Methods for treating lower risk myelodysplastic syndrome

Abstract

The present disclosure relates to the use of Pelabusib and pharmaceutically acceptable salts and hydrates thereof for the treatment of lower risk myelodysplastic syndrome (LR-MDS) and related conditions thereof.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 433,833, filed December 20, 2022, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Myelodysplastic syndromes (MDS) are a heterogeneous collection of clonal bone marrow stem cell disorders characterized by ineffective hematopoiesis leading to cytopenia, with one-third of patients eventually progressing to acute myeloid leukemia (AML). More than 80% of MDS patients carry more than one known relapse mutation at diagnosis (Haferlach et al., Leukemia [Leukemia] 2014; 28:241-7). The genomes of most MDS cases are complex, containing a dominant clone and numerous clones with multiple co-mutations that may contribute to disease progression and / or relapse. In addition to acquired somatic mutations, cytokine abnormalities, and immune dysregulation, alterations in the bone marrow microenvironment also play an indispensable role in pathogenesis.

[0004] Abnormalities in the microenvironment disrupt normal hematopoietic integrity, leading to an increased apoptosis index, abnormal cell biology, and impaired development of bone marrow progenitor cells. The abnormal microenvironment may also act as an environment for the selective expansion of MDS clones, contributing to disease progression. Dysregulation of key regulators in bone marrow stem cells and progenitor cells results in hematopoietic abnormalities, apoptosis, and cell proliferation, thereby increasing the risk of infection, bleeding, and progression to AML (Ganan-Gomez et al., Leukemia. 2015; 29:1458-69).

[0005] MDS is classified by risk according to the original and revised versions of the International Prognostic Scoring System (IPSS-R). See, for example, Greenberg et al., Blood [Blood] 1997; 89:2079-88 and Greenberg et al., Blood [Blood] 2012; 120:2454-65. Approximately 80% of patients with lower-risk MDS have anemia, and transfusion dependence is associated with lower survival in this population. In patients ≥60 years of age, chronic anemia is associated with a variety of complications, including a higher risk of cardiovascular complications, falls and fractures, and shorter survival. Even without conversion to AML, MDS is often fatal due to complications associated with cytopenia and infection.

[0006] For lower risk MDS (LR-MDS), particularly those with anemia and dependence on transfusions, the available treatment options are limited. Typically, first-line treatment for lower risk MDS is erythropoiesis stimulating agents (ESAs), which aim for early erythropoiesis and increased proliferation. However, the response to ESAs is often reduced in RBC transfusion-dependent MDS patients. Luspatercept (an activin ligand trap that reduces aberrant Smad 2 / 3 signaling) was recently approved by the U.S. Food and Drug Administration (FDA) for the treatment of anemia in adults with very low to intermediate risk MDS with ring sideroblasts or with myelodysplastic syndromes / myeloproliferative neoplasms with ring sideroblasts and thrombocytosis who are ESA therapy failed and who require ≥2 RBC units within 8 weeks. However, luspatercept is not indicated for other MDS subtypes and can not be suitable for patients with several common complications, including thromboembolism and hypertension. Moreover, most patients receiving luspatercept therapy do not achieve the desired response. Lenalidomide is another treatment option for lower risk MDS patients; however, it is only approved for patients with del 5q cytogenetic abnormalities. Currently, the only known therapy for MDS is bone marrow transplantation. However, this intensive treatment is only available for eligible patients and for patients with higher risk MDS.

[0007] Accordingly, additional treatment options are needed to treat MDS and its related conditions. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 IL-6 protein release from PBMCs of primary MDS patients stimulated with LPS while receiving pelabresib treatment determined by electrochemiluminescence-based immunoassay is shown.

[0009] Figure 2 Percentage of megakaryocytic-erythroid CD34+ progenitor cells (left) and percentage of CD34- primitive / erythroblasts in isolated hematopoietic stem cell samples treated with erythroid expansion supplement only (DMSO only) or with erythroid expansion supplement and 250 nM pelabresib (right) n=2 donors is shown.

[0010] Figure 3 Cytokine release from PBMCs of primary MDS patients stimulated with LPS while receiving pelabresib treatment determined by electrochemiluminescence-based immunoassay is shown. Values have been normalized to the “DMSO only” control, n=7-10 donors, mean ± SEM. SUMMARY

[0011] LR-MDS is characterized by excessive apoptosis of bone marrow cells and an autoimmune disease-like profile. In addition, multiple genetic abnormalities common in MDS (e.g., TET2 and SF3B1 mutations) can induce NF-kB and proinflammatory signaling, which can impair erythropoiesis and cause death of erythroid cells. A meta-analysis of multiple studies showed that levels of proinflammatory cytokines (e.g., TNF-a, IL-6, and IL-8) were significantly higher in MDS patients as compared to controls (Shi et al., Medicine (Baltimore). 2019; 98: e15844). Moreover, these cytokine levels were higher in lower-risk MDS patients than in higher-risk MDS patients (Shetty et al., Leuk Res. 1996; 20: 891-900). The NF-kB pathway plays a central role in regulating these cytokines (Liu et al., Signal Transduct Target Ther. 2017; 2). Mesenchymal activation of NF-kB signaling is common in LR-MDS, and activation of NF-κB drives an inflammatory program that attenuates hematopoiesis in low-risk myelodysplastic syndromes (Ping et al., Leukemia. 2019; 33: 536-41). BET proteins regulate gene expression of key oncogenic pathways such as NF-kB or TGFb signaling, which are important drivers of proinflammatory signaling and ineffective hematopoiesis in MDS.

[0012] CPI-0610 is a selective and potent small molecule BET inhibitor that has shown clinical activity in lymphoma and myelofibrosis (MF), where NF-kB signaling and proinflammatory cytokine expression are relevant drivers of disease processes. In lymphoma and MF patients, CPI-0610 can reduce levels of inflammatory cytokines regulated by the NF-κB pathway (Blum et al., Annals of Oncology. 2018; 29 and Talpaz et al., EHA Library. 2020; 293580).

[0013] In addition to improving hematopoiesis by reducing the proinflammatory environment, pemafibrate can directly promote erythropoiesis. In patients enrolled in a pemafibrate clinical trial (Group 1 of the MANIFEST trial (NCT02158858)), 57.9% (11 of 19) of patients achieved an increase in Hgb level of >1.5 g / dL without transfusion, which investigated pemafibrate monotherapy in patients with advanced MF refractory or intolerant to JAK inhibitors (Talpaz et al., EHA Library. [EHA Library] 2020; 293580). Consistent with this, exploratory analysis of erythroid progenitors by CD71 immunohistochemical staining was performed on all available pairs of bone marrow biopsies collected at baseline and week 24 in a cohort of 37 patients. Semi-quantitative analysis showed an increase in red cell progenitors in 59% (22 of 37 patients) (Mertz et al., American Society of Hematology 2020). Ex vivo proliferation / differentiation studies showed that pemafibrate promoted red cell maturation (using CD34+ cells isolated from blood samples collected from healthy donors and MF patients) and differentiation in the presence of a cytokine cocktail. Moreover, pemafibrate treatment rescued the inhibitory effect of ruxolitinib on erythroid differentiation in a dose-dependent manner (Mertz et al., American Society of Hematology 2020).

[0014] Furthermore, in a phase 2 trial of pemafibrate as monotherapy or in combination with ruxolitinib in patients with refractory advanced MF, treatment with pemafibrate induced an erythroid response. In Group 1 of the study, 21% of patients with relapsed / refractory MF dependent on transfusions achieved RBC-TI for >12 weeks with a median duration of 44 weeks (Talpaz et al., EHA Library. [EHA Library] 2020; 293580). In Group 2 of the study, 36% of patients with transfusion-dependent MF who received pemafibrate in addition to ruxolitinib achieved RBC-TI for >12 weeks with a median duration of 39 weeks (Verstovsek et al., Blood. [Blood] 2020; 136:51-52).

[0015] Accordingly, provided herein are methods of treating lower risk MDS, including low risk MDS and very low risk MDS, using pemafibrate or a pharmaceutically acceptable salt thereof.

[0016] Also provided herein are methods of using pemafibrate or a pharmaceutically acceptable salt thereof for treating lower risk MDS dependent on RBC transfusions, including low risk MDS and very low risk MDS dependent on RBC transfusions.

[0017] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for treating anemia associated with lower risk MDS, including low risk MDS and very low risk MDS.

[0018] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for improving hemoglobin levels (e.g., increasing hemoglobin levels) in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0019] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for treating cytopenia in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0020] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for treating ineffective erythropoiesis in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0021] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for improving bone marrow fibrosis in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0022] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for normalizing platelets in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0023] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for reducing spleen size in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0024] Further provided herein are methods of using pelabutib or a pharmaceutically acceptable salt thereof for reducing transfusion burden in a subject having lower risk MDS, including low risk MDS and very low risk MDS, and who is dependent on transfusions prior to treatment. DETAILED DESCRIPTION

[0025] In a first embodiment, provided herein are methods for treating lower risk MDS, including low risk MDS and very low risk MDS, in a subject in need thereof, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein, as part of the first embodiment, is the use of pelabutib or a pharmaceutically acceptable salt thereof for the treatment of lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein, as part of the first embodiment, is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for the treatment of lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein, as part of the first embodiment, is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for the treatment of lower risk MDS, including low risk MDS and very low risk MDS.

