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NCT Number: NCT03789591

Hydroxyurea Optimization Through Precision Study

Hydroxyurea Optimization through Precision Study (HOPS) is a prospective, multi-center, randomized trial that will directly compare a novel, individualized dosing strategy of hydroxyurea to standard weight-based dosing for children with SCA. The primary objective of the study is to evaluate whether a pharmacokinetics-based starting hydroxyurea dose thieves superior fetal hemoglobin response to to standard weight-based initial dosing. Patients will be recruited from the pediatric sickle cell clinic at Cincinnati Children's Hospital Medical Center and from additional pediatric sickle cell centers within the United States.

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Key information

Conditions

Sickle Cell Disease Anemia Anemia, Hemolytic Anemia, Hemolytic, Congenital Anemia, Sickle Cell Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Hematologic Diseases Hemic and Lymphatic Diseases Hemoglobinopathies Sickle Cell Anemia

Age range

6 month–21 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Phoenix Children's Hospital, Phoenix, Arizona, United States

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About this study

The trial will recruit patients who have decided to initiate hydroxyurea therapy. All participants will have pharmacokinetics studies performed at baseline, following a 20 mg/kg oral dose of hydroxyurea. Pharmacokinetic sampling will use a sparse sampling approach, requiring collection of blood at 3 time points (15 minutes, 60 minutes, 180 minutes) following the hydroxyurea dose. Enrolled participants will be randomized to receive either hydroxyurea using a starting dose of 20 mg/kg/day (Standard Arm) or a personalized PK-guided dose (Alternative Arm) to target an area under the curve (AUC) of 115 mg*h/L based to approximate hydroxyurea exposure seen when patients are escalated to maximum tolerated dose (MTD).

Following randomization and selection of the initial dose, participants in both arms will follow the same procedures of laboratory medication holds for hematological toxicity. The primary endpoint is fetal hemoglobin (HbF) six months following the initiation of hydroxyurea therapy with the hypothesis that participants starting with a PK-guided dose will achieve HbF at least 5% greater than those starting with a 20 mg/kg dose. Based upon the estimated number of new hydroxyurea starts at each site, it is anticipated that it will take 24 months to enroll the 116 participants required to achieve sufficient power to assess the primary endpoint. The study will conclude for each participant 12 months following hydroxyurea initiation.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of sickle cell anemia (HbSS, HbSD, HbS/β0-thalassemia, or similarly severe SCA genotype)
  • Age 6 months to 21 years at the time of enrollment
  • Clinical decision by patient, family, and healthcare providers to initiate hydroxyurea therapy

Exclusion criteria

  • Current treatment with chronic, monthly blood transfusions or erythrocytapheresis
  • Treatment with hydroxyurea within the past 3 months
  • Hemoglobin SC disease, HbS/β+-thalassemia
  • Current treatment with other investigational sickle cell medications
  • Current known pregnancy or lactation

Treatment and study plan

Hydroxyurea

Drug

The alternative arm will use PK data to choose a starting hydroxyurea dose to achieve an AUC of 115 mg*h/L to approximate maximum tolerated dose. On the standard arm, participants will start at the traditional, weight-based dose of 20 mg/kg/day. Following selection of the starting dose, all participants will follow the same dose escalation and laboratory monitoring procedures.

Primary outcomes

  1. Fetal Hemoglobin (HbF) Response Following Six Months of Hydroxyurea Therapy

    Time frame: 6 months after starting daily hydroxyurea therapy

    The primary outcome will be HbF response six months after starting hydroxyurea therapy with the hypothesis that participants in the Alternative Arm (PK-guided starting dose) will have at least 5% higher HbF than the Standard Arm (20 mg/kg starting dose)

Secondary outcomes

  1. F Cells

    Time frame: Baseline, 6 and 12 months after initiating daily hydroxyurea therapy

    In addition to traditional %HbF measurement, F cells will be measured at baseline, 6 months, and 12 months

  2. Gene Expression Patterns of Study Participants

    Time frame: 6 Months after initial Hydroxyurea therapy

    The epigenomic signature and gene expression patterns of study participants receiving hydroxyurea therapy at MTD. MTD is defined as a stable dose without any dose increases (except to account for weight gain), holds, or decreases within 8 weeks with laboratory criteria within the target range. This outcome will explain the mechanisms that yield high HbF responses.

Sponsors and collaborators

Lead sponsor

Lifespan

Other

Collaborators

  • Doris Duke Charitable Foundation

Registry information

Official study title

Hydroxyurea Optimization Through Precision Study (HOPS): A Prospective, Multi-center, Randomized Trial of Personalized, Pharmacokinetics-guided Dosing of Hydroxyurea Versus Standard Weight-based Dosing for Children With Sickle Cell Anemia.

Acronym: HOPS

Important dates

Study start
2019
Primary completion
2025
Study completion
2025
First posted
Dec 28, 2018
Registry last updated
Jun 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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