Pharmacological Evaluation of a First-in-Class Hemoglobin Elevating Agent (HbEA) AND017 in a Rat 5/6 Nephrectomy Model

Background

Two hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI), daprodustat and vadadustat, have been approved by FDA to treat dialysis dependent (DD) chronic kidney disease (CKD) anemia patients in US while all HIF-PHIs failed in getting approval by FDA in treating non-dialysis dependent (NDD) CKD anemia in US due to safety concerns. We aimed to fill the gap between safety and efficacy in all previous ESAs including rHuEPOs and HIF-PHIs; thus, we took a traditional medicinal chemistry approach to identifying safe and potent anemia drugs. Starting from N-heterocyclic acyl glycine, a common pharmacophore of known HIF-PHIs, we focused on optimization of the structure of lead compounds against their in vivo hemoglobin elevation potency in rodents while purposely not optimizing their potencies in molecular level (HIF PH inhibiting) and cellular level; ultimately, we discovered 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 is a non-GLP study to evaluate the effect of AND017 on rat 5/6 nephrectomy CKD model to support the clinical trials of AND017 in treating anemia in CKD patients.

Methods

Ninety male SD rats (age 7-9 weeks) were conducted 5/6 nephrectomy or sham surgery; 35 days after surgery, 50 rats were randomly divided into 5 groups (10 rats each group): group 1 (sham surgery), group 2 (5/6 nephrectomy, vehicle), groups 3, 4, and 5 (5/6 nephrectomy dosed, AND017 1.25, 2.5, and 5 mg/kg PO QD respectively). All rats were dosed orally with vehicle or AND017 QD between days 36 and 63. 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, 35 (pre-dosing), 49, and 63 respectively. RBC, HGB, and HCT were immediately tested by a Hematology System. All statistical tests were conducted, and the levels 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

In terms of body weight, when compared to group 2, rats in AND017 treated groups had no significant difference during the study, while rats in group 1 had significant difference. The HGB levels (g/L) for all 5 groups were between 123±5 and 127±7 on day 1; were 155±5**, 133±7, 134±4, 134±3, and 133±5 respectively on day 35, were 157±4**, 137±9, 145±8, 159±4**, and 182±11** respectively on day 49, were 154±6**, 131±10, 143±12*, 165±13**, and 214±13** on day 63 respectively. The RBC numbers (×10⁶cells/μL) for all 5 groups were between 5.83±0.27 and 5.92±0.29 on day 1, were 7.95±0.46**, 6.95±0.31, 6.91±0.31, 7.14±0.27, and 6.82±0.32 respectively on day 35, were 8.31±0.46**, 7.14±0.47, 7.46±0.38, 8.27±0.27**, and 8.91±0.61** respectively on day 49, and were 8.30±0.28, 6.91±0.52, 7.47±0.76, 8.75±0.56, and 10.26±0.65 respectively on day 63. The hematocrits (%) for 5 groups were between 38.2±1.5 and 39.4±2.0 on day 1, were 41.6±1.6**, 36.3±1.9, 36.3±1.4, 37.2±1.2, and 36.3±1.7 respectively on day 35, were 41.8±1.3**, 36.8±2.4, 39.4±1.9*, 43.9±1.4**, and 51.4±2.8** respectively on day 49, and were 41.0±1.2**, 35.2±2.3, 39.0±3.6*, 45.7±3.1**, and 59.1±3.7** respectively on day 63. (Significance analysis was compared to group 2，* p<0.05，** p < 0.01)

Conclusion

The rat 5/6 nephrectomy CKD anemia model was successfully established; on day 63, RBC, HGB, and HCT for rats in three AND017-dosed groups were significantly improved compared to rats with 5/6 nephrectomy control; therefore, AND017 was a potent hemoglobin elevating agent (HbEA) in 5/6 rat nephrectomy CKD anemia model, indicating AND017 could potentially be a very potent and safe new treatment for anemia associated with CKD.

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.