[0026] In a second embodiment, provided herein are methods for treating RBC transfusion dependent lower risk MDS, including RBC transfusion dependent low risk MDS and very low risk MDS, in a subject in need thereof, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein, as part of the second embodiment, is the use of pelabutib or a pharmaceutically acceptable salt thereof for the treatment of RBC transfusion dependent lower risk MDS, including RBC transfusion dependent low risk MDS and very low risk MDS. In another alternative, provided herein, as part of the second embodiment, is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for the treatment of RBC transfusion dependent lower risk MDS, including RBC transfusion dependent low risk MDS and very low risk MDS. In yet another alternative, provided herein, as part of the second embodiment, is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for the treatment of RBC transfusion dependent lower risk MDS, including RBC transfusion dependent low risk MDS and very low risk MDS.

[0027] In a third embodiment, provided herein are methods for treating anemia associated with lower risk MDS, including low risk MDS and very low risk MDS, in a subject in need thereof, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the third embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the treatment of anemia associated with lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the third embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for the treatment of anemia associated with lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the third embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for the treatment of anemia associated with lower risk MDS, including low risk MDS and very low risk MDS.

[0028] In a fourth embodiment, provided herein are methods for improving (e.g., increasing) hemoglobin levels in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the fourth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for improving (e.g., increasing) hemoglobin levels in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the fourth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for improving (e.g., increasing) hemoglobin levels in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the fourth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for improving (e.g., increasing) hemoglobin levels in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0029] In a fifth embodiment, provided herein is a method for treating cytopenia in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the fifth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for treating cytopenia in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the fifth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating cytopenia in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the fifth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for use in treating cytopenia in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0030] In a sixth embodiment, provided herein is a method for treating ineffective erythropoiesis in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the sixth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for treating ineffective erythropoiesis in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the sixth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating ineffective erythropoiesis in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the sixth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for use in treating ineffective erythropoiesis in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0031] In a seventh embodiment, provided herein is a method for improving bone marrow fibrosis in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the seventh embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for improving bone marrow fibrosis in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the seventh embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for improving bone marrow fibrosis in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the seventh embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for improving bone marrow fibrosis in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0032] In an eighth embodiment, provided herein is a method for normalizing platelets in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the eighth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for normalizing platelets in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the eighth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for normalizing platelets in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the eighth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for normalizing platelets in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0033] In a ninth embodiment, provided herein is a method for reducing spleen size in a subject having lower risk MDS, including low risk MDS and very low risk MDS, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the ninth embodiment is the use of pelabutib or a pharmaceutically acceptable salt for reducing spleen size in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In another alternative, provided herein as part of the ninth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for reducing spleen size in a subject having lower risk MDS, including low risk MDS and very low risk MDS. In yet another alternative, provided herein as part of the ninth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for reducing spleen size in a subject having lower risk MDS, including low risk MDS and very low risk MDS.

[0034] In a tenth embodiment, provided herein is a method for reducing transfusion burden in a subject having lower risk MDS, including low risk MDS and very low risk MDS, and who is dependent on transfusions prior to treatment, comprising administering to the subject an effective amount of pelabutib or a pharmaceutically acceptable salt thereof. Alternatively, provided herein as part of the tenth embodiment is the use of pelabutib or a pharmaceutically acceptable salt for reducing transfusion burden in a subject having lower risk MDS, including low risk MDS and very low risk MDS, and who is dependent on transfusions prior to treatment. In another alternative, provided herein as part of the tenth embodiment is the use of pelabutib or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for reducing transfusion burden in a subject having lower risk MDS, including low risk MDS and very low risk MDS, and who is dependent on transfusions prior to treatment. In yet another alternative, provided herein as part of the tenth embodiment is a pharmaceutical composition comprising pelabutib or a pharmaceutically acceptable salt thereof for reducing transfusion burden in a subject having lower risk MDS, including low risk MDS and very low risk MDS, and who is dependent on transfusions prior to treatment.

[0035] Pelabutib (CPI-0610), i.e., 2-((4S)-6-(4-chlorophenyl)-l-methyl-4H- benzo[c]isoxazolo[4,5-e]azepin-4-yl)acetamide, is exemplified in U.S. Patent No. 8,796,261 as compound 144, which has the structural formula:

[0036]

[0037] The term pelabutib as used herein includes crystalline and / or hydrated forms of pelabutib, such as the monohydrate and crystalline Form A monohydrate disclosed in U.S. 9,969,747, and is included in an aspect as part of the present application.

[0038] The pelabutib or pharmaceutically acceptable salt described herein can be formulated as a pharmaceutical composition and administered to a subject (e.g., a human) in a variety of forms adapted to the chosen route of administration. Typical routes of administering such pharmaceutical compositions include, but are not limited to, oral, topical, buccal, transdermal, inhalation, parenteral, sublingual, rectal, vaginal, and intranasal. The term “parenteral” as used herein includes subcutaneous injection, intravenous, intramuscular, intrathecal, intrasternal injection or infusion techniques. Methods of formulating pharmaceutical compositions are well known in the art, e.g., as disclosed in “Remington: The Science and Practice of Pharmacy” Edited by Science University of Philadelphia, 21st Edition, 2005, Lippincott, Williams & Wilkins, Philadelphia, PA.

[0039] As used herein, “lower risk MDS” means MDS according to IPSS-R prognostic risk category / score characteristics of low or very low risk MDS. See Greenberg P.L. et al. Revised international prognostic scoring system for myelodysplastic syndromes. Blood. 2012; 120:2454-65.

[0040] As used herein, “low risk MDS” means MDS defined by IPSS-R prognostic risk category / score of low risk MDS. See Greenberg P.L. et al. Revised international prognostic scoring system for myelodysplastic syndromes. Blood. 2012; 120:2454-65. For example, low risk MDS means MDS in a subject with an IPSS-R prognostic risk score of >1.5-3.

[0041] As used herein, “very low risk MDS” refers to very low risk MDS as defined by IPSS-R prognostic risk category / score. See Greenberg P.L. et al. Revised international prognostic scoring system for myelodysplastic syndromes. Blood. 2012; 120:2454-65. For example, very low risk MDS refers to MDS in a subject with an IPSS-R prognostic risk score of < 1.5.

[0042] The terms “lower risk MDS-related anemia,” “anemia associated with lower risk MDS,” and “anemia resulting from lower risk MDS” are synonymous and each refer to anemia developed or acquired by a subject as a result of having / having lower risk MDS.

[0043] The terms “subject” and “patient” are synonymous and each refer to a mammal in need of treatment, such as companion animals (e.g., dogs, cats, and the like), farm animals (e.g., cows, pigs, horses, sheep, goats, and the like), and laboratory animals (e.g., rats, mice, guinea pigs, and the like). Unless otherwise indicated, the subject is a human in need of treatment.

[0044] The terms “administer,” “administering,” and “administration” refer to providing, implanting, absorbing, ingesting, injecting, inhaling, or otherwise introducing pelabibenduz or a pharmaceutically acceptable salt thereof or a composition into a subject’s body or onto a subject’s body surface.

[0045] The terms “treatment,” “treat,” and “treating” refer to reversing, alleviating, delaying the onset of, or inhibiting the progression of a disease or one or more symptoms of a disease described herein. In some embodiments, treatment can be administered after one or more signs or symptoms of the disease have developed or have been observed (i.e., therapeutic treatment). In other embodiments, treatment is administered in the absence of signs or symptoms of the disease. For example, treatment can be administered to a susceptible subject prior to the onset of symptoms (i.e., prophylactic treatment). Treatment can also continue after symptoms have resolved, for example, to delay or prevent recurrence. In certain embodiments, treatment includes delaying the onset of at least one symptom of the disorder for a period of time.

[0046] The term "effective amount" or "therapeutically effective amount" of perabrosib or a pharmaceutically acceptable salt thereof described herein refers to an amount of perabrosib or a pharmaceutically acceptable salt thereof sufficient to provide a therapeutic benefit in the treatment of a disorder described herein. In one aspect, an effective amount is about 0.01 to about 100 mg / kg body weight / day of perabrosib or a pharmaceutically acceptable salt thereof, such as, for example, about 0.1 to about 100 mg / kg body weight / day.

