Effectiveness of Nontraditional Hydroxyurea Algorithms: Novel and Clinical Evaluations (ENHANCE)

Cincinnati Children's Hospital Medical Center

Status and phase: Enrolling; Phase 4

Conditions: Sickle-β0-thalassemia (HbSβ0); Sickle Cell Anemia (HbSS)

Treatments: Drug: PK-optimized oral hydroxyurea at MTD until 15 years of age.

Study type: Interventional

Funder types: Other

Identifiers

NCT07177300

ENHANCE

GCF_Quinn (Other Grant/Funding Number)

Details and patient eligibility

About

The main reason for this research study is to learn more about hydroxyurea and the treatment of sickle cell anemia (SCA). Hydroxyurea is a medication that has been studied for many years and has been shown to provide benefits for people with SCA.

In this research study, the investigators hope to learn more about how to improve the dosing and monitoring of hydroxyurea and learn more about the long-term effects of hydroxyurea over time. Hydroxyurea is usually dosed based only on your weight. Our study will use a new way to select a starting dose that is based on how each patient absorbs hydroxyurea.

Full description

The EHANCE study will address key knowledge gaps about hydroxyurea for young children with SCA in nine innovative ways:

• Novel functional assessments of brain, heart, kidneys, spleen, and eyes to assess organ protection in young children who receive hydroxyurea at MTD;

• State-of-the-art assays to assess the benefits of hydroxyurea on growth, development, and reproductive health into puberty including serial measurements of pubertal development and sex hormones;

• A simplified PK-guided strategy to optimize hydroxyurea initiation and dosing, with a long-term goal of validating pharmacogenomic approaches to expand treatment and achieve sustained HbF induction;

• A novel single-cell quantitative HbF/F-cell assay, developed utilizing imaging flow cytometry, will determine the distribution of HbF/F-cell across all F-cells, rather than simply estimating the mean value of HbF/F-cell;

• Collection of genomic DNA samples to allow serial quantitation of clonal hematopoiesis in treated children, to evaluate the possibility for potential emergence of clones with an increased risk of leukemic transformation;

• Studies on primary erythroblasts freshly isolated from patients and control subjects with single cell multiome analysis to evaluate in vivo cis and trans-acting elements that regulate HbF and how they are affected by hydroxyurea;

• Evaluation of cellular mechanisms by which hydroxyurea at MTD can regularly achieve >30% HbF with near-pancellular distribution, similar to levels currently touted with 'curative' gene therapy regimens;

• Exploration of the benefits of early hydroxyurea treatment initiation, in terms of γ-globin de-repression to optimize HbF induction, through unknown cellular mechanisms that may be developmentally regulated.

  3. SPECIFIC AIMS Aim 1: Document the long-term benefits and risks of long-term hydroxyurea treatment at MTD.

Aim 2: Perform pharmacokinetic (PK) and pharmacodynamic (PD) assessment of hydroxyurea at MTD.

Aim 3: Investigate the cellular mechanisms by which hydroxyurea leads to induction of protective HbF and how timing of treatment initiation and dose optimization affect the efficacy of this process.

Enrollment: 50 estimated patients

Sex: All

Ages: 6+ months old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Diagnosis of sickle cell anemia (HbSS) or sickle-β0-thalassemia (HbSβ0)
• Age 6 months at the time of enrollment
• Clinical decision by patient, family, and healthcare provider to initiate hydroxyurea therapy

Exclusion criteria

• Current treatment with regularly scheduled blood transfusions
• Sickle-hemoglobin C disease (HbSC), sickle-β+-thalassemia (HbSβ+)

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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50 participants in 1 patient group

Observational Treatment Group (Single Arm)

Experimental group

Description:

All children with sickle cell anemia who are started on hydroxyurea for clinical indicators between 6 months and 5 years of age can do so on this observational study with PK-optimized hydroxyurea dosing.

Treatment:

Drug: PK-optimized oral hydroxyurea at MTD until 15 years of age.