Inclusion Criteria:

        Subjects must satisfy the following criteria to be randomized in the study:

          1. Subject is ≥18 years of age at the time of signing the ICF.

          2. Subject has a diagnosis of PMF according to the 2016 World Health Organization (WHO)
             criteria or diagnosis of post-ET or post-PV MF according to the IWG-MRT 2007 criteria
             , confirmed by the most recent local pathology report.

          3. Subject is requiring RBC transfusions as defined as:

             a. Average RBC-transfusion frequency: 4 to 12 RBC units/12 weeks immediately up to
             randomization. There must be no interval > 6 weeks (42 days) without ≥ 1 RBC
             transfusion.

             b. RBC transfusions are scored in determining eligibility when given for treatment of:

             - Symptomatic (ie, fatigue or shortness of breath) anemia with a pretransfusion Hgb ≤
             9.5 g/dL or

               -  Asymptomatic anemia with a pretransfusion Hgb ≤ 7 g/dL c. RBC transfusions given
                  for worsening of anemia due to bleeding or infections are not scored in
                  determining eligibility.

          4. Subjects on continuous (eg, absent of dose interruptions lasting ≥ 2 consecutive
             weeks) JAK2 inhibitor therapy as approved in the country of the study site for the
             treatment for MPN-associated MF as part of their standard-of-care therapy for at least
             32 weeks, on stable daily dose for at least 16 weeks immediately up to the date of
             randomization and anticipated to be on a stable daily dose of that JAK2 inhibitor for
             at least 24 weeks after randomization.

          5. Subject has an Eastern Cooperative Oncology Group (ECOG) performance score of ≤ 2.

          6. A female of childbearing potential (FCBP) for this study is defined as a female who:
             1) has achieved menarche at some point, 2) has not undergone a hysterectomy or
             bilateral oophorectomy or 3) has not been naturally postmenopausal (amenorrhea
             following cancer therapy does not rule out childbearing potential) for at least 24
             consecutive months (eg, has had menses at any time in the preceding 24 consecutive
             months). Females of childbearing potential (FCBP)participating in the study must:

             a. Have 2 negative pregnancy tests as verified by the Investigator prior to starting
             study therapy. She must agree to ongoing pregnancy testing during the study, and after
             end of IP. This applies even if the subject practices true abstinence* from
             heterosexual contact.

             b. Either commit to true abstinence* from heterosexual contact (which must be reviewed
             on a monthly basis and source documented) or agree to use, and be able to comply with,
             effective contraception** without interruption, 28 days prior to starting IP, during
             the study therapy (including dose interruptions), and for 12 weeks (approximately 5
             times the mean terminal half-life of IP based on multiple-dose PK data) after
             discontinuation of study therapy.

          7. Male subjects must: Practice true abstinence* (which must be reviewed on a monthly
             basis) or agree to use a condom during sexual contact with a pregnant female or a
             female of childbearing potential** while participating in the study, during dose
             interruptions and for at least 12 weeks (approximately 5 times the mean terminal
             half-life of IP based on multiple-dose PK data) following IP discontinuation, even if
             he has undergone a successful vasectomy.

             * True abstinence is acceptable when it is in line with the preferred and usual
             lifestyle of the subject. [Periodic abstinence (eg, calendar, ovulation,
             symptothermal, postovulation methods) and withdrawal are not acceptable methods of
             contraception.]

             ** Agreement to use highly effective methods of contraception that alone or in
             combination result in a failure rate of a Pearl index of less than 1% per year when
             used consistently and correctly throughout the course of the study. Such methods
             include: Combined (estrogen and progestogen containing) hormonal contraception: Oral,
             Intravaginal, Transdermal; Progestogen-only hormonal contraception associated with
             inhibition of ovulation: Oral, Injectable hormonal contraception, Implantable hormonal
             contraception; Placement of an intrauterine device (IUD); Placement of an intrauterine
             hormone-releasing system (IUS); Bilateral tubal occlusion; Vasectomized partner;
             Sexual Abstinence.

          8. Subject must understand and voluntarily sign an ICF prior to any study-related
             assessments/procedures being conducted.

          9. Subject is willing and able to adhere to the study visit schedule and other protocol
             requirements including the use of the electronic patient reported outcomes device.

        Exclusion Criteria:

        The presence of any of the following will exclude a subject from randomization:

          1. Subject with anemia from cause other than MPN-associated MForJAK2 inhibitor therapy
             (eg, iron deficiency, vitamin B12 and/or folate deficiencies, autoimmune or hemolytic
             anemia, infection, or any type of known clinically significant bleeding or
             sequestration).

