Inclusion Criteria:

          -  Patients must give voluntary written consent before performance of any study related
             procedures not part of standard medical care

          -  Diagnosis of MDS or MDS/MPN according to 2016 WHO criteria12

          -  Primary therapy failure with either hypomethylating agents (decitabine or azacitidine)
             defined as:

          -  Progression (according to 2006 IWG criteria)13 after initiation of azacitidine or
             decitabine treatment; or

          -  Failure to achieve complete or partial response or hematological improvement
             (according to 2006 IWG)13 after at least 4-6 cycles (4-weeks cycle) of azacitidine or
             decitabine; or

          -  Relapse after initial complete or partial response or hematological improvement
             (according to 2006 IWG criteria)13 observed after at least 4 cycles of azacitidine or
             decitabine.

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status < 2

          -  Subjects must have normal organ and marrow function defined as:

          -  If total bilirubin < 2x upper limit of normal (</= 3 x ULN if considered to be due to
             leukemic involvement or Gilbert's syndrome) at the discretion of the treating
             physician following discussion with PI)

          -  Calculated creatinine clearance value of > 30ml/min AND a serum creatinine < 1.5mg/dL

          -  LVEF >/= 50%

          -  Female patients who:

          -  Are postmenopausal for at least 1 year before the screening visit, OR

          -  Are surgically sterile, OR

          -  Agree to practice true abstinence from heterosexual contact or agree to use effective
             contraception without interruption during the study therapy and 90 days after the last
             dose

          -  Male patients who:

          -  Are surgically sterile, OR

          -  Agree to practice true abstinence from heterosexual contact or agree to use effective
             contraception without interruption during the study therapy and 90 days after the last
             dose

        Exclusion Criteria:

          -  Prior treatment with CPX-351, or known hypersensitivity to CPX-351 or its components.

          -  Prior treatment with intensive chemotherapy.

          -  Any serious medical condition, laboratory abnormality, or psychiatric illness that, in
             the view of the treating physician, would place the participant at an unacceptable
             risk if he or she were to participate in the study or would prevent that person from
             giving informed consent.

          -  Any active malignancy (unrelated, non-hematological malignancy) diagnosed within the
             past 6 months of starting the study drug (other than curatively treated
             carcinoma-in-situ of the cervix or non-melanoma skin cancer).

          -  Patients with 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.

          -  Known history of HIV or active hepatitis B or C.

          -  Major surgery within 2 weeks prior to study enrollment.

          -  Pregnant or lactating females

          -  Male and female patients who are fertile who do not agree to use an effective barrier
             methods of birth control (i.e. abstinence or 2 forms of contraception) to avoid
             pregnancy while receiving study treatment.