A method for treating anemia using ActRIIB ligand trap and fedratinib.

Abstract

This invention provides a novel therapy for treating anemia in patients with myeloproliferative neoplasm-associated myelofibrosis. [Solution] This specification provides a method for treating anemia in a subject requiring treatment, comprising administering an ActRIIB ligand trap to the subject, and then administering fedratinib to the subject.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 009,400, filed on 13 April 2020, the contents of which are incorporated herein by reference in their entirety.

[0002] Reference to electronically submitted sequence listings This application incorporates, in its entirety, by reference to the computer-readable format (CRF) of the sequence listing in ASCII text format submitted with this specification. The sequence listing text file submitted with this specification, titled 14247-487-228_SEQ_LISTING.TXT, was created on April 4, 2021, and has a size of 73,372 bytes.

[0003] 1. Field This specification provides a method for treating anemia in subjects requiring treatment using activin type IIB (ActRIIB) ligand trap in combination with fedratinib. This specification provides a method for treating anemia in subjects with myeloproliferative neoplasm-(MPN-)-associated myelofibrosis using activin type IIB (ActRIIB) in combination with fedratinib. [Background technology]

[0004] 2.Background Myeloproliferative neoplasm-associated myelofibrosis (MF) is a serious and life-threatening disease that may be present as a first-time or primary myelofibrosis (PMF) or develop from a previous polycythemia vera (post-PV MF) or essential thrombocythemia (post-ET MF) (Non-Patent Literature 1). This disease is characterized by clonal myeloproliferation, ineffective erythropoiesis, bone marrow stromatous changes, extramedullary hematopoiesis of the liver and spleen, and abnormal cytokine expression (Non-Patent Literature 2). Patients usually present with splenomegaly, constitutional symptoms, moderate to severe anemia, thrombocytopenia, and leukocytosis.

[0005] Primary myelofibrosis is a member of the group of Philadelphia chromosome (Ph1)-negative myeloproliferative neoplasms (MPNs), which also include PV and ET (Non-Patent Literature 3). Almost all patients with PV, and about half of patients with ET and PMF, have a Janus kinase 2 (JAK2) mutation, usually JAK2V617F. Mutations in JAK2, CALR, and MPL result in activation of JAK / signal transducers and transcriptional (STAT) signaling pathway activators, which lead to cell proliferation and inhibit cell death. The result is clonal proliferation (Non-Patent Literature 4).

[0006] Polycythemia vera (PV) and essential thrombocythemia (ET) are characterized by elevated levels of red blood cells (RBCs) and platelets. However, approximately 10% of affected patients develop myelofibrosis that is morphologically indistinguishable from PMF. These conditions are called post-PV MF and post-ET MF (Non-Patent Literature 5) and are clinically named MPN-associated myelofibrosis. Patients with MPN-associated myelofibrosis have a similar prognosis to those with PMF and a cumulative risk of approximately 10% conversion to acute myeloid leukemia (AML).

[0007] Approximately 70% of individuals with MF are in the intermediate-2 or high-risk category (Non-Patent Literature 6), representing the greatest unmet medical need. Symptomatic distension of the spleen and liver, the need for RBC transfusions, cachexia, and other MF-related symptoms significantly impair the quality of life of these patients (Non-Patent Literature 7).

[0008] Anemia is a decrease in the number of red blood cells or a below-normal amount of hemoglobin in the blood. Anemia can be caused by a reduction in the oxygen-binding capacity of hemoglobin. Anemia is the most common blood disorder. Anemia is present at diagnosis in about two-thirds of patients with MPN-associated myelofibrosis and develops in almost all patients during the course of the disease. Overall, anemia and RBC transfusion dependence are strong independent prognostic variables regarding survival and the risk of conversion to the acute transformation phase (Non-Patent Literature 8; Non-Patent Literature 9). The causes of anemia in MPN-associated myelofibrosis are complex (Non-Patent Literature 10; Non-Patent Literature 11). In addition to the underlying disease, some drugs used to treat MPN-associated myelofibrosis, such as hydroxyurea (hydroxycarbamide) and JAK2 inhibitors (e.g., ruxolitinib), can worsen anemia. For example, ruxolitinib showed significant improvement in spleen size and symptom relief, but this was often associated with moderate to severe thrombocytopenia and anemia (Non-Patent Literature 12).

[0009] Given the current lack of safe and effective drug therapies for treating anemia in patients with MPN-associated myelofibrosis, there is a significant unmet medical need for the development of novel therapies to treat anemia in MPN-associated MF patients.

[0010] Two related type II receptors, ActRIIA and ActRIIB, were identified as type II receptors for activin (Non-Patent Literature 13; Non-Patent Literature 14). In addition to activin, ActRIIA and ActRIIB can biochemically interact with several other TGF-beta family proteins, including BMP7, Nodal, GDF8, and GDF11 (Non-Patent Literature 15; Non-Patent Literature 16; Non-Patent Literature 17; Non-Patent Literature 18). ALK4 is the primary type I receptor for activin, particularly activin A, and ALK-7 can also act as a receptor for activin, particularly activin B.

[0011] Luspatercept, which is an ActRIIB ligand inhibitor, is described for the treatment of various indications. See, for example, Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4. [[PRIOR ART DOCUMENT]] [[PATENT DOCUMENTS]]

[0012] [[Patent Document 1]] US Patent Application Publication No. 2018 / 0050085A1, specification [[Patent Document 2]] U.S. Patent No. 8,058,229, specification [[Patent Document 3]] U.S. Patent No. 8,361,957, specification [[Patent Document 4]] U.S. Patent No. 8,343,933, specification [[NON-PATENT DOCUMENTS]]

[0013] [[Non-Patent Document 1]] WHO classification of tumours of haematopoietic and lymphoid tissues,ed.by Swerdlow,(IARC Press,2008) [[Non-Patent Document 2]] Tefferi,2016,Am.J.Hematol.91(12):1262-1271 [[Non-Patent Document 3]] Tefferi,2007,Clin.Adv.Hematol.Onlco.5:113-115 [[Non-Patent Document 4]] Ihle,2007,Curr.Opin.Genet.Dev.17(1):8-14 [[Non-Patent Document 5]] Campbell and Green,2005,Hematology Am.Soc.Hematol.Educ.Program 201-208 [[Non-Patent Document 6]] Gangat et al., 2011, J. Clin. Oncol. 29(4): 392-397 [Non-Patent Document 7] Mesa et al., Leukemia 21(9): 1964-1970 [Non-Patent Document 8] Passamonti et al., 2010, Blood 115(9): 1703-1708 [Non-Patent Document 9] Elena et al., 2011, Haematologica 96(1): 167-170 [Non-Patent Document 10] Barosi et al., 2010, Leuk Res. 34(9): 1119-1120 [Non-Patent Document 11] Cervantes et al., 2009, Blood 113(13): 2895-2901 [Non-Patent Document 12] Verstovsek et al., 2017, J. Hematol. Oncol. 10(1): 55 [Non-Patent Document 13] Mathews and Vale, 1991, Cell 65: 973-982 [Non-Patent Document 14] Attisano et al., 1992, Cell 68: 97-108 [Non-Patent Document 15] Yamashita et al., 1995, J. Cell Biol. 130: 217-226 [Non-Patent Document 16] Lee and McPherron, 2001, Proc. Natl. Acad. Sci. 98: 9306-9311 [Non-Patent Document 17] Yeo and Whitman, 2001, Mol. Cell 7: 949-957 [Non-Patent Document 18] Oh et al., 2002, Genes Dev. 16: 2749-54 Summary of Invention [Means for solving the problem]

[0014] 3. Overview In one embodiment, the Specified Publicly Provided Method for Treating Anemia in a Subject Requiring Treatment, comprising: administering an activin receptor type IIB (ActRIIB) ligand trap to the subject; and then administering fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof to the subject.

[0015] In another embodiment, the Specified also provides a method for treating anemia in a subject requiring treatment, comprising: (a) obtaining a first measurement of hemoglobin (Hgb) levels in the subject; (b) administering an initial dose of ActRIIB ligand trap to the subject; (c) administering fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof to the subject; (d) obtaining a second measurement of hemoglobin (Hgb) levels in the subject at the end of a first period following the administration of the initial dose of ActRIIB ligand trap; and then (e) administering a next dose of ActRIIB ligand trap to the subject based on the second measurement of hemoglobin (Hgb) levels compared to the first measurement of hemoglobin (Hgb) levels, or based on the number of red blood cell transfusions the subject received during the first period.

[0016] In some embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously.

[0017] In some embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective for treating anemia.

[0018] In some embodiments, the subjects are those diagnosed with myelofibrosis.

[0019] In some embodiments, the myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis.

[0020] In some embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (PV-MF), or post-essential thrombocythemia myelofibrosis (ET-MF).

[0021] In some embodiments, myelofibrosis is an intermediate or high-risk primary myelofibrosis (PMF).

[0022] In some embodiments, the myelofibrosis is intermediate or high-risk post-polycythemia vera myelofibrosis (post-PV MF).

[0023] In some embodiments, the myelofibrosis is intermediate or high-risk post-essential thrombocythemia myelofibrosis (post-ET MF).

[0024] In some embodiments, the subject is a human.

[0025] In some embodiments, anemia is associated with myeloproliferative neoplasm (MPN)-associated myelofibrosis.

[0026] In some embodiments, the subject is either red blood cell (RBC) transfusion-dependent or transfusion-independent.

[0027] In some embodiments, the subject is RBC transfusion-dependent.

[0028] In some embodiments, subjects received 4 to 12 RBC units in an RBC transfusion within 84 days prior to the administration of the ActRIIB ligand trap.

[0029] In some embodiments, subjects have a hemoglobin (Hgb) level of 11.5 g / dL or less without red blood cell (RBC) transfusion.

[0030] In some embodiments, the subjects are transfusion-independent.

[0031] In some embodiments, subjects received 4 or fewer red blood cell (RBC) units in an RBC transfusion within 84 days prior to the administration of the ActRIIB ligand trap.

[0032] In some embodiments, the subjects have a hemoglobin (Hgb) level of 9.5 g / dL or less.

[0033] In some embodiments, subjects were treated with fedratinib for at least 8 weeks, at least 16 weeks, at least 24 weeks, at least 32 weeks, or at least 40 weeks prior to the administration of an initial dose of the ActRIIB ligand trap and concurrent administration of fedratinib or a pharmaceutically acceptable salt or hydrate thereof.

[0034] In some embodiments, the subject has been previously treated with ruxolitinib.

[0035] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered daily.

[0036] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered orally.

[0037] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered at a dose of 400 mg / day.

[0038] In some embodiments, the ActRIIB ligand trap is administered once at the beginning of each treatment cycle, with each cycle lasting 21 days.

[0039] In some embodiments, the ActRIIB ligand trap is administered to the subject for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cycles.

[0040] In some embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject.

[0041] In some embodiments, the pharmaceutically effective amount of ActRIIB ligand trap administered is 0.6 mg / kg, 0.8 mg / kg, 1 mg / kg, 1.33 mg / kg, or 1.75 mg / kg.

[0042] In some embodiments, the pharmaceutically effective dose of the ActRIIB ligand trap administered is 1.33 mg / kg.

[0043] In some embodiments, a first measurement of hemoglobin (Hgb) levels is obtained before the administration of an initial dose of the ActRIIB ligand trap.

[0044] In some embodiments, the first measurement of hemoglobin (Hgb) levels is obtained concurrently with the administration of the initial dose of the ActRIIB ligand trap, or approximately 3, 6, 9, 12, 15, 18, 21, or 24 weeks after the administration of the initial dose of the ActRIIB ligand trap.

[0045] In some embodiments, a second measurement of hemoglobin (Hgb) levels is obtained approximately 3 weeks, 6 weeks, 9 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, 24 weeks, 7 months, 8 months, 9 months, 10 months, 11 months, or 12 months after the initial dose of the ActRIIB ligand trap has been administered to the subject.

[0046] In some embodiments, the first period is 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, or 8 weeks.

[0047] In some embodiments, the first period is 6 weeks.

[0048] In some embodiments, the initial dose of the ActRIIB ligand trap is 1.33 mg / kg.

[0049] In some embodiments, the following doses of ActRIIB ligand trap are 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, or 1.75 mg / kg.

[0050] In some embodiments, the next dose of ActRIIB ligand trap is 1.33 mg / kg.

[0051] In some embodiments, when the second measurement of the Hgb level is 2 g / dL or more higher than the first measurement of the Hgb level, the next dose of the ActRIIB ligand trap is less than the initial dose of the ActRIIB ligand trap.

[0052] In some embodiments, when a subject has received one or more RBC transfusions during a first period, or when a second measurement of Hgb level is 0 to approximately 1 g / dL higher than a first measurement of Hgb level, or when the first measurement of Hgb level decreases by 1 g / dL or more during a period of approximately 6 weeks without transfusions, the next dose of ActRIIB ligand trap is greater than the initial dose of ActRIIB ligand trap.

[0053] In some embodiments, the next dose of ActRIIB ligand trap is the same as the initial dose of ActRIIB ligand trap.

[0054] In some embodiments, the method further includes classifying hematological events, hepatic events, non-hematological events, or gastrointestinal events in the subject into grades 1, 2, 3, 4, or 5 according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE); and administering the following doses of fedratinib or a pharmaceutically acceptable salt or hydrate thereof.

[0055] In some embodiments, the following doses of fedratinib or a pharmaceutically acceptable salt or hydrate thereof are 300 mg / day, 200 mg / day, or 100 mg / day.

[0056] In some embodiments, the ActRIIB ligand trap is a humanized fusion protein consisting of the extracellular domain of ActRIIB and the human IgG1 Fc domain.

[0057] In some embodiments, the ActRIIB ligand trap is a fusion protein containing the extracellular domain of ActRIIB and the human IgG1 Fc domain.

[0058] In some embodiments, the ActRIIB ligand trap is a polypeptide comprising an amino acid sequence selected from the group consisting of: 90% identical to SEQ ID NO: 3; 95% identical to SEQ ID NO: 3; 98% identical to SEQ ID NO: 3; 90% identical to SEQ ID NO: 6; 95% identical to SEQ ID NO: 6; 98% identical to SEQ ID NO: 6; 90% identical to SEQ ID NO: 7; 95% identical to SEQ ID NO: 7; 98% identical to SEQ ID NO: 7; 90% identical to SEQ ID NO: 11; 95% identical to SEQ ID NO: 11; 98% identical to SEQ ID NO: 11; and SEQ ID NO: 11.

[0059] In some embodiments, the ActRIIB ligand trap is a polypeptide comprising an amino acid sequence selected from the group consisting of 90% identical to SEQ ID NO: 11; 95% identical to SEQ ID NO: 11; 98% identical to SEQ ID NO: 11; and SEQ ID NO: 11.

[0060] In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11.

[0061] In some embodiments, the ActRIIB ligand trap is a polypeptide encoded by the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34.

[0062] In some embodiments, the method increases the hemoglobin (Hgb) level in the subject by at least 0.5 g / dL, at least 1.0 g / dL, at least 1.5 g / dL, at least 2.0 g / dL, or at least 2.5 g / dL.

[0063] In some embodiments, the method increases the hemoglobin (Hgb) level in the subject by at least 1.5 g / dL.

[0064] In some embodiments, the method reduces the amount of red blood cell (RBC) transfusions received by the subject within a period of 56 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units.

[0065] In some embodiments, the method reduces the amount of RBC transfusion received by the subject by at least 4 units over a 56-day period.

[0066] In some embodiments, the method reduces the amount of red blood cell (RBC) transfusions received by the subject within an 84-day period by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units.

[0067] In some embodiments, the method increases the hemoglobin (Hgb) level in a subject by at least 1.5 g / dL over a continuous period of 84 days.

[0068] In some embodiments, subjects remain without red blood cell (RBC) transfusions for a continuous period of 84 days.

[0069] In some embodiments, the method increases the hemoglobin (HGB) level in the subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the HGB level in the subject before the treatment.

[0070] In some embodiments, the method increases the hematocrit (HCT) level in the subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the HCT level in the subject before the treatment.

[0071] In some embodiments, the method reduces the mean corpuscular volume (MCV) level in the subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the MCV level in the subject before the treatment.

[0072] In some embodiments, the method increases the cellular hemoglobin concentration (CHC) level in the subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the CHC level in the subject before the treatment.

[0073] In some embodiments, the method reduces the erythrocyte distribution width (RDW) level in the subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the RDW level in the subject before the treatment.

[0074] In some embodiments, the level of reticulocytes in the subject remains the same as the level of reticulocytes in the subject before the treatment, or remains within the range of approximately 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% or less.

[0075] In some embodiments, the level of reticulocytes in the subject remains equivalent to or within the range of approximately 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% of the level of reticulocytes in the reference population.

[0076] In some embodiments, the leukocyte level in the subject remains the same as or within the range of approximately 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% compared to the leukocyte level in the subject before the treatment. [Brief explanation of the drawing]

[0077] [Figure 1] This describes the overall study design for patient treatment with the combination of raspatercept and fedratinib. [Modes for carrying out the invention]

[0078] 5. Detailed explanation 5.1 Abbreviations and Terminology As used herein, the term “about” when used in conjunction with a number refers to any number up to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% of the number being referenced. In certain embodiments, the term “about” encompasses the exact number listed.

[0079] As used herein, "ActRII" refers to activin receptor type II. As used herein, "ActRIIB" refers to activin receptor type IIB. See, for example, Attisano et al., 1992, Cell 68:97-108. GenBank(trademark) acceptance number NM_001106.3 provides an exemplary human ActRIIB nucleic acid sequence. GenBank(trademark) acceptance number NP_001097.2 provides an exemplary human ActRIIB amino acid sequence.

[0080] "β 0 This refers to the allele associated with a lack of beta-globin subunit synthesis.

[0081] "β + This refers to the allele associated with a reduction in beta-globin subunit synthesis.

[0082] As used herein, "BL" refers to the baseline.

[0083] As used herein, "CHC" refers to cellular hemoglobin concentration.

[0084] As used herein, "ECD" refers to the extracellular domain.

[0085] As used herein, "EPO" refers to erythropoietin.

[0086] As used herein, “fedratinib” refers to compounds of N-tert-butyl-3-[(5-methyl-2-{4-[2-(pyrrolidine-1-yl)ethoxy]anilino}pyrimidine-4-yl)amino]benzenesulfonamide (CAS No. 936091-26-8) and its pharmaceutically acceptable salts and / or hydrates (such as dichloride monohydrate). It is also known as SAR302503 or TG101348, and its structure: [ka] It holds.

[0087] As used herein, both "Hb" and "Hgb" refer to hemoglobin.

[0088] As used herein, “HI-E” refers to the hematological improvement of red blood cells. In certain embodiments, HI-E is as defined by the IWG. In certain embodiments, HI-E is as defined by the revised 2006 IWG. In certain embodiments, HI-E for patients with a low transfusion burden is an increase of at least 1.5 g / dL in the patient's hemoglobin concentration over at least 8 weeks. In certain embodiments, HI-E for patients with a high transfusion burden is a decrease of at least 4 units in RBC transfusion over 8 weeks.

[0089] As used herein, "HTB" refers to high transfusion burden. In certain embodiments, HTB subjects receive 4 RBC units or more over 8 weeks.

[0090] As used herein, "IgG" refers to immunoglobulin G.

[0091] As used herein, "IPSS-R" refers to the International Prognostic System (Revised).

[0092] As used herein, “IWG” refers to the International Working Group. See, for example, Cheson et al. Blood. 2000 96:3671–3674. In certain embodiments, IWG refers to the revised 2006 criteria. See, for example, Cheson et al., 2006, Blood, 108(2).

[0093] As used herein, "LTB" refers to low transfusion burden. In certain embodiments, LTB subjects receive 4 RBC units or less over 8 weeks.

[0094] As used herein, "raspatercept" refers to the product obtained from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11, and subsequent protein purification procedures.

[0095] As used herein, "MedDRA" refers to the Glossary of Regulatory Terms for Pharmaceuticals.

[0096] As used herein, "MCV" refers to mean corpuscular volume.

[0097] As used herein, "MDS" refers to myelodysplastic syndrome.

[0098] As used herein, "mg / kg" in the context of ActRIIB ligand trap dosage refers to milligrams of ActRIIB ligand trap per kilogram of the weight of the subject to which the ActRIIB ligand trap will be administered.

[0099] As used herein, "MPN-associated myelofibrosis" refers to myeloproliferative neoplasm-associated myelofibrosis.

[0100] As used herein, "PD" refers to pharmacodynamics.

[0101] As used herein, "PK" refers to pharmacokinetics.

[0102] As used herein, "PMF" refers to primary myelofibrosis.

[0103] As used herein, "post-ET MF" refers to post-essential thrombocythemia myelofibrosis.

[0104] As used herein, "post-PV MF" refers to post-polycythemia vera myelofibrosis.

[0105] As used herein, "RA" refers to refractory anemia.

[0106] As used herein, "RAEB" refers to refractory anemia with an excess of blast cells.

[0107] As used herein, "RBC" refers to a red blood cell.

[0108] As used herein, "RBC-TI" refers to red blood cell transfusion dependence.

[0109] As used herein, "RDW" refers to the erythrocyte distribution width.

[0110] As used herein, "SC" refers to the subcutaneous tissue.

[0111] As used herein, "WPSS" refers to the World Health Organization (WHO) Prognostic System.

[0112] In certain embodiments, “to treat,” “to cure,” or “to treat” anemia includes the remission of at least one symptom of anemia. Non-limiting examples of anemia include fatigue, lethargy, palpitations, shortness of breath, headache, difficulty concentrating, dizziness, pallor, leg cramps, and insomnia.

[0113] 5.2 Overview This specification provides a method for treating anemia in subjects requiring treatment, comprising administering to the subject an ActRIIB ligand trap (e.g., raspatercept, expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11, and the product resulting from a subsequent protein purification procedure; see Section 5.4), and then administering to the subject fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (see Section 5.3). Dosage regimens are described in Sections 5.5 and 5.8. The patient populations that can be treated using the methods provided herein are described in Section 5.6.

[0114] 5.3 Fedratinib Fedratinib (INREBIC®) is an oral kinase inhibitor with activity against wild-type and mutagenically activated Janus kinase 2 (JAK2) and fibromyalgia syndrome (FMS)-like tyrosine kinase 3 (FLT3). Fedratinib is a JAK2-selective inhibitor with higher efficacy against JAK2 than its family members JAK1, JAK3, and tyrosine kinase 2 (TYK2). In cell models expressing mutagenically active JAK2 or FLT3, fedratinib reduced the phosphorylation of transcription (STAT3 / 5) protein signal transducers and activators, inhibiting cell proliferation and inducing apoptotic cell death. In a mouse model of myeloproliferative disorder driven by JAK2V617F, fedratinib blocked STAT3 / 5 phosphorylation, increasing survival and improving disease-related symptoms, including leukopenia, hematocrit, splenomegaly, and fibrosis.

