A Study of Alisertib in Combination With Endocrine Therapy in Patients With HR-positive, HER2-negative Recurrent or Metastatic Breast Cancer

Inclusion Criteria:

• Aged ≥18 years at signing of informed consent.

• Pathology-confirmed diagnosis of adenocarcinoma of the breast with evidence ofrecurrent or metastatic disease not amenable to curative therapy.

• Progression on or after treatment with at least two prior lines of endocrine therapyin the recurrent or metastatic setting. a. If metastatic disease recurrence occursduring or within six months of discontinuing adjuvant endocrine therapy, then thatendocrine therapy will count as one line of prior therapy.

• Participants must have received a CDK4/6i in combination with endocrine therapy inthe recurrent or metastatic setting.

• HR-positive and HER2-negative tumor status reported per local laboratory testing. HRand HER2 testing must be performed consistent with current American Society ofClinical Oncology/College of American Pathologists (ASCO/CAP) or European Society ofMedical Oncology (ESMO) guidelines:

Exclusion Criteria:

• Treatment with chemotherapy in the recurrent or metastatic setting.

• Prior treatment with an Aurora Kinase A (AURKA) specific-targeted orpan-Aurora-targeted agent, including alisertib, in any setting.

Note: There are additional inclusion and exclusion criteria. The study center will determine if you meet all of the criteria.