Ruxolitinib for Premalignant Breast Disease

Inclusion Criteria:

- Have a breast biopsy showing ADH (atypical ductal hyperplasia), ALH (atypical lobular
hyperplasia), LCIS (lobular carcinoma in situ), or DCIS (ductal carcinoma in situ)
requiring surgical excision.

- NOTE: Tissue from the diagnostic biopsy must be accessible/available for research
correlates (i.e., a tissue block or ~10 unstained slides). Due to the nature of
the study, fewer slides may be accepted with prior permission from the Protocol
Chair if there is insufficient tissue.

- Women and men age 18 and older.

- Adequate hematologic and organ function, defined as follows:

- Absolute neutrophil count ≥ 1500/mm3

- Hemoglobin ≥ 9.0 g/dL

- Platelet levels >200 x 109/L

- Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN)

- AST/ALT ≤ 2.5 x institutional ULN

- Alkaline phosphatase ≤ 5 x institutional ULN

- Creatinine clearance > 50 mL/min as calculated by the Cockroft-Gault method

- Willing to not use concomitant strong CYP3A4 inhibitors as this could interfere with
the metabolism of ruxolitinib (i.e azole antifungals, clarithromycin, conivaptan,
grapefruit juice, mibefradil, nefazodone, protease inhibitors, telithromycin).

- Women of child bearing potential must have a negative pregnancy test prior to starting
therapy. The effects of ruxolitinib on the developing human fetus are unknown. For
this reason and because class C agents are potentially teratogenic, women of
child-bearing potential and men must agree to use adequate contraception (hormonal or
barrier method of birth control; abstinence) prior to study entry and for the duration
of study participation.

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

Exclusion Criteria:

- Participants may not be receiving any other investigational agents within 30 days of
enrollment.

- Participants with current or previous history of invasive breast cancer.

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

- Pregnant or nursing women are excluded from this study

- HIV-positive participants on combination antiretroviral therapy are ineligible because
of the potential for pharmacokinetic interactions with ruxolitinib. Appropriate
studies will be undertaken in participants receiving combination antiretroviral
therapy when indicated.

- Prior or current treatment with a JAK inhibitor, for any indication.

- Known Hepatitis B or C participants