[0115] Fedratinib demonstrated clinical efficacy in a randomized, placebo-controlled phase 3 trial (JAKARTA [EFC12153]) in patients with previously untreated intermediate-2 or high-risk MF.

[0116] On August 16, 2019, fedratinib (INREBIC®) was approved by the US FDA for the treatment of adult patients with intermediate-2 or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis.

[0117] In certain embodiments, fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof may be used in the methods provided herein (see Section 5.5).

[0118] In some embodiments, as used herein, “fedratinib” refers to fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof. In some embodiments, “fedratinib” refers to fedratinib dihydrochloride. In some embodiments, “fedratinib” refers to fedratinib dihydrochloride monohydrate.

[0119] 5.4 ACTRIIB Ligand Trap In certain embodiments, the ActRIIB ligand trap described in this section may be used in the methods provided herein (see Section 5.5). In certain embodiments, the ActRIIB ligand trap for use with the method comprises the amino acid sequence of SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap for use with the method is a product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11.

[0120] As used herein, the term “ActRIIB” refers to the family of activin receptor type IIB (ActRIIB) proteins derived from any species and variants derived from such ActRIIB proteins by mutagenesis or other modifications. References to ActRIIB herein are understood to refer to any of the currently identified forms of the receptor. Members of the ActRIIB family are generally transmembrane proteins comprising a ligand-binding extracellular domain with a cysteine-rich region, a transmembrane domain, and a cytoplasmic domain with expected serine / threonine kinase activity.

[0121] ActRIIB ligand traps to be used in the compositions and methods described herein include, but are not limited to, activin-binding soluble ActRIIB polypeptides; antibodies that bind to activin (particularly activin A or B subunits, also referred to as beta-A or beta-B) and disrupt ActRIIB binding; antibodies that bind to ActRIIB and disrupt activin binding; non-antibody proteins selected for activin or ActRIIB binding; and randomized peptides selected for activin or ActRIIB binding that can be conjugated to an Fc domain.

[0122] In certain embodiments, two or more different proteins (or other moieties) having activin or ActRIIB binding activity, particularly activin conjugates that block type I (e.g., soluble type I activin receptor) and type II (e.g., soluble type II activin receptor) binding sites, can be linked together to inhibit ActRIIB and thus create bifunctional or multifunctional conjugated molecules that can be used in the compositions and methods described herein. In certain embodiments, activin-ActRIIB signaling axis antagonists that inhibit ActRIIB include nucleic acid aptamers, small molecules, and other drugs used in the compositions and methods described herein.

[0123] Such ActRIIB ligand traps may be prepared and modified as previously described in Section 5.5.2 of International Publication No. 2014 / 066486, which is incorporated herein by reference as a whole.

[0124] (a) ActRIIB ligand trap containing ActRIIB antibody In certain embodiments, the ActRIIB ligand trap to be used in the compositions and methods described herein comprises an antibody that binds to activin (particularly activin A or B subunit) and disrupts ActRIIB binding.

[0125] (b) ActRIIB ligand trap containing ActRIIB polypeptide As used herein, the term “ActRIIB polypeptide” refers to polypeptides comprising any naturally occurring polypeptide of an ActRIIB family member and any variant thereof (including variants, fragments, fusions, and peptide-mimicking forms) that retain useful activity. For example, an ActRIIB polypeptide includes polypeptides derived from sequences of any known ActRIIB receptor having at least about 80% identity with the ActRIIB polypeptide sequence, and optionally, at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, or more identity. For example, an ActRIIB polypeptide may bind to the ActRIIB protein and / or activin and inhibit its function. An example of an ActRIIB polypeptide is the human ActRIIB precursor polypeptide (SEQ ID NO: 2 or SEQ ID NO: 14). With respect to the ActRIIB precursor polypeptide whose amino acid sequence is shown as SEQ ID NO: 2 or SEQ ID NO: 14 (i.e., human ActRIIB precursor polypeptide), the signal peptide of the ActRIIB precursor polypeptide is located at amino acids 1-18; the extracellular domain is located at amino acids 19-134; and potential N-linked glycosylation sites are located at amino acid positions 42 and 65. The nucleic acid sequence encoding the human ActRIIB precursor polypeptide of SEQ ID NO: 2 is disclosed as SEQ ID NO: 5 (SEQ ID NO: 5 provides alanine at the codon corresponding to amino acid position 64, but may instead be readily modified by those skilled in the art using methods known in the art to provide arginine at the codon corresponding to amino acid position 64). See Table 1 for sequence descriptions.

[0126] The amino acid numbering for all ActRIIB-related polypeptides described herein is based on the amino acid numbering for SEQ ID NO: 2 and SEQ ID NO: 14 (which differ only in the amino acid expressed at position 64), unless otherwise specified. For example, when an ActRIIB polypeptide is described as having a substitution / mutation at amino acid position 79, it should be understood that position 79 refers to the 79th amino acid in SEQ ID NO: 2 or SEQ ID NO: 14 from which the ActRIIB polypeptide originates. Similarly, when an ActRIIB polypeptide is described as having alanine or arginine at amino acid position 64, it should be understood that position 64 refers to the 64th amino acid in SEQ ID NO: 2 or SEQ ID NO: 14 from which the ActRIIB polypeptide originates.

[0127] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises a polypeptide containing the activin-binding domain of ActRIIB. In certain embodiments, the activin-binding domain of ActRIIB comprises the extracellular domain of ActRIIB, or a portion thereof. In certain embodiments, the extracellular domain of ActRIIB, or a portion thereof, is soluble. Exemplary modifications of the ActRIIB polypeptide are disclosed in U.S. Patent Application Publication No. 20090005308 and U.S. Patent Application Publication No. 20100068215, which are incorporated herein by reference as a whole.

[0128] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein is a soluble ActRIIB polypeptide. The term “soluble ActRIIB polypeptide” generally refers to a polypeptide comprising the extracellular domain of the ActRIIB protein, including any naturally occurring extracellular domain of the ActRIIB protein and any variant thereof (including mutants, fragments, and peptide-mimicking forms). Soluble ActRIIB polypeptides can bind to activin; however, wild-type ActRIIB protein does not exhibit significant selectivity for binding to activin for GDF8 / 11. In certain embodiments, modified forms of ActRIIB having different binding properties may be used in the methods provided herein. Such modified forms are disclosed, for example, in International Publication No. 2006 / 012627 and International Publication No. 2010 / 019261, which are incorporated herein by reference as a whole. Natural or modified ActRIIB proteins can be given further specificity to activin by coupling them with a second activin-selective binder. Exemplary soluble ActRIIB polypeptides include the extracellular domain of human ActRIIB polypeptides (e.g., SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 24, and 29).

[0129] Fc fusion proteins having the ActRIIB extracellular sequence disclosed by Hilden et al. (Blood, 1994, 83(8):2163-70), which has alanine at the position corresponding to amino acid 64 of the ActRIIB precursor amino acid sequence, i.e., SEQ ID NO: 2 (hereinafter referred to as "A64"), have been demonstrated to have relatively low affinity for activin and GDF-11. In contrast, Fc fusion proteins having arginine at position 64 of the ActRIIB precursor amino acid sequence (hereinafter referred to as "R64") have affinity for activin and GDF-11 in the low nanomolar to high picomolar concentration range (see, for example, U.S. Patent Application Publication No. 20100068215, in which the disclosure is incorporated as a whole). The ActRIIB precursor amino acid sequence having arginine at position 64 is shown in SEQ ID NO: 14. Therefore, in certain embodiments, the ActRIIB polypeptide used according to the compositions and methods described herein may comprise either (i) an ActRIIB precursor amino acid sequence, i.e., alanine at the position corresponding to amino acid 64 of SEQ ID NO: 2; or (ii) an ActRIIB precursor amino acid sequence, i.e., arginine at position 64 of SEQ ID NO: 14. In other embodiments, the ActRIIB polypeptide used according to the compositions and methods described herein may comprise an amino acid other than alanine or arginine at the position corresponding to amino acid 64 of the ActRIIB precursor amino acid sequence, i.e., SEQ ID NO: 2 or SEQ ID NO: 14.

[0130] Deletion of the C-terminal proline knot of the extracellular domain of ActRIIB has been shown to reduce receptor affinity for activin (see, e.g., Attisano et al., Cell, 1992, 68(1):97-108). The ActRIIB-Fc fusion protein "ActRIIB(20-119)-Fc," which contains amino acids 20-119 of SEQ ID NO: 14 (i.e., SEQ ID NO: 18), reduced binding to GDF-11 and activin compared to the ActRIIB fusion protein "ActRIIB(20-134)-Fc," which contains amino acids 20-134 of SEQ ID NO: 14 (i.e., SEQ ID NO: 17), including the proline knot region and the complete near-membrane domain. However, the ActRIIB-Fc fusion protein "ActRIIB(20-129)-Fc," which contains amino acids 20-129 of SEQ ID NO: 14, retains similar activity to the uncleaved extracellular domain of ActRIIB, even if the proline knot region is disrupted, although this activity is slightly reduced. Therefore, all ActRIIB polypeptides containing extracellular domains that terminate at amino acids 134, 133, 132, 131, 130, and 129 of SEQ ID NO: 14 (or SEQ ID NO: 2) are predicted to be active, while constructs that terminate at amino acid 134 or 133 may be mostly active. Similarly, mutations at any of residues 129-134 are not predicted to alter ligand binding affinity by a large margin, as indicated by the fact that mutations at P129 and P130 of SEQ ID NO: 14 do not substantially reduce ligand binding. Therefore, while ActRIIB polypeptides used according to the methods and compositions described herein may end as early as amino acid 109 (i.e., the last cysteine) of SEQ ID NO: 14 (or SEQ ID NO: 2), forms ending at or between amino acid positions 109 and 119 of SEQ ID NO: 14 (or SEQ ID NO: 2) are predicted to have reduced ligand binding ability.

[0131] Amino acid 29 in SEQ ID NO: 2 and SEQ ID NO: 14 represents the first cysteine ​​in the ActRIIB precursor sequence. ActRIIB polypeptides beginning at or before the N-terminal amino acid 29 of SEQ ID NO: 2 or SEQ ID NO: 14 are predicted to retain ligand-binding activity. A mutation from alanine to asparagine at position 24 of SEQ ID NO: 2 or SEQ ID NO: 14 introduces an N-linked glycosylation sequence without substantially affecting ligand binding. This confirms that mutations in the region between the signal-cleaved peptide corresponding to amino acids 20-29 of SEQ ID NO: 2 or SEQ ID NO: 14 and the cysteine ​​crosslinking region are well tolerated. In particular, ActRIIB polypeptides beginning at amino acid positions 20, 21, 22, 23, and 24 of SEQ ID NO: 2 or SEQ ID NO: 14 are predicted to retain activity, and ActRIIB polypeptides beginning at amino acid positions 25, 26, 27, 28, and 29 of SEQ ID NO: 2 or SEQ ID NO: 14 are also predicted to retain activity. ActRIIB polypeptides beginning at amino acid positions 22, 23, 24, or 25 of SEQ ID NO: 2 or SEQ ID NO: 14 will exhibit maximum activity.

[0132] In summary, the active portion (i.e., ActRIIB polypeptide) of the ActRIIB precursor protein (i.e., SEQ ID NO: 2 or SEQ ID NO: 14) to be used according to the methods and compositions described herein will generally contain amino acids 29-109 of SEQ ID NO: 2 or SEQ ID NO: 14, and such ActRIIB polypeptide may begin, for example, at a residue corresponding to any one of amino acids 19-29 of SEQ ID NO: 2 or SEQ ID NO: 4 and end at a position corresponding to any one of amino acids 109-134 of SEQ ID NO: 2 or SEQ ID NO: 14. Specific examples of ActRIIB polypeptides incorporated herein include those beginning at amino acid positions 19-29, 20-29, or 21-29 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending at amino acid positions 119-134, 119-133, or 129-134, or 129-133 of SEQ ID NO: 2 or SEQ ID NO: 14. Other specific examples of ActRIIB polypeptides incorporated herein include those beginning at amino acid positions 20-24 (or 21-24, or 22-25) of SEQ ID NO: 2 or SEQ ID NO: 14 and ending at amino acid positions 109-134 (or 109-133), 119-134 (or 119-133), or 129-134 (or 129-133) of SEQ ID NO: 2 or SEQ ID NO: 14. Variant ActRIIB polypeptides within these ranges, in particular those having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity or homology with the corresponding portion of SEQ ID NO: 2 or SEQ ID NO: 14, are also to be considered.

[0133] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises a cleaved form of the extracellular domain of ActRIIB. The shortening may be present at the carboxyl terminus and / or amino terminus of the ActRIIB polypeptide. In certain embodiments, the shortening may be an amino acid length of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 relative to the extracellular domain of the mature ActRIIB polypeptide. In certain embodiments, the shortening may be an N-terminal amino acid of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 relative to the extracellular domain of the mature ActRIIB polypeptide. In certain embodiments, the shortening may be the C-terminal amino acids of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 of the extracellular domain of the mature ActRIIB polypeptide. For example, the cleavage form of ActRIIB comprises a polypeptide having amino acids 20-119; 20-128; 20-129; 20-130; 20-131; 20-132; 20-133; 20-134; 20-131; 21-131; 22-131; 23-131; 24-131; and 25-131, where the amino acid positions refer to the amino acid positions in SEQ ID NO: 2 or SEQ ID NO: 14.

[0134] Additional exemplary cleavage types of ActRIIB include: (i) polypeptides beginning with any amino acid 21-29 of SEQ ID NO: 2 or SEQ ID NO: 14 (optionally beginning with amino acids 22-25 of SEQ ID NO: 2 or SEQ ID NO: 14) and ending with any amino acids 109-134 of SEQ ID NO: 2 or SEQ ID NO: 14; (ii) polypeptides beginning with any amino acid 20-29 of SEQ ID NO: 2 or SEQ ID NO: 14 (optionally beginning with amino acids 22-25 of SEQ ID NO: 2 or SEQ ID NO: 14) and ending with any amino acids 109-133 of SEQ ID NO: 2 or SEQ ID NO: 14; (iii) polypeptides beginning with any of amino acids 20-24 of SEQ ID NO: 2 or SEQ ID NO: 14 (optionally starting with amino acids 22-25 of SEQ ID NO: 2 or SEQ ID NO: 14) and ending with any of amino acids 109-133 of SEQ ID NO: 2 or SEQ ID NO: 14; (iv) polypeptides beginning with any of amino acids 21-24 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending with any of amino acids 109-134 of SEQ ID NO: 2 or SEQ ID NO: 14 (vi) polypeptides ending in any of 18-133; (vi) polypeptides beginning with any of amino acids 21-24 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending in any of amino acids 118-134 of SEQ ID NO: 2 or SEQ ID NO: 14; (vii) polypeptides beginning with any of amino acids 20-24 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending in any of amino acids 128-133 of SEQ ID NO: 2 or SEQ ID NO: 14; (viii) polypeptides beginning with any of amino acids 20-24 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending in any of amino acids 128-133 of SEQ ID NO: 2 or SEQ ID NO: 14 Polypeptides ending in either of the following: (ix) Polypeptides beginning with any of amino acids 21-29 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending with any of amino acids 118-134 of SEQ ID NO: 2 or SEQ ID NO: 14; (x) Polypeptides beginning with any of amino acids 20-29 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending with any of amino acids 118-133 of SEQ ID NO: 2 or SEQ ID NO: 14; (xi) Polypeptides beginning with any of amino acids 21-29 of SEQ ID NO: 2 or SEQ ID NO: 4 and ending with any of amino acids 128-134 of SEQ ID NO: 2 or SEQ ID NO: 14;and (xii) a polypeptide comprising one of the amino acids 20-29 of SEQ ID NO: 2 or SEQ ID NO: 14 and one of the amino acids 128-133 of SEQ ID NO: 2 or SEQ ID NO: 14. In certain embodiments, the ActRIIB polypeptide comprises, essentially, or consists of an amino acid sequence beginning at amino acid position 25 of SEQ ID NO: 2 or SEQ ID NO: 4 and ending at amino acid position 131 of SEQ ID NO: 2 or SEQ ID NO: 14. In other particular embodiments, the ActRIIB polypeptide comprises, essentially, or consists of the amino acids of SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, or 29.

[0135] Any of the ActRIIB polypeptides used in the compositions and methods described herein may be produced as homodimers. Any of the ActRIIB polypeptides used in the compositions and methods described herein may be formulated as fusion proteins having heterologous portions including constant regions of the IgG heavy chain, such as the Fc domain. Any of the ActRIIB polypeptides used in the compositions and methods described herein may optionally be combined with one or more additional amino acid substitutions, deletions, or insertions to SEQ ID NO: 2 or SEQ ID NO: 14 to contain an acidic amino acid at the position corresponding to position 79 of SEQ ID NO: 2 or SEQ ID NO: 14.

[0136] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises an extracellular domain of ActRIIB having one or more amino acid substitutions / mutations. Such amino acid substitutions / mutations may, for example, be a conversion from leucine at amino acid position 79 in SEQ ID NO: 2 or SEQ ID NO: 14 to an acidic amino acid such as aspartic acid or glutamic acid. For example, position L79 in SEQ ID NO: 2 or SEQ ID NO: 14 may be modified in the ActRIIB extracellular domain polypeptide to confer modified activin-myostatin (GDF-11) binding properties. L79A and L79P mutations reduce GDF-11 binding to a degree higher than activin binding. L79E and L79D mutations retain GDF-11 binding but demonstrate significantly reduced activin binding.

[0137] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein includes a cleaved form of the ActRIIB extracellular domain that also has an amino acid substitution, for example, the conversion of leucine at amino acid position 79 of SEQ ID NO: 2 or SEQ ID NO: 14 to an acidic amino acid such as aspartic acid or glutamic acid. In certain embodiments, the cleaved form of the extracellular domain of the ActRIIB polypeptide having an amino acid substitution used in the compositions and methods described herein is SEQ ID NO: 9. The cleaved and / or having one or more amino acid substitutions of ActRIIB can be ligated to the Fc domain of an antibody as discussed above.

[0138] Functionally active fragments of the ActRIIB polypeptide can be obtained, for example, by screening polypeptides generated by recombination from corresponding fragments of nucleic acids encoding the ActRIIB polypeptide. In addition, fragments can be chemically synthesized using methods known in the art, such as conventional Merrifield solid-phase f-Moc or t-Boc chemical reactions. Once fragments are generated (by recombination or chemical synthesis), those peptidyl fragments can be tested to identify those that can function as antagonists (traps) in signal transduction mediated by the ActRIIB protein or activin.

[0139] In addition, functionally active variants of the ActRIIB polypeptide can be obtained, for example, by screening a library of modified polypeptides generated by recombination from the corresponding mutagenic nucleic acids encoding the ActRIIB polypeptide. Variants can be generated and tested to identify those that can function as antagonists (inhibitors) of signaling mediated by the ActRIIB protein or activin. In certain embodiments, the functional variant of the ActRIIB polypeptide contains an amino acid sequence that is at least 75% identical to an amino acid sequence selected from SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29. In certain embodiments, the functional variant has an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to an amino acid sequence selected from SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29.

[0140] The ligand-binding pocket of ActRIIB has been demonstrated to be defined by residues Y31, N33, N35, L38-T41, E47, E50, Q53-K55, L57, H58, Y60, S62, K74, W78-N83, Y85, R87, A92, and E94-F101 of SEQ ID NO: 2 or SEQ ID NO: 14. Conservative mutations will be tolerated at these positions, but the K74A mutation is predicted to be well tolerated, as are the R40A, K55A, F82A mutations and the mutation at position L79. R40 is K in the genus Xenopus, indicating that a basic amino acid will be tolerated at this position. Q53 is R in bovine ActRIIB and K in Xenopus ActRIIB, and therefore amino acids containing R, K, Q, N, and H will be tolerated at this position. Accordingly, the general formula for the ActRIIB polypeptide for use in the methods and compositions described herein is one that includes amino acids 29-109 of SEQ ID NO: 2 or SEQ ID NO: 14, but optionally includes starting at amino acid positions in the range of 20-24 or 22-25 of SEQ ID NO: 2 or SEQ ID NO: 14 and ending at amino acid positions in the range of 129-134 of SEQ ID NO: 2 or SEQ ID NO: 14, and including 1, 2, 5 or 15 or fewer consecutive amino acid changes in the ligand-binding pocket, and 0, 1 or more discontinuous modifications at amino acid positions 40, 53, 55, 74, 79 and / or 82 of SEQ ID NO: 2 or SEQ ID NO: 14 in the ligand-binding pocket. Such an ActRIIB polypeptide may retain more than 80%, 90%, 95%, or 99% sequence identity or sequence homology to the sequence of amino acids 29-109 of SEQ ID NO: 2 or SEQ ID NO: 14. The extracellular domains of the binding pocket that are particularly well-acceptable in terms of variability include the amino and carboxyl terminals of ActRIIB, as well as positions 42-46 and 65-73. The modification from asparagine to alanine at position 65 of SEQ ID NO: 2 or SEQ ID NO: 14 (N65A) is actually predicted to improve ligand binding in the A64 background and therefore not have a detrimental effect on ligand binding in the R64 background.This change likely eliminates glycosylation at N65 in the A64 background, thus demonstrating that significant changes in this region may be acceptable. While changes at R64A are not well-tolerated, R64K is well-tolerated, and therefore another basic residue such as H may be acceptable at position 64.

[0141] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises a conjugate / fusion protein containing the extracellular domain of the ActRIIB receptor (e.g., the activin-binding domain) linked to the Fc portion of the antibody. Such a conjugate / fusion protein may include any of the ActRIIB polypeptides disclosed herein (e.g., any of SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29), any ActRIIB polypeptide known in the art, or any ActRIIB polypeptide known in the art and / or prepared using the methods provided herein.

[0142] In certain embodiments, the extracellular domain is linked to the Fc portion of the antibody via a linker, such as a peptide linker. Exemplary linkers include short polypeptide sequences such as 2-10, 2-5, 2-4, or 2-3 amino acid residues (e.g., glycine residues), such as a Gly-Gly-Gly linker. In certain embodiments, the linker includes the amino acid sequence Gly-Gly-Gly (GGG). In another specific embodiment, the linker includes the amino acid sequence Thr-Gly-Gly-Gly (TGGG). Optionally, the Fc domain may have one or more mutations at residues such as Asp-265, lysine 322, and Asn-434. In certain cases, a mutant Fc domain having one or more of these mutations (e.g., Asp-265 mutations) has reduced binding ability to the Fcγ receptor compared to a wild-type Fc domain. In other cases, mutant Fc domains having one or more of these mutations (e.g., the Asn-434 mutation) have increased binding ability to MHC class I-associated Fc receptors (FcRNs) compared to wild-type Fc domains. Exemplary fusion proteins containing the soluble extracellular domain of ActRIIB fused to the Fc domain are described in SEQ ID NOs: 6, 7, 10, 11, 20, 21, 24, 25, 26, 27, 30, 32, and 33.