[0047] The specific dosage and treatment regimen for any particular patient will depend on a variety of factors, including the activity of the specific compound employed, the age, body weight, general health status, sex, diet, time of administration, rate of excretion, drug combination, and the judgment of the treating physician, and the severity of the particular disease being treated. In one aspect, perabrosib or a pharmaceutically acceptable salt thereof can be formulated at a dose of about 50 mg to about 500 mg for administration, for example, once, twice, or three times per day. In another aspect, 2-((4S)-6-(4-chlorophenyl)-l-methyl-4H- benzo[c]isoxazolo[4,5-e]azepin-4-yl)acetamide or a pharmaceutically acceptable salt thereof can be formulated at a dose of about 50 mg to about 500 mg for administration, for example, once, twice, or three times per day. In another aspect, 2-((4S)-6-(4-chlorophenyl)-l-methyl-4H- benzo[c]isoxazolo[4,5-e]azepin-4-yl)acetamide or a pharmaceutically acceptable salt thereof can be formulated at a dose of about 50 mg to about 500 mg for administration, for example, once, twice, or three times per day, wherein 2-((4S)-6-(4-chlorophenyl)-l-methyl-4H- benzo[c]isoxazolo[4,5-e]azepin-4-yl)acetamide is monohydrate or crystalline Form A monohydrate. For example, perabrosib can be administered at a dose of about 50 mg to about 300 mg per day, about 50 mg to about 175 mg per day, about 50 mg to about 150 mg per day, about 75 mg to about 300 mg per day, about 75 mg to about 200 mg per day, about 75 mg to about 175 mg per day, about 75 mg to about 150 mg per day, about 70 mg to about 160 mg per day, about 100 mg to about 300 mg per day, about 150 mg to about 250 mg per day, or at a dose of about 50 mg per day, at a dose of about 75 mg per day, or at a dose of about 125 mg per day, about 150 mg per day, about 175 mg per day, about 200 mg per day, about 225 mg per day, or about 250 mg per day. In one aspect, perabrosib monohydrate can be formulated at a dose of about 50 mg to about 500 mg for administration, for example, once, twice, or three times per day. For example, perabrosib monohydrate can be administered at a dose of about 50 mg to about 300 mg per day, about 50 mg to about 175 mg per day, about 50 mg to about 150 mg per day, about 75 mg to about 300 mg per day, about 75 mg to about 175 mg per day, about 75 mg to about 150 mg per day, about 70 mg to about 160 mg per day, about 100 mg to about 300 mg per day, about 150 mg to about 250 mg per day, or at a dose of about 50 mg per day, at a dose of about 75 mg per day, at a dose of about 125 mg per day, about 150 mg per day, about 175 mg per day, about 200 mg per day, about 225 mg per day, or about 250 mg per day.In one aspect, the monohydrate crystalline Form A of pelabutib as described herein can be formulated at a dose of about 50 mg to about 500 mg for administration, for example, once, twice, or three times per day. For example, the monohydrate crystalline Form A of pelabutib as described herein can be administered at a dose of about 50 mg to about 300 mg per day, about 50 mg to about 175 mg per day, about 50 mg to about 150 mg per day, about 75 mg to about 300 mg per day, about 75 mg to about 175 mg per day, about 75 mg to about 150 mg per day, about 70 mg to about 160 mg per day, about 100 mg to about 300 mg per day, about 150 mg to about 250 mg per day, or at a dose of about 50 mg per day, about 75 mg per day, about 125 mg per day, about 150 mg per day, about 175 mg per day, about 200 mg per day, about 225 mg per day, or about 250 mg per day. In one aspect, pelabutib, or a pharmaceutically acceptable salt thereof, can be formulated at a dose of 50 mg to 500 mg for administration, for example, once, twice, or three times per day. For example, pelabutib can be administered at a dose of 50 mg to 300 mg per day, 50 mg to 175 mg per day, 50 mg to 150 mg per day, 75 mg to 300 mg per day, 75 mg to 175 mg per day, 75 mg to 150 mg per day, 70 mg to 160 mg per day, 100 mg to 300 mg per day, 150 mg to 250 mg per day, or at a dose of 50 mg per day, 75 mg per day, 125 mg per day, 150 mg per day, 175 mg per day, 200 mg per day, 225 mg per day, or 250 mg per day. In one aspect, pelabutib Form A monohydrate can be formulated at a dose of 50 mg to 500 mg for administration, for example, once, twice, or three times per day. For example, pelabutib Form A monohydrate can be administered at a dose of 50 mg to 300 mg per day, 50 mg to 175 mg per day, 50 mg to 150 mg per day, 75 mg to 300 mg per day, 75 mg to 200 mg per day, 75 mg to 175 mg per day, 75 mg to 150 mg per day, 70 mg to 160 mg per day, 100 mg to 300 mg per day, 150 mg to 250 mg per day, or at a dose of 50 mg per day, 75 mg per day, 125 mg per day, 150 mg per day, 175 mg per day, 200 mg per day, 225 mg per day, or 250 mg per day. In one aspect, the monohydrate crystalline Form A of pelabutib as described herein can be formulated at a dose of 50 mg to 500 mg for administration, for example, once, twice, or three times per day.For example, the monohydrate crystalline Form A of pelabutine described herein can be administered at a dose of 50 mg to 300 mg per day, 50 mg to 175 mg per day, 50 mg to 150 mg per day, 75 mg to 300 mg per day, 75 mg to 200 mg per day, 75 mg to 175 mg per day, 75 mg to 150 mg per day, 70 mg to 160 mg per day, 100 mg to 300 mg per day, 150 mg to 250 mg per day, or at a dose of 50 mg per day, 75 mg per day, 125 mg per day, 150 mg per day, 175 mg per day, 200 mg per day, 225 mg per day, or 250 mg per day.

[0048] As used herein, the expression of a range of values is intended to be a shorthand method of referring individually to each separate value falling within the range, and each individual value is incorporated herein as if it were individually recited herein. For example, a range of values from X to Y is intended to include X and Y, as well as all values between X and Y.

[0049] The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

[0050] In an eleventh embodiment, the perlapine used in the described methods (e.g., in any of the first through tenth embodiments) is crystalline. Alternatively, as part of the eleventh embodiment, the perlapine used in the described methods is a hydrate. In another alternative, as part of the eleventh embodiment, the perlapine used in the described methods is a monohydrate. Alternatively, as part of the eleventh embodiment, the perlapine used in the described methods (e.g., as in any of the first through tenth embodiments) is crystalline Form A (e.g., monohydrate crystalline Form A) characterized by at least three, at least four, at least five, or six x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°. In another alternative, as part of the eleventh embodiment, the perlapine used in the described methods (e.g., as in any of the first through tenth embodiments) is crystalline Form A (e.g., monohydrate crystalline Form A) characterized by x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 9.42°, 12.91°, 18.09°, 18.48°, 18.80°, 19.70°, 21.42°, and 25.17°. In yet another alternative, as part of the eleventh embodiment, the perlapine used in the described methods (e.g., as in any of the first through tenth embodiments) is crystalline Form A (e.g., monohydrate crystalline Form A) characterized by x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 8.11°, 9.42°, 12.91°, 14.10°, 14.97°, 18.09°, 18.48°, 18.80°, 19.70°, 21.42°, and 25.17°, 26.07°, and 26.53°. Additional details regarding the characterization of crystalline Form A (e.g., monohydrate crystalline Form A) of perlapine and the hydrated forms can be found in U.S. Patent No. 9,969,747, the contents of which are incorporated herein by reference.

[0051] It will be appreciated that the 2-theta values of the X-ray powder diffraction pattern of monohydrate crystalline Form A can vary slightly from instrument to instrument and also depend on variations in sample preparation and batch-to-batch variations. For example, without wishing to be bound by theory, it is believed that some variation in the 2-theta values can be attributed to the amount of water contained in the lattice, e.g., in the case of the hydrated form (e.g., monohydrate) and the anhydrous form. Thus, the XRPD pattern / assignment of crystalline Form A (e.g., monohydrate crystalline Form A) should not be understood as absolute and can vary by ±0.2 degrees, except for the 2Θ angles 8.11°, 14.10°, 14.97°, 26.07°, and 26.53° of crystalline Form A (e.g., monohydrate crystalline Form A), which can vary by ±0.3 degrees.

[0052] In a twelfth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) is classified as a transfusion-dependent (TD) subject. Alternatively, as part of the twelfth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) is classified as a transfusion-dependent (TD) subject prior to treatment. As used herein, the term “transfusion-dependent (TD)” refers to a subject who requires regular transfusions. The term “red blood cell (RBC) transfusion-dependent LR-MDS” refers to LR-MDS in which the patient is also transfusion-dependent (TD).

[0053] In a thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through twelfth embodiments) becomes transfusion independent during treatment. In some aspects, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through twelfth embodiments) becomes transfusion independent for a period of time during treatment. As used herein, the term “transfusion independent” (TI) refers to those subjects who do not require regular transfusions. In one aspect, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by an absence of RBC transfusions for a period of at least continuously about 4 weeks, at least continuously about 6 weeks, at least continuously about 8 weeks, at least continuously about 10 weeks, or at least continuously about 12 weeks during treatment. In one aspect, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by an absence of RBC transfusions for a period of continuously about 8 weeks during treatment. In one aspect, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by an absence of RBC transfusions for a period of at least continuously 10 days, at least continuously about 15 days, at least continuously about 20 days, at least continuously about 25 days, at least continuously about 30 days, at least continuously about 35 days, at least continuously about 40 days, at least continuously about 45 days, at least continuously about 50 days, at least continuously about 55 days, at least continuously about 60 days, at least continuously about 70 days, at least continuously about 75 days, at least continuously about 80 days, or at least continuously about 85 days during treatment. In one aspect, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by an absence of RBC transfusions for a period of continuously about 10 to about 90 days, continuously about 20 to about 90 days, continuously about 30 to about 90 days, continuously about 40 to about 90 days, continuously about 50 to about 90 days, continuously about 50 to about 60 days, continuously about 55 to about 58 days, continuously about 80 to about 90 days, or continuously about 82 to about 56 days during treatment. In one aspect, as part of the thirteenth embodiment, a subject treated by pelabibsub or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by an absence of RBC transfusions during any 56 consecutive days after the start of treatment.In one aspect, as part of the thirteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through eleventh embodiments) becomes transfusion independent, wherein the transfusion independence is characterized by the absence of RBC transfusions during any consecutive 84 days after the start of treatment.

