Inclusion Criteria:

- Patients must have histologically confirmed estrogen receptor (ER)/progesterone
receptor (PR)/human epidermal growth factor receptor 2 (HER2) negative carcinoma of
the breast that is metastatic or unresectable and for which standard curative or
palliative measures do not exist or are no longer effective; for purposes of this
study, triple negative disease will be tumors that have ER/PR < 10% and HER2 =< 1+ by
immunohistochemistry (IHC) or HER2 fluorescent in situ hybridization (FISH)
non-amplified (ratio < 2)

- Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of
0, 1 or 2

- Patients must have no more than two prior chemotherapy regimens for metastatic breast
cancer; in patients who develop disease recurrence within 6 months of adjuvant or
neoadjuvant chemotherapy, the adjuvant or neoadjuvant therapy will be considered one
prior regimen for metastatic disease

- ECOG performance status =< 2 (Karnofsky >= 60%)

- Life expectancy of greater than 3 months

- Absolute neutrophil count >= 1,500/mcL

- Platelets >= 100,000/mcL

- Total bilirubin within normal limits unless clinical diagnosis of Gilbert's syndrome

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
[SGOT])/alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase [SGPT])
=< 2.5 X institutional upper limit of normal

- Creatinine within normal institutional limits OR creatinine clearance >= 60
mL/min/1.73 m^2 for patients with creatinine levels above institutional normal

- Patients must be disease free of prior malignancy for >= 5 years with the exception
of curatively treated squamous cell carcinomas of the skin or carcinoma in situ of
the cervix or breast

- Must have at least one site of objective measurable or evaluable disease; baseline
measurements and evaluations must be obtained within 4 weeks of start of therapy

- Patients must have no history of prior therapy with dinaciclib

- Concurrent use of hormonal therapy is not permitted; concurrent radiation therapy is
not permitted; bisphosphonates are allowed, provided that they were started no less
than two weeks prior to initiating protocol therapy

- Patients must have completed and recovered from the effects of prior chemotherapy (=<
grade 2 toxicity) excluding alopecia

- Women of child-bearing potential and men must agree to use adequate contraception
(barrier method of birth control; abstinence) prior to study entry and for the
duration of study participation; should a woman become pregnant or suspect she is
pregnant while she or her partner is participating in this study, she should inform
her treating physician immediately; men treated or enrolled on this protocol must
also agree to use adequate contraception prior to the study, for the duration of
study participation, and 4 months after completion of dinaciclib administration

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

Exclusion Criteria:

- Patients who have had chemotherapy or radiotherapy within 3 weeks (6 weeks for
nitrosoureas or mitomycin C) prior to entering the study or those who have not
recovered from adverse events

- Patients who are receiving any other investigational agents

- Patients with untreated brain metastases should be excluded from this clinical trial
because they may develop progressive neurologic dysfunction that would confound the
evaluation of neurologic and other adverse events

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition as epirubicin or dinaciclib

- Patients receiving any medications or substances that are inhibitors or inducers of
cytochrome P450 3A4/5 (CYP3A4/5) are ineligible

- 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

- Pregnant women are excluded from this study; breastfeeding should be discontinued if
the mother is treated with dinaciclib

- Human immunodeficiency virus (HIV)-positive patients on combination antiretroviral
therapy are ineligible

- Patients who have had prior organ allograft or require immunosuppressive therapy

- Patients who have received a cumulative dose of doxorubicin of greater than 360
mg/m^2 or epirubicin of greater than 600 mg/m^2; patients who have received > 240
mg/m^2 of doxorubicin or > 400 mg/m^2 of epirubicin should be advised to undergo
evaluation of left ventricular ejection fraction (LVEF) with echocardiogram or multi
gated acquisition scan (MUGA) prior to initiating therapy

- Patients with a history of New York Heart Association class 3 or 4 heart failure, or
history of myocardial infarction, unstable angina or cerebral vascular accident (CVA)
within 6 months of protocol registration

- LVEF < 50% by MUGA or echocardiogram (ECHO)

- Patients who have history of PR prolongation or atrioventricular (AV) block