[0143] In certain embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises the extracellular domain of ActRIIB, or a portion thereof, ligated to the Fc portion of the antibody, wherein the ActRIIB ligand trap contains an amino acid sequence that is at least 75% identical to an amino acid sequence selected from SEQ ID NOs: 6, 7, 10, 11, 20, 21, 24, 25, 26, 27, 30, 32, and 33. In other embodiments, the ActRIIB ligand trap used in the compositions and methods described herein comprises the extracellular domain of ActRIIB, or a portion thereof, ligated to the Fc portion of the antibody, wherein the ActRIIB ligand trap contains an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to an amino acid sequence selected from SEQ ID NOs: 6, 7, 10, 11, 20, 21, 24, 25, 26, 27, 30, 32, and 33.

[0144] In certain embodiments, the ActRIIB ligand trap to be used in the compositions and methods described herein is a fusion protein between the extracellular domain of the human ActRIIB receptor and the Fc moiety of IgG1. In another particular embodiment, the ActRIIB ligand trap to be used in the compositions and methods described herein is a fusion protein between the cleaved extracellular domain of the human ActRIIB receptor and the Fc moiety of IgG1. In yet another particular embodiment, the ActRIIB ligand trap to be used in the compositions and methods described herein is a fusion protein between the cleaved extracellular domain of the human ActRIIB receptor and the Fc moiety of IgG1, wherein the cleaved extracellular domain of the human ActRIIB ligand trap has an amino acid substitution at the amino acid position corresponding to amino acid 79 of SEQ ID NO: 2 or SEQ ID NO: 14. In one embodiment, the amino acid substitution at the amino acid position corresponding to amino acid 79 of SEQ ID NO: 2 or SEQ ID NO: 14 is a substitution of leucine to aspartic acid (i.e., L79D mutation).

[0145] In certain embodiments, the ActRIIB ligand trap to be used in the compositions and methods described herein is SEQ ID NO: 10 or 11, which represents a fusion protein between the extracellular domain of the human ActRIIB receptor and the Fc portion of IgG1, wherein the ActRIIB extracellular domain comprises amino acids 25-131 of SEQ ID NO: 14 having the L79D mutation. The nucleic acid sequence encoding the ActRIIB-Fc fusion protein of SEQ ID NO: 10 is shown in SEQ ID NO: 31.

[0146] In another specific embodiment, the ActRIIB ligand trap to be used in the compositions and methods described herein is SEQ ID NO: 20 or 21, which represents a fusion protein between the extracellular domain of the human ActRIIB receptor and the Fc portion of IgG1, wherein the ActRIIB extracellular domain comprises amino acids 25-131 of SEQ ID NO: 2 having the L79D mutation.

[0147] In certain embodiments, mutant ActRIIB polypeptides, including the addition of a further N-linked glycosylation site (NXS / T) that increases the serum half-life of the ActRIIB-Fc fusion protein compared to the ActRIIB(R64)-Fc form, may be used in the methods and compositions described herein. In certain embodiments, the introduction of asparagine at position 24 of SEQ ID NO: 2 or SEQ ID NO: 14 (A24N) results in the generation of an NXT sequence that confers a longer half-life. Other NX(T / S) sequences may be found at 42-44 (NQS) and 65-67 (NSS), the latter of which may not be efficiently glycosylated at R at position 64 (i.e., in the R64 polypeptide). NXS / T sequences may generally be introduced at positions outside the ligand-binding pocket of ActRIIB, which will be discussed in detail above. Particularly suitable sites for introducing non-endogenous NXS / T sequences include amino acids 20-29, 20-24, 22-25, 109-134, 120-134, or 129-134 of SEQ ID NO: 2 or SEQ ID NO: 14. NXS / T sequences can also be introduced into linkers between ActRIIB sequences and Fc or other fusion components. Such sites can be introduced with minimal effort by introducing N at a reasonable position relative to an existing S or T, or by introducing S or T at a position corresponding to an existing N. Thus, desirable modifications that will generate N-binding glycosylation sites are A24N, R64N, S67N (sometimes combined with the N65A modification), E106N, R112N, G120N, E123N, P129N, A132N, R112S, and R112T (having all amino acid positions corresponding to the positions they may be found in SEQ ID NO: 2 or SEQ ID NO: 14). Any S expected to be glycosylated may be modified to T without generating an immunogenic site for the protection provided by glycosylation. Similarly, any T expected to be glycosylated may be modified to S. Thus, modified S67T and S44T are incorporated herein. Similarly, the S26T modification may be used in the A24N variant. Thus, the ActRIIB polypeptide may contain one or more additional non-endogenous N-linked glycosylation consensus sequences.

[0148] In certain embodiments, the methods and compositions described herein may use isolated or purified ActRIIB polypeptides, i.e., ActRIIB polypeptides isolated from other proteins or otherwise substantially free of other proteins, in conjunction with the methods and compositions described herein. ActRIIB polypeptides are generally produced by expression from recombinant nucleic acids.

[0149] In certain embodiments, the ActRIIB polypeptides used in the methods and compositions described herein are encoded by isolated and / or recombinant nucleic acids comprising the fragments, functional variants, and fusion proteins disclosed herein. For example, SEQ ID NO: 5 encodes a naturally occurring human ActRIIB precursor polypeptide. The nucleic acid may be single-stranded or double-stranded. Such nucleic acids may be DNA or RNA molecules. These nucleic acids may be used, for example, in methods for producing ActRIIB polypeptides or as direct therapeutic agents (e.g., in gene therapy techniques).

[0150] In certain embodiments, it is understood that nucleic acids that can be used to generate ActRIIB polypeptides suitable for use in the methods and compositions described herein further include nucleic acids that are variants of SEQ ID NO: 5 and variants of those nucleic acid sequences encoding soluble ActRIIB polypeptides (e.g., nucleic acids encoding SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29). Variant nucleotide sequences include sequences that differ due to one or more nucleotide substitutions, additions, or deletions, such as allele variants.

[0151] In certain embodiments, isolated or recombinant nucleic acid sequences that can be used to generate ActRIIB polypeptides suitable for use in the methods and compositions described herein are at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% identical to those nucleic acid sequences encoding SEQ ID NO: 5 or soluble ActRIIB polypeptides (e.g., nucleic acids encoding SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, 29). Those skilled in the art will understand that nucleic acid sequences complementary to those encoding SEQ ID NO: 5 or the soluble ActRIIB polypeptide (e.g., nucleic acids encoding SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29), and those encoding SEQ ID NO: 19 or the soluble ActRIIB polypeptide (e.g., nucleic acids encoding SEQ ID NOs: 3, 4, 9, 12, 13, 15, 16, 17, 18, 19, 22, 23, 28, and 29) may be used in conjunction with the methods and compositions described herein. In further embodiments, the nucleic acid sequences may be isolated, recombinant, and / or fused with heterologous nucleotide sequences, or present in a DNA library.

[0152] Assay Various ActRIIB polypeptide variants, or soluble ActRIIB polypeptide variants, may be tested for their ability to inhibit ActRIIB signaling. In addition, compounds may be tested for their ability to inhibit ActRIIB signaling. Once the activity of the ActRIIB ligand trap is confirmed, these compounds may be used in conjunction with the methods provided herein. The assays below are described for ActRIIA, but may be carried out in the same manner as those for ActRIIB.

[0153] For example, the effect of ActRIIA polypeptide variants on the expression of genes involved in bone formation or bone destruction can be evaluated. This can be carried out in the presence of one or more recombinant ActRIIA ligand proteins (e.g., activin), if necessary, and cells can be transfected to produce ActRIIA and / or its variants, and optionally, ActRIIA ligands. Similarly, ActRIIA polypeptides can be administered to mice or other animals, and one or more bone properties, such as density or volume, can be evaluated. The rate of fracture healing can also be evaluated. Dual-energy X-ray absorptiometry (DEXA) is a well-established, non-invasive quantitative technique for assessing bone density in animals. In humans, central DEXA systems can be used to assess bone density in the spine and pelvis. These are the best predictors of overall bone density. Peripheral DEXA systems can be used to assess bone density in peripheral bones, such as the bones of the hand, wrist, ankle, and foot. Conventional X-ray imaging systems, including CAT scans, can be used to assess bone growth and fracture healing. In addition, bone density can be measured using quantitative computed tomography (qCT). The mechanical strength of the bone can also be evaluated.

[0154] In certain embodiments, the use of ActRIIA polypeptides (e.g., soluble ActRIIA polypeptides) and activin polypeptides is provided to identify compounds (pharmaceuticals) that are agonists or antagonists of the activin-ActRIIA signaling pathway. Compounds identified by this screening may be tested to evaluate their ability to modulate bone growth or calcification in vitro. Optionally, these compounds may be further tested in animal models to evaluate their ability to modulate tissue growth in vivo.

[0155] Numerous methods exist for screening therapeutic agents for regulating tissue growth by targeting activin and ActRIIA polypeptides. In certain embodiments, high-throughput screening of compounds may be performed to identify agents that disrupt the activin or ActRIIA-mediated effects on bone. In certain embodiments, assays are performed to screen and identify compounds that specifically inhibit or reduce the binding of ActRIIA polypeptides or activin. Alternatively, assays may be used to identify compounds that enhance the binding of ActRIIA polypeptides to activin. In further embodiments, compounds may be identified by their ability to interact with activin or ActRIIA polypeptides.

[0156] A variety of assay formats are available, and those not expressly described herein will also be understood by those skilled in the art in light of this disclosure. As described herein, the test compounds (agents) used herein may be prepared by any combinatorial chemical method. Alternatively, the compounds of interest may be naturally occurring biomolecules synthesized in vivo or in vitro. The compounds (agents) to be tested for their ability to act as regulators of tissue growth may be produced, for example, by bacteria, yeast, plants or other organisms (e.g., natural products), chemically produced (e.g., small molecules including peptide mimes), or produced by recombinants. Examples of test compounds intended herein include non-peptidyl organic molecules, peptides, polypeptides, peptide mimes, sugars, hormones, and nucleic acid molecules. In certain embodiments, the test agent is a small organic molecule having a molecular weight of less than about 2,000 daltons.

[0157] Test compounds may be provided as single, separate entities or in libraries of higher complexity, such as those prepared by combinatorial chemistry. These libraries may include, for example, alcohols, alkyl halides, amines, amides, esters, aldehydes, ethers, and other classes of organic compounds. The presentation of test compounds to the test system may be in isolated forms or as mixtures of compounds, particularly in the initial screening steps. Optionally, compounds may be derivatized with other compounds and may have derivatizing groups that facilitate the isolation of the compounds. Non-limiting examples of derivatizing groups include biotin, fluorescein, digoxigenin, green fluorescent protein, isotopes, polyhistidines, magnetic beads, glutathione S-transferase (GST), photoactivating crosslinkers, or any combination thereof.

[0158] In many drug screening programs testing libraries of compounds and natural extracts, high-throughput assays are desirable to maximize the number of compounds investigated over a given period. Assays performed in cell-free systems, such as those induced by purified or semi-purified proteins, are often preferred as “primary” screening because they can be designed to allow for the rapid development and relatively easy detection of modifications at molecular targets mediated by the test compound. Furthermore, the effects of cytotoxicity or bioavailability of the test compound can generally be ignored in in vitro systems, and instead, the assay focuses primarily on the drug’s effect on molecular targets, such as those evident in modifications of the binding affinity between ActRIIA polypeptide and activin.

[0159] For illustrative purposes, in an exemplary screening assay, the compound of interest is contacted with isolated ActRIIA polypeptides and purified ActRIIA polypeptides that can typically bind to activin. Next, a composition containing an ActRIIA ligand is added to the mixture of the compound and the ActRIIA polypeptide. Detection and quantification of the ActRIIA / activin complex provides a means for determining the efficacy of the compound in inhibiting (or enhancing) complex formation between the ActRIIA polypeptide and activin. The efficacy of the compound can be evaluated by constructing a dose-response curve from data obtained using various concentrations of the test compound. Furthermore, a control assay may also be performed to provide a baseline for comparison. For example, in a control assay, isolated activin and purified activin are added to the composition containing the ActRIIA polypeptide, and the formation of the ActRIIA / activin complex is quantified in the absence of the test compound. Generally, it will be understood that the order in which the reactants may be mixed may be varied and may be mixed simultaneously. Furthermore, cell extracts and lysates may be used instead of purified proteins to obtain a suitable cell-free assay system.

[0160] The formation of a complex between ActRIIA polypeptide and activin can be detected by various methods. For example, the regulation of complex formation can be quantified by immunoassay or chromatographic detection using detectably labeled proteins such as radiolabeled (e.g., 32P, 35S, 14C, or 3H), fluorescently labeled (e.g., FITC), or enzyme-labeled ActRIIA polypeptide or activin.

[0161] In certain embodiments, the use of fluorescence polarization assays and fluorescence resonance energy transfer (FRET) assays to directly or indirectly measure the degree of interaction between ActRIIA polypeptides and their binding proteins is intended herein. Furthermore, other forms of detection, such as those based on optical waveguides (International Publication No. 96 / 26432 and U.S. Patent No. 5,677,196), surface plasmon resonance (SPR), surface charge sensors, and surface force sensors, are compatible with many embodiments described herein.

[0162] Furthermore, interaction trap assays, also known as "two-hybrid assays," may be used to identify agents that disrupt or enhance the interaction between ActRIIA polypeptides and their binding proteins. See, for example, U.S. Patent No. 5,283,317; Zervos et al. (1993) Cell 72:223-232; Madura et al. (1993) J Biol Chem 268:12046-12054; Bartel et al. (1993) Biotechniques 14:920-924; and Iwabuchi et al. (1993) Oncogene 8:1693-1696). In certain embodiments, the use of reverse two-hybrid systems to identify compounds (e.g., small molecules or peptides) that dissociate the interaction between ActRIIA polypeptides and their binding proteins is contemplated herein. For example, see Vidal and Legrain, (1999) Nucleic Acids Res 27:919-29; Vidal and Legrain, (1999) Trends Biotechnol 17:374-81; and U.S. Patent Nos. 5,525,490, 5,955,280, and 5,965,368.

[0163] In certain embodiments, target compounds are identified by their ability to interact with ActRIIA or activin polypeptides. The interaction between the compound and ActRIIA or activin polypeptide may be covalent or non-covalent. For example, such interactions may be identified at the protein level using in vitro biochemical methods including photocrosslinking, radiolabeled ligand binding, and affinity chromatography (Jakoby WB et al., 1974, Methods in Enzymology 46:1). In certain cases, compounds may be screened in mechanism-based assays, such as assays that detect compounds that bind to activin or ActRIIA polypeptides. This may include solid-phase or liquid-phase binding events. Alternatively, the gene encoding activin or ActRIIA polypeptide may be transfected into cells with a reporter system (e.g., β-galactosidase, luciferase, or green fluorescent protein) and screened against the library, preferably by high-throughput screening or by individual members of the library. Other mechanism-based binding assays may be used, such as binding assays that detect changes in free energy. The binding assay may be performed using targets immobilized on wells, beads, or tips, or captured by immobilized antibodies, or separated by capillary electrophoresis. The bound compound can typically be detected using colorimetric analysis or fluorescence or surface plasmon resonance.

[0164] 5.5 Treatment Methods This specification provides a method for treating anemia in a subject requiring treatment, comprising: administering to the subject an activin receptor type IIB (ActRIIB) ligand trap (such as the ActRIIB ligand trap described in Section 5.4); and then administering to the subject fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3). In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt and / or hydrate are administered simultaneously. In certain embodiments, the co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt and / or hydrate is pharmaceutically effective for treating anemia.

[0165] In some embodiments, the subjects are those described in Section 5.6. In some embodiments, the subjects are human. In some embodiments, the subjects are those diagnosed with myelofibrosis. In some embodiments, the subjects are those diagnosed with myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is intermediate or high-risk myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF). In certain embodiments, myelofibrosis is intermediate or high-risk post-polycythemia vera myelofibrosis (post-PV MF). In certain embodiments, myelofibrosis is intermediate or high-risk post-essential thrombocythemia myelofibrosis (post-ET MF).

[0166] In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is primary myelofibrosis. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is polycythemia vera myelofibrosis. In some further embodiments, polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation or a JAK2 exon 12 mutation, or a thrombopoietin receptor (MPL) mutation. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is post-polycythemia vera myelofibrosis. In some further embodiments, post-polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is essential thrombocytopenia or post-essential thrombocytopenia myelofibrosis. In some embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis is associated with or caused by a JAK2 mutation, such as the JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In some embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis includes reticulin fibrosis or trichrome fibrosis.

[0167] In certain embodiments, the subject has anemia. In certain embodiments, the anemia is associated with myelofibrosis. In certain embodiments, the anemia is associated with MPN-associated myelofibrosis. In certain embodiments, the anemia is associated with primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF).

[0168] In certain embodiments, anemia is anemia associated with ineffective erythropoiesis, thalassemia, alpha-thalassemia, beta-thalassemia, myelodysplastic syndrome (MDS), or nonproliferative chronic myelomonocytic leukemia (CMML).

[0169] In some embodiments, the subject is one of the subjects described in Section 5.6. In some embodiments, the subject is a human being.

[0170] In some embodiments, the subject is red blood cell transfusion dependent or transfusion-independent. In certain embodiments, the subject is red blood cell transfusion dependent. In certain embodiments, the subject is transfusion-independent. In certain embodiments, the subject is red blood cell transfusion-independent.

[0171] In some embodiments, as used herein, “transfusion” refers to red blood cell (RBC) transfusion.

[0172] In some embodiments, if a subject receives 4 or fewer RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or red blood cell transfusion-independent. In some embodiments, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received RBC units during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received an RBC transfusion during the period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0173] In one embodiment, if a subject receives 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent.

[0174] In one embodiment, a transfusion-independent or RBC transfusion-independent subject has received 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In another embodiment, a transfusion-independent or RBC transfusion-independent subject has not received any RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In yet another embodiment, transfusion-independent or RBC transfusion-independent subjects have not received RBC transfusions during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less.

[0175] In some embodiments, a subject is transfusion-dependent if the subject received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject has received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 16 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 10 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.In some embodiments, a subject is transfusion-dependent if the subject received 4 to 8 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4–6 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0176] In some embodiments, a subject is transfusion-dependent if it received 4 or more RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4 to 16 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, if a subject receives 4 to 12 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 6 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, a subject is transfusion-dependent if it received 6–12, 6–10, or 6–8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if it received 8–12 or 8–10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0177] In one embodiment, a transfusion-dependent red blood cell subject has received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, a transfusion-dependent red blood cell subject has received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0178] In one embodiment, the RBC transfusion-dependent subject has received 4 or more red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0179] In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 6 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 6 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0180] In one embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0181] In some embodiments, fedratinib is administered to the subject as part of a composition. In some embodiments, the composition is one of the compositions described in Section 5.7.

[0182] In some embodiments, fedratinib is administered in the doses described in Section 5.8. In one embodiment, fedratinib is administered in doses of 400 mg / day, 300 mg / day, 200 mg / day, or 100 mg / day. In another embodiment, fedratinib is administered to the subject at the frequencies described in Section 5.8. In a preferred embodiment, fedratinib is administered daily.

[0183] In some embodiments, fedratinib is administered to the subject via the route of administration described in Section 5.10. In preferred embodiments, fedratinib is administered orally to the subject.

[0184] In some embodiments, the ActRIIB ligand trap is administered to the subject as part of a composition. In some embodiments, the composition is one of the compositions described in Section 5.7.

[0185] In some embodiments, the ActRIIB ligand trap is administered to the subject via the administration route described in Section 5.10. In some embodiments, the ActRIIB ligand trap is administered intravenously or subcutaneously to the subject. In preferred embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject.

[0186] In some embodiments, fedratinib is administered in the doses described in Section 5.8. In some embodiments, the ActRIIB ligand trap is administered in doses of 0.3 mg / kg to 2.0 mg / kg, for example, 0.3 mg / kg, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In some embodiments, the ActRIIB ligand trap is administered in a pharmaceutically effective amount. In one embodiment, the pharmaceutically effective amount of ActRIIB ligand trap administered is 1.33 mg / kg. In some embodiments, the ActRIIB ligand trap is administered to subjects at the frequencies described in Section 5.8. In some embodiments, the ActRIIB ligand trap is administered to subjects once every 14 days, once every 21 days, once every 28 days, once every 35 days, or once every 42 days. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once every 21 days. In some embodiments, the ActRIIB ligand trap is administered to the subject once, two, or three times per treatment cycle. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once per treatment cycle. In some embodiments, the ActRIIB ligand trap is administered to the subject for at least one, two, three, four, five, six, seven, eight, nine, or ten cycles. In one embodiment, the ActRIIB ligand trap is administered to the subject for at least six, seven, eight, nine, or ten cycles. In another embodiment, the ActRIIB ligand trap is administered to the subject for six cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for seven cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for eight cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for nine cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for ten cycles. In one embodiment, the ActRIIB ligand trap is administered once at the start of each treatment cycle.

[0187] In some embodiments, the ActRIIB ligand trap is the ActRIIB ligand trap described in Section 5.4. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence described in SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide encoded by the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34. In preferred embodiments, the ActRIIB ligand trap is a raspa tercept.

[0188] In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising an amino acid sequence selected from the group consisting of (a) 90% identical to SEQ ID NO: 3; (b) 95% identical to SEQ ID NO: 3; (c) 98% identical to SEQ ID NO: 3; (d) SEQ ID NO: 3; (e) 90% identical to SEQ ID NO: 6; (f) 95% identical to SEQ ID NO: 6; (g) 98% identical to SEQ ID NO: 6; (h) SEQ ID NO: 6; (i) 90% identical to SEQ ID NO: 7; (j) 95% identical to SEQ ID NO: 7; (k) 98% identical to SEQ ID NO: 7; (l) SEQ ID NO: 7; (m) 90% identical to SEQ ID NO: 11; (n) 95% identical to SEQ ID NO: 11; (o) 98% identical to SEQ ID NO: 11; and (p) SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11. In a particular embodiment, the ActRIIB ligand trap is a humanized fusion protein consisting of the extracellular domain of ActRIIB and the human IgG1 Fc domain.

[0189] Furthermore, this specification also provides a method for treating a subject in need of treatment, comprising: (a) obtaining a first measurement of hemoglobin (Hgb) levels in the subject; (b) administering an initial dose of an ActRIIB ligand trap (such as an ActRIIB ligand inhibitor as described in Section 5.4) to the subject; (c) administering fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3) to the subject; (d) obtaining a second measurement of hemoglobin (Hgb) levels in the subject at the end of a first period following the administration of the initial dose of the ActRIIB ligand trap; and then (e) administering a next dose of the ActRIIB ligand trap to the subject based on the second measurement of hemoglobin (Hgb) levels compared to the first measurement of hemoglobin (Hgb) levels, or based on the number of red blood cell transfusions the subject received during the first period. In certain embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective for treating anemia.