[0054] In the fourteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through thirteenth embodiments) experiences an improvement (e.g., an increase) in hemoglobin level after treatment. In one aspect, as part of the fourteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through thirteenth embodiments) experiences an improvement in hemoglobin level characterized by an increase in mean hemoglobin of > 0.5 g / dL, > 1.0 g / dL, or > 1.5 g / dL during treatment. In one aspect, as part of the fourteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through thirteenth embodiments) experiences an improvement in hemoglobin level characterized by an increase in mean hemoglobin of > 0.5 g / dL, > 1.0 g / dL, or > 1.5 g / dL during a period of at least consecutive about 4 weeks, at least consecutive about 6 weeks, at least consecutive about 8 weeks, at least consecutive about 10 weeks, or at least consecutive about 12 weeks, or during a period of time as otherwise described in the above twelfth embodiment, wherein the subject is also transfusion independent. In one aspect, as part of the fourteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through thirteenth embodiments) experiences an improvement in hemoglobin level characterized by an increase in mean hemoglobin of > 1.0 g / dL during at least consecutive about 8 weeks, wherein the subject is transfusion independent.

[0055] In a fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E). In one aspect, as part of the fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E) defined as a reduction in RBC transfusions of >2, >3, >4, >5, or >6 units during treatment. In one aspect, as part of the fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E) defined as a reduction in RBC transfusions of >2, >3, >4, >5, or >6 units during a period of at least about 4 consecutive weeks, at least about 6 consecutive weeks, at least about 8 consecutive weeks, at least about 10 consecutive weeks, or at least about 12 consecutive weeks, or for a period of time as otherwise described in the thirteenth embodiment above, wherein the subject is also not transfusion dependent (for patients with a baseline RBC transfusion burden of >4 units / 8 weeks). In one aspect, as part of the fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E) defined as a reduction in RBC transfusions of >4 units during a period of at least about 8 consecutive weeks, wherein the subject is also not transfusion dependent (for patients with a baseline RBC transfusion burden of >4 units / 8 weeks). In one aspect, as part of the fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E) defined as an increase in mean hemoglobin of >0.5 g / dL, >1.0 g / dL, >1.5 g / dL, or >2.0 g / dL during a period of at least about 4 consecutive weeks, at least about 6 consecutive weeks, at least about 8 consecutive weeks, at least about 10 consecutive weeks, or at least about 12 consecutive weeks, or for a period of time as otherwise described in the thirteenth embodiment above, wherein the subject is also not transfusion dependent (for patients with a baseline RBC transfusion burden of <4 units / 8 weeks). In one aspect, as part of the fifteenth embodiment, a subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fourteenth embodiments) experiences a red cell response (mHI-E) defined as an increase in mean hemoglobin of >1.5 g / dL during a period of at least about 8 consecutive weeks, wherein the subject is also not transfusion dependent (for patients with a baseline RBC transfusion burden of <4 units / 8 weeks).

[0056] In a sixteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fifteenth embodiments) experiences a neutrophil response (HI-N). In one aspect, as part of the sixteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through fifteenth embodiments) experiences a neutrophil response (HI-N) defined as a relative increase in neutrophil count of >100% and an absolute increase of >0.5 x 10 9 / L from baseline at each assessment during any consecutive 8-week period after baseline for patients with a baseline neutrophil count <1.0 x 10 9 / L.

[0057] In a seventeenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through sixteenth embodiments) has a platelet count of >75 x 10 9 / L prior to treatment. Alternatively, as part of the seventeenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through sixteenth embodiments) has a platelet count of <75 x 10 9 / L prior to treatment.

[0058] In an eighteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through seventeenth embodiments) experiences a platelet response (HI-P) during treatment. In one aspect, as part of the eighteenth embodiment, the subject treated by pelabutib or a pharmaceutically acceptable salt or composition thereof (including any of the first through seventeenth embodiments) experiences a platelet response (HI-P) defined as an absolute increase in platelet count of >30 x 10 9 / L from baseline at each assessment during any consecutive 8-week period after baseline (for patients with a baseline platelet count between 20 x 10 9 / L and 100 x 10 9 / L), or a platelet count of >20 x 10 9 / L and a relative increase of >100% from baseline (for patients with a baseline platelet count <20 x 10 9 / L.

[0059] In a nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose ranging from about 50 mg / day to about 200 mg / day. Alternatively, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose ranging from about 100 mg / day to about 150 mg / day. In another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose ranging from about 150 mg / day to about 200 mg / day. In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose ranging from about 50 mg / day to about 100 mg / day. In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 75 mg / day, about 100 mg / day, about 125 mg / day, about 150 mg / day, or about 175 mg / day. In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 75 mg / day. In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 125 mg / day. In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 175 mg / day.In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 125 mg / day, provided that the subject has a baseline platelet count of >75 x 109 / L prior to treatment. 9 In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 75 mg / day, provided that the subject has a baseline platelet count of <75 x 109 / L prior to treatment. 9 In yet another alternative, as part of the nineteenth embodiment, pelabutib (e.g., pelabutib monohydrate or pelabutib monohydrate crystalline Form A) is administered to a subject treated by a method described herein (including any of the first through eighteenth embodiments) at a dose of about 75 mg / day, provided that the subject has a baseline platelet count of <75 x 109 / L prior to treatment.

[0060] Example

[0061] Investigation of the effect of pelabutib on cytokine secretion by primary MDS patient cells

[0062] This study aims to evaluate the anti-inflammatory activity of pelabutib on MDS patient cells from different donors. The NF-kB pathway is central in the regulation of cytokines such as TNF-a, IL-6 and IL-8, which are elevated in MDS patients and play a role in the pathogenesis of myelodysplastic syndromes (references: e.g., doi: 10.1097 / MD.0000000000015844).

[0063] Primary MDS patient samples (frozen peripheral blood mononuclear cells (PBMCs)) were purchased from Discovery Life Sciences. For sample selection, we selected patients with low (ideally below 5%) blast counts, excluded patients with multilineage dysplasia, and (if available) reviewed blood parameters such as white blood cell counts and disease staging records to select patients showing characteristics of LR-MDS. Freshly thawed PBMCs were seeded at 50 000 cells / well in 96-well flat bottom plates. IL-6 production was induced by addition of 0.001 pg / mL lipopolysaccharide (LPS-B5, Invivogen). In addition, a nine-point dose titration series of Cipatinib (CPI-0610) ranging from 5 pM to 3.3 nM was added in duplicate. The absolute amount of DMSO per well was kept constant. “DMSO only” served as control for IL-6 maximum secretion. Assay plates were incubated at 37°C, 5% CO2 for about 18 hours. After centrifugation, cell supernatants were collected and IL-6 protein in the supernatants was quantified using the Human IL-6 Kit (V-PLEX, meso scale discovery). Assay plates were read on the Meso Sector S600. Data analysis: In Microsoft Excel, the mean background signal was subtracted from the raw data of all wells (0 pg / mL brand calibrator as background control). Values of compound treated wells were normalized to the “DMSO only” control, which was set to 100% IL-6 release. Mean values of normalized values per experiment were plotted using GraphPad Prism8. Half maximal inhibitory concentrations (IC50) were calculated by log-transformation of compound concentrations and applying the “log(inhibitor) versus response-variable slope (four parameters)” function. Mean values ± SD and fitted curves are shown in the figures.

[0064] As shown in Figure 1 Cipatinib inhibited IL-6 release in donor PBMCs in a dose-dependent manner. Values were normalized to the “DMSO only” control, n = 2 donors, mean values ± SD, IC50 = 248 nM.

[0065] Additional studies were performed in triplicate using a eight-point dose titration series of perifosine (CPI-0610) ranging from 5 mM to 8.2 nM following the same procedure described above. After centrifugation, cell supernatants were collected and used to quantify IFNy, TNFa, IL-6, IL-8 or IL-10 proteins in the supernatants using the Proinflammatory Panel 1 Human Kit (IFNy, TNFa, IL-6 and IL-10) or the Human IL-8 Kit (both V-PLEX, Meso Scale Diagnostics). Assay plates were read on a Meso Sector S600. Data analysis: In Microsoft Excel, the mean background signal was subtracted from the raw data of all wells (0 pg / mL brand calibrator as background control). Values of compound-treated wells were normalized to the “DMSO only” control, which was set to 100% cytokine release. Normalized values mean of all experiments for each cytokine were plotted using GraphPad Prism 8. Half maximal inhibitory concentration (IC50) was calculated by log-transformation of the compound concentrations and applying the “log(inhibitor) versus response - variable slope (four parameters)” function. 50 ). Mean ± SEM and fitted curves are shown in the graphs. Results are shown in Figure 3 , where perifosine inhibited the release of IFNy, TNFa, IL-6, IL-8 and IL-10.

[0066] Effect of perifosine on erythropoiesis of hematopoietic stem cells isolated from bone marrow of MDS patients

[0067] Primary MDS patient samples (frozen bone marrow mononuclear cells (BMMC)) were purchased from Discovery Life Sciences. For sample selection, we selected patients with low (ideally below 5%) blast counts, excluded patients with multilineage dysplasia and, if available, checked blood parameters such as white blood cell counts and disease stage records to select patients showing characteristics of LR-MDS.

