with or

without treatment with adjuvant chemotherapy. The test provides an individualized EPclin

score based on the tumor gene expression, tumor size and nodal status, and categorizes

patients as High or Low risk of distant recurrence.

The primary objective of this study is to evaluate the distant recurrence-free survival

(DRFS) at 5-10 years in patients with ER+/HER2- early stage breast cancer with EPclin Low

scores that did not extend endocrine therapy.

Data collection is prospective and patient enrollment is expected to occur over 24

months. The study will enroll patients who are near the 5-year post-diagnosis time point

when decisions on extending endocrine therapy are being made. Patient breast cancer

tumors, stored from surgical collection after initial diagnosis, will be tested with

EndoPredict and a report generated. The provider will convey the report results to the

patient and establish a treatment plan to continue or forgo endocrine therapy. Patients

will then be followed for 6 years with data collection every year, and outcomes (distant

and local disease recurrence, second primary breast cancer, etc.) recorded.

The associations between outcomes and treatment, EPclin score and risk category, EP

molecular score, and clinicopathologic features will be investigated in all patients and

in subpopulations (node negative, node positive, treated with or without chemotherapy,

etc.).