[0190] In some embodiments, the subjects are those described in Section 5.6. In some embodiments, the subjects are human. In some embodiments, the subjects are those diagnosed with myelofibrosis. In some embodiments, the subjects are those diagnosed with myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is intermediate or high-risk myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF). In certain embodiments, myelofibrosis is intermediate or high-risk post-polycythemia vera myelofibrosis (post-PV MF). In certain embodiments, myelofibrosis is intermediate or high-risk post-essential thrombocythemia myelofibrosis (post-ET MF).

[0191] In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is primary myelofibrosis. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is polycythemia vera myelofibrosis. In some further embodiments, polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation or a JAK2 exon 12 mutation, or a thrombopoietin receptor (MPL) mutation. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is post-polycythemia vera myelofibrosis. In some further embodiments, post-polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is essential thrombocytopenia or post-essential thrombocytopenia myelofibrosis. In some further embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis is associated with or caused by a JAK2 mutation, such as a JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In some further embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis includes reticuline fibrosis or trichrome fibrosis.

[0192] In certain embodiments, the subject has anemia. In certain embodiments, the anemia is associated with myelofibrosis. In certain embodiments, the anemia is associated with MPN-associated myelofibrosis. In certain embodiments, the anemia is associated with primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF).

[0193] In certain embodiments, anemia is anemia associated with ineffective erythropoiesis, thalassemia, alpha-thalassemia, beta-thalassemia, myelodysplastic syndrome (MDS), or nonproliferative chronic myelomonocytic leukemia (CMML).

[0194] In some embodiments, the subject is one of the subjects described in Section 5.6. In some embodiments, the subject is a human being.

[0195] In some embodiments, the subject is red blood cell transfusion dependent or transfusion-independent. In certain embodiments, the subject is red blood cell transfusion dependent. In certain embodiments, the subject is transfusion-independent. In certain embodiments, the subject is red blood cell transfusion-independent.

[0196] In some embodiments, as used herein, “transfusion” refers to red blood cell (RBC) transfusion.

[0197] In some embodiments, if a subject receives 4 or fewer RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or red blood cell transfusion-independent. In some embodiments, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received RBC units during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received an RBC transfusion during the period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0198] In one embodiment, if a subject receives 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent.

[0199] In one embodiment, a transfusion-independent or RBC transfusion-independent subject has received 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to the fedratinib and / or ActRIIB ligand trapping of the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In another embodiment, a transfusion-independent or RBC transfusion-independent subject has not received any RBC units in an RBC transfusion during the 84-day period prior to the fedratinib and / or ActRIIB ligand trapping of the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In yet another embodiment, transfusion-independent or RBC transfusion-independent subjects have not received RBC transfusions during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less.

[0200] In some embodiments, a subject is transfusion-dependent if the subject received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject has received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 16 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 10 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.In some embodiments, a subject is transfusion-dependent if the subject received 4 to 8 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4–6 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0201] In some embodiments, a subject is transfusion-dependent if it received 4 or more RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4 to 16 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, if a subject receives 4 to 12 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 6 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, a subject is transfusion-dependent if it received 6–12, 6–10, or 6–8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if it received 8–12 or 8–10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0202] In one embodiment, a transfusion-dependent red blood cell subject has received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, a transfusion-dependent red blood cell subject has received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0203] In one embodiment, the RBC transfusion-dependent subject has received 4 or more red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0204] In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 6 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 6 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0205] In one embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0206] In some embodiments, fedratinib is administered to the subject as part of a composition. In some embodiments, the composition is one of the compositions described in Section 5.7.

[0207] In some embodiments, fedratinib is administered in the doses described in Section 5.8. In one embodiment, fedratinib is administered in doses of 600 mg / day, 500 mg / day, 400 mg / day, 300 mg / day, 200 mg / day, or 100 mg / day. In another embodiment, fedratinib is administered to the subject at the frequencies described in Section 5.8. In a preferred embodiment, fedratinib is administered daily.

[0208] In some embodiments, fedratinib is administered to the subject via the route of administration described in Section 5.10. In preferred embodiments, fedratinib is administered orally to the subject.

[0209] In some embodiments, the ActRIIB ligand trap is administered to the subject as part of a composition. In some embodiments, the composition is one of the compositions described in Section 5.7.

[0210] In some embodiments, the ActRIIB ligand trap is administered to the subject via the administration route described in Section 5.10. In some embodiments, the ActRIIB ligand trap is administered intravenously or subcutaneously to the subject. In preferred embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject.

[0211] In some embodiments, fedratinib is administered in the doses described in Section 5.8. In some embodiments, the ActRIIB ligand trap is administered in doses of 0.3 mg / kg to 2.0 mg / kg, for example, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In some embodiments, the ActRIIB ligand trap is administered in a pharmaceutically effective amount. In one embodiment, the pharmaceutically effective amount of ActRIIB ligand trap administered is 1.33 mg / kg. In some embodiments, the ActRIIB ligand trap is administered to subjects at the frequencies described in Section 5.8. In some embodiments, the ActRIIB ligand trap is administered to subjects once every 14 days, once every 21 days, once every 28 days, once every 35 days, or once every 42 days. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once every 21 days. In some embodiments, the ActRIIB ligand trap is administered to the subject once, two, or three times per treatment cycle. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once per treatment cycle. In some embodiments, the ActRIIB ligand trap is administered to the subject for at least one, two, three, four, five, six, seven, eight, nine, or ten cycles. In one embodiment, the ActRIIB ligand trap is administered to the subject for at least six, seven, eight, nine, or ten cycles. In another embodiment, the ActRIIB ligand trap is administered to the subject for six cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for seven cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for eight cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for nine cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for ten cycles. In one embodiment, the ActRIIB ligand trap is administered once at the start of each treatment cycle.

[0212] In some embodiments, the ActRIIB ligand trap is the ActRIIB ligand trap described in Section 5.4. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence described in SEQ ID NO: 11. In some embodiments, the ActRIIB ligand trap is a polypeptide encoded by the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34. In preferred embodiments, the ActRIIB ligand trap is a raspa tercept.

[0213] In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising an amino acid sequence selected from the group consisting of (a) 90% identical to SEQ ID NO: 3; (b) 95% identical to SEQ ID NO: 3; (c) 98% identical to SEQ ID NO: 3; (d) SEQ ID NO: 3; (e) 90% identical to SEQ ID NO: 6; (f) 95% identical to SEQ ID NO: 6; (g) 98% identical to SEQ ID NO: 6; (h) SEQ ID NO: 6; (i) 90% identical to SEQ ID NO: 7; (j) 95% identical to SEQ ID NO: 7; (k) 98% identical to SEQ ID NO: 7; (l) SEQ ID NO: 7; (m) 90% identical to SEQ ID NO: 11; (n) 95% identical to SEQ ID NO: 11; (o) 98% identical to SEQ ID NO: 11; and (p) SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11. In a particular embodiment, the ActRIIB ligand trap is a humanized fusion protein consisting of the extracellular domain of ActRIIB and the human IgG1 Fc domain.

[0214] 5.5.1 Dose adjustment or delay of ActRIIB ligand trap In some embodiments, the dose of the ActRIIB ligand trap is adjusted during treatment of the subject in the method described herein. In some embodiments, the dose of the ActRIIB ligand trap is adjusted before each treatment cycle. In some embodiments, the dose of the ActRIIB ligand trap is adjusted based on a first and second measurement of hemoglobin (Hgb) levels in the subject. In some embodiments, the dose of the ActRIIB ligand trap is adjusted based on, in one embodiment, the dose of the ActRIIB ligand trap being adjusted based on a comparison of a first and second measurement of hemoglobin (Hgb) levels obtained before two treatment cycles.

[0215] In some embodiments, the first measurement of hemoglobin (Hgb) levels is taken before the administration of the initial dose of the ActRIIB ligand trap. In some embodiments, the first measurement of hemoglobin (Hgb) levels is taken before each treatment cycle. In some embodiments, the first measurement of hemoglobin (Hgb) levels is taken before the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, or 10th treatment cycle. In some embodiments, the first measurement of hemoglobin (Hgb) levels is taken concurrently with the administration of the initial dose of the ActRIIB ligand trap, or approximately 3, 6, 9, 12, 15, 18, 21, or 24 weeks after the administration of the initial dose of the ActRIIB ligand trap. In some embodiments, the first measurement of hemoglobin (Hgb) levels is taken concurrently with the administration of the initial dose of the ActRIIB ligand trap. In some embodiments, the first measurement of hemoglobin (Hgb) levels is obtained approximately 3, 6, 9, 12, 15, 18, 21, or 24 weeks after administration of the initial dose of the ActRIIB ligand trap.

[0216] In some embodiments, the first period is 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, 24 weeks, 7 months, 8 months, 9 months, 10 months, 11 months, or 12 months. In some embodiments, the first period is 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, or 24 weeks. In some embodiments, the first period is 3 or 6 weeks. In a particular embodiment, the first period is 3 weeks. In a particular embodiment, the first period is 6 weeks.

[0217] In some embodiments, a second measurement of Hgb levels is taken approximately 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, 24 weeks, 7 months, 8 months, 9 months, 10 months, 11 months, or 12 months after the first measurement of Hgb levels in the subject. In some embodiments, a second measurement of Hgb levels is taken approximately 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 15 weeks, 18 weeks, or 21 weeks after the first measurement of Hgb levels in the subject. In some embodiments, a second measurement of Hgb levels is taken approximately 3 or 6 weeks after the first measurement of Hgb levels in the subject. In some embodiments, a second measurement of Hgb levels is taken approximately 3 weeks after the first measurement of Hgb levels in the subject. In some embodiments, a second measurement of Hgb levels is taken approximately 6 weeks after the first measurement of Hgb levels in the subject.

[0218] In some embodiments, a second measurement of hemoglobin (Hgb) levels is taken before the administration of the initial dose of the ActRIIB ligand trap. In some embodiments, a second measurement of hemoglobin (Hgb) levels is taken before each treatment cycle, starting from the second treatment cycle. In some embodiments, a second measurement of hemoglobin (Hgb) levels is taken before the 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, or 10th treatment cycle. In some embodiments, a second measurement of hemoglobin (Hgb) levels is taken concurrently with the administration of the next dose of the ActRIIB ligand trap, or approximately 3, 6, 9, 12, 15, 18, 21, or 24 weeks after the administration of the initial dose of the ActRIIB ligand trap. In some embodiments, a second measurement of hemoglobin (Hgb) levels is taken concurrently with the administration of the next dose of the ActRIIB ligand trap. In some embodiments, a second measurement of hemoglobin (Hgb) levels is obtained approximately 3, 6, 9, 12, 15, 18, 21, or 24 weeks after administration of the initial dose of the ActRIIB ligand trap. In some embodiments, the second measurement is obtained approximately 6 weeks after administration of the initial dose of the ActRIIB ligand trap.

[0219] In some embodiments, the initial dose of the ActRIIB ligand trap is 0.3 mg / kg, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 0.30 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 0.33 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 0.45 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 0.6 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 0.8 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 1.0 mg / kg. In preferred embodiments, the initial dose of the ActRIIB ligand trap is 1.33 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 1.75 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 2.0 mg / kg.

[0220] In some embodiments, the next dose of the ActRIIB ligand trap is 0.30 mg / kg, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, or 1.75 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.30 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.33 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.45 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.6 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 0.8 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.0 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.33 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.75 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 2.0 mg / kg.

[0221] In a particular embodiment, the next dose of ActRIIB ligand trap is approximately 0.5 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, 2.0 mg, 2.1 mg, and 2.2 mg from the initial dose of ActRIIB ligand trap. Approximately 2.3 mg, 2.4 mg, 2.5 mg, 2.5 mg, 2.6 mg, 2.7 mg, 2.8 mg, 2.9 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.5 mg, 5 mg, 6 mg, 7 mg, 8 mg, 9 mg, 10 mg, 11 mg, 12 mg, 13 mg, 14 mg, 15 mg, 16 mg, 17 mg, 18 mg, 19 mg, 20 mg, or 35 mg more. In a particular embodiment, the next dose of ActRIIB ligand trap is approximately 0.05 mg / kg, 0.06 mg / kg, 0.07 mg / kg, 0.08 mg / kg, 0.09 mg / kg, 0.1 mg / kg, 0.11 mg / kg, 0.12 mg / kg, 0.13 mg / kg, 0.14 mg / kg, 0.15 mg / kg, 0.16 mg / kg, and 0.17 mg / kg from the initial dose of ActRIIB ligand trap. g / kg, approximately 0.18 mg / kg, approximately 0.19 mg / kg, approximately 0.20 mg / kg, approximately 0.21 mg / kg, approximately 0.22 mg / kg, approximately 0.23 mg / kg, approximately 0.24 mg / kg, approximately 0.25 mg / kg, approximately 0.26 mg / kg, approximately 0.27 mg / kg, approximately 0.28 mg / kg, approximately 0.29 mg / kg, approximately 0.3 mg / kg, approximately 0.35 mg / kg, approximately 0.4 mg / kg, approximately 0.45 mg / kg, or approximately 0.5 mg / kg more.

[0222] For certain uses, the following doses are approximately 0.5 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, 2.0 mg, 2.1 mg, 2.2 mg, 2.3 mg, 2.4 mg, and 2 mg respectively, from the initial dose. 0.5mg, approximately 2.5mg, approximately 2.6mg, approximately 2.7mg, approximately 2.8mg, approximately 2.9mg, approximately 3.0mg, approximately 3.5mg, approximately 4.0mg, approximately 4.5mg, approximately 5mg, approximately 6mg, approximately 7mg, approximately 8mg, approximately 9mg, approximately 10mg, approximately 11mg, approximately 12mg, approximately 13mg, approximately 14mg, approximately 15mg, approximately 16mg, approximately 17mg, approximately 18mg, approximately 19mg, approximately 20mg, or approximately 35mg more. or approximately 0.05 mg / kg, 0.06 mg / kg, 0.07 mg / kg, 0.08 mg / kg, 0.09 mg / kg, 0.1 mg / kg, 0.11 mg / kg, 0.12 mg / kg, 0.13 mg / kg, 0.14 mg / kg, 0.15 mg / kg, 0.16 mg / kg, 0.17 mg / kg, 0.18 mg / kg, 0.19 mg / kg from the initial dose. g, approximately 0.20 mg / kg, approximately 0.21 mg / kg, approximately 0.22 mg / kg, approximately 0.23 mg / kg, approximately 0.24 mg / kg, approximately 0.25 mg / kg, approximately 0.26 mg / kg, approximately 0.27 mg / kg, approximately 0.28 mg / kg, approximately 0.29 mg / kg, approximately 0.3 mg / kg, approximately 0.35 mg / kg, approximately 0.4 mg / kg, approximately 0.45 mg / kg, or approximately 0.5 mg / kg less.

[0223] In some embodiments, the next dose of ActRIIB ligand trap is the same as the initial dose of ActRIIB ligand trap.

[0224] In some embodiments, when the second measured Hgb level is 0.5 g / L or higher, 1.0 g / L or higher, 1.5 g / L or higher, 2.0 g / L or higher, or 2.5 g / L or higher than the first measured Hgb level, the next dose of the ActRIIB ligand trap is less than the initial dose of the ActRIIB ligand trap. In some embodiments, when the second measured Hgb level is 2.0 g / L or higher than the first measured Hgb level, the next dose of the ActRIIB ligand trap is less than the initial dose of the ActRIIB ligand trap.

[0225] In some embodiments, when a second measurement of Hgb level is 0.5 g / L or higher, 1.0 g / L or higher, 1.5 g / L or higher, 2.0 g / L or higher, or 2.5 g / L or higher than a first measurement of Hgb level, the dose of ActRIIB ligand trap to be administered is reduced. In some embodiments, when a second measurement of Hgb level is 2.0 g / L or higher than a first measurement of Hgb level, the dose of ActRIIB ligand trap to be administered is reduced.

[0226] In some embodiments, when a subject has received one or more RBC transfusions during the first period, or when a second measurement of Hgb level is 0 to approximately 1 g / dL higher than the first measurement of Hgb level, or when the first measurement of Hgb level decreases by 1 g / dL or more during a period of approximately 6 weeks without transfusions, the next dose of ActRIIB ligand trap is greater than the initial dose of ActRIIB ligand trap. In some embodiments, when a subject has received one or more RBC transfusions during the first period, the next dose of ActRIIB ligand trap is greater than the initial dose of ActRIIB ligand trap. In some embodiments, when a second measurement of Hgb level is 0 to approximately 1 g / dL higher than the first measurement of Hgb level, the next dose of ActRIIB ligand trap is greater than the initial dose of ActRIIB ligand trap. In some embodiments, when the first measured Hgb level decreases by 1 g / dL or more during a transfusion-free period of approximately 6 weeks, the next dose of ActRIIB ligand trap is greater than the initial dose of ActRIIB ligand trap.

[0227] In some embodiments, the administration of ActRIIB ligand traps is delayed when the subject has grade 4 thrombocytopenia or grade 3 thrombocytopenia with active bleeding. In some embodiments, the administration of ActRIIB ligand traps is delayed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 weeks. In one embodiment, the administration of ActRIIB ligand traps is delayed for 1 cycle. In another embodiment, the administration of ActRIIB ligand traps is delayed for 2 cycles. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for 3 cycles. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for 4 cycles. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for up to 3 weeks. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for up to 6 weeks. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for up to 9 weeks. In yet another embodiment, the administration of ActRIIB ligand traps is delayed for up to 12 weeks. In some embodiments, leukocyte, neutrophil, and platelet counts are measured weekly during the delay of ActRIIB ligand trap administration.

[0228] In some embodiments, the administration of the ActRIIB ligand trap is delayed when the subject has grade 4 neutropenia or grade 4 leukopenia (worsening by grade 2). In some embodiments, the administration of the ActRIIB ligand trap is delayed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 weeks. In one embodiment, the administration of the ActRIIB ligand trap is delayed for 1 cycle. In another embodiment, the administration of the ActRIIB ligand trap is delayed for 2 cycles. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for 3 cycles. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for 4 cycles. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for up to 3 weeks. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for up to 6 weeks. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for up to 9 weeks. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for up to 12 weeks. In some embodiments, white blood cell (WBC), neutrophil, and platelet counts are measured weekly during the delay in the administration of the ActRIIB ligand trap.

[0229] In some embodiments, the object is 120 × 10 9 / L or more, or 30 x 10 9The administration of the ActRIIB ligand trap is delayed when the white blood cell count (WBC) is greater than 120 × 10¹⁶ / L and more than three times the baseline WBC. In some embodiments, the administration of the ActRIIB ligand trap is delayed for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 weeks. In one embodiment, the administration of the ActRIIB ligand trap is delayed for 1 week. In another embodiment, the administration of the ActRIIB ligand trap is delayed for 2 weeks. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for 3 weeks. In yet another embodiment, the administration of the ActRIIB ligand trap is delayed for 4 weeks. In some embodiments, the administration of the ActRIIB ligand trap is delayed and the subject's WBC is measured weekly. In some embodiments, the administration of the ActRIIB ligand trap is delayed when the subject's WBC is 120 × 10¹⁶ 9 / L or less, 30×10 9 The delay continues until it falls below / L or is less than three times the baseline WBC.

[0230] 5.5.2 Dose adjustment or delay of fedratinib In some embodiments, the dose of fedratinib administered to a subject is reduced when the subject experiences an adverse event. In some embodiments, the dose of fedratinib administered to a subject is reduced when the subject experiences a hematological, hepatic, non-hematological, or gastrointestinal adverse event that is graded 1, 2, 3, 4, or 5 according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE). In some embodiments, the dose of fedratinib administered to a subject is reduced to 300 mg / day, 200 mg / day, or 100 mg / day. In one embodiment, the dose of fedratinib administered to a subject is reduced to 300 mg / day. In another embodiment, the dose of fedratinib administered to a subject is reduced to 200 mg / day. In yet another embodiment, the dose of fedratinib administered to a subject is reduced to 100 mg / day. In yet another embodiment, the dose of fedratinib administered to a subject is reduced to 0 mg / day. In yet another embodiment, the administration of fedratinib is interrupted.

[0231] In some embodiments, administration of fedratinib is delayed when the subject has grade 4 or grade 3 thrombocytopenia with active bleeding. In some embodiments, administration of fedratinib is delayed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 weeks. In one embodiment, administration of fedratinib is delayed by 1 week. In another embodiment, administration of fedratinib is delayed by 2 weeks. In yet another embodiment, administration of fedratinib is delayed by 3 weeks. In yet another embodiment, administration of fedratinib is delayed by 4 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 3 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 4 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 3 weeks until the subject's thrombocytopenia is grade 3 or lower. In yet another embodiment, administration of fedratinib is delayed up to four weeks until thrombocytopenia in the subject is grade 3 or lower. In yet another embodiment, administration of fedratinib is delayed up to three weeks until thrombocytopenia in the subject is grade 3 or lower without bleeding. In yet another embodiment, administration of fedratinib is delayed up to four weeks until thrombocytopenia in the subject is grade 3 or lower without bleeding. In some embodiments, when fedratinib is administered after the delay, it is administered at the next dose of fedratinib. In some embodiments, the next dose of fedratinib is the same as the dose of fedratinib before the delay. In some embodiments, the next dose of fedratinib is 400 mg / day. In some embodiments, the next dose of fedratinib is 100 mg / day lower than the dose of fedratinib before the delay. In some embodiments, the dose of fedratinib administered to the subject is reduced to 300 mg / day, 200 mg / day, or 100 mg / day. In some embodiments, the next dose of fedratinib is 300 mg / day, 200 mg / day, or 100 mg / day.

[0232] In some embodiments, administration of fedratinib is delayed when the subject has grade 4 neutropenia. In some embodiments, administration of fedratinib is delayed by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 weeks. In one embodiment, administration of fedratinib is delayed by 1 week. In another embodiment, administration of fedratinib is delayed by 2 weeks. In yet another embodiment, administration of fedratinib is delayed by 3 weeks. In yet another embodiment, administration of fedratinib is delayed by 4 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 3 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 4 weeks. In yet another embodiment, administration of fedratinib is delayed by up to 3 weeks until the neutropenia in the subject is grade 2 or lower. In yet another embodiment, administration of fedratinib is delayed by up to 4 weeks until the neutropenia in the subject is grade 2 or lower. In some embodiments, when fedratinib is administered after a delay, it is administered at the next dose. In some embodiments, the next dose of fedratinib is the same as the dose of fedratinib before the delay. In some embodiments, the next dose of fedratinib is 400 mg / day. In some embodiments, the next dose of fedratinib is 100 mg / day lower than the dose of fedratinib before the delay. In some embodiments, the dose of fedratinib administered to the subject is reduced to 300 mg / day, 200 mg / day, or 100 mg / day. In some embodiments, the next dose of fedratinib is 300 mg / day, 200 mg / day, or 100 mg / day.