[0068] Using freshly thawed cells, hematopoietic stem cells (CD34+) were isolated by EasySep Human CD34+ Selection Kit II (StemCell Technologies). Cells were seeded in 96-well flat bottom plates at a density of 1000 cells / well (for erythropoiesis) or 2500 cells / well (for CC100 differentiation cocktail). Differentiation cocktail StemSpan TM Erythropoiesis Extender Supplement (for erythropoiesis) or StemSpan TMCC100 (differentiation cocktail). A 5-point titration series of pelabutibum monohydrate ranging from 500 nM to 31.25 nM was tested in duplicate. "DMSO only" treated wells served as controls and were used to prepare flow cytometry controls (e.g. FMO). On day 3 or day 4 post-seeding, a feed step was performed for erythropoiesis. On day 7, cells were analyzed by flow cytometry. Cell staining was performed according to the manufacturer's instructions using the following antibodies: BV421 anti-human CD34 [clone: 561] (BioLegend), AF700 anti-human CD71 [clone: M-A712] (BD Biosciences), FITC anti-human CD235a [clone: GA-R2 (HIR2)] (BD Biosciences), and the dye eFluor506 (Invitrogen) (live / dead) (Invitrogen / ThermoFisher) to distinguish between live and dead cells. Cells were acquired on a BD FACS LSR x20 Fortessa. Gating was performed as follows: exclude cell debris -> single cells -> live cells. Within the live cells, the percentage of CD34+CD71+ (megakaryocyte-erythroid progenitor cells (MEPs)) and CD34-CD71+ (primitive / erythroblasts (pro-EBs / EBs)) was determined and plotted in GraphPad Prism 8 for each donor.

[0069] As shown in Figure 2 Pelabutibum enhanced differentiation of CD34+ stem cells to erythropoiesis from LR-MDS donors.

[0070] Phase 2 clinical study of pelabutibum treatment in transfusion-dependent lower risk myelodysplastic syndrome (MDS) patients

[0071] A phase 2b study will evaluate the efficacy and safety of pelabutibum in transfusion-dependent lower risk MDS patients.

[0072] Study design

[0073] The phase 2 part of the study is a multicenter, open-label study of pelabutibum treatment in lower risk MDS patients. Pelabutibum monohydrate will be administered orally once daily (QD) for 14 consecutive days followed by 7 days of rest, which is considered 1 treatment cycle (1 cycle = 21 days), until unacceptable toxicity, disease progression, or other discontinuation criteria (i.e. intervention / therapy required by the eligibility criteria exclusion, patient non-compliance, pregnancy, or other medical condition that interferes with participation in the study) occur.

[0074] Baseline platelet count > 75 x 10 9Patients with a platelet count of / L will receive an initial dose of perapuscib monohydrate at 125 mg QD or 150 mg QD. Baseline platelet count <75 × 10⁹ / L. 9 Patients with a platelet count of 9 / L will start with a dose of 75 mg QD, or a baseline platelet count ≥50 × 10⁹ / L. 9 / L<75×10 9 Patients with a platelet count of 75 mg QD will begin with a dose of 75 mg QD. The dose of pelabusesibuline monohydrate can be increased in increments of 25 mg QD, usually not exceeding once every two cycles, up to a maximum of 175 mg QD or 200 mg QD, provided that: 1) the platelet count is ≥75 × 10⁶. 9 / L, 2) Absolute neutrophil count (ANC) ≥750 × 10 in the absence of growth factors. 6 3) No bleeding events were experienced, and 4) No one or more grade 3 adverse events (AEs) attributable to pelabuxis were observed. Baseline PLT counts ≥50 × 10⁹ / L will be used. 9 Patients with a blood glucose level <75×10⁹ / L were clinically evaluated, with a single starting dose of 75 mg.

[0075] Inclusion criteria

[0076] Subjects who meet all of the following criteria can be included in the phase 2 study:

[0077] 1. Males or females aged 18 or older.

[0078] 2. MDS diagnosed according to the 2016 World Health Organization (WHO) criteria (Arber et al., Blood. [Blood] 2016; 127:2391-405), except for patients diagnosed with therapy-related MDS or diseases with del(5q) abnormalities. Patients with secondary MDS or MDS with isolated del(5q) are ineligible. Patients with overlapping MDS / MPN are ineligible, except for MDS / MPN patients with ringed sideroblasts and thrombocytosis [MDS / MPN-RS-T].

[0079] 3. IPSS-R is classified as a very low, low or intermediate risk disease (Greenberg et al., Blood. 2012; 120:2454-65).

[0080] 4. Patients with ≥15% of erythroid precursor cells or >5% of circumferential sideroblasts in the bone marrow and with SF3B1 mutation should have previously received rotexip treatment.

[0081] 5. Patients with < 15% of erythroid precursors that are ringed sideroblasts in the bone marrow and no SF3B1 mutation should be either refractory or intolerant to prior ESA treatment or are unlikely to benefit from ESA therapy (endogenous erythropoietin levels > 200 U / L).

[0082] 6. Must be dependent on RBC transfusions requiring 2-6 units of packed RBCs (pRBCs) per 8 weeks on average during the 16 weeks prior to enrollment, and absence of a period of 8 consecutive weeks without RBC transfusions during these 16 weeks.

[0083] 7. Acceptable laboratory assessments obtained within 28 days prior to the first dose of study drug:

[0084] a. Absolute neutrophil count (ANC) > 750 x 10 6 / L without growth factors in the past 14 days.

[0085] b. Platelet count > 50 x 10 9 / L without one or more platelet transfusions or platelet stimulating agents.

[0086] c. Peripheral blood and bone marrow blast counts < 5%

[0087] d. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 2.5 x upper limit of normal (ULN).

[0088] e. Serum direct bilirubin < 2.0 x ULN.

[0089] f. Calculated or measured creatinine clearance (CrCl) > 30 mL / min.

[0090] 8. Eastern Cooperative Oncology Group (ECOG) performance status < 2

[0091] 9. Patients must be able to swallow solid forms of medication.

[0092] 10. Male and female patients of reproductive potential and the patient's partner must agree to use at least one highly effective method of contraception (preferably a method with low user dependency, especially when contraception is introduced due to participation in the clinical study) at the time of receiving study treatment and for the male partner of the male patient for 94 days and for the female partner of the female patient for 184 days after the last dose of study drug. Note: Patients can be referred to the investigator for information on reproductive cell donation and cryopreservation prior to treatment. Male patients should be informed of the risk of testicular toxicity and offered adequate advice on sperm preservation.

[0093] Alternative inclusion criteria

[0094] If all of the following criteria are met, the subject is eligible for the Phase 2 study:

[0095] 1. Patients must be > 18 years of age and of legal consent age in the jurisdiction where the study is conducted at the time of signing the informed consent form (ICF).

[0096] 2. Patients have a documented diagnosis of MDS according to the World Health Organization (WHO) 2022 classification (Arber et al., Blood. 2016; 127: 2391-405) and meet the IPSS-R classification (Greenberg et al., Blood. 2012; 120: 2454-65) of very low, low, or intermediate risk disease with a score < 3.5 and < 5% blasts in the bone marrow.

[0097] 3. Patients require RBC transfusions, documented according to the following criteria:

[0098] 3a. An average RBC transfusion requirement of 2 to 6 units per 8 weeks confirmed within at least 16 weeks immediately preceding the start of treatment,

[0099] 3b. Hgb levels must be < 9.5 g / dL at the time of RBC transfusion or within 7 days prior to RBC transfusion administration for the transfusion to be counted as meeting the eligibility criteria, and

[0100] Note: RBC transfusions performed for elective surgery, infection, or bleeding episode do not qualify as required transfusions to meet the eligibility criteria.

[0101] 3c. No consecutive 56 days without RBC transfusion within 16 weeks immediately preceding the start of treatment.

[0102] 4. Acceptable laboratory assessments obtained within 28 days prior to the first dose of study drug:

[0103] 4a. Absolute neutrophil count (ANC) > 750 x 10 9 / L without growth factors within 14 days prior to starting study treatment,

[0104] 4b. Platelet count > 75 x 10 9 / L without one or more PLT transfusions or PLT stimulating agents within 14 days prior to starting study treatment. Patients with a platelet count > 75 x 10 9 / L are eligible for inclusion in the 2-dose level cohort of pelabutibumab monotherapy (Phase 1 and 2).

[0105] 4c. Platelet count > 50 and < 75 x 109 / L. PLT count > 50 and < 75 x 10 9 / L are only eligible to be enrolled in the safety cohort (peralbelisib monotherapy in Phase 2),

[0106] 4d. Calculated or measured creatinine clearance > 45 mL / min. (Cockroft and Gault (Nephron 1976; 16(1): 31-41. doi: 10.1159 / 000180580) was used),

[0107] 4e. Bilirubin < 1.5 x upper limit of normal (ULN), and

[0108] 4f. Aspartate aminotransferase (AST) and / or alanine aminotransferase (ALT) alone elevated < 3 x ULN of local reference range (if the elevation can be attributed to liver involvement, e.g., MDS with cirrhosis, then < 5 x).

[0109] 5. Patient has an Eastern Cooperative Oncology Group (ECOG) score of 0, 1, or 2.

[0110] 6. Patient is willing to avoid pregnancy or fathering children according to the following criteria:

[0111] • Male patients and their female partners of childbearing potential must agree to take appropriate precautions to avoid fathering children (with at least 99% certainty) from screening until 94 days after the last dose of peralbelisib. In addition, male patients must not donate sperm during this period. The patient should be counseled on methods of contraception that are at least 99% effective and confirm their understanding.

