Inclusion Criteria:

          -  Histologically-confirmed, primary, invasive breast cancer diagnosed within 5 years of
             entry into a companion DTC screening protocol.

          -  Qualifying risk status, at diagnosis utilizing receptor testing by ASCO/CAP guidelines

          -  Patients must have completed all primary therapy for the index malignancy at least 4
             weeks prior to study entry. Prior treatment-related toxicity must be resolved or
             improving to Grade 1 with the exception of alopecia and up to Grade 3 peripheral
             neuropathy, prior to study enrollment. Concurrent receipt of adjuvant endocrine and
             bone modifying agents is allowed per standard of care guidelines. Tamoxifen is not
             allowed due to drug-drug interactions with HCQ.

          -  Bone marrow aspirate after completion of therapy demonstrates detectable DTCs (via
             IHC)

          -  No evidence of recurrent local or distant breast cancer by physical examination, blood
             tests or symptom-directed imaging, per NCCN guidelines.

          -  ECOG performance status =/< 2

          -  Ability to swallow oral medications

          -  No contraindications to the study medications or uncontrolled medical illness.

          -  Adequate bone marrow function

          -  Adequate liver function

          -  Adequate renal function

          -  Anticoagulation is allowed if target INR =/< 1.5 on a stable dose of warfarin or on a
             stable dose of anticoagulant for >2 weeks at time of randomization

          -  Ability to provide informed consent

        Exclusion Criteria

          -  Concurrent enrollment on another investigational therapy

          -  Prior treatment with a CDK 4/6 inhibitor

          -  Known hypersensitivity to hydroxychloroquine or any of its derivatives

          -  Patients with hormone-receptor positive breast cancer may not be receiving tamoxifen
             due to drug-drug interactions with hydroxychloroquine

          -  Patients who have received bone modifying agents within 3 months

          -  Patients who have any severe and/or uncontrolled medical conditions or other
             conditions that could affect their participation in the study

          -  Female patients who are pregnant or breast feeding, or adults of reproductive
             potential who are not using effective birth control methods.

          -  Women of childbearing potential must have a negative serum pregnancy test within 7
             days prior to the first dose of Abema