Pharmacological Evaluation of a First-in-Class Hemoglobin Elevating Agent (HbEA) AND017 in Sprague Dawley Rats

Background

Inhibiting hypoxia-inducible factor prolyl hydroxylase (HIF-PH) by oral small molecules has been intensively pursued in treating chronic kidney disease (CKD) anemia during the past 20 years, leading to approval of daprodustat and vadadustat by FDA in treating dialysis-dependent (DD) CKD anemia in US while both plus roxadustat failed in getting approval by FDA in treating non-dialysis dependent (NDD) CKD anemia in US due to safety concerns. Although designed as potent HIF PH inhibitors, these three -dustats behaved differently in animal models and patients in terms of the disconnected relationship between the observed erythropoietin (EPO) level and hemoglobin (Hb) elevation in patients. It is also well-known that the high level of rHuEpo as treatment in CKD anemia patients is associated with cardiovascular risks. In order to identify new safe and efficacious anemia drugs, we took a traditional medicinal chemistry approach, i.e., by iterative cycles of chemical synthesis of a series of N-heterocyclic acyl glycine based on the pharmacophore of known HIF-PH inhibitors, and pharmacological evaluation of Hb elevation in vivo in rodents while purposely not optimizing their ability in HIF PH inhibition and EPO elevation; this culminated the discovery of a first-in-class, highly efficacious hemoglobin elevating agent (HbEA), AND017. It has been shown that AND017 had excellent efficacy 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. This current study is a non-GLP evaluation of AND017 in elevating Hb in normal male SD rats before its nomination as a clinical candidate for CKD anemia and other anemias.

Methods

Forty male SD rats (age 7-9 weeks) were randomly divided into 4 groups (10 rats each group), group 1 (vehicle), groups 2, 3, and 4 (AND017 1.25, 2.5, and 5 mg/kg respectively). All rats were dosed orally with vehicle or AND017 QD between days 1 and 28, and stopped dosing during the recovery period between days 29 and 56. Body weights were measured twice a week during the study. Whole blood was collected from orbital vein of each rat into tube containing EDTA-2K on days 1, 14, 28, 42, and 56, respectively. RBC, HGB, and HCT were immediately tested by a Hematology System. All statistical tests were conducted, and the level of significance were set at 5% or P < 0.05. The group means and standard deviations were calculated. One-way ANOVA analysis of variance was used among the groups.

Results

There were no abnormal clinical observations found in the rats during the study period; their body weights between any of the AND017 treated groups and vehicle group had no significant difference at all time points. The HGB levels (g/L) for groups 1 to 4 were between 126±3 and 126±5 on day 1, were 149±5, 158±7*, 172±7**, and 203±10** respectively on day 28, and were 155±7, 152±8, 159±6, and 155±3 respectively on day 56. The RBC numbers (×10⁶cells/μL) for groups 1 to 4 were between 5.75 and 5.88 on day 1, were 7.59±0.34, 7.75±0.21, 8.55±0.47**, and 9.80±0.57** respectively on day 28, and were 8.19±0.38, 7.90±0.23, 8.28±0.29, and 7.81±0.36* respectively on day 56. The hematocrits (%) for group 1 to 4 were between 38.7 and 39.1 on day 1, were 41.7±1.5, 44.0±2.0, 48.6±2.5**, and 57.9±2.7** respectively on day 28, and were 42.5±1.4, 41.7±1.5, 43.6±1.5, and 41.9±0.9 respectively on day 56. (Significance analysis was compared to group 1，* p<0.05，** p<0.01)

Conclusion

RBC, HGB, and HCT in normal SD male rats were significantly increased after dosing AND017 at 2.5 and 5 mg/kg PO QD for 4 weeks and gradually recovered to background levels after stopping dosing; therefore, AND017 is a potent first-in-class hemoglobin elevating agent (HbEA) in vivo.

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

Liu:Kind Pharmaceuticals, LLC: Current Employment, Current holder of stock options in a privately-held company. Deng:Kind Pharmaceuticals, LLC: Current Employment, Current holder of stock options in a privately-held company.