[0112] • Women of childbearing potential (WOCBP) must have a negative serum pregnancy test at screening and must agree to take appropriate precautions to avoid pregnancy (with at least 99% certainty) from screening until the end of relevant systemic exposure (i.e., 184 days after the last dose of peralbelisib). They must also agree to undergo regular urine pregnancy testing during study treatment and monthly pregnancy testing for up to 184 days after the last dose of peralbelisib. They must also avoid breastfeeding and donating oocytes during the study and for 184 days after the last dose of peralbelisib. The patient should be counseled on methods of contraception that are at least 99% effective and confirm their understanding.

[0113] • Women without childbearing potential (i.e., rendered infertile by hysterectomy and / or bilateral oophorectomy, or postmenopausal and amenorrheic for > 12 months without other medical cause) are eligible.

[0114] Example cohorts for peralbelisib monotherapy

[0115] Patients in the monotherapy cohort were eligible for inclusion in the study if they met all of the above-listed alternative exclusion criteria and the following additional criteria:

[0116] 7. The patient was refractory to, intolerant of, or unlikely to benefit from at least one prior therapy (excluding RBC transfusions) according to investigator assessment.

[0117] 8. Baseline ring sideroblast (RS) status (RS+ defined as >15% of red cell precursors in the bone marrow that are RS or >5% (but <15%) in the presence of SF3B1 mutation). Up to 40% of randomized patients were RS+. The upper limit of enrollment for the total of 60 patients randomized to 2 dose levels in Phases 1 and 2 will be set based on RS status.

[0118] Note: This does not apply to patients enrolled in the single agent pelabutibumab monotherapy and with a PLT count >50-<75 x 109 / L (Safety Cohort; n=10). 9

[0119] Exclusion Criteria

[0120] Subjects will be excluded from the Phase 2 study if they meet all of the following criteria:

[0121] A. Medical Conditions

[0122] 1. Secondary MDS patients or patients with del 5q abnormality are not eligible. Patients with MDS / myelodysplastic / myeloproliferative neoplasm (MPN) overlap are not eligible except for MDS / MPN with ring sideroblasts and thrombocytosis [MDS / MPN-RS-T].

[0123] 2. Clinically significant anemia known to be due to iron, vitamin B12, or folate deficiency, or autoimmune or hereditary hemolytic anemia.

[0124] 3. Currently known active or chronic infection with HIV, hepatitis B, or hepatitis C. Patients are not required to have serological screening for these viruses. However, patients with a past history of viral hepatitis or who are currently suspected of having viral hepatitis should have serological testing for hepatitis B and C to determine if there is any current evidence suggesting that they are still infected with these viruses.

[0125] ​4. Patients with a severe flare of active clinically uncontrolled infection with a chronic infection. Patients are eligible for enrollment only if they have recovered to ≤ Grade 1 for at least 2 weeks prior to the first dose of study drug. COVID-19 testing is not mandatory during the screening process for this study. However, based on local epidemiology and each patient’s individual risk of COVID-19 exposure and / or vaccination status, the Investigator should consider testing, and in the case of a positive COVID-19, should consider deferring initiation of study treatment until the infection has resolved.

[0126] 5. Patients with certain gastrointestinal (GI) disorders that, in the Investigator’s judgment, can interfere with their ability to swallow a solid form of the drug and absorption of the drug orally (e.g., inflammatory bowel disease [i.e., ulcerative colitis, Crohn’s disease, or celiac disease]) are not eligible to participate in this study.

[0127] 6. Impaired cardiac function or clinically significant cardiac disease, including the following:

[0128] - Acute myocardial infarction or unstable angina within ≤ 6 months prior to initiation of study drug.

[0129] - QTcF > 500 msec at screening ECG.

[0130] - New York Heart Association Class III or IV congestive heart failure.

[0131] - Uncontrolled clinically significant arrhythmias (patients with rate-controlled atrial fibrillation are not excluded). Note that patients with a history of coronary artery disease and revascularization history are not excluded.

[0132] 7. Persistent uncontrolled hypertension (resting systolic blood pressure > 160 mm Hg and resting diastolic blood pressure > 100 mm Hg) despite maximal treatment with at least 2 antihypertensive agents.

[0133] 8. Persistent uncontrolled diabetes mellitus (HbAlc > 9%) despite maximal treatment with oral and / or injectable antihyperglycemic agents.

[0134] 9. History of concurrent or secondary malignancy, with the exception of adequately treated localized basal cell carcinoma or squamous cell carcinoma of the skin, cervical carcinoma in situ, superficial bladder cancer, asymptomatic prostate cancer without known metastatic disease and requiring no therapy or hormonal therapy only with a normal prostate specific antigen > 1 year prior to randomization, Stage 1 or 2 cancer that has been adequately treated and is currently in complete remission, or any other cancer that has been in complete remission > 3 years.

[0135] 10. Has any other serious and / or uncontrolled concomitant illness that, in the investigator's opinion, may affect the patient's participation in the study or analysis of the study data. This includes, but is not limited to, clinically significant pulmonary or neurological disease.

[0136] B. Prior / Concomitant Therapy

[0137] 11. Prior treatment with a hypomethylating agent (HMA) (azacitidine, decitabine)

[0138] 12. Prior treatment with lenalidomide

[0139] 13. Prior treatment with a study agent for MDS.

[0140] 14. Prior treatment with immunosuppressive therapy for MDS (e.g., anti-thymocyte globulin [ATG], cyclosporine regimen, etc.)

[0141] 15. Prior treatment with a BET inhibitor

[0142] 16. Received a strong CYP3A4 inhibitor or inducer within 7 days prior to the first dose of study drug (including St. John's wort). Initiation of treatment or concomitant use of strong CYP3A4 inhibitors or inducers during study treatment is prohibited.

[0143] 17. Prior hematopoietic stem cell transplant

[0144] 18. Patients who have initiated iron chelation therapy within 56 days prior to Cycle 1 Day 1 (C1D1) are not eligible to participate in this study, with the exception of patients who have been on stable or decreasing doses of iron chelation therapy for > 8 weeks prior to enrollment

[0145] C. Other Exclusions

[0146] 19. Women who are lactating or pregnant, as evidenced by a positive high sensitivity serum β-hCG pregnancy test obtained within 72 hours prior to the first dose of study drug. Women patients who are not of childbearing potential (postmenopausal for > 1 year; have had permanent sterilization by hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) do not require serum pregnancy testing.

[0147] 20. Inability or unwillingness to comply with the study protocol or study requirements.

[0148] Alternative Exclusion Criteria

[0149] Patients are excluded from the study if they meet any of the following criteria:

[0150] A. Medical Conditions

[0151] 1. Secondary MDS patients, MDS / MPN overlap patients (except MDS / MPN with RS and thrombocytosis).

[0152] 2. Patients with known clinically significant anemia due to iron, vitamin B12, or folate deficiency, patients with known autoimmune or hereditary hemolytic anemia, patients with clinically significant hemorrhagic drug-induced anemia, patients with known hypothyroidism.

[0153] 3. Patients with known active or chronic infection with HIV, hepatitis B, or hepatitis C. Patients do not need to be screened serologically for these viruses. However, patients with a past history of viral hepatitis or who are currently suspected of having viral hepatitis should be tested serologically for hepatitis B and C to determine if there is currently any evidence that they are still infected with these viruses.

[0154] 4. Patients with a severe flare of active clinically uncontrolled infection with a chronic infection. Patients are eligible for enrollment only if they have recovered to Grade <1 for at least 2 weeks prior to the first dose of study treatment. COVID-19 testing is not mandatory during the screening process for this study. However, based on the local epidemiology and the individual COVID-19 exposure risk and / or vaccination status of each patient, the Investigator should consider testing, and in the case of COVID-19 positivity, should consider deferring the start of study treatment until the infection has resolved.

[0155] 5. Patients with certain GI disorders that, in the Investigator’s judgment, can interfere with their ability to swallow a solid form of the drug and the absorption of the drug orally (e.g., inflammatory bowel disease or celiac disease).

[0156] 6. Patients with impaired cardiac function or with clinically significant cardiac disease, including the following:

[0157] 6a. Acute myocardial infarction or unstable angina <6 months prior to the start of study treatment,

[0158] 6b. Fridericia-corrected QT interval (QTcF) >470 msec at screening electrocardiogram (ECG) (QTcF interval is not relevant in patients with pacemaker-controlled arrhythmia),

[0159] 6c. New York Heart Association Class III or IV congestive heart failure, or

[0160] 6d. Uncontrolled clinically significant arrhythmias (patients with rate-controlled atrial fibrillation are not excluded).

[0161] Note: Patients with a history of coronary artery disease and revascularization procedures are not excluded.

[0162] 7. Patients with persistent uncontrolled hypertension (resting systolic blood pressure > 160 mm Hg and resting diastolic blood pressure > 100 mm Hg).

[0163] 8. Patients with persistent uncontrolled diabetes mellitus (glycosylated hemoglobin [HbAlc] > 9%).

