A Study of LY2523355 in Participants With Breast Cancer

Inclusion Criteria:

- Have histologic or cytologic diagnosis of metastatic or locally recurrent breast
cancer that is not amenable to therapy given with curative intent.

- Have measurable disease defined by Response Evaluation Criteria In Solid Tumors
(RECIST) 1.1 guidelines.

- Have received 2 or more prior standard cytotoxic chemotherapy regimens for metastatic
breast cancer and be, in the opinion of the investigator, an appropriate candidate for
experimental therapy. Regimens received in the neoadjuvant or adjuvant setting are not
counted as prior regimens.

- Have received a prior taxane in the neoadjuvant, adjuvant, or metastatic setting.

- Have recovered from the acute effects of prior chemotherapy, hormonal therapy, and
radiation prior to study enrollment.

- Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG)
scale.

- Have adequate organ function.

Exclusion Criteria:

- Have Common Terminology Criteria for Adverse Events (CTCAE) Grade 2 or greater
(moderate or worse) peripheral neuropathy

- Have a second primary malignancy.

- Have symptomatic, untreated, or uncontrolled central nervous system metastases.

- Have received autologous stem cell transplant following high-dose chemotherapy.

- Have serious preexisting medical conditions that in the opinion of the investigator
would preclude participation in this study.

- Have active symptomatic fungal, bacterial, and/or known viral infection including
active human immunodeficiency virus (HIV) or viral hepatitis.

- Have previously received LY2523355 in another study investigating this agent or
therapy with ixabepilone or an ixabepilone-containing regimen.

- Have a history of radiation therapy involving more than 25 percent of the bone marrow.

- Have a Fridericia corrected QT (QTcF) interval of >470 milliseconds (msec) on
screening electrocardiogram (ECG).

- Have QRS widening of >120 msec on screening ECG.

- Cannot change or stop taking a strong Cytochrome P450 3A4 (CYP3A4) inhibitor or CYP3A4
inducer per the ixabepilone label.

- Have hypersensitivity to drugs formulated with Cremophor® EL per the ixabepilone
label.