[0233] In some embodiments, the therapeutic efficacy of the methods described herein is measured using the revised hematological improvement-erythrocyte response (HI-E). In some embodiments, HI-E is defined over any continuous period of 84 days or more (12 weeks) using the International Working Group (IWG) efficacy criteria for MDS (MDS-IWG efficacy criteria). The MDS-IWG efficacy criteria are disclosed, for example, in Cheson et al., 2006, Blood. 108:419-425, which is incorporated herein by reference in whole.

[0234] In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 0.5 g / dL, at least 1.0 g / dL, at least 1.5 g / dL, at least 2.0 g / dL, or at least 2.5 g / dL. In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 0.5 g / dL. In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 1.0 g / dL. In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 1.5 g / dL. In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 2.0 g / dL. In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 2.5 g / dL. In some embodiments, the increase in Hgb level is compared to baseline. In a preferred embodiment, baseline is the Hgb level in the subject prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, baseline is the Hgb level in the reference population.

[0235] In some embodiments, the methods described herein reduce the RBC transfusion burden of the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100%. In some embodiments, the methods described herein reduce the RBC transfusion burden of the subject by at least 40%. In some embodiments, the methods described herein reduce the RBC transfusion burden of the subject by at least 50%. In some embodiments, the methods described herein reduce the RBC transfusion burden of the subject by at least 60%. In some embodiments, the methods described herein reduce the RBC transfusion burden of the subject by at least 70%.

[0236] In some embodiments, the methods described herein reduce the amount of red blood cell (RBC) transfusions received by a subject within a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units. In some embodiments, the methods described herein reduce the amount of red blood cell (RBC) transfusions received by a subject by at least 4 units over a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject over a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days by at least 8 units. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject over a period of 56 days by at least 4 units. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject over a period of 63 days by at least 4 units. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject over a period of 70 days by at least 4 units. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject by at least 4 units over a period of 77 days. In some embodiments, the method described herein reduces the amount of red blood cell (RBC) transfusions received by a subject by at least 4 units over a period of 84 days.

[0237] In some embodiments, the subject remains RBC transfusion-free for 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 98, or 105 consecutive days. In some embodiments, the subject remains RBC transfusion-free for 84 consecutive days. In some embodiments, the subject remains RBC transfusion-free for 91 consecutive days. In some embodiments, the subject remains RBC transfusion-free for 105 consecutive days. In some embodiments, the subject becomes transfusion-independent for a continuous period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 98, or 105 days. In some embodiments, the subject becomes transfusion-independent for a continuous period of 84 days. In some embodiments, the subject is RBC transfusion-free for a continuous period of 91 days. In some embodiments, the subject becomes transfusion-independent for a continuous period of 105 days.

[0238] In some embodiments, the subject becomes RBC transfusion-free for at least 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 consecutive weeks. In some embodiments, the subject becomes RBC transfusion-free for at least 8 consecutive weeks. In some embodiments, the subject becomes RBC transfusion-free for at least 10 consecutive weeks. In some embodiments, the subject becomes RBC transfusion-free for at least 15 consecutive weeks. In some embodiments, the subject becomes transfusion-independent for at least 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 consecutive weeks. In some embodiments, the subject becomes transfusion-independent for at least 8 consecutive weeks. In some embodiments, the subject becomes transfusion-independent for at least 10 consecutive weeks. In some embodiments, the subject becomes transfusion-independent for at least 15 consecutive weeks.

[0239] In some embodiments, the methods described herein increase the hemoglobin (Hgb) level in a subject by at least 1.5 g / dL or decrease the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units over a period of 56 days compared to baseline, wherein the subject is either red blood cell transfusion dependent or transfusion-independent.

[0240] In some embodiments, the methods described herein reduce the subject's RBC transfusion burden by at least 50% and decrease the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units within a period of 84 days from baseline, wherein the subject is red blood cell transfusion dependent.

[0241] In some embodiments, the method described herein increases the hemoglobin (Hgb) level in a subject by at least 1.5 g / dL compared to baseline, and the subject is transfusion-free for 84 consecutive days, wherein the subject is transfusion-independent. In certain embodiments, the method described herein increases the hemoglobin (Hgb) level in a subject by at least 1.5 g / dL compared to baseline for 84 consecutive days without RBC transfusion (transfusion-free), wherein the subject is transfusion-independent.

[0242] In some embodiments, subjects are in a state of RBC transfusion-free status for 84 consecutive days, where the subjects are either transfusion-dependent or transfusion-independent.

[0243] In some embodiments, the methods described herein increase the hemoglobin (HGB) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the HGB level in the subject before the treatment. In some embodiments, the methods described herein increase the hemoglobin (HGB) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 20%, 200%, or 500% higher than the HGB level in the subject before administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0244] In some embodiments, the methods described herein increase the hematocrit (HCT) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the HCT level in the subject before the treatment. In some embodiments, the methods described herein increase the hematocrit (HCT) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 20%, 200%, or 500% higher than the HCT level in the subject before administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0245] In some embodiments, the methods described herein reduce the mean corpuscular volume (MCV) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the MCV level in the subject before the treatment. In some embodiments, the methods described herein reduce the mean corpuscular volume (MCV) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the MCV level in the subject before administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0246] In some embodiments, the methods described herein increase the cellular hemoglobin concentration (CHC) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% higher than the CHC level in the subject before the treatment. In some embodiments, the methods described herein increase the cellular hemoglobin concentration (CHC) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 10%, 20%, 20%, or 500% higher than the CHC level in the subject before administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0247] In some embodiments, the methods described herein reduce the erythrocyte distribution width (RDW) level in a subject to a level equivalent to or about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the RDW level in the subject before the treatment. In some embodiments, the methods described herein reduce the erythrocyte distribution width (RDW) level in a subject to a level equivalent to or approximately 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% lower than the RDW level in the subject before administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0248] In certain embodiments, an anemic response is measured. In some embodiments, an anemic response is measured because it relates to an increase in hemoglobin (Hgb), e.g., the percentage of subjects who achieve a hemoglobin increase of ≥1.5 g / dL from baseline over any consecutive 84-day period without RBC transfusion. In some embodiments, an anemic response is measured because it relates to an increase in red blood cell (RBC) transfusion independence, e.g., the percentage of subjects who become RBC transfusion-free over any consecutive 84-day period. In some embodiments, an anemic response is measured because it relates to the time to an anemic response, e.g., the time from the first administration of raspatercept to the first onset of an anemic response. In some embodiments, an anemic response is measured because it relates to the duration of an anemic response, e.g., the maximum duration of an anemic response in a subject. In some embodiments, an anemic response is measured because it relates to the frequency of RBC transfusions, e.g., the average number of RBC units transfused per subject every four weeks. In some embodiments, the anemia response is measured because it relates to the frequency of RBC transfusion dependence, for example, the proportion of RBC transfusion-dependent subjects that reduce their transfusion load by ≥50% from baseline over any consecutive 84-day period. In some embodiments, an anemic response is measured because it is related to the proportion of subjects who achieve a reduction in fatigue symptoms as assessed, and is recorded via the Revised Myeloproliferative Neoplasm (MPN) Symptom Assessment Form (MPN-SAF) (see Emanual et al., “Myeloproliferative Neoplasm (MPN) Symptom Assessment Form Total Symptom Score: Prospective International Assessment of an Abbreviated Symptom Burden Scoring System Among Patients With MPNs,” J.Clin.Oncol.30(33):4098-4103(2012)) (e.g., measuring fatigue, night sweats, itching, abdominal discomfort, left subcostal pain, early satiety, and bone pain (e.g., in subjects who achieve an ≥50% reduction in fatigue symptoms as measured by MPN-SAF)).In some embodiments, the anemia response is measured because it relates to the proportion of subjects who achieve a reduction of ≥50% in the Total Symptom Score (TSS) as recorded and assessed via the Revised Myeloproliferative Neoplasm (MPN) Symptom Assessment Form (MPN-SAF) (see Emanual et al., “Myeloproliferative Neoplasm (MPN) Symptom Assessment Form Total Symptom Score: Prospective International Assessment of an Abbreviated Symptom Burden Scoring System Among Patients With MPNs,” J.Clin.Oncol.30(33):4098-4103(2012)) (e.g., measuring fatigue, night sweats, itching, abdominal discomfort, left subcostal pain, early satiety, and bone pain). In some embodiments, the anemia response is measured because it relates to a health-related quality of life (HRQoL) scale (e.g., measuring the mean change in HRQoL questionnaire domain scores compared to baseline scores). In some embodiments, the anemic response is measured because it relates to the EQ-5D-5L questionnaire score (EuroQol, Rotterdam, The Netherlands) (e.g., measuring the mean change in EQ-5D-5L questionnaire domain scores compared to baseline scores). In some embodiments, the anemic response is measured because it relates to adverse events (AEs), e.g., the type, frequency, and severity of adverse events. In some embodiments, the anemic response is measured using anti-drug antibodies (ADAs) (e.g., the frequency of anti-drug antibodies and their impact on efficacy, safety, or pharmacokinetics in the subject). In some embodiments, the anemic response is measured using pharmacokinetic parameters, e.g., plasma concentration-time curves, area under the curve (AUC), Cmax.

[0249] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap (such as the ActRIIB ligand trap described in Section 5.4) containing the amino acid sequence of SEQ ID NO: 11 at doses of 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg to the subject (the ActRIIB ligand trap is administered subcutaneously to the subject once every 21 days); and administering fedratinib or a pharmaceutically acceptable salt or hydrate thereof (as described in Section 5.3). In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously. In certain embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof is pharmaceutically effective for treating anemia.

[0250] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap containing the amino acid sequence of SEQ ID NO: 11 (such as the ActRIIB ligand trap described in Section 5.4) at doses of 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg to the subject (the ActRIIB ligand trap is administered subcutaneously to the subject once every 21 days); followed by administration of fedratinib or a pharmaceutically acceptable salt or hydrate thereof (as described in Section 5.3). In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously. In certain embodiments, co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective for treating anemia.

[0251] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap (such as the ActRIIB ligand trap described in Section 5.4) to the subject, followed by the administration of fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3), the method increasing the hemoglobin (Hgb) level in the subject by at least 0.5 g / dL, at least 1.0 g / dL, at least 1.5 g / dL, at least 2.0 g / dL, or at least 2.5 g / dL. In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously. In certain embodiments, co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in treating anemia.

[0252] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap (such as the ActRIIB ligand trap described in Section 5.4) to the subject, followed by the administration of fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3), the method reducing the subject's RBC transfusion burden by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100%. In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously. In certain embodiments, the co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in treating anemia.

[0253] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap (such as the ActRIIB ligand trap described in Section 5.4) to the subject, followed by the administration of fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3), the method reducing the red blood cell (RBC) transfusions received by the subject within a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units. In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously. In certain embodiments, the co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective for treating anemia.

[0254] This specification also provides a method for treating anemia in subjects requiring treatment, the method comprising administering an ActRIIB ligand trap (such as the ActRIIB ligand trap described in Section 5.4) to the subject, followed by the administration of fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof (as described in Section 5.3) to the subject, wherein the subject becomes RBC transfusion-free or transfusion-independent for a continuous period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 98, or 105 days.

[0255] 5.6 Patient population The subjects treated according to the methods described herein may be any mammal, such as rodents and primates, and, in a preferred embodiment, humans. In certain embodiments, the subject is humans. In certain embodiments, anemia can be treated in any mammal, such as rodents and primates, and, in a preferred embodiment, humans, using the methods described herein.

[0256] In certain embodiments, subjects treated according to the methods described herein may be of any age. In certain embodiments, subjects treated according to the methods described herein are under 18 years of age. In certain embodiments, subjects treated according to the methods described herein are under 13 years of age. In other certain embodiments, subjects treated according to the methods described herein are under 12 years of age, under 11 years of age, under 10 years of age, under 9 years of age, under 8 years of age, under 7 years of age, under 6 years of age, or under 5 years of age. In other certain embodiments, subjects treated according to the methods described herein are 1-3 years of age, 3-5 years of age, 5-7 years of age, 7-9 years of age, 9-11 years of age, 11-13 years of age, 13-15 years of age, 15-20 years of age, 20-25 years of age, 25-30 years of age, or over 30 years of age. In another specific embodiment, the subjects treated according to the method described herein are 30–35 years old, 35–40 years old, 40–45 years old, 45–50 years old, 50–55 years old, 55–60 years old, or over 60 years old. In another specific embodiment, the subjects treated according to the method described herein are 60–65 years old, 65–70 years old, 70–75 years old, 75–80 years old, or over 80 years old.

[0257] In certain embodiments, the subject requires typical lifetime red blood cell transfusions. In certain embodiments, the subject has a high transfusion burden. In certain embodiments, a high transfusion burden is 12 or more red blood cell units over 24 weeks prior to treatment according to the method provided herein. In certain embodiments, the subject has a low transfusion burden. In certain embodiments, a low transfusion burden is 7 to 12 red blood cell units over 24 weeks prior to treatment according to the method provided herein.

[0258] In some embodiments, the subjects treated according to the methods provided herein are subjects diagnosed with myelofibrosis. In some embodiments, the subjects are subjects diagnosed with myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is intermediate or high-risk myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF). In certain embodiments, myelofibrosis is intermediate or high-risk post-polycythemia vera myelofibrosis (post-PV MF). In certain embodiments, myelofibrosis is intermediate or high-risk post-essential thrombocythemia myelofibrosis (post-ET MF).

[0259] In certain embodiments, the subject treated according to the methods provided herein has myeloproliferative neoplasm-associated myelofibrosis. In certain embodiments, myeloproliferative neoplasm-associated myelofibrosis is primary myelofibrosis. In some embodiments, myeloproliferative neoplasm-associated myelofibrosis is polycythemia vera myelofibrosis. In further specific embodiments, polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation or a JAK2 exon 12 mutation, or a thrombopoietin receptor (MPL) mutation. In certain embodiments, myeloproliferative neoplasm-associated myelofibrosis is post-polycythemia vera myelofibrosis. In further specific embodiments, post-polycythemia vera myelofibrosis is associated with or caused by a JAK2 mutation, e.g., a JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In certain embodiments, myeloproliferative neoplasm-associated myelofibrosis is essential thrombocytopenia or post-essential thrombocytopenia myelofibrosis. In further specific embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis is associated with or caused by a JAK2 mutation, such as a JAK2 V617F mutation, or a thrombopoietin receptor (MPL) mutation. In further specific embodiments, essential thrombocytopenia or post-essential thrombocythemia myelofibrosis includes reticulin fibrosis or trichrome fibrosis.

[0260] In certain embodiments, the subject treated according to the method provided herein has anemia. In certain embodiments, the subject treated according to the method provided herein has myeloproliferative neoplasm-associated myelofibrosis and anemia. In certain embodiments, anemia is associated with myelofibrosis. In certain embodiments, anemia is associated with MPN-associated myelofibrosis. In certain embodiments, anemia is associated with primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF).

[0261] In certain embodiments, the methods described herein can be used to treat anemia in subjects such as ineffective erythropoiesis or anemia associated with thalassemia.

[0262] In certain embodiments, the subject treated according to the method described herein as beta-thalassemia (see Sections 5.5 and 5.9). In certain embodiments, beta-thalassemia is transfusion-dependent beta-thalassemia. Transfusion-dependent beta-thalassemia is also known as "Cooley's anemia." In certain embodiments, beta-thalassemia is beta-thalassemia major. In certain embodiments, transfusion-dependent beta-thalassemia is beta-thalassemia major. In certain embodiments, beta-thalassemia is transfusion-independent beta-thalassemia. In certain embodiments, beta-thalassemia is beta-thalassemia intermediate. In certain embodiments, transfusion-dependent beta-thalassemia is non-beta-thalassemia intermediate. In certain embodiments, the subject has HbE / beta-thalassemia. In certain embodiments, the subject (i) has beta-thalassemia major; (ii) has severe HbE / beta-thalassemia; and (iii) is transfusion-dependent. In certain embodiments, the subject (i) has an intermediate form of beta-thalassemia; (ii) has mild / moderate HbE / beta-thalassemia; and (iii) is transfusion-independent.

[0263] In certain specific embodiments, the subject to be treated according to the methods described herein (see Section 5.5 and Section 5.9) has transfusion-dependent beta-thalassemia. In certain specific embodiments, the subject has been diagnosed with transfusion-dependent beta-thalassemia. In certain specific embodiments, the subject has been diagnosed with beta-thalassemia and hemoglobin E. In certain specific embodiments, the diagnosis is confirmed by genetic analysis. In certain specific embodiments, the transfusion-dependent beta-thalassemia is beta-thalassemia major. In certain specific embodiments, the transfusion-dependent beta-thalassemia is beta-thalassemia major. In certain specific embodiments, the subject comprises a genotype comprising homozygosity or compound heterozygosity for a variant beta-globin allele. In certain specific embodiments, the homozygosity comprises β 0 / β 0 , wherein β 0 refers to an allele associated with absence of beta-globin chain synthesis. In certain specific embodiments, the homozygosity comprises β + / β + , wherein β + refers to an allele associated with reduced beta-globin chain synthesis. In certain specific embodiments, the compound heterozygosity comprises β 0 / β + , wherein β 0 refers to an allele associated with absence of beta-globin chain synthesis, and β + refers to an allele associated with reduced beta-globin chain synthesis. In certain specific embodiments, the compound heterozygosity comprises β 0 / HbE, wherein β 0 refers to an allele associated with absence of beta-globin chain synthesis, and HbE refers to hemoglobin E. In certain specific embodiments, the compound heterozygosity comprises β + / HbE, wherein β +refers to an allele associated with reduced beta-globin chain synthesis, and HbE refers to hemoglobin E. In certain embodiments, the subject has symptomatic thalassemia. In certain embodiments, the subject has co-inherited duplication of the alpha-globin gene. In certain embodiments, the subject has been diagnosed with transfusion-dependent beta-thalassemia. In certain embodiments, the diagnosis is confirmed by genetic analysis. In certain embodiments, the subject is an infant human subject. In certain embodiments, the subject has hereditary persistence of fetal hemoglobin.

[0264] In some embodiments, the subject to be treated according to the methods provided herein has been previously treated with ruxolitinib. In certain embodiments, the subject to be treated according to the methods provided herein has been administered a stable dose of ruxolitinib for at least 112 days immediately prior to treatment.

[0265] In some embodiments, the subject to be treated according to the methods provided herein has not been previously treated with ruxolitinib.

[0266] In some embodiments, the subject is a human.

[0267] In some embodiments, the subject is red blood cell transfusion-dependent or transfusion-independent. In certain embodiments, the subject is red blood cell transfusion-dependent. In certain embodiments, the subject is transfusion-independent. In certain embodiments, the subject is red blood cell transfusion-independent.

[0268] In some embodiments, as used herein, "transfusion" refers to red blood cell (RBC) transfusion.

[0269] In some embodiments, if a subject receives 4 or fewer RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or red blood cell transfusion-independent. In some embodiments, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received RBC units during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-independent or RBC transfusion-independent if the subject has not received an RBC transfusion during the period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0270] In one embodiment, if a subject receives 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject receives 1, 2, or 3 RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC units in an RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent. In one embodiment, if a subject does not receive any RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, the subject is transfusion-independent or RBC transfusion-independent.

[0271] In one embodiment, a transfusion-independent or RBC transfusion-independent subject has received 4 or fewer RBC units in an RBC transfusion during the 84-day period prior to the fedratinib and / or ActRIIB ligand trapping of the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In another embodiment, a transfusion-independent or RBC transfusion-independent subject has not received any RBC units in an RBC transfusion during the 84-day period prior to the fedratinib and / or ActRIIB ligand trapping of the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less. In yet another embodiment, transfusion-independent or RBC transfusion-independent subjects have not received RBC transfusions during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less.

[0272] In some embodiments, a subject is transfusion-dependent if the subject received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject has received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 16 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4 to 10 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.In some embodiments, a subject is transfusion-dependent if the subject received 4 to 8 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if the subject received 4–6 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0273] In some embodiments, a subject is transfusion-dependent if it received 4 or more RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, a subject is transfusion-dependent if it received 4 to 16 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap. In some embodiments, if a subject receives 4 to 12 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, if a subject receives 4 to 6 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap, the subject is red blood cell transfusion dependent. In some embodiments, a subject is transfusion-dependent if it received 6–12, 6–10, or 6–8 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, a subject is transfusion-dependent if it received 8–12 or 8–10 RBC units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0274] In one embodiment, a transfusion-dependent red blood cell subject has received four or more RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, a transfusion-dependent red blood cell subject has received 4 to 12 RBC units during a period of at least 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0275] In one embodiment, the RBC transfusion-dependent subject has received 4 or more red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 red blood cell units during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0276] In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during a period of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 6 weeks without RBC transfusion during the 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have an interval of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 4, 5, 6, or 7 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject. In some embodiments, RBC transfusion-dependent subjects do not have intervals of more than 6 weeks without RBC transfusion during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject.

[0277] In one embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no intervals of more than 2, 3, 4, 5, 6, 7, or 8 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 or more RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less. In yet another embodiment, the RBC-dependent subject has received 4 to 12 RBC units in RBC transfusions during the 84-day period prior to administration of fedratinib and / or ActRIIB ligand trap to the subject, and has no interval of more than 6 weeks without RBC transfusion, and the RBC-dependent subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

[0278] In certain embodiments, the subject treated according to the method provided herein has thrombocytopenia. In certain embodiments, the subject treated according to the method provided herein has 1 × 10 per liter 11 The subject has the following platelets. In a particular embodiment, the subject treated according to the method provided herein has neutropenia. In a particular embodiment, the subject treated according to the method provided herein has 1 × 10 per liter 9 The absolute number of neutrophils is as follows:

[0279] In certain embodiments, the subject treated according to the method provided herein has 13,000 or fewer leukocytes per μL, 12,000 or fewer leukocytes per μL, 11,000 or fewer leukocytes per μL, 10,000 or fewer leukocytes per μL, 7,500 or fewer leukocytes per μL, or 500 or fewer leukocytes per μL.

[0280] In certain embodiments, the hemoglobin level in a subject treated according to the method provided herein is 10 g / dL, 9 g / dL, 8 g / dL, or 7 g / dL or less. In certain embodiments, the hemoglobin level in a subject treated according to the method provided herein is 7 g / dL to 7.5 g / dL, 7.5 g / dL to 8 g / dL, 8 g / dL to 8.5 g / dL, 8.5 g / dL to 9.0 g / dL, 9.0 g / dL to 9.5 g / dL, or 9.5 g / dL to 10.0 g / dL.

[0281] In certain embodiments, subjects treated according to the methods provided herein have a low transfusion burden. In certain embodiments, subjects with a low transfusion burden treated according to the methods provided herein require a maximum of 0, 1, 2, or 3 units of red blood cells per 8 weeks. In certain embodiments, subjects treated according to the methods provided herein have a high transfusion burden. In certain embodiments, subjects with a high transfusion burden treated according to the methods provided herein require at least 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 units of red blood cells per 8 weeks.