[0164] 9. Patients with a history of concurrent or secondary malignancy, with the following exceptions: adequately treated localized basal cell carcinoma or squamous cell carcinoma of the skin, cervical carcinoma in situ, superficial bladder cancer, asymptomatic prostate cancer without known metastatic disease and without the need for therapy or hormonal therapy only and with a normal prostate specific antigen > 1 year prior to the start of treatment, Stage 1 or 2 cancer that has been adequately treated and is currently in complete remission, or any other cancer that has been in complete remission for > 3 years.

[0165] 10. Patients with any other serious and / or uncontrolled concomitant illnesses that, in the investigator's opinion, could confound the study or safety analysis. This includes, but is not limited to, clinically significant pulmonary or neurological disease.

[0166] B. Concomitant therapy

[0167] 11. Prior treatment with an HMA (azacitidine, decitabine) with the last dose < 8 weeks prior to the first dose of study treatment. Patients can be enrolled at the discretion of the investigator. (The last dose should be > 8 weeks prior to the first dose of study treatment.)

[0168] 12. Prior treatment with an immunomodulatory drug ([IMiD], e.g., lenalidomide) for a condition other than del(5q) abnormality. Patients can be enrolled at the discretion of the investigator. (The last dose of IMiD should be > 8 weeks prior to the first dose of study treatment.)

[0169] 13. Concomitant therapy with study medication within 28 days (or 5 half-lives, whichever is longer) prior to the first dose of study treatment.

[0170] 14. Prior treatment with immunosuppressive therapy for MDS (e.g., anti-thymocyte globulin, cyclosporine regimen, etc.).

[0171] 15. Prior treatment with a BET inhibitor.

[0172] 16. Treatment with a potent CYP3A4 inhibitor or inducer within 7 days prior to the first dose of study treatment (including St. John's wort). Treatment or concomitant use of potent CYP3A4 inhibitors or inducers is prohibited during study treatment.

[0173] 17. Prior hematopoietic stem cell transplant.

[0174] 18. Patients who have initiated iron chelation therapy within 56 days prior to the first dose of study treatment are not eligible to participate in this study, with the exception of patients who have been on stable or decreasing doses of iron chelation therapy for > 8 weeks prior to the first dose of study treatment.

[0175] 19. Prior androgen therapy within 8 weeks of the first dose of study treatment, with the exception of hypogonadotropic hypogonadism.

[0176] 20. RBC hematopoietic growth factor concomitant therapy within 28 days of the first dose of study treatment.

[0177] C. Other Exclusions

[0178] 21. Inability to sign the informed consent form (including compliance with the ICF and the requirements and restrictions listed in this protocol).

[0179] 22. Patient unwilling and unable to comply with the study visit schedule and other protocol requirements. Patients who are legally incarcerated or under the protection of the law.

[0180] 23. Concurrent enrollment in another interventional clinical trial.

[0181] 24. History of hypersensitivity to any of the study treatments or excipients or to drugs of a similar chemical class.

[0182] 25. Female patients who are lactating or pregnant or who are not on adequate contraception therapy per inclusion criteria.

[0183] 26. Male patients who do not agree to use contraception (if they have a female partner who is of childbearing potential) and who do not avoid donating sperm during the treatment period and for at least 94 days after the last dose of study treatment.

[0184] 27. Patients with a history of cerebrovascular accidents (including ischemic, embolic, and hemorrhagic cerebrovascular accidents), transient ischemic attacks, deep venous thrombosis (including proximal and distal), pulmonary embolism or arterial embolism, arterial thrombosis or other venous thrombotic events within 6 months prior to randomization. Note: Prior superficial thrombotic phlebitis is not an exclusion criterion.

[0185] Primary Endpoints

[0186] The primary endpoints of this study include eight weeks of RBC transfusion independence (TI), defined as the absence of RBC transfusions during a consecutive 56-day period after treatment initiation.

[0187] Secondary Endpoints

[0188] Secondary endpoints include the following:

[0189] - 12 weeks of RBC TI, defined as the absence of RBC transfusions during a consecutive 84-day period after treatment initiation;

[0190] - Time to 8-week RBC TI defined as the time from first dose of study drug to first occurrence of a 56-day RBC TI;

[0191] - Duration of 8-week RBC-TI defined as the time between the last RBC transfusion before the 8-week RBC TI was achieved and the first RBC transfusion after it was achieved (if there were multiple occurrences, the one associated with the longest duration applies);

[0192] - Hgb response defined as an increase in mean Hgb of >1.0 g / dL from baseline during any 8-week period without RBC transfusions after baseline;

[0193] - Erythroid response (mHI-E) defined as a decrease in RBC transfusions of >4 units from baseline during any 8-week period after baseline (for patients with a baseline RBC transfusion burden of >4 units / 8 weeks), or an increase in mean Hgb of >1.5 g / dL from baseline during any 56-day period without RBC transfusions after baseline (for patients with a baseline RBC transfusion burden of <4 units / 8 weeks); and

[0194] - Safety and tolerability will be assessed by incidence of AEs and SAEs, as well as changes in vital signs, physical examinations, and clinical laboratory values.

[0195] Exploratory Endpoints

[0196] Exploratory endpoints include the following:

[0197] - Time to 12-week RBC TI defined as the time from first dose of study drug to first occurrence of an 84-day RBC TI.

[0198] - Duration of 12-week TI defined as the time between the last RBC transfusion before the 12-week RBC TI was achieved and the first RBC transfusion after it was achieved (if there were multiple occurrences, the one associated with the longest duration applies).

[0199] - Neutrophil response (HI-N) defined as a relative increase in neutrophil count of >100% and an absolute increase of >0.5 x 10 9 / L from baseline at each assessment during any 8-week period after baseline for patients with a baseline neutrophil count of <1.0 x 10 9 / L.

[0200] - Platelet response (HI-P) defined as an absolute increase in platelet count of >30 x 10 9 / L (for patients with baseline platelet counts <20 x 10 9 / L and 100 x 10 9 / L (for patients with baseline platelet counts <20 x 10 9 / L and a relative increase of >100% compared to baseline (for patients with baseline platelet counts <20 x 10 9 / L (for patients with baseline platelet counts <20 x 10

[0201] - PK of pelabibutab will be assessed by Cmax.

[0202] - Target engagement is defined as the change in gene expression in peripheral blood pre- and post-treatment.

[0203] - Effects of PD on blood and bone marrow cells, as assessed by including but not limited to: effects on RBC and Mk progenitor populations, genes that modulate RBC and Mk lineage differentiation.

[0204] - Changes in inflammatory cytokines in blood samples pre- and post-treatment, and changes in cytokine transcription levels in bone marrow aspirates.

[0205] - Changes in cytogenetic and mutational profile in blood and / or bone marrow samples pre-treatment, during treatment and at the end of treatment QoL, as assessed by EORTC-QLC-30 and FACT-An questionnaires. Changes in HRQoL at Week 24 compared to baseline.

[0206] Dose adjustments

[0207] As an alternative, for patients with baseline platelet (PLT) counts >75 x 10 9 / L, pelabibutab monohydrate will be administered at two starting dose levels (i.e. 75 mg and 150 mg). For patients with baseline PLT counts >50 x 10 9 / L <75 x 10 9 / L, a single starting dose level of 75 mg will be used for further clinical evaluation. Pelabibutab monohydrate will be administered QD for 14 consecutive days followed by 7 days of rest, which is considered 1 treatment cycle (1 cycle = 21 days) until unacceptable toxicity, disease progression occurs.

[0208] The dose of pelabibutab monohydrate can be increased in increments of 25 mg QD, usually not more than once every 2 cycles, up to a maximum of 175 mg or 200 mg QD, provided that the following are observed:

[0209] - Platelet counts >75 x 10 9 / L

[0210] - Absolute neutrophil count (ANC) >750 x 106 / L (no growth factors)

[0211] - No bleeding events

[0212] - No Grade >3 AEs attributed to pelabutib

[0213] Dose adjustment guidelines in the continuous treatment period, including reduction and / or suspension of pelabutib treatment due to reduced platelet counts, are provided in Table 2, and dose adjustment guidelines due to other toxicities are provided in Table 1.

[0214] Table 1 - Dose adjustment table for toxicities in MDS patients

[0215]

[0216]

[0217]

[0218] ALT = alanine aminotransferase; ANC = absolute neutrophil count; CBC = complete blood count; ET = essential thrombocythemia; ULN = upper limit of normal

[0219] If a patient becomes infected with COVID-19 during the study, the investigator should use their clinical judgment regarding study drug discontinuation, as needed in consultation with the sponsor’s medical monitor, based on the patient’s symptoms, disease status, comorbidities, and concomitant medications. For Grade >3 infections, pelabutib should be suspended. For Grade 1-2 COVID-19 infections and / or COVID-19 related medical conditions, pelabutib can also be suspended based on the investigator’s clinical judgment and local and institutional standard of care.

[0220] Table 2 - Pelabutib dose adjustment for reduced platelet counts in MDS patients

[0221]

[0222] BID = twice a day; ET = essential thrombocythemia; PLT = platelets; QD = once a day.aTreatment is suspended if associated with bleeding. This clinical decision can be made at the discretion of the investigator.bPLT is checked at least weekly and dosing is resumed to maintain cycle structure. For example, if toxicity occurs on Day 8 of a cycle and resolves on Day 15 of the same cycle, the dose is continued to be suspended for the remaining time of the 7-day rest (i.e., for an additional 6 days) and dosing is resumed on Day 1 of the next planned cycle. If treatment is suspended for >28 days due to study treatment-related toxicity, treatment should be discontinued. Longer periods of interruption due to a need to mitigate handling (clinical benefit) must be discussed with and approved by the company medical monitor.

