In Vivo Studies of a Novel HDAC Inhibitor for Treating Hemoglobin Disorders

PROJECT SUMMARY The β-hemoglobinopathies are prevalent genetic blood diseases with few treatment options. It is estimate that 7% of the worldandapos;s population carries an abnormal hemoglobin gene with 400,000 infants born annually with a severe life threatening hemoglobinopathy. Drug mediated induction of normal, but developmentally silenced, fetal hemoglobin (HbF) expression reduces anemia and ameliorates clinical severity in the β- hemoglobinopathies. Histone deacetylase (HDAC) 1, 2, and 3, are components of the NURD repressor complex, which promotes silencing of the fetal γ-globin genes in adult erythroid cells. Prior generation HDAC inhibitors increase HbF in patients with β-hemoglobinopathies, but had limitations for pharmaceutical application and/or required titration to reduce anti-proliferative effects. Cetya has generated a library of high potency HDAC inhibitors, one of which, CT-101, has demonstrated efficacy in inducing HbF expression in β- thalassemia and sickle cell erythroid progenitors and in the β-YAC mouse model that contains the normal human β-globin gene locus,without significant anti-proliferative effects. We will test the central hypothesis that CT-101 has a sufficiently wide margin of activity, without significant inhibition of erythroid cell growth, to be developed as a new agent for treatment of β-hemoglobinopathies. We propose to conduct studies to evaluate CT-101 in the β-YAC model to optimize dose and schedule, and then confirm efficacy in the Townes sickle cell disease mouse model. Cetya will scale the CT-101 manufacturing process and produce sufficient quantities to support the murine studies and oral formulation development. The goal of this project is to develop the new high-potency HDAC inhibitor CT-101 for an IND and clinical therapeutics. To test our hypothesis the following aims will be completed. Aim 1. Test the hypothesis that CT-101 induces HbF expression in the preclinical β- YAC and Townes sickle cell disease mouse models through epigenetic histone modifications. Aim 2. Scale the manufacturing processes and produce sufficient quantities of CT-101 to conduct IND-enabling studies required for a Phase I clinical study. Aim 3. Develop an oral dosage formulation of CT-101 suitable for human administration. The expected outcome of this Phase 2 project is to develop CT-101 as an oral effective HbF inducer. Our experimental approach rests on the scientifically validated concept of the inhibition of sickle hemoglobin polymerization by HbF and red blood cell sickling by reversing a well-known epigenetic γ-globin gene silencing mechanism. Development of the potent HDAC inhibitor CT-101 will impact the field and addresses an unmet need for additional disease modifying therapy for β-hemoglobinopathies.PROJECT NARRATIVE This proposal will build on findings obtained in our Phase I grant, utilizing transgenic mouse models to determine the optimal dose and schedule for a future clinical study in patients. The manufacturing process for the compound, CT-101, will be optimized at Cetya, and then manufacturing scaled for animal studies and formulation for oral dosage in human trials. Upon completion of the proposed activities in this Phase 2 grant, IND-enabling studies will be performed and CT101 advanced rapidly into clinical trials. !