Pharmacological Evaluation of a First-in-Class Hemoglobin Elevating Agent (HbEA) AND017 in a Hbbd3th β-Thalassemia Mouse Model

Background

β-Thalassemia is prevalent in tropical and subtropical regions like Mediterranean, Middle East, Indian subcontinent and Southeast Asia including southern provinces in China; the disease poses serious health, medical and economic burdens on the affected families and societies. Treatments include blood transfusion plus iron chelation, hematopoietic stem cell transplantation, and recently FDA approved luspatercept, a "ligand trap" for various members of the TGF-β superfamily, and gene therapies; however, none of them can be widely applicable due to social-economical limitations. Thus, safe and effective oral, small molecule drugs, even non curative ones, would provide significant economically viable alternatives. Recently, we discovered a first-in-class highly efficacious hemoglobin elevating agents (HbEA), AND017, via traditional medicinal chemistry approach to identifying novel small molecules to elevate hemoglobin in rodents with the aim of overcoming safety concerns of all known erythropoietin stimulating agents (ESAs) including rHuEPOs and HIF-PHIs. AND017, a first-in-class HbEA, was found to be uniquely safe and effective in elevating hemoglobin in normal Sprague Dawley (SD) rats, rats of 5/6 nephrectomy CKD anemia model, mice of Hbb^d3th β-thalassemia model, mice of c-Myc mutant knock-in MDS model and mice of Townes sickle cell disease (SCD) model. In this study, we evaluated AND017 in mice of Hbb^d3th β-thalassemia model.

Methods

Twenty-two Hbb^d3th/d3th mice (female/F: 14; male/M: 8; 9-15 weeks) were randomly divided into 4 groups: G1 and G2 (2M+3F, each), G3 and G4 (2M+4F, each). Mice in G1 to G4 were orally dosed once daily with vehicle or AND017 (5, 10, and 15 mg/kg) respectively for 42 days. Body weight, behavior and activity including food and water consumption were observed, monitored, and recorded daily. RBC, HGB, and HCT were measured and calculated by hematology system on days 0, 15, 29, and 43 respectively. Blood smears were prepared and examined microscopically. The level of statistical significance was set at 5% or P < 0.05; the data were compared between groups at the same time point or within the same groups at different time points.

Results

The Hbb^d3th/d3th mice had similar symptoms to human β-thalassemia patients, such as lower body weight, hypochromic, microcytic anemia with anisocytosis, poikilocytosis etc. AND017 was well tolerated, with weight gain rates higher for G2 to G4 than G1. HGB levels (g/L) for G1 to G4 were 76.00, 74.60, 74.80, and 75.00 respectively on day 0; were 80.40, 81.20, 83.60^#, and 90.17^## on day 15; were 78.00, 83.00, 88.04^#, and 97.5*^/#### on day 29; and were 78.00, 80.20, 89.40*^/##, and 94.83***^/#### respectively on day 43. The RBC numbers (×10⁶cells/μL) for G1 to G4 were between 7.77 and 7.90 on day 0, were 8.05, 8.35, 8.60^##, and 8.95^# on day 15; were 8.27, 8.59, 9.15**^/#, and 9.72^#### on day 29; and were 8.29, 8.58, 9.30^##, and 9.45**^/#### respectively on day 43. The hematocrits (%) for G1 to G4 were between 26.20 and 27.78 on day 1, were 31.12, 31.16^#, 31.92^##, 34.50## on day 15, were 29.05, 32.10^##, 33.02*^/##, and 36.13^### on day 29, and were 28.48, 31.04*^/##, 33.36**^/###, and 36.10**^/#### respectively on day 43. Microscopic examination of blood smears showed marked improvement in the morphology of RBCs upon treatment with AND017 dose dependently. (significance: *: across-group comparison; ^#: in-group comparison; *^/#, **^/##, ***^/###, and ****^/####: for p < 0.05, 0.01, 0.001, and 0.0001 respectively)

Conclusion

AND017, a potent first-in-class hemoglobin elevating agent (HbEA), significantly and dose-dependently increased RBC numbers, Hb levels, and HCTs in a β-thalassemia mouse model. The increases in body weights and morphology improvements in red blood cells indicated AND017 could be a safe and effective oral treatment for β-thalassemia patients. Future clinical trials for AND017 in treating thalassemia are warranted.

Disclosures: Liu, Xiong and Deng are current employees and option holders of private company Kind Pharmaceuticals.