[0223] Toxicity dose adjustments

[0224] Dose adjustment guidelines in the context of continuous treatment periods (including reduction and / or suspension of plerixafor due to other toxicities) are provided in Table 3, and dose adjustment guidelines due to reduction in PLT count are provided in Table 4.

[0225] Table 3: Table of dose adjustments for toxicity in patients with myelodysplastic syndromes in the plerixafor monotherapy cohort

[0226]

[0227]

[0228]

[0229] ALT = alanine aminotransferase; ANC = absolute neutrophil count; CBC = complete blood count; ET = essential thrombocythemia; QD = once daily; ULN = upper limit of normal.

[0230] If a patient becomes infected with COVID-19 during the study, the investigator should use their clinical judgment regarding study treatment discontinuation, as needed in consultation with the sponsor’s medical monitor, based on the patient’s symptoms, disease status, comorbidities, and concomitant medications. Plerixafor can also be suspended based on the investigator’s clinical judgment, as well as local and institutional standard of care, for Grade 1-2 COVID-19 infection and / or COVID-19 related medical conditions.

[0231] Table 1: Plerixafor dose adjustments for reduction in platelet count in patients with myelodysplastic syndromes

[0232]

[0233] BID = twice daily; ET = essential thrombocythemia; PLT = platelet; QD = once daily.

[0234] aTreatment is suspended if associated with bleeding. This clinical decision can be made at the discretion of the investigator.

[0235] bPLT is checked at least weekly and dosing is resumed to maintain cycle structure. For example, if toxicity occurs on Day 8 of a cycle and resolves on Day 15 of the same cycle, the dose is continued to be suspended during the remaining time of the 7-day rest (i.e., for an additional 6 days) and dosing is resumed on Day 1 of the next planned cycle. If treatment is suspended > 35 days due to study treatment-related toxicity, treatment should be discontinued. Longer periods of suspension due to need for palliative handling (clinical benefit) must be discussed with and approved by the Constellation medical monitor.

[0236] Re-escalation of perifabiline after dose reduction due to toxicity

[0237] Patients who have had a dose reduction or interruption of perifabiline due to an AE can have their dose of perifabiline increased as follows:

[0238] • If the toxicity indicated in Table 3 resolves to the specified grade (with the proviso noted below) for at least 1 cycle, the dose level can be escalated by 1 higher dose level (25 mg / day) per cycle. This procedure can be repeated until the original dose level (defined as the dose level received prior to the downward titration) is reached.

[0239] • If a patient experiences Grade 4 neutropenia, and the toxicity resolves (ANC > 0.75 x 10 9 / L) for at least 1 cycle, the dose level can be escalated by 1 dose level per cycle.

[0240] • If a patient experiences any grade of thrombocytopenia, all dose adjustments must be made according to Table 4. The decision to re-escalate must be made according to the criteria defined in perifabiline.

[0241] • If a dose is reduced due to non-hematologic toxicity, the dose cannot be increased until the toxicity resolves to < Grade 1 for at least 1 cycle. If the same toxicity reoccurs after dose re-escalation, further dose increases are prohibited.

[0242] • If a dose is reduced due to Grade 4 non-hematologic toxicity, subsequent dose increases are prohibited.

[0243] If these criteria are met, the dose of perifabiline monohydrate can be increased in increments of 25 mg QD, no more frequently than every 2 cycles, to a maximum dose of 125 mg QD.

[0244] While a number of embodiments of the application have been described, it is apparent that modifications and alterations can be made by those skilled in the art without departing from the inventive concepts disclosed herein. Thus, it is intended that the scope of the application be governed by the following claims and their equivalents.

[0245] The contents of all references (including literature references, issued patents, published patent applications, and co-pending patent applications) cited throughout this application are expressly incorporated herein by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Claims

1. A method of treating lower risk myelodysplastic syndrome (LR-MDS) in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of pelabutib or a pharmaceutically acceptable salt thereof.

2. The method of claim 1, wherein a therapeutically effective amount of pelabutib is administered to the subject.

3. The method of claim 1 or 2, wherein the pelabutib is a hydrate.

4. The method of claim 1 or 3, wherein the pelabutib is a monohydrate.

5. The method of any one of claims 1 to 4, wherein the pelabutib is in crystalline form.

6. The method of any one of claims 1 to 5, wherein the pelabutide is in crystalline Form A characterized by, at least three, at least four, at least five, or six x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°.

7. The method of any one of claims 1 to 6, wherein the pelabutide is in crystalline Form A characterized by, at least three x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°.

8. The method of any one of claims 1 to 7, wherein the pelabutide is in crystalline Form A characterized by, at least four x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°.

9. The method of any one of claims 1 to 8, wherein the pelabutide is in crystalline Form A characterized by, at least five x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°.

10. The method of any one of claims 1 to 9, wherein the pelabutide is in crystalline Form A characterized by, x-ray powder diffraction peaks at 2Θ angles selected from 4.73°, 18.09°, 18.48°, 18.80°, 19.70°, and 25.17°.

11. The method of any one of claims 1 to 10, wherein the LR-MDS is low risk MDS.

12. The method of any one of claims 1 to 11, wherein the LR-MDS is very low risk MDS.

13. The method of any one of claims 1 to 12, wherein the subject is anemic.

14. The method of any one of claims 1 to 13, wherein the subject is dependent on red blood cell transfusions prior to treatment.

15. The method of claim 14, wherein the subject becomes transfusion independent during treatment.

16. The method of claim 14 or 15, wherein transfusion independence is characterized by the absence of RBC transfusions for a period of about 8 consecutive weeks during treatment.

17. The method of claim 15, wherein transfusion independence is characterized by the absence of RBC transfusions during any consecutive 56-day period after the start of treatment.

18. The method of any one of claims 1 to 17, wherein the subject experiences an improvement in hemoglobin level during treatment.

19. The method of claim 18, wherein the improvement in hemoglobin level is characterized by an increase in hemoglobin level of about > 1.0 g / dL during treatment.

20. The method of any one of claims 1 to 16, 18, and 19, wherein the subject becomes transfusion independent, characterized by absence of RBC transfusions for a period of about 8 consecutive weeks during treatment, and wherein the subject experiences an improvement in hemoglobin characterized by an increase in mean hemoglobin of > 1.0 g / dL during the period of transfusion independence of about 8 consecutive weeks.

21. The method of any one of claims 1 to 16, 18, and 19, wherein the subject becomes transfusion independent, characterized by the absence of RBC transfusions for a period of about 8 consecutive weeks during treatment, and wherein the subject experiences an erythroid response (mHI-E), defined as a reduction of >4 units of RBC transfusions during the period of about 8 consecutive weeks of independence from transfusions.

22. The method of any one of claims 1 to 16, 18, and 19, wherein the subject becomes transfusion independent, characterized by the absence of RBC transfusions for a period of about 8 consecutive weeks during treatment, and wherein the subject experiences an erythroid response (mHI-E), defined as an increase in mean hemoglobin of >1.5 g / dL during the period of about 8 consecutive weeks of independence from transfusions.

23. The method of any one of claims 1 to 22, wherein the subject experiences a neutrophil response (HI-N) during treatment.

24. The method of any one of claims 1 to 23, wherein the subject experiences a neutrophil response (HI-N) during treatment characterized by, For patients with baseline neutrophil count < 1.0 x 10 9 / L, a relative increase in neutrophil count of > 100% and an absolute increase of > 0.5 x 10 9 / L from baseline at each assessment during any consecutive 8-week period after baseline.

25. The method of any one of claims 1 to 24, wherein the subject has a platelet count of >75 x 10 9 / L prior to treatment.

26. The method of any one of claims 1 to 24, wherein the subject has a platelet count of < 75 x 10 9 / L prior to treatment.

27. The method of any one of claims 1 to 24, wherein the subject has a platelet count of >50 x 10 9 / L to <75 x 10 9 / L prior to treatment.

28. The method of any one of claims 1 to 27, wherein the subject experiences a platelet response (HI-P) during treatment.

29. The method of any one of claims 1 to 24, wherein the subject has a baseline platelet count between 20 x 10 9 / L and 100 x 10 9 / L and experiences a platelet response (HI-P) during treatment, characterized by An absolute increase of >30 x 10 9 / L at each assessment during any consecutive 8-week period after baseline compared to baseline.

30. The method of any one of claims 1 to 24, wherein the subject has a baseline platelet count of <20 x 10 9 / L and experiences a platelet response (HI-P) during treatment, which is characterized by an increase of >100% at each assessment compared to baseline during any period of 8 consecutive weeks after baseline.

31. The method of any one of claims 1 to 30, wherein the subject is administered about 75 mg / day of pelabutib.

32. The method of claim 31, wherein the subject has a baseline platelet count of < 75 x 10 9 / L prior to treatment.

33. The method of any one of claims 1 to 30, wherein the subject is administered about 125 mg / day of pelabutib.

34. The method of any one of claims 1 to 30, wherein the subject is administered about 150 mg / day of pelabutib.

35. The method of any one of claims 31, 33, and 34, wherein the subject has a baseline platelet count of > 75 x 10 9 / L prior to treatment.

36. The method of any one of claims 1 to 30, wherein the subject is administered about 175 mg / day of pelabutib.

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