Inclusion Criteria:

          1. Age ≥18 years old.

          2. Willing and able to give informed consent.

          3. Diagnosed with CML in chronic phase and have either the b3a2 (e14a2) or b2a2 (e13a2)
             variants that give rise to the p210 BCR-ABL protein. Subtype classification whether
             b3a2 (e14a2) or b2a2 (e13a2) is not required for study eligibility.

          4. Must have a documented history of attempting only one prior imatinib discontinuation
             under the guidance of a treating physician.

          5. Must have met all the following criteria prior to first attempt to discontinue their
             imatinib:

               -  Stable molecular response (MR4; < 0.01% IS) for > 2 years, as documented on at
                  least four tests, performed at least three months apart (e.g. If a patient has
                  had >4 PCR tests performed during the two years leading up to their initial TKI
                  discontinuation, any value between 0.01 and 0.05% IS is considered a stable
                  result, however, at least four tests must be < 0.01% IS).

               -  Treatment with imatinib for a minimum of three years prior to discontinuing
                  imatinib.

          6. Must have relapsed (defined as loss of major molecular response (MMR), real-time
             quantitative polymerase chain reaction (RQ-PCR) for BCR-ABL >0.1% IS after first
             attempted imatinib discontinuation.

          7. After first failed TFR attempt, must have a minimum duration of one year of
             retreatment with imatinib (up to 400mg PO QD), and must plan to remain on imatinib for
             a minimum of 12 months during the combination treatment phase.

          8. Eastern Cooperative Oncology Group (ECOG) performance status 0-3.

          9. Must have a RQ-PCR for BCR-ABL < 0.0032% IS (MR4.5) reported by the trial designated
             central lab at the time of study enrollment.

         10. Female patients must meet one of the following:

               -  Postmenopausal for at least one year before the screening visit,

               -  Surgically sterile,

               -  If they are of childbearing potential, agree to practice two effective methods of
                  contraception from the time of signing of the informed consent form through 90
                  days after the last dose of study drug,

               -  Must also adhere to the guidelines of any treatment-specific pregnancy prevention
                  program, if applicable

               -  Agree to practice true abstinence when this is in line with the preferred and
                  usual lifestyle of the subject. (Periodic abstinence [e.g., calendar, ovulation,
                  symptothermal, postovulation methods] and withdrawal are not acceptable
                  contraception methods.)

         11. Male patients, even if surgically sterilized (i.e., status post vasectomy), must agree
             to one of the following:

               -  Practice effective barrier contraception during the entire study treatment period
                  and through 90 days after the last study drug dose,

               -  Must also adhere to the guidelines of any treatment-specific pregnancy prevention
                  program, if applicable,

               -  Agree to practice true abstinence when this is in line with the preferred and
                  usual lifestyle of the subject. (Periodic abstinence [e.g., calendar, ovulation,
                  symptothermal, postovulation methods] and withdrawal are not acceptable methods
                  of contraception.)

        Exclusion Criteria:

        A potential subject who meets any of the following exclusion criteria is ineligible to
        participate in the study.

          1. History of accelerated or blast phase CML.

          2. A second malignancy requiring active treatment.

          3. History of recent (within 12 months) acute pancreatitis or chronic pancreatitis

          4. Subjects who have previously received treatment with asciminib.

          5. Subjects with platelet (PLT) count < 100 × 109/L or an absolute neutrophil count (ANC)
             of < 1 × 109/L or hemoglobin < 8 g/dL.

          6. Aspartate aminotransferase (AST) and alanine transaminase (ALT) ≥3 times the
             institutional upper limit of normal.

          7. Creatinine ≥ 2 times the institutional upper limit of normal.

          8. Total bilirubin ≥ 1.5 times the institutional upper limit of normal (unless direct
             bilirubin is within normal limits).

          9. Lipase > institutional upper limit of normal.

         10. Pregnant or lactating.

         11. Unable to comply with lab appointment schedule and patient-reported outcome (PRO)
             assessments.

         12. Another investigational drug within four weeks of enrollment.

         13. Any serious medical or psychiatric illness that could, in the investigator's opinion,
             interfere with the completion of treatment according to this protocol.

         14. Patient has undergone a prior allogeneic stem cell transplant.

         15. Screening 12-lead ECG showing a baseline corrected QT interval >480msec (patients with
             a pacemaker will still be eligible with QTc>500msec).