Inclusion Criteria:

          1. Diagnosis of:

               -  Relapsed or refractory AML (refractory to a standard anthracycline-based
                  induction regimen or a hypomethylating agent for patients unfit for intensive
                  chemotherapy or for whom no standard or curative therapy exists),

               -  ALL,

               -  Acute biphenotypic leukemia (assigned to the appropriate group by the treating
                  physician by documented analysis of relevant laboratory values and
                  pathology/cytogenetics),

               -  Advanced MDS defined as ≥5% bone marrow blasts or ≥2% blasts in the peripheral
                  blood (including patients who have progressed following treatment with
                  hypomethylating agents),

               -  Advanced MPN (excluding patients with ET, PV, or low risk MF), and MDS/MPN
                  overlap syndrome with ≥5% bone marrow blasts or ≥2% blasts in the peripheral
                  blood, or

               -  Advanced CML after failure/progression of at least 3 prior TKIs

          2. Age ≥18 years

          3. No prior antineoplastic drug therapy for at least 14 days, with the exception of
             hydroxyurea, prior to starting OTS167. Patients with rapidly proliferative disease may
             continue to receive hydroxyurea

          4. Patients refractory to all approved therapies or for which no approved or conventional
             therapies are available

          5. Patients with a diagnosis of advanced CML must have been treated with 3 prior TKIs,
             and the last therapy must have been discontinued at least 14 days prior to starting
             OTS167

          6. Adequate organ function as defined below:

               -  Liver function (total bilirubin <2 mg/dL and aspartate aminotransferase and/or
                  alanine aminotransferase <3 × upper limit of normal (ULN) or <5 × ULN if related
                  to leukemic involvement)

               -  Renal function (creatinine <1.5 × ULN)

          7. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2

          8. Negative urine pregnancy test within 1 week prior to Cycle 1 Day 1 for each woman of
             childbearing potential

          9. Able to understand the potential risks, benefits, and requirements of the study and
             are willing to provide informed consent; an informed consent form (ICF) for this study
             that is signed by the patient or his/her legally authorized representative is required
             prior to enrollment

        Exclusion Criteria:

          1. Pregnant or breastfeeding patients (pregnant and breastfeeding women are excluded from
             this study because the agents used in this study may have unknown or unrecognized
             potential for teratogenic or abortifacient effects). Patients of childbearing
             potential must consent and agree to practice documented (type) adequate contraception
             during the course of on study treatment.

          2. Evidence of any form of active, uncontrolled, bacterial, viral (including hepatitis A,
             B, or C or known human immunodeficiency virus [HIV] seropositivity), or fungal
             infection. Patients who are positive for hepatitis B core antibody, hepatitis B
             surface antigen, or hepatitis C antibody must have a negative polymerase chain
             reaction (PCR) result before enrollment; those who are PCR-positive will be excluded.
             Evidence of congestive heart failure (New York Heart Association Class III or IV);
             myocardial infarction or stroke within 6 months; unstable angina; uncontrolled or
             unstable/medically important cardiac arrhythmia; prolonged QT interval corrected for
             heart rate (QTc) >450 msec (males) or >470 msec (females); uncontrolled epilepsy;
             uncontrolled bleeding; recent major surgical procedures within 30 days before Cycle 1
             Day 1 without full recovery from the same; or any other serious comorbid medical
             condition that would preclude investigational study treatment

          3. Any psychiatric illness/social situations that would limit compliance with study
             requirements

          4. Documented hypersensitivity to any of the components of OTS167 or supportive care
             medicaments

          5. Central nervous system (CNS) leukemia

          6. MPN patients with ET, PV, or low risk MF

          7. Women of childbearing potential and men must agree prior to study entry to use
             appropriate contraception for the duration of study participation and until 30 days
             after receipt of the last dose of study drug

          8. Documented concurrent malignancy. Exceptions include cervical carcinoma in-situ,
             non-melanoma skin cancer (basal and squamous cell carcinoma), localized prostate
             cancer (Gleason score <6), and resected melanoma-in-situ. Other localized solid tumors
             in situ and other low risk cancers may also be exempt after discussion with the
             Sponsor Medical Monitor.