Summary: Sickle cell disease (SCD) primarily afflicts African-Americans in the US, exacerbating an existing health disparity. Approximately 1 in 13 African-American babies is born with the sickle cell trait and ~100,000 individuals live with SCD. Along with a range of adverse physiological effects resulting in painful vaso-occlusive crises (VOC), patients suffer from poorer quality of life and a significantly decreased life expectancy (only 54 years). A handful of drugs are currently FDA approved; however, despite their benefits, there are drawbacks. Hydroxyurea is effective for two genotypes accounting for only 60% of SCD patients and the frequency of painful episodes is reduced by only 50%. Newer drugs (L-glutamine, crizanlizumab, voxelotor) lack improvement in hemoglobin levels or lack reduction in number of VOCs. Alternative treatments, such as chronic blood transfusion therapy or hematopoietic stem cell transplantation, can provide benefit but can also lead to serious complications or impose roadblocks including cost and finding matching donors. There is a significant unmet need for potent, novel multi-modal SCD therapeutics that achieve optimal efficacy, safety, and quality of life. To meet this need, Vascular Vision proposes a sulfated oxidized non-anticoagulant low molecular weight heparin (S-NACH) to provide an extensive range of bioactivities without causing bleeding, a common dose limiting effect associated with the clinical use of low molecular weight heparins. Proof-of-concept in vitro and in vivo preclinical studies have established efficacy through multiple modes including anti-adhesion, anti-inflammation, anti-sickling, vascular antithrombotic, and endothelial relaxation. Our subcutaneous nanoformulation (VVP728) demonstrated improved SCD pharmacodynamics. This SBIR Phase II proposes IND-enabling studies to determine tolerability of nanoformulated S-NACH (VVP728) in support of first in human trials (FIH) through the following Specific Aims: Aim 1. Scale up manufacturing to establish PK/PD and support IND-enabling studies. To support preclinical PK/PD and GLP toxicology testing, we will scale up the manufacturing of research grade drug substance (DS: S-NACH) and drug product (DP: VVP728). Milestones: (1) Develop analytical and bioanalytical methods, (2) Deliver research grade DS (2 kg) and DP (1.5 kg) under GLP, and (3) Determine PK and vascular antithrombotic activity in rats and PD in Townes SCD mouse model for DS vs DP. Aim 2: Determine GLP safety profile of S-NACH. We will conduct dose range finding studies (7 days) and GLP repeated dose studies (28 days) in rodent (rat) and non-rodent (dog) as well as in vitro assessments of protein binding, transporter and CYP inhibition, effect on hERG current in transfected HEK-293 cells, and genotoxicity. In vivo central nervous system (CNS: rats), respiratory (dogs), and cardiovascular (dogs) assessments will be completed. Milestones: (1) Establish protein binding and potential for inhibi...