[0282] 5.7 Pharmaceutical Compositions This specification also provides “pharmaceutical compositions” comprising the ActRIIB ligand trap provided herein or fedratinib or a pharmaceutically acceptable salt or hydrate thereof provided herein, and one or more pharmaceutically acceptable carriers. In certain embodiments, the pharmaceutical composition comprises the ActRIIB ligand trap provided herein. In certain embodiments, the pharmaceutical composition comprises fedratinib or a pharmaceutically acceptable salt or hydrate thereof provided herein, and one or more pharmaceutically acceptable carriers. In certain embodiments, the ActRIIB ligand trap is present in a therapeutically effective amount. In certain embodiments, the ActRIIB ligand trap is present in a prophylactically effective amount. The pharmaceutical composition may be used according to the methods and uses provided herein. Thus, for example, the pharmaceutical composition may be administered to a subject to perform the therapeutic or prophylactic methods and uses provided herein. The pharmaceutical compositions provided herein may be formulated to be compatible with the intended method or route of administration; exemplary routes of administration are described herein.

[0283] Pharmaceutical compositions typically comprise ActRIIB ligand traps or fedratinib or pharmaceutically acceptable salts or hydrates thereof, as provided herein, and pharmaceutically acceptable carriers. Suitable pharmaceutically acceptable carriers include, but are not limited to, antioxidants (e.g., ascorbic acid), preservatives (e.g., benzyl alcohol, methylparaben, p-hydroxybenzoate), emulsifiers, suspending agents, dispersants, solvents, buffers, lubricants, fillers, and / or diluents. For example, a suitable medium may be physiological saline solution. Typical buffers that may be used include, but are not limited to, pharmaceutically acceptable weak acids, weak bases, or mixtures thereof. Buffer components may also include water-soluble reagents such as phosphoric acid, tartaric acid, succinic acid, citric acid, acetic acid, and salts thereof.

[0284] The medium may contain other pharmaceutically acceptable excipients for modifying or maintaining the pH, osmolarity, viscosity, or stability of the pharmaceutical composition. In certain embodiments, the medium is an aqueous buffer. In certain embodiments, the medium comprises, for example, sodium chloride.

[0285] The pharmaceutical compositions provided herein may further contain other pharmaceutically acceptable formulating agents. For pharmaceutically acceptable formulating agents, see, for example, Remington’s Pharmaceutical Sciences, 18th Ed. (1990, Mack Publishing Co., Easton, Pa. 18042) pages 1435-1712, and The Merck Index, 12th Ed. (1996, Merck Publishing Group, Whitehouse, NJ).

[0286] In certain specific embodiments, the ActRIIB ligand trap and fedratinib are suitably formulated for the combination therapy described herein.

[0287] In certain specific embodiments, the ActRIIB ligand trap is formulated together with a pharmaceutically acceptable carrier for use according to the methods described herein. For example, the ActRIIB ligand trap may be administered alone or as a component of a pharmaceutical formulation (therapeutic composition). The ActRIIB ligand trap may be formulated for administration by any convenient method for use in human or veterinary medicine.

[0288] In a preferred embodiment, the ActRIIB ligand trap is formulated for subcutaneous administration.

[0289] In another preferred embodiment, the ActRIIB ligand trap is packaged in a container as a sterile, preservative-free lyophilized powder or cake. In a particular embodiment, the container contains 25 mg of ActRIIB ligand trap. In a particular embodiment, the container containing 25 mg of ActRIIB ligand trap contains a total of 37.5 mg of protein. In a particular embodiment, the ActRIIB ligand trap in the container containing 25 mg of ActRIIB ligand trap is reconstituted with 0.68 mL of sterile water for injection. In a particular embodiment, the container contains 75 mg of ActRIIB ligand trap. In a particular embodiment, the container containing 75 mg of ActRIIB ligand trap contains a total of 87.5 mg of protein. In a particular embodiment, the ActRIIB ligand trap in the container containing 75 mg of ActRIIB ligand trap is reconstituted with 1.6 mL of sterile water for injection. In certain embodiments, the ActRIIB ligand trap in the container is reconstituted with a certain volume of sterile water for injection such that the final concentration of the reconstituted ActRIIB ligand trap in sterile water for injection is 50 mg / mL with a pH of approximately 6.5. In certain embodiments, the ActRIIB ligand trap is administered to the subject within 10 hours of reconstitution. In certain embodiments, the container contains the ActRIIB ligand trap at a concentration of 50 mg / mL in a solution based on 10 mM citrate buffer, the solution based on 10 mM citrate buffer contains 10 mM citrate, pH 6.5, 9% sucrose, and 0.02% polysorbate 80. In certain embodiments, the container is stored at 2°C to 8°C. In certain embodiments, the container is stored at 2°C to 8°C for 18 months. In certain embodiments, the container is a 3 mL glass vial with a gray butyl-coated stopper. In certain embodiments, the container is a 3 mL glass vial with a gray rubber stopper. In certain embodiments, the rubber stopper is secured with a crimp-on aluminum flip cap with a colored plastic button. In certain embodiments, a 3 mL glass vial contains a 25 mg ActRIIB ligand trap, and the colored plastic button is red.In a particular embodiment, a 3 mL glass vial contains 75 mg of ActRIIB ligand trap, and the colored plastic button is white. In a particular embodiment, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In a particular embodiment, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In a particular embodiment, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence described in SEQ ID NO: 11.

[0290] In certain embodiments, the ActRIIB ligand trap is packaged in a container as a sterile, preservative-free lyophilized powder or cake. In certain embodiments, the container contains 50 mg / mL of ActRIIB ligand trap in 10 mM citrate buffer pH 6.5. In certain embodiments, the container contains 56 mg of ActRIIB ligand trap, 0.19 mg of citrate monohydrate, 3.03 mg of trisodium citrate dihydrate, 0.24 mg of polysorbate 80, and 100.80 mg of sucrose. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence described in SEQ ID NO: 11.

[0291] In certain embodiments, the therapeutic methods provided herein include systemic administration of the composition (including the ActRIIB ligand trap) or topical administration as an implantable tablet or device. When administered, the therapeutic compositions for use provided herein are in a pyrogen-free, physiologically acceptable form. Other therapeutically useful agents, which may be optionally included in the compositions as described above, may be administered concurrently with or sequentially with the compound of interest (e.g., the ActRIIB ligand trap described in Section 5.4).

[0292] Typically, ActRIIB ligand traps are administered parenterally. In preferred embodiments, ActRIIB ligand traps are administered subcutaneously. Suitable pharmaceutical compositions for parenteral administration may contain one or more ActRIIB polypeptides in combination with one or more pharmaceutically acceptable sterile isotonic aqueous or nonaqueous solutions, dispersions, suspensions, or emulsions, or sterile powders that can be reconstituted into sterile injection solutions or dispersions immediately before use, which may contain antioxidants, buffers, bacteriostatic agents, solutes or suspensions or thickeners to make the preparation isotonic with the blood of the target recipient. Examples of suitable aqueous and nonaqueous carriers that can be used in pharmaceutical compositions for use in the methods described herein include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol), and suitable mixtures thereof, vegetable oils, such as olive oil, and organic esters for injection, such as ethyl oleate. Adequate fluidity can be maintained, for example, by the use of coating materials such as lecithin, by maintaining the required particle size in the case of dispersions, and by the use of surfactants.

[0293] The compositions described herein may also contain adjuvants such as preservatives, humectants, emulsifiers, and dispersants. Prevention of microbial action can be ensured by the inclusion of various antimicrobial and antifungal agents, such as parabens, chlorobutanol, and phenolsorbic acid. It may also be desirable to include isotonic agents such as sugars and sodium chloride in the composition. In addition, delayed absorption of injectable dosage forms can be achieved by the inclusion of absorption-delaying agents such as aluminum monostearate and gelatin.

[0294] In certain embodiments, the ActRIIB ligand trap is substantially pure in the pharmaceutical composition. Specifically, up to 20%, 10%, 5%, 2.5%, 1%, 0.1%, or up to 0.05% of the compound in the pharmaceutical composition consists of compounds other than the ActRIIB ligand trap and a pharmaceutically acceptable carrier.

[0295] In a particular embodiment, the ActRIIB ligand trap is administered to the patient at room temperature according to the method provided herein.

[0296] In certain embodiments, fedratinib is formulated with a pharmaceutically acceptable carrier for use with the methods described herein.

[0297] In certain embodiments, fedratinib may be administered orally, topically, or parenterally to a subject in conventional forms of preparations such as capsules, microcapsules, tablets, granules, powders, lozenges, pills, suppositories, injections, suspensions, syrups, patches, creams, lotions, ointments, gels, sprays, solutions, and emulsions. Suitable formulations include diluents (e.g., sucrose, starch, mannitol, sorbitol, lactose, glucose, cellulose, talc, calcium phosphate, or calcium carbonate), binders (e.g., cellulose, methylcellulose, hydroxymethylcellulose, polypropylpyrrolidone, polyvinylpyrrolidone, gelatin, gum arabic, polyethylene glycol, sucrose, or starch), disintegrants (e.g., starch, carboxymethylcellulose, hydroxypropyl starch, low-substituted hydroxypropylcellulose, sodium bicarbonate, calcium phosphate, or calcium citrate), lubricants (e.g., magnesium stearate, light anhydrous silicic acid, talc, or sodium lauryl sulfate), flavorings (e.g., citric acid, menthol, glycine, or orange powder), preservatives (e.g., sodium benzoate, sodium bisulfite, methylparaben, or propylparaben), stabilizers (e.g., citric acid, sodium citrate, or acetic acid), and suspending agents (e.g., methylcellulose, polyvinylpyrrolidone). It can be prepared by commonly used methods using conventional organic or inorganic additives such as pyrroliclone (or aluminum stearate), a dispersant (e.g., hydroxypropyl methylcellulose), water, and a base wax (e.g., cocoa butter, white petrolatum, or polyethylene glycol). The effective amount of the compound in the pharmaceutical composition may be present at a level that will produce the desired effect for both oral and parenteral administration.

[0298] In a preferred embodiment, fedratinib is formulated for oral administration.

[0299] In certain embodiments, fedratinib is formulated for parental administration. In one embodiment, fedratinib is packaged in a container as a sterile, preservative-free lyophilized powder or cake.

[0300] In certain embodiments, fedratinib is formulated in the form of capsules or tablets. In certain embodiments, fedratinib is formulated in the form of microtablets or micropellets, and the microtablets or micropellets are enterically coated. In certain embodiments, the microtablets or micropellets are contained in capsules. In preferred embodiments, fedratinib is formulated in the form of capsules.

[0301] 5.8 Dosage and regimen 5.8.1 ActRIIB Ligand Trap Dosage In certain embodiments, the ActRIIB ligand trap administered to a subject according to the method provided herein (see Sections 5.5 and 5.9) is a product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11. In certain embodiments, the dose of the ActRIIB ligand trap (e.g., a product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11) is approximately 0.3 mg / kg to 2.0 mg / kg. In certain embodiments, the dose of the ActRIIB ligand trap (e.g., the product resulting from expression from an open reading frame having the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO: 34 encoding SEQ ID NO: 11) is approximately 0.30 mg / kg, 0.35 mg / kg, approximately 0.4 mg / kg, approximately 0.45 mg / kg, approximately 0.5 mg / kg, approximately 0.6 mg / kg, approximately 0.7 mg / kg, approximately 0.8 mg / kg, approximately 0.9 mg / kg, approximately 1.0 mg / kg, or approximately 1.25 mg / kg. In certain embodiments, the dose of the ActRIIB ligand trap is approximately 0.3 mg / kg, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In certain embodiments, the dose of the ActRIIB ligand trap is approximately 0.3 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 0.33 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 0.45 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 0.6 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 0.8 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 1.0 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 1.33 mg / kg.In certain embodiments, the dose of ActRIIB ligand trap is approximately 1.75 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 2.0 mg / kg. In some embodiments, ActRIIB ligand trap is administered in a pharmaceutically effective amount. In one embodiment, the pharmaceutically effective amount of ActRIIB ligand trap administered is 1.33 mg / kg.

[0302] In certain embodiments, the dose of ActRIIB ligand trap is the initial dose. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 0.3 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 0.33 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 0.45 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 0.6 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 0.8 mg / kg. In certain embodiments, the dose of ActRIIB ligand trap is approximately 1.0 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 1.33 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 1.75 mg / kg. In certain embodiments, the initial dose of ActRIIB ligand trap is approximately 2.0 mg / kg.

[0303] In certain embodiments, the dose of the ActRIIB ligand trap is as follows: In some embodiments, the next doses of the ActRIIB ligand trap are 0.30 mg / kg, 0.33 mg / kg, 0.45 mg / kg, 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, 1.75 mg / kg, or 2.0 mg / kg. In some embodiments, the next doses of the ActRIIB ligand trap are 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, or 1.75 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.30 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.33 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.45 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.6 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 0.8 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.0 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.33 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 1.75 mg / kg. In some embodiments, the next dose of ActRIIB ligand trap is 2.0 mg / kg.

[0304] In a particular embodiment, the next dose of ActRIIB ligand trap is approximately 0.5 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, 2.0 mg, 2.1 mg, and 2.2 mg from the initial dose of ActRIIB ligand trap. Approximately 2.3 mg, 2.4 mg, 2.5 mg, 2.5 mg, 2.6 mg, 2.7 mg, 2.8 mg, 2.9 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.5 mg, 5 mg, 6 mg, 7 mg, 8 mg, 9 mg, 10 mg, 11 mg, 12 mg, 13 mg, 14 mg, 15 mg, 16 mg, 17 mg, 18 mg, 19 mg, 20 mg, or 35 mg more. In a particular embodiment, the next dose of ActRIIB ligand trap is approximately 0.05 mg / kg, 0.06 mg / kg, 0.07 mg / kg, 0.08 mg / kg, 0.09 mg / kg, 0.1 mg / kg, 0.11 mg / kg, 0.12 mg / kg, 0.13 mg / kg, 0.14 mg / kg, 0.15 mg / kg, 0.16 mg / kg, and 0.17 mg / kg from the initial dose of ActRIIB ligand trap. g / kg, approximately 0.18 mg / kg, approximately 0.19 mg / kg, approximately 0.20 mg / kg, approximately 0.21 mg / kg, approximately 0.22 mg / kg, approximately 0.23 mg / kg, approximately 0.24 mg / kg, approximately 0.25 mg / kg, approximately 0.26 mg / kg, approximately 0.27 mg / kg, approximately 0.28 mg / kg, approximately 0.29 mg / kg, approximately 0.3 mg / kg, approximately 0.35 mg / kg, approximately 0.4 mg / kg, approximately 0.45 mg / kg, or approximately 0.5 mg / kg more.

[0305] For certain uses, the following doses are approximately 0.5 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, 2.0 mg, 2.1 mg, 2.2 mg, 2.3 mg, 2.4 mg, and 2 mg respectively, from the initial dose. 0.5mg, approximately 2.5mg, approximately 2.6mg, approximately 2.7mg, approximately 2.8mg, approximately 2.9mg, approximately 3.0mg, approximately 3.5mg, approximately 4.0mg, approximately 4.5mg, approximately 5mg, approximately 6mg, approximately 7mg, approximately 8mg, approximately 9mg, approximately 10mg, approximately 11mg, approximately 12mg, approximately 13mg, approximately 14mg, approximately 15mg, approximately 16mg, approximately 17mg, approximately 18mg, approximately 19mg, approximately 20mg, or approximately 35mg more. or approximately 0.05 mg / kg, 0.06 mg / kg, 0.07 mg / kg, 0.08 mg / kg, 0.09 mg / kg, 0.1 mg / kg, 0.11 mg / kg, 0.12 mg / kg, 0.13 mg / kg, 0.14 mg / kg, 0.15 mg / kg, 0.16 mg / kg, 0.17 mg / kg, 0.18 mg / kg, 0.19 mg / kg from the initial dose. g, approximately 0.20 mg / kg, approximately 0.21 mg / kg, approximately 0.22 mg / kg, approximately 0.23 mg / kg, approximately 0.24 mg / kg, approximately 0.25 mg / kg, approximately 0.26 mg / kg, approximately 0.27 mg / kg, approximately 0.28 mg / kg, approximately 0.29 mg / kg, approximately 0.3 mg / kg, approximately 0.35 mg / kg, approximately 0.4 mg / kg, approximately 0.45 mg / kg, or approximately 0.5 mg / kg less.

[0306] In certain embodiments, the following doses are administered more frequently than the initial dose. In certain embodiments, the following doses are administered less frequently than the initial dose. In certain embodiments, the following doses are administered at the same frequency as the initial dose. In certain embodiments, the following doses are administered every 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 days. In certain embodiments, the following doses are administered every 21 days. In certain embodiments, the following doses are administered continuously and / or indefinitely.

[0307] In some embodiments, the ActRIIB ligand trap is administered to the subject once every 14 days, once every 21 days, once every 28 days, once every 35 days, or once every 42 days. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once every 21 days. In some embodiments, the ActRIIB ligand trap is administered to the subject once, two, or three times per treatment cycle. In a preferred embodiment, the ActRIIB ligand trap is administered to the subject once per treatment cycle. In some embodiments, the ActRIIB ligand trap is administered to the subject for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cycles. In one embodiment, the ActRIIB ligand trap is administered to the subject for at least 6, 7, 8, 9, or 10 cycles. In another embodiment, the ActRIIB ligand trap is administered to the subject for 6 cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for 7 cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for 8 cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for 9 cycles. In yet another embodiment, the ActRIIB ligand trap is administered to the subject for 10 cycles. In one embodiment, the ActRIIB ligand trap is administered once at the start of each treatment cycle.

[0308] In certain embodiments, the following doses are administered more frequently than the initial dose. In certain embodiments, the following doses are administered less frequently than the initial dose. In certain embodiments, the following doses are administered at the same frequency as the initial dose. In certain embodiments, the following doses are administered every 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 days. In certain embodiments, the following doses are administered every 21 days. In certain embodiments, the following doses are administered continuously and / or indefinitely.

[0309] In certain embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject. In certain embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject in the upper arm, abdomen, or thigh. In certain embodiments, the ActRIIB ligand trap is administered to the subject every 21 days. In certain embodiments, the ActRIIB ligand trap is administered to the subject every 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 days. In certain embodiments, the ActRIIB ligand trap is administered subcutaneously to the subject in the upper arm, abdomen, or thigh every 21 days.

[0310] In certain embodiments, the ActRIIB ligand trap is part of the composition as described in Section 5.7. In certain embodiments, the ActRIIB ligand trap is a sterile, preservative-free, lyophilized powder reconstituted in water for injection. In certain embodiments, a single dose of the ActRIIB ligand trap is reconstituted in a volume of more than 1 mL of water for injection. In such embodiments, a single dose of the ActRIIB ligand trap is administered to the subject via two injections of equivalent volumes of the reconstituted ActRIIB ligand inhibitor. In certain embodiments, the two injections are administered to the subject at separate sites, for example, one injection in the right thigh and one injection in the left thigh.

[0311] 5.8.2 Dosage of Fedratinib In certain embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered orally to the subject. In certain embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered daily to the subject. In certain embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 days to the subject.

[0312] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered to the subject at doses of 600 mg / day, 500 mg / day, 400 mg / day, 300 mg / day, 200 mg / day, or 100 mg / day.

[0313] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered to the subject in an initial dose of 400 mg / day, 300 mg / day, 200 mg / day, or 100 mg / day. In one preferred embodiment, the initial dose is 400 mg / day. In another embodiment, the initial dose is 300 mg / day. In yet another embodiment, the initial dose is 200 mg / day. In yet another embodiment, the initial dose is 100 mg / day.

[0314] In some embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered to a subject in the following doses: 400 mg / day, 300 mg / day, 200 mg / day, or 100 mg / day. In certain embodiments, the following dose of fedratinib is determined according to the method provided in Section 5.5. In one preferred embodiment, the following dose is 400 mg / day. In another embodiment, the following dose is 300 mg / day. In yet another embodiment, the following dose is 200 mg / day. In yet another embodiment, the following dose is 100 mg / day.

[0315] 5.9 Combination Therapy In certain embodiments, fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof is administered before or concurrently with the administration of the ActRIIB ligand trap.

[0316] In certain embodiments, fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered after the administration of the ActRIIB ligand trap.

[0317] In certain embodiments, the subject has been previously treated with fedratinib or a pharmaceutically acceptable salt or hydrate thereof prior to the administration of the ActRIIB ligand trap.

[0318] In certain embodiments, the subject is previously treated with an ActRIIB ligand trap before administration of fedratinib or a pharmaceutically acceptable salt or hydrate thereof.

[0319] In certain embodiments, the subject has been previously treated with fedratinib or a pharmaceutically acceptable salt or hydrate prior to co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof.

[0320] In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is simultaneous administration.

[0321] In certain embodiments, the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously.

[0322] In certain embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective for treating anemia.

[0323] In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in treating anemia, and the respective doses of ActRIIB ligand trap and fedratinib are sufficient to reduce or alleviate one or more symptoms of anemia. In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in treating anemia, and the respective doses of ActRIIB ligand trap and fedratinib are sufficient to reduce or alleviate one or more symptoms of anemia caused by or associated with myeloproliferative neoplasm-associated myelofibrosis. In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in preventing the worsening of at least one symptom of anemia.

[0324] In certain embodiments, the combination therapy of ActRIIB ligand trap and fedratinib exhibits a synergistic effect in treating anemia. In certain embodiments, the dose of ActRIIB ligand trap in combination therapy with fedratinib is less than the pharmaceutically effective dose of ActRIIB ligand trap in monotherapy. In certain embodiments, the dose of fedratinib in combination therapy is less than the pharmaceutically effective dose of fedratinib in monotherapy.

[0325] In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in increasing the hemoglobin level in a subject compared to the baseline hemoglobin level in the subject. In the context of evaluating the increase in hemoglobin level in a subject, “baseline” refers to the time immediately preceding the first administration of fedratinib and / or ActRIIB ligand trap to the subject. In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in increasing the hemoglobin (Hgb) level in a subject by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 100% over any 84 consecutive days after the subject has received an initial dose of ActRIIB ligand trap. In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective, and the subject has received transfusions of 4 or fewer units of red blood cells during a period of 84 consecutive days. In a particular embodiment, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective, and the subject receives transfusions of 0 units of red blood cells over a continuous period of 84 days.In certain embodiments, co-administration of ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in increasing hemoglobin levels by at least 0.5 g / dL, at least 0.8 g / dL, at least 1.0 g / dL, at least 1.2 g / dL, at least 1.5 g / dL, at least 1.8 g / dL, at least 2.0 g / dL, at least 2.2 g / dL, at least 2.4 g / dL, at least 2.6 g / dL, at least 2.8 g / dL, at least 3.0 g / dL, at least 3.2 g / dL, at least 3.4 g / dL, at least 3.6 g / dL, at least 3.8 g / dL, at least 4.0 g / dL, at least 5.0 g / dL, or at least 6.0 g / dL over any consecutive 84-day period following administration of an initial dose of ActRIIB ligand trap. In certain embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in increasing hemoglobin levels in subjects for at least 3, at least 4, at least 5, at least 6, at least 12, at least 18, at least 24, or at least 48 months after administration of the ActRIIB ligand trap. In certain embodiments, co-administration of an ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof is pharmaceutically effective in reducing the frequency of red blood cell transfusions in subjects compared to the frequency of red blood cell transfusions in subjects at baseline.