          2. Subject use of hydroxyurea, immunomodulatory compounds such as pomalidomide,
             thalidomide, ESAs, androgenic steroids or other drugs with potential effects on
             hematopoiesis ≤ 8 weeks immediately up to the date of randomization.

               1. Systemic corticosteroids are permitted for nonhematological conditions providing
                  the subject is receiving a constant dose equivalent to ≤ 10 mg prednisone for the
                  4 weeks immediately up to randomization.

               2. Iron chelation therapy (ICT) is permitted providing the subject is receiving a
                  stable dose for the 8 weeks immediately up to randomization.

          3. Subject with any of the following laboratory abnormalities at screening:

               1. Neutrophils: < 1 x 109/L

               2. White blood count (WBC): > 100 x 109/L

               3. Platelets: the lowest allowable level as approved for the concomitant JAK2
                  inhibitor but not < 25 x 109/L or > 1000 x 109/L

               4. Peripheral blood myeloblasts:> 5%

               5. Estimated glomerular filtration rate:< 40 mL/min/1.73 m2 (via the 4-variable
                  modification of diet in renal disease [MDRD] formula) or nephrotic subjects (eg,
                  urine albumin-to-creatinine ratio > 3500 mg/g)

               6. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT):> 3.0 x upper
                  limit of normal (ULN)

               7. Direct bilirubin: ≥ 2 x ULN

                    -  Higher levels are acceptable if these can be attributed to active red blood
                       cell precursor destruction within the bone marrow (eg, ineffective
                       erythropoiesis)

          4. Subject with uncontrolled hypertension, defined as repeated elevations of systolic
             blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, that is not resolved
             at the time of randomization.

          5. Subject with prior history of malignancies, other than disease under study, unless the
             subject has been free of the disease for ≥ 3 years. However, subject with the
             following history/concurrent conditions is allowed:

               1. Basal or squamous cell carcinoma of the skin

               2. Carcinoma in situ of the cervix

               3. Carcinoma in situ of the breast

               4. Incidental histologic finding of prostate cancer (T1a or T1b using the tumor,
                  nodes, metastasis [TNM] clinical staging system)

          6. Subject with prior hematopoietic cell transplant or subject anticipated to receive a
             hematopoietic cell transplant during the 24 weeks from the date of randomization. 7.
             Subject with stroke, myocardial infarction, deep venous thrombosis, pulmonary or
             arterial embolism within 6 months immediately up to the date of randomization.

        8. Subject with major surgery within 2 months up to the date of randomization. Subject must
        have completely recovered from any previous surgery immediately up to the date of
        randomization.

        9. Subject with a major bleeding event (defined as symptomatic bleeding in a critical area
        or organ and/or bleeding causing a decrease in Hgb of ≥ 2 g/dL or leading to transfusion of
        ≥ 2 units of packed red cells) in the last 6 months prior to the date of randomization.

        10.Subject with inadequately controlled heart disease and/or have a known left ventricular
        ejection fraction < 35%.

        11.Subject with uncontrolled systemic fungal, bacterial, or viral infection (defined as
        ongoing signs/symptoms related to the infection without improvement despite appropriate
        antibiotics, antiviral therapy, and/or other treatment).

        12.Subject with known human immunodeficiency virus (HIV), evidence of active Hepatitis B
        (HepB) as demonstrated by the presence of Hepatitis B surface antigen (HBsAg) and/or
        positive for Hepatitis B virus DNA (HBVDNA-positive), and/or evidence of active Hepatitis C
        (HepC) as demonstrated by a positive Hepatitis C virus RNA (HCV-RNA) test of sufficient
        sensitivity.

        13.Subject with prior therapy of luspatercept or sotatercept. 14.Subject with history of
        severe allergic or anaphylactic reactions or hypersensitivity to recombinant proteins or
        excipients in the investigational product.

        15.Pregnant or breastfeeding females. 16.Subject participation in any other clinical
        protocol or investigational trial that involves use of experimental therapy (including
        investigational agents) and/or therapeutic devices within 30 days or for investigational
        agents within five half-lives, whichever comes later, immediately up to the date of
        randomization.

        17.Subject with any significant medical condition, laboratory abnormality, psychiatric
        illness, or is considered vulnerable by local regulations (eg, imprisoned or
        institutionalized) that would prevent the subject from participating in the study or places
        the subject at unacceptable risk if he/she were to participate in the study. 18.Subject
        with any condition or concomitant medication that confounds the ability to interpret data
        from the study.