[0326] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the RBC transfusion burden of the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100%. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the RBC transfusion burden of the subject by at least 40%. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the RBC transfusion burden of the subject by at least 50%. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the RBC transfusion burden of the subject by at least 60%. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the RBC transfusion burden of the subject by at least 70%.

[0327] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by a subject within a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by subjects by at least 4 units over a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by a subject within a period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by a subject within a period of 56 days by at least 4 units. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units over a 63-day period. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units over a 70-day period.In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units over a 77-day period. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the amount of red blood cell (RBC) transfusions received by the subject by at least 4 units over an 84-day period.

[0328] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become RBC transfusion-free or transfusion-independent for a continuous period of 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 98, or 105 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become RBC transfusion-free for a continuous period of 84 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become RBC transfusion-free for a continuous period of 91 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become RBC transfusion-free for a continuous period of 105 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become transfusion-independent for a continuous period of 84 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become transfusion-independent for a continuous period of 91 days. In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, and subjects become transfusion-independent for a continuous period of 105 days.

[0329] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in increasing hemoglobin (Hgb) levels in subjects by at least 1.5 g / dL or reducing the amount of red blood cell (RBC) transfusions received by the subjects by at least 4 units over a 56-day period compared to baseline, where the subjects are red blood cell transfusion-dependent or transfusion-independent.

[0330] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in reducing the subject's RBC transfusion burden by at least 50% and decreasing the red blood cell (RBC) transfusions received by the subject by at least 4 units within 84 days from baseline, where the subject is red blood cell transfusion dependent.

[0331] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in increasing hemoglobin (Hgb) levels in subjects by at least 1.5 g / dL compared to baseline, and subjects are transfusion-free for 84 consecutive days, where the subjects are transfusion-independent. In specific embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective in increasing hemoglobin (Hgb) levels in subjects by at least 1.5 g / dL compared to baseline for 84 consecutive days without RBC transfusion (transfusion-free), where the subjects are transfusion-independent.

[0332] In some embodiments, co-administration of ActRIIB ligand trap and fedratinib is pharmaceutically effective, resulting in subjects being RBC transfusion-free for 84 consecutive days, and the subjects being either transfusion-dependent or transfusion-independent.

[0333] In a particular embodiment, one RBC unit refers to RBCs of approximately 150 mL, 200 mL, 250 mL, 300 mL, 350 mL, 100-200 mL, 150-250 mL, 200-300 mL, 250-300 mL, or 250-350 mL.

[0334] 5.9.1 Clinical utility of the combination Therapy with JAK2 inhibitors (e.g., ruxolitinib or fedratinib) may be associated with moderate to severe thrombocytopenia and anemia. These side effects can be managed using dose reduction and treatment discontinuation (Verstovsek, 2017, J. Hematol. Oncol. 10:55).

[0335] This specification also provides a method for safely administering a JAK2 inhibitor to a subject for the treatment of myelofibrosis without dose reduction, comprising administering an activin receptor type IIB (ActRIIB) ligand trap (e.g., raspatercept) to the subject and administering a JAK2 inhibitor to the subject. Without being bound by theory, the ActRIIB ligand trap eliminates or reduces one or more side effects associated with JAK2 therapy (such as thrombocytopenia or anemia).

[0336] In certain embodiments, the JAK2 inhibitor is ruxolitinib. In certain embodiments, the JAK2 inhibitor is fedratinib. In some embodiments, the JAK2 inhibitor is administered at a usual dose. In some embodiments, the usual dose of the JAK2 inhibitor is the recommended starting dose. In one embodiment, when the JAK2 inhibitor is ruxolitinib, the usual dose is 20 mg twice daily. In another embodiment, when the JAK2 inhibitor is ruxolitinib, the usual dose is 15 mg twice daily. In one embodiment, when the JAK2 inhibitor is fedratinib, the usual dose is 400 mg once daily. In another embodiment, when the JAK2 inhibitor is fedratinib, the usual dose is 300 mg once daily. In yet another embodiment, when the JAK2 inhibitor is fedratinib, the usual dose is 200 mg once daily. In certain embodiments, the JAK2 inhibitor is administered at at least 75%, 80%, 85%, 90%, or 95% of the recommended starting dose. In certain embodiments, when a potent CYP3A4 inhibitor is administered concurrently, the usual dose is the adjusted usual dose. In certain embodiments, when a potent CYP3A4 inhibitor is administered concurrently, the recommended starting dose is the adjusted recommended starting dose.

[0337] In certain embodiments, the JAK2 inhibitor is administered at a normal dose for a long period of time. In certain embodiments, the JAK2 inhibitor is administered at a normal dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months. In certain embodiments, the JAK2 inhibitor is administered at a normal dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 years.

[0338] In certain embodiments, the dose of the JAK2 inhibitor is not reduced due to adverse effects when an activin receptor type IIB (ActRIIB) ligand trap is administered concurrently. In certain embodiments, the adverse effect is anemia. In certain embodiments, the adverse effect is thrombocytopenia. In certain embodiments, the adverse effect is neutropenia.

[0339] In certain embodiments, the method further includes monitoring any adverse effects caused by the JAK2 inhibitor. In certain embodiments, the adverse effect is anemia. In certain embodiments, the adverse effect is thrombocytopenia. In certain embodiments, the adverse effect is neutropenia. In certain embodiments, the subject's total blood count (CBC), red blood cell count, or platelet count is monitored. In one embodiment, the subject's total blood count (CBC), red blood cell count, or platelet count is measured monthly. In another embodiment, the subject's total blood count (CBC), red blood cell count, or platelet count is measured every 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 weeks. In yet another embodiment, the subject's total blood count (CBC), red blood cell count, or platelet count is measured once, twice, three, or four times a week.

[0340] In certain embodiments, myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis. In certain embodiments, myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF).

[0341] This specification also provides a method for reducing adverse effects caused by the administration of a JAK2 inhibitor for the treatment of myelofibrosis in a subject, the method comprising administering an activin receptor type IIB (ActRIIB) ligand trap to the subject. In certain embodiments, the adverse effect is anemia. In certain embodiments, the adverse effect is thrombocytopenia. In certain embodiments, the adverse effect is neutropenia. In certain embodiments, the dose of the JAK2 inhibitor is not reduced due to adverse effects when the activin receptor type IIB (ActRIIB) ligand trap is administered concurrently. In certain embodiments, adverse effects are monitored by measuring the subject's total blood count (CBC), red blood cell count, or platelet count. In one embodiment, the subject's total blood count (CBC), red blood cell count, or platelet count is measured monthly. In another embodiment, the subject's total blood count (CBC), red blood cell count, or platelet count is measured every 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 weeks. In another embodiment, the subject's total blood cell count (CBC), red blood cell count, or platelet count is measured once, twice, three times, or four times per week.

[0342] In some embodiments, the ActRIIB ligand trap (e.g., raspatercept) is administered according to the dosage and regimen described in Sections 5.5 and 5.8. In some embodiments, the pharmaceutically effective dose of the ActRIIB ligand trap to be administered is 0.6 mg / kg, 0.8 mg / kg, 1 mg / kg, 1.33 mg / kg, or 1.75 mg / kg. In some embodiments, the pharmaceutically effective dose of the ActRIIB ligand trap to be administered is 1.33 mg / kg. In some embodiments, the initial dose of the ActRIIB ligand trap is 1.33 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, or 1.75 mg / kg. In some embodiments, the next dose of the ActRIIB ligand trap is 1.33 mg / kg. In some embodiments, the ActRIIB ligand trap is administered once at the beginning of each treatment cycle, with each cycle lasting 21 days. In some embodiments, the ActRIIB ligand trap is administered to the subject for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cycles.

[0343] This specification provides a method for treating myelofibrosis in a subject, Administer a JAK2 inhibitor to the target patient; The subjects will be administered an activin receptor type IIB (ActRIIB) ligand trap. Includes; A method is also provided in which the simultaneous administration of an activin receptor type IIB (ActRIIB) ligand trap is carried out at an effective dose in which the JAK2 inhibitor dose is not adjusted due to adverse effects. In certain embodiments, the JAK2 inhibitor dose is not reduced. In certain embodiments, the adverse effect is anemia. In one embodiment, the adverse effect is a decrease in red blood cell count. In one embodiment, the adverse effect is an increase in red blood cell (RBC) transfusion units.

[0344] This specification provides a method for treating myelofibrosis in a subject, Administer JAK2 inhibitors at the initial dose; To administer to activin receptor type IIB (ActRIIB) ligand traps; and Maintaining an initial dose of JAK2 inhibitors for an extended period. Methods including this are also provided.

[0345] In certain embodiments, the co-administration of an activin receptor type IIB (ActRIIB) ligand trap is done at a dose effective in reducing or mitigating adverse effects. In certain embodiments, the JAK2 inhibitor dose is not reduced. In certain embodiments, the adverse effect is anemia. In some embodiments, the initial dose of the JAK2 inhibitor is the recommended starting dose. In one embodiment, when the JAK2 inhibitor is ruxolitinib, the initial dose is 20 mg twice daily. In another embodiment, when the JAK2 inhibitor is ruxolitinib, the initial dose is 15 mg twice daily. In one embodiment, when the JAK2 inhibitor is fedratinib, the initial dose is 400 mg once daily. In another embodiment, when the JAK2 inhibitor is fedratinib, the initial dose is 300 mg once daily. In yet another embodiment, when the JAK2 inhibitor is fedratinib, the initial dose is 200 mg once daily. In certain embodiments, the JAK2 inhibitor is administered at at least 75%, 80%, 85%, 90%, or 95% of the recommended starting dose. In certain embodiments, when a potent CYP3A4 inhibitor is administered concurrently, the initial dose is an adjusted dose. In certain embodiments, when a potent CYP3A4 inhibitor is administered concurrently, the recommended starting dose is an adjusted recommended starting dose. In certain embodiments, the JAK2 inhibitor is administered at the initial dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months. In certain embodiments, the JAK2 inhibitor is administered at the initial dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 years.

[0346] This specification also provides a method for treating anemia in a subject with an activin receptor type IIB (ActRIIB) ligand trap, comprising administering the activin receptor type IIB (ActRIIB) ligand trap to a subject in need of treatment, wherein the subject is receiving concomitant administration of a JAK2 inhibitor for the treatment of myelofibrosis. In certain embodiments, the concomitant treatment of the JAK2 inhibitor is administered at a normal dose for a long period of time. In certain embodiments, the JAK2 inhibitor is administered at a normal dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months. In certain embodiments, the JAK2 inhibitor is administered at a normal dose for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 years.

[0347] In one embodiment of the method described in Section 5.9.1, the activin receptor type IIB (ActRIIB) ligand trap is the activin receptor type IIB (ActRIIB) ligand trap disclosed herein.

[0348] 5.10 Route of administration In certain embodiments, the ActRIIB ligand trap is administered by injection. In certain embodiments, the ActRIIB ligand trap is administered subcutaneously. In certain embodiments, the ActRIIB ligand trap is administered once every three weeks. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO: 11. In certain embodiments, the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence described in SEQ ID NO: 11. In preferred embodiments, the ActRIIB ligand trap is a raspatercept.

[0349] The route of administration of fedratinib or its pharmaceutically acceptable salts or hydrates is independent of the route of administration of the ActRIIB ligand trap provided herein. In one preferred embodiment, fedratinib is administered orally. In another embodiment, fedratinib is administered intravenously. In yet another embodiment, fedratinib is administered subcutaneously. [Examples]

[0350] 6. Examples 6.1 Example 1: Phase 3B, multicenter, single-arm, open-label efficacy and safety study of fedratinib with concurrent raspatercept for the treatment of anemia in patients with myeloproliferative neoplasm (MPN)-associated myelofibrosis. This example relates to a secondary study of a Phase 3B, multicenter, single-arm, open-label trial. The main trial evaluates the efficacy and safety of fedratinib in subjects with MPN-related MF (including PMF, post-PV, and post-ET MF) classified as intermediate or high-risk by the Dynamic International Prognostic Scoring System (DIPSS). This secondary study evaluates the safety, tolerability, and efficacy of raspatercept and ActRIIB ligand trap when concomitated with fedratinib in subjects with MPN-related MF and anemia. This secondary study is initiated 32 weeks after the initial fedratinib administration. This secondary study is divided into a secondary study screening period (during the main trial), a secondary study treatment period (consisting of the secondary study treatment period and anemia response assessment at week 24 of the secondary study (day 169 of the secondary study)), and a subsequent secondary study post-treatment follow-up period (consisting of safety follow-up at day 42 and a secondary study long-term follow-up period). The overall study design is shown in Figure 1.

[0351] This supplemental study primarily evaluates the safety and tolerability of raspatercept when administered concurrently with fedratinib and assesses its efficacy in two groups of patients with MPN-related MF and anemia: 1) Group A (transfusion-dependent): patients with a baseline RBC transfusion burden of 4-12 RBC units / 84 days and no interval of >6 weeks (42 days) without RBC transfusion; 2) Group B (transfusion-independent): patients with a baseline RBC transfusion burden of <4 RBC units / 84 days or anemia (Hgb levels of ≤9.5 g / dL recorded on ≥3 different days including the day of administration during the 84-day period up to day 1 (C1D1) of supplemental study cycle 1).

[0352] Patients who meet the criteria for blood transfusion or anemia and who have received stable administration of fedratinib for at least 32 weeks during the main study while also receiving fedratinib for 16 weeks immediately preceding day 1 of cycle 1 of the secondary study (C1D1) are eligible to participate in the secondary study.

[0353] The interim safety monitoring review will be conducted after approximately six subjects have completed at least two cycles of treatment with raspatercept in the secondary trial by the time of safety monitoring. Safety will be continuously evaluated using all available safety data for this concurrent treatment (including at least six subjects who received two cycles) and compared for each treatment to the safety data for monotherapy. If no significant toxicity (defined as unacceptable or uncontrollable toxicity) is observed, enrollment will continue and be completed for the remaining subjects.

[0354] Participants will receive concurrent treatment with raspatercept until the anemia response assessment at week 24 of the secondary study (day 169 of the secondary study), and concurrent treatment may be continued as long as the clinical benefit (anemia, spleen, or symptomatic response) as assessed by the principal investigator continues to be obtained, unless the participant develops a progressive disease (according to the International Working Group - Myeloproliferative Neoplasm Research and Therapy (IWG-MRT) 2013 criteria) or unacceptable toxicity, withdraws consent, or meets any other criteria for treatment discontinuation. At the time of evaluation, participants may choose to 1) continue concurrent treatment, 2) discontinue raspatercept and continue with fedratinib monotherapy, or 3) continue with both study treatments.

[0355] Due to differences in the administration schedule and event tables, outpatient visits in the secondary trial will differ from those in the primary trial. Planned outpatient visits in the secondary trial will be conducted on a 3-week cycle based on the established raspatercept administration schedule. From the time a subject enters the secondary trial, they will continue with the following secondary trial event schedule.

[0356] Approximately 25 patients from the main trial who have been previously treated with ruxolitinib and have PMF, post-PV MF, or post-ET MF and anemia will be enrolled in an optional secondary trial. Intermediate safety monitoring will be conducted after approximately 6 patients have completed at least two cycles of concurrent treatment.

[0357] 6.1.1 Test design and test duration (a) Screening period Screening for the secondary trial will be conducted while subjects are receiving treatment in the primary trial. Any subject with anemia who has received at least 32 weeks of fedratinib treatment is eligible and may be selected for the secondary trial at any time. All subjects who sign consent for the secondary trial will proceed to a screening period of up to 28 days.

[0358] (b) Registration Eligible subjects are assigned to either Group A or Group B based on the inclusion criteria they meet. Group A: Transfusion-dependent anemia (4-12 RBC units / 84 days) Group B: Non-transfusion dependent (only anemia with <4 RBC units / 84 days or Hgb ≤ 9.5 g / dL)

[0359] Ineligible participants will continue the main trial, receiving only fedratinib and completing the periodic outpatient visits required for the main trial.

[0360] (c) Treatment period The starting dose of raspatercept is 1.33 mg / kg, administered by subcutaneous injection. Anemia response assessment (Week 24 (Day 169 of the supplementary study))

[0361] All enrolled subjects will remain on the therapy until at least week 24 of the secondary trial (day 168 of the secondary trial). Anemia response assessments, which evaluate clinical utility (anemia, spleen, or symptomatic response), will be performed to determine whether subjects should continue with the concurrent treatment.

[0362] Subjects may remain in concurrent treatment after anemia response assessment at week 24 of the secondary study (day 169 of the secondary study) if they continue to demonstrate clinical benefit and do not meet any of the treatment discontinuation criteria (i.e., unacceptable toxicity, progressive disease, or withdrawal from the subject). Clinical benefit will be assessed cycle by cycle after anemia response assessment.

[0363] 6.1.2 Inclusion Criteria Approximately 25 patients from the main trial who have been previously treated with ruxolitinib and have PMF, post-PV MF, or post-ET MF, and who also have anemia (as defined below), will be enrolled in this subtrial.

[0364] To be eligible for the exam, you must meet the following criteria regarding the main exam: 1. The subject must be at least 18 years old at the time of signing the Informed Consent Form (ICF); 2. Participants must have a US East Coast Cancer Clinical Trials Group (ECOG) performance status (PS) of 0, 1, or 2; 3. The subjects are those diagnosed with primary myelofibrosis (PMF) according to the 2016 World Health Organization (WHO) criteria, as confirmed by the most recent local pathology report, or with post-ET or post-PV myelofibrosis according to the IWG-MRT 2007 criteria; 4. The subjects are those with an intermediate or high DIPSS risk score; 5. The subjects are those with a height of ≥450 cm as determined by MRI or CT scan evaluation. 3 Having measurable splenomegaly during the screening period, as demonstrated by the spleen volume or by a palpable spleen measuring ≥5 cm below the left costal margin; 6. The subjects must have been previously exposed to ruxolitinib, have been diagnosed with MF (PMF, post-ET MF, or post-PV MF), and meet at least one of the following criteria (a or b): a. Treatment with ruxolitinib for ≥ 3 months; b. Treatment with ruxolitinib for ≥28 days in combination with any of the following: i. The need for red blood cell transfusion (at least 2 units / month for 2 months) or ii. Grade 3 or higher thrombocytopenia, anemia, hematoma, and / or bleeding during treatment with ruxolitinib; 7. Before initiating the last therapy prior to fedratinib treatment, the patient must have recovered to Grade 1 or baseline levels from previous therapy. 8. The subject must understand and voluntarily sign the ICF before any examination-related assessment / procedure is performed; 9. Participants must have the willingness and ability to comply with the trial outpatient schedule and other protocol requirements; 10. Women of childbearing potential (FCBP) a. Two negative pregnancy tests, as verified by the principal investigator, must be performed before commencing the study therapy. Women must consent to continued pregnancy testing during the study and after the completion of the study therapy. This applies even if the subject is practicing complete abstinence from heterosexual contact*; b. Commit to completely abstaining from contact with the opposite sex (this must be verified monthly and the source must be documented), or agree to and adhere to using highly effective contraception without interruption 14 days before the start of the investigational drug, during the study therapy (including discontinuation of administration), and for 30 days after the discontinuation of the study therapy. 11. For men, a. During participation in the study, during discontinuation of the investigational drug, and for at least 30 days after discontinuation of the investigational drug, or longer if required by each compound and / or local regulations, men must agree to practice complete abstinence (which must be confirmed monthly) or to use condoms during sexual contact with pregnant or potentially pregnant women, even if they have undergone a successful vasectomy.

[0365] In addition to the criteria for the main examination, all subjects must meet the following inclusion criteria when enrolling in the secondary examination: 1. Participants must understand and voluntarily sign the optional ICF of the supplementary examination before any supplementary examination-related assessment / procedure is performed. 2. Participants must have taken fedratinib for at least 32 weeks (approximately 8 cycles). 3. Participants must have received a stable dose of fedratinib for at least 16 weeks (approximately 4 cycles) leading up to the scheduled registration date (SC1D1) [the dose level will not change]. 4. The subjects have anemia defined as any of the following: a. Group A-Transfusion dependent (TD) anemia - RBC transfusion frequency*: 4-12 RBC units / 84 days up to SC1D1 day (day 1 of supplementary study cycle 1) without an interval of >6 weeks (42 days) without RBC transfusion. - The subjects must have an Hgb level of <11.5 g / dL in SC1D1 prior to administration of raspatercept. b. Group B-Non-transfusion dependent (NTD) anemia - RBC transfusion frequency: <4 RBC units / 84 days up to SC1D1; or - At least three Hgb levels of ≤9.5 g / dL recorded on ≥3 different days, including the day of administration, during the 84-day period leading up to secondary study C1D1. There must be ≥14 days between each Hgb measurement. Subjects with an interval of ≥42 days between hemoglobin measurements will not be enrolled. * "Baseline" is defined as the 84-day phased period (three 28-day cycles) preceding day 1 of the supplemental study cycle 1. Any transfusion given for symptomatic Hgb ≤ 7 or Hgb ≤ 9.5 g / dL will be counted towards the baseline transfusion requirement. Transfusions given solely for bleeding or infection will not be counted towards the eligible baseline transfusion requirement. 5. The subjects were those with an East Coast Cancer Clinical Trials Group (ECOG) performance score of ≤2.

[0366] Participants must be willing and capable of complying with the trial outpatient schedule and other protocol requirements.

[0367] 6.1.3 Exclusion criteria 1. Any of the following abnormal clinical laboratory values: a. Platelets <50,000 / μL b. Neutrophil absolute count (ANC) < 1.0 × 10⁹ / L c. White blood cell count (WBC) > 100 × 10⁹ / L d. ≥5% myeloblasts in peripheral blood e. Estimated glomerular filtration rate <30 mL / min / 1.73 m2 (following the formula for dietary changes in renal disease [MDRD]) f. Serum amylase or lipase > 1.5 × ULN (upper limit of normal range) g. >3 × ULN aspartate aminotransferase (AST) or alanine aminotransferase (ALT) For total bilirubin with h. > 1.5 × ULN and total bilirubin with 1.5 to 3.0 × ULN, the proportion of direct bilirubin is eligible if it is < 25% of total bilirubin. 2. The target group is pregnant or breastfeeding women. 3. Patients who have previously undergone splenectomy. 4. Patients who have previously undergone or are scheduled to undergo hematopoietic stem cell transplantation. 5. Subjects with a history of encephalopathy, including Wernicke's encephalopathy. 6. Subjects exhibiting signs or symptoms of encephalopathy, including Wernicke's encephalopathy (e.g., severe ataxia, ophthalmoplegia, or cerebellar symptoms). 7. Subjects with thiamine deficiency (defined as those whose whole blood thiamine levels are below the normal range according to the institution's standards and have not been corrected prior to enrollment in this study) 8. Subjects involved in concurrent treatment with or use of pharmaceuticals, herbs, or foods known to be potent or moderate inducers of cytochrome P450 3A4 (CYP3A4), or dual CYP2C19 and CYP3A4 inhibitors. 9. Patients receiving any chemotherapy, immunomodulatory therapy (e.g., thalidomide, interferon-alpha), anagrelide, immunosuppressive therapy, or systemic corticosteroids >10 mg / day of prednisone or equivalent. Patients with a history of exposure to hydroxyurea (e.g., Hydrea) may be enrolled in the study unless it was administered within 14 days prior to the initiation of fedratinib treatment. 10. The subjects were those who received ruxolitinib within 14 days prior to starting fedratinib. 11. Subjects receiving treatment with myeloproliferative factors (e.g., granulocyte colony-stimulating factor [G-CSF]) within 14 days prior to the initiation of fedratinib treatment. 12. Subjects who have previously been exposed to Janus kinase (JAK) inhibitors other than ruxolitinib for two or more cycles. 13. Patients receiving treatment with aspirin at a dose of >150 mg per day 14. Patients who have undergone major surgery within 28 days prior to initiating fedratinib treatment. 15. Subjects diagnosed with chronic liver disease (e.g., chronic alcoholic liver disease, autoimmune hepatitis, sclerosing cholangitis, primary biliary cirrhosis, hemoglobinosis, non-alcoholic steatohepatitis). 16. Subjects with malignant tumors other than those previously studied, excluding those who have not required treatment for malignant tumors for at least three years prior to enrollment. However, subjects with the following medical history / comorbidities may be enrolled on the condition that they have successfully received treatment: non-invasive skin cancer, in-vivo cervical cancer, in-vivo carcinoma of the breast, incidental histological findings of prostate cancer (T1a or T1b using the Tumor, Nodule, Metastasis [TNM] clinical staging system), or disease-free individuals receiving only hormone therapy. 17. Patients with uncontrolled congestive heart failure (New York Heart Association Functional Classification 3 or 4) 18. Subjects with known human immunodeficiency virus (HIV), known active infectious hepatitis B (HepB), and / or known active infectious hepatitis C (HepC). 19. Subjects with severe active infection 20. Patients with any significant gastric disorder or other disorder that would inhibit the absorption of oral medication. 21. Individuals who cannot swallow capsules. 22. Subjects must have any significant medical condition, abnormal clinical test values, or psychiatric disorder that would prevent them from participating in the study. 23. Subjects have any condition, including the presence of abnormal clinical laboratory values, and if a subject participates in the study, the subject will be placed at an unacceptable risk. 24. The subject has any condition that impairs his ability to interpret data from the test. 25. Patients who have participated in any clinical trial of an investigational drug (drug, biologic, or device) within 30 days prior to the initiation of fedratinib treatment. Subjects with an average life expectancy of less than 26.6 months

[0368] 6.1.4 Exclusion Criteria for Supplementary Examinations 1. Patients with MPN-related MF or anemia from causes other than JAK2 inhibitor therapy (e.g., iron deficiency, vitamin B12 and / or folate deficiency, autoimmune or hemolytic anemia, infection, or any known clinically significant bleeding or necrotic bone formation). 2. Subjects with any of the following abnormal clinical laboratory values ​​in SC1D1: a. Neutrophils <1 × 10⁹ / L b. White blood cell count (WBC) > 100 × 10⁹ / L c. Platelets <50 × 10⁹ / L or >1000 × 10⁹ / L d. Peripheral blood myeloblasts > 5% e. Estimated glomerular filtration rate <40 mL / min / 1.73 m2 (using the formula for dietary changes in four-variable renal disease [MDRD]) f. > 3.0 × Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) at the upper limit of the normal range (ULN) g. Direct bilirubin ≥ 2 × ULN (higher levels are acceptable if these may be due to the destruction of active erythrocyte precursors in the bone marrow (i.e., inactive erythrocyte production)). 3. Subjects who, despite appropriate treatment, have a diastolic blood pressure of ≥90 mmHg or a systolic blood pressure of ≥140 mmHg prior to SC1D1. 4. Subjects with malignant tumors other than those previously studied. However, subjects who have not required treatment for malignant tumors for at least three years prior to enrollment are excluded. Nevertheless, subjects with the following medical history / comorbidities are acceptable: a. Basal or squamous cell carcinoma of the skin b. Cervical carcinoma in vivo c. In vivo carcinoma of the breast d. Incidental histological findings in prostate cancer (tumor, node, metastasis [TNM] clinical staging system, T1a or T1b) 5. Patients who have experienced a stroke, deep vein thrombosis, pulmonary embolism, or arterial embolism within the 6 months prior to SC1D1. 6. Applicants must have undergone major surgery within two months prior to the registration date. Applicants must have fully recovered from any previous surgery by the registration date. 7. Patients with poorly controlled cardiac disease and / or a known left ventricular ejection fraction of <35%. 8. Subjects with an uncontrolled systemic fungal, bacterial, or viral infection (defined as a progressive sign / symptom associated with an infection that does not improve despite appropriate antibiotics, antiviral therapy, and / or other treatments). 9. Patients who have previously received raspatercept or sotatercept therapy. 10. Subjects with a history of severe allergy, anaphylactic reaction, or hypersensitivity to recombinant proteins or excipients in the investigational drug (see Raspatercept IB). 11. Subjects who have experienced a major bleeding event (defined as symptomatic bleeding in a vital site or organ and / or bleeding resulting in a decrease in Hgb of ≥2 g / dL or leading to a transfusion of ≥2 units of concentrated red blood cells) in the last six months prior to registration. 12. Subjects who have used erythropoietin stimulants (ESAs) for ≤56 days prior to SC1D1.

[0369] 6.1.5 Therapeutic Administration and Schedule Participants will continue to receive fedratinib at the same dose level administered during the main study. In addition, participants will also receive raspatercept on day 1 of each 21-day treatment cycle until at least day 168 following day 1 of cycle 1 (SC1D1) of the secondary study, unless they experience progression to AML, unacceptable toxicity, withdrawal of consent, or meet any other treatment discontinuation criteria before the response assessment on day 169. Each treatment cycle is 21 days long.

[0370] (a) Administration of fedratinib The fedratinib dose is preferably 400 mg / day PO (4 x 100 mg capsules), which is administered orally once daily to outpatients at the same time each day, preferably with dinner. However, fedratinib may be taken with or without meals. If a dose is missed, the next dose should be taken the following day at the same time as the missed dose.

[0371] To minimize drug toxicity in individual subjects, flexible dose-modification regimens may be used, with possible daily doses of 100 mg, 200 mg, 300 mg, or 400 mg. For administrative purposes, a cycle is defined as 4 weeks (28 days). Subjects may continue treatment with fedratinib until unacceptable toxicity occurs, there is no therapeutic effect, disease progression occurs, or consent is withdrawn.

[0372] (b) Administration of raspatercept Raspatercept is administered at an initial dose level of 1.33 mg / kg on day 1 of every 21-day cycle. The dose may be escalated from the start of cycle 3 as described herein. Raspatercept is administered to subjects by subcutaneous injection. Subjects are assessed for Hgb, WBC, blood myeloblast percentage, and blood pressure before each administration.

[0373] The starting doses of raspatercept, including dose increases and decreases, are listed in Table 1.

[0374] [Table 1]

[0375] (c) Dosage setting of raspatercept Immediately upon assessment by the principal investigator prior to day 1 of cycle 3 of the secondary study and all subsequent treatment cycles, subjects may have dose levels that increase from an initial dose level of 1.33 mg / kg to a maximum of 1.75 mg / kg during the secondary study treatment period.

[0376] A subject may be eligible for dose adjustment if they were evaluated at the same dose level in two of the most recent treatment cycles and did not meet any of the protocol dose delay and / or reduction criteria in those two most recent treatment cycles. The dose level may be increased by one dose level if one or more of the following criteria are met: • The patient has experienced ≥1 RBC transfusion event (due to a pre-transfusion Hgb of ≤9.5 g / dL) between the two most recent treatment cycles (approximately 6 weeks). A decrease in Hgb of ≥1 g / dL was observed during a period of approximately 6 weeks without blood transfusion, and this decrease was not preceded by RBC transfusion (the decrease in Hgb occurred ≥ 14 days after the last RBC transfusion). • Hgb levels do not increase by more than 1 g / dL from the baseline mean pre-transfusion Hgb level.

[0377] Dose levels should be set individually for each target.

[0378] 6.1.6 Evaluation Items The primary objective is to evaluate the safety and tolerability of fedratinib administered concurrently with raspatercept. With a sample size of 25, the standard error for estimates of response rate and adverse event rate is less than 0.1. For the revised 8-week hematological improvement-related anemia response (erythrocyte response (HI-E)) secondary endpoint, the estimated response rate is at least 50%, based on the predicted percentage of patients experiencing a mean increase of ≥1.5 g / dL in hemoglobin at 12 weeks or a ≥50% reduction in RBC transfusions (at least 4 units) over any 12-week period.

[0379] The primary and secondary endpoints of this secondary study are listed in Table 2 below. Any data collected during the secondary study, including but not limited to spleen volume, palpation spleen size, MFSAF v4.0 (Myelofibrosis Symptom Assessment Form), and thiamine (and Mini-Mental State Examination [MMSE]) monitoring, may be used for primary study analysis.

[0380] [Table 2]

[0381] 6.1.7 RBC transfusion The administration of red blood cell transfusions based on Hgb levels and symptoms should not be modified for individual subjects during the screening and treatment periods.

[0382] For any RBC transfusions received during the study (either at the study site or an external facility), the Hgb level immediately prior to transfusion should be collected along with several other parameters (i.e., the number of units transfused, the volume transfused, and the date of transfusion).

[0383] Each subject has a “pre-transfusion hemoglobin threshold” for requesting a transfusion during the study, which is determined based on transfusion history. The baseline pre-transfusion hemoglobin threshold is the mean of all documented pre-transfusion hemoglobin values ​​for the 12 weeks prior to day 1 of cycle 1 of the secondary study. During treatment, if the pre-transfusion hemoglobin level increases by ≥1 g / dL compared to the pre-transfusion hemoglobin threshold for the subject (at the time of the next predicted transfusion event), the transfusion should be delayed by at least 7 days and / or the number of units transfused should be reduced by 1 or more RBC units.

[0384] For this study, RBC or whole blood transfusions are considered equivalent.

[0385] 7. Explanation of the array

[0386] [Table 3]

[0387] [Table 4]

[0388] [Table 5]

[0389] [Table 6]

[0390] [Table 7]

[0391] [Table 8]

[0392] [Table 9]

[0393] [Table 10]

[0394] [Table 11]

[0395] [Table 12]

[0396] 8. Equal parts While the present invention is described in detail with reference to its specific embodiments, it will be understood that functionally equivalent modifications fall within the scope of the invention. Indeed, various modifications of the invention, in addition to those shown and described herein, will be apparent to those skilled in the art from the above and accompanying drawings. Such modifications are intended to fall within the scope of the accompanying claims. Those skilled in the art will recognize or confirm, through mere conventional experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

[0397] All publications, patents, and patent applications referenced herein are incorporated by reference to the same extent as each individual publication, patent, or patent application is incorporated by reference specifically, individually, and as a whole.

Claims

1. A therapeutic agent for anemia in patients requiring treatment, comprising an activin receptor type IIB (ActRIIB) ligand trap, The subject was administered the ActRIIB ligand trap at a dose of 1 mg / kg once every 21 days; then The invention is characterized by being used to administer fedratinib or a pharmaceutically acceptable salt and / or hydrate thereof to the subject, The ActRIIB ligand trap is a fusion protein between the extracellular domain of the human ActRIIB receptor and the Fc portion of IgG1, and A therapeutic agent wherein the extracellular domain of the human ActRIIB receptor contains amino acids 25-131 of SEQ ID NO: 14 having the L79D mutation.

2. A therapeutic agent for anemia in patients requiring treatment, comprising an ActRIIB ligand trap, (a) A first measurement of hemoglobin (Hgb) level is obtained in the subject; (b) The subjects are administered an initial dose of the ActRIIB ligand trap once every 21 days during the first period; (c) The subject is administered fedratinib or a pharmaceutically acceptable salt or hydrate thereof; (d) At the end of the first period, a second measurement of the Hgb level is obtained in the subject; then (e) The ActRIIB ligand trap is used to administer the subject in the following doses based on the second measurement of Hgb level compared to the first measurement of Hgb level, or based on the number of red blood cell transfusions the subject received during the first period: The ActRIIB ligand trap is a fusion protein between the extracellular domain of the human ActRIIB receptor and the Fc portion of IgG1. The extracellular domain of the human ActRIIB receptor comprises amino acids 25-131 of SEQ ID NO: 14 having the L79D mutation, and A therapeutic agent in which the initial dose of the ActRIIB ligand trap is 1 mg / kg.

3. The therapeutic agent according to claim 1 or 2, wherein the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof are administered simultaneously to the subject.

4. The therapeutic agent according to any one of claims 1 to 3, wherein co-administration of the ActRIIB ligand trap and fedratinib or a pharmaceutically acceptable salt or hydrate thereof to the subject is pharmaceutically effective in treating the anemia.

5. The therapeutic agent according to any one of claims 1 to 4, wherein the subject is a subject diagnosed with myelofibrosis.

6. The therapeutic agent according to claim 5, wherein the myelofibrosis is myeloproliferative neoplasm (MPN)-associated myelofibrosis.

7. The therapeutic agent according to claim 5, wherein the myelofibrosis is intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (PV-MF), or post-essential thrombocythemia myelofibrosis (ET-MF).

8. The therapeutic agent according to claim 7, wherein the myelofibrosis is an intermediate or high-risk primary myelofibrosis (PMF).

9. The therapeutic agent according to claim 7, wherein the myelofibrosis is intermediate or high-risk post-polycythemia vera myelofibrosis (post-PV MF).

10. The therapeutic agent according to claim 7, wherein the myelofibrosis is intermediate or high-risk post-thrombocythemia myelofibrosis (ET-post-MF).

11. The therapeutic agent according to any one of claims 1 to 10, wherein the subject is a human.

12. The therapeutic agent according to any one of claims 1 to 11, wherein the anemia is related to myeloproliferative neoplasm (MPN)-associated myelofibrosis.

13. The therapeutic agent according to any one of claims 1 to 11, wherein the subject is transfusion-dependent or transfusion-independent of red blood cells (RBCs).

14. The therapeutic agent according to any one of claims 1 to 13, wherein the subject is RBC transfusion dependent.

15. The therapeutic agent according to claim 14, wherein the subject has received 4 to 12 RBC units in an RBC transfusion within 84 days prior to the administration of the ActRIIB ligand trap.

16. The therapeutic agent according to claim 14, wherein the subject has a hemoglobin (Hgb) level of 11.5 g / dL or less.

17. The therapeutic agent according to any one of claims 1 to 13, wherein the subject is transfusion-independent.

18. The therapeutic agent according to claim 17, wherein the subject received 4 or fewer red blood cell (RBC) units in a red blood cell (RBC) transfusion within 84 days prior to the administration of the ActRIIB ligand trap.

19. The therapeutic agent according to claim 17, wherein the subject has a hemoglobin (Hgb) level of 9.5 g / dL or less.

20. The therapeutic agent according to any one of claims 1 to 19, wherein the subject has been treated with fedratinib or a pharmaceutically acceptable salt or hydrate thereof for at least 8 weeks, at least 16 weeks, at least 24 weeks, at least 32 weeks, or at least 40 weeks prior to the administration of the ActRIIB ligand trap.

21. The therapeutic agent according to any one of claims 1 to 20, wherein the subject has been previously treated with ruxolitinib.

22. The therapeutic agent according to any one of claims 1 to 21, wherein the fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered to the subject daily.

23. The therapeutic agent according to any one of claims 1 to 22, wherein the fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered orally to the subject.

24. The therapeutic agent according to any one of claims 1 to 23, wherein the fedratinib or a pharmaceutically acceptable salt or hydrate thereof is administered to the subject at a dose of 400 mg / day.

25. The therapeutic agent according to any one of claims 1 to 24, wherein the ActRIIB ligand trap is administered subcutaneously to the subject.

26. The therapeutic agent according to any one of claims 2 to 25, wherein the first measurement of the Hgb level is obtained before the administration of the initial dose of the ActRIIB ligand trap.

27. The therapeutic agent according to any one of claims 2 to 25, wherein the first measurement of the Hgb level is obtained simultaneously with the administration of the initial dose of the ActRIIB ligand trap, or is obtained approximately 3 weeks, 6 weeks, 9 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, or 24 weeks after the administration of the initial dose of the ActRIIB ligand trap.

28. The therapeutic agent according to any one of claims 2 to 27, wherein the second measurement of the Hgb level is obtained approximately 3 weeks, 6 weeks, 9 weeks, 12 weeks, 15 weeks, 18 weeks, 21 weeks, 24 weeks, 7 months, 8 months, 9 months, 10 months, 11 months, or 12 months after the initial dose of the ActRIIB ligand trap is administered to the subject.

29. The therapeutic agent according to any one of claims 2 to 28, wherein the first period is 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, or 8 weeks.

30. The therapeutic agent according to claim 29, wherein the first period is 6 weeks.

31. The therapeutic agent according to any one of claims 2 to 30, wherein the next dose of the ActRIIB ligand trap is 0.6 mg / kg, 0.8 mg / kg, 1.0 mg / kg, 1.33 mg / kg, or 1.75 mg / kg.

32. The therapeutic agent according to any one of claims 2 to 30, wherein the next dose of the ActRIIB ligand trap is 1.33 mg / kg.

33. The therapeutic agent according to any one of claims 2 to 30, wherein when the second measured value of the Hgb level is 2 g / dL or more higher than the first measured value of the Hgb level, the next dose of the ActRIIB ligand trap is less than the initial dose of the ActRIIB ligand trap.

34. The therapeutic agent according to any one of claims 2 to 30, wherein when the subject has received one or more RBC transfusions during the first period, or when the second measured value of Hgb level is 0 g / dL to about 1 g / dL higher than the first measured value of Hgb level, or when the first measured value of Hgb level decreases by 1 g / dL or more during a period of approximately 6 weeks without transfusion, the next dose of the ActRIIB ligand trap is greater than the initial dose of the ActRIIB ligand trap.

35. The therapeutic agent according to any one of claims 2 to 30, wherein the next dose of the ActRIIB ligand trap is the same as the initial dose of the ActRIIB ligand trap.

36. The treatment involves classifying hematological events, hepatic events, non-hematological events, or gastrointestinal events in the subject into grades 1, 2, 3, 4, or 5 according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE); then The therapeutic agent according to any one of claims 1 to 35, further comprising administering the following doses of fedratinib or a pharmaceutically acceptable salt or hydrate thereof.

37. The therapeutic agent according to claim 36, wherein the following doses of fedratinib or a pharmaceutically acceptable salt or hydrate thereof are 300 mg / day, 200 mg / day, or 100 mg / day.

38. The ActRIIB ligand trap, (a) Those that are 90% identical to sequence number 11; (b) Those that are 95% identical to sequence number 11; (c) Those that are 98% identical to Sequence ID No. 11; and (d) Sequence ID 11 A therapeutic agent according to any one of claims 1 to 37, which is a polypeptide comprising an amino acid sequence selected from the group consisting of the following.

39. The therapeutic agent according to any one of claims 1 to 38, wherein the ActRIIB ligand trap is a polypeptide comprising the amino acid sequence of SEQ ID NO:

11.

40. The therapeutic agent according to any one of claims 1 to 38, wherein the ActRIIB ligand trap is a polypeptide encoded by the nucleotide sequence of SEQ ID NO: 34 or a degenerate version of SEQ ID NO:

34.

41. The therapeutic agent according to any one of claims 1 to 39, wherein the administration increases the hemoglobin (Hgb) level in the subject by at least 0.5 g / dL, at least 1.0 g / dL, at least 1.5 g / dL, at least 2.0 g / dL, or at least 2.5 g / dL compared to the hemoglobin (Hgb) level in the subject before administration.

42. The therapeutic agent according to claim 41, wherein the administration increases the Hgb level in the subject by at least 1.5 g / dL compared to the Hgb level in the subject before administration.

43. The therapeutic agent according to any one of claims 1 to 39, wherein the administration reduces the number of red blood cell (RBC) transfusions received by the subject within a period of 56 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units.

44. The therapeutic agent according to claim 43, wherein the administration reduces the number of RBC transfusions received by the subject within a period of 56 days by at least 4 units.

45. The therapeutic agent according to any one of claims 1 to 39, wherein the administration reduces the number of red blood cell (RBC) transfusions received by the subject within a period of 84 days by at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 units.

46. The therapeutic agent according to any one of claims 1 to 39, wherein the administration increases the hemoglobin (Hgb) level in the subject by at least 1.5 g / dL over a continuous period of 84 days.

47. The therapeutic agent according to any one of claims 1 to 39, wherein the administration causes the subject to be free from red blood cell (RBC) transfusions for a continuous period of 84 days.

48. The therapeutic agent according to any one of claims 1 to 47, wherein the administration increases the hemoglobin (Hgb) level in the subject by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% compared to the Hgb level in the subject before the administration.

49. The therapeutic agent according to any one of claims 1 to 48, wherein the administration increases the hematocrit (HCT) level in the subject by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% compared to the HCT level in the subject before the administration.

50. The therapeutic agent according to any one of claims 1 to 49, wherein the administration reduces the mean corpuscular volume (MCV) in the subject to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% compared to the MCV in the subject before the administration.

51. The therapeutic agent according to any one of claims 1 to 50, wherein the administration increases the cellular hemoglobin concentration (CHC) in the subject to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 200%, or 500% compared to the CHC in the subject before the administration.

52. The therapeutic agent according to any one of claims 1 to 51, wherein the administration reduces the erythrocyte distribution width (RDW) in the subject to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100% compared to the RDW in the subject before the administration.

53. The therapeutic agent according to any one of claims 1 to 52, wherein the administration keeps the level of reticulocytes in the subject within a range of 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% of the level of reticulocytes in the subject before the administration.

54. The therapeutic agent according to any one of claims 1 to 53, wherein the administration keeps the level of reticulocytes in the subject within a range greater than or less than 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% of the level of reticulocytes in the reference population.

55. The therapeutic agent according to any one of claims 1 to 54, wherein the administration keeps the level of white blood cells in the subject within a range of 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20% of the level of white blood cells in the subject before the treatment.

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