Optimizing Hydroxyurea Therapy in Children With SCA In Malaria Endemic Areas

Study Overview
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Brief Summary
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The Novel use Of Hydroxyurea in an African Region with Malaria (NOHARM) study is the first placebo-controlled randomized clinical trial of hydroxyurea treatment in a malaria endemic region. NOHARM has now achieved full enrollment; all children have completed the blinded portion of the protocol and are in the open-label study treatment portion. This extension study of maximum tolerated dose (MTD), addresses the next critical set of questions about the optimal dosing and monitoring of hydroxyurea treatment for children with SCA in low-resource settings. By providing guidance about optimal hydroxyurea treatment, the NOHARM MTD Study will directly inform policies that can transform the health of African children living with SCA.

Detailed Description
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All children enrolled in NOHARM received hydroxyurea treatment at a fixed daily dose of 20 mg/kg/day. This dose was selected as a likely safe dose, but does not escalate hydroxyurea to MTD as is commonly done in the US. Without this information, we cannot know whether hydroxyurea treatment at the MTD would be feasible (since it requires closer monitoring to avoid hematological toxicities), safe (since adverse events may be greater with MTD, risk of malaria may be altered by MTD, and risk of infections as a result of neutropenia could also be greater with MTD) or beneficial (MTD is associated with higher hemoglobin and fetal hemoglobin concentration). In this extension MTD study of open-label hydroxyurea for children in NOHARM who complete the initial study, consented children will be randomized to either fixed-dose or MTD hydroxyurea treatment for a minimum of 24 months. If hydroxyurea treatment continues to prove safe and effective in this low-resource malaria endemic area, and an optimal dosing scheme is determined, then the long-term goal is for all study children to transition to hydroxyurea treatment provided through the Ugandan Ministry of Health. To provide for a smooth transition, we will continue all children at either MTD or fixed dose hydroxyurea until a common end date (November 2019), at which time all study participants will have received a minimum of 24 months of additional hydroxyurea (either MTD or fixed dose). Addmedica, the Paris-based pharmaceutical company that provides the current active drug and placebo for the NOHARM trial, has agreed to provide additional hydroxyurea for this MTD study at no cost to the study or the participants. The Specific Aims of the NOHARM MTD proposal include two initiatives for participants who are currently enrolled in NOHARM: Aim 1. To determine the safety and efficacy of maximum tolerated dose (MTD) vs. fixed dose (20 mg/kg/day) hydroxyurea treatment in children with SCA in a low-resource, malaria endemic setting. For safety, we will compare adverse events and severe adverse events, including hematologic toxicities. For efficacy, we will assess hemoglobin level, fetal hemoglobin percentage (% HbF), and incidence of vaso-occlusive events such as pain crisis and acute chest syndrome. Aim 2. To compare the clinical outcomes of MTD vs. fixed dose hydroxyurea treatment in children with SCA in a low-resource, malaria endemic setting. Clinical outcomes assessed will include growth and malaria incidence over a 24-month follow-up period, and differences in renal, splenic, and cerebrovascular function between study entry and 24-month follow-up.

Official Title
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Optimizing Hydroxyurea Therapy in Children With Sickle Cell Anemia In Malaria Endemic Areas: The NOHARM Maximum Tolerated Dose (MTD) Study

Conditions
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Sickle Cell Anemia, Sickle Cell Disease, Malaria

Intervention / Treatment
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* Drug: Hydroxyurea


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children with confirmed SCA who participated in the NOHARM study of hydroxyurea at the Mulago Hospital Sickle Cell Clinic (MHSCC), will be eligible for the MTD study after completing both 12-months of blinded study treatment and then an additional 12-months of open-label hydroxyurea for the second year of the study. The age range for enrollment into NOHARM, which began in 2014, was 1-4 years. Therefore, the children who will be enrolled in the follow up MTD study will be 3-6 years of age. Exclusion Criteria: Not willing to come for all scheduled clinical visits or accept randomization

Ages Eligible for Study
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Minimum Age: 24 Months
Maximum Age: 72 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MTD Dose Escalation<br>Maximum tolerated dose of Hydroxyurea, 25-30 mg/kg/day | Drug: Hydroxyurea<br>* Administered once a day in tablet form (100mg or scored 1000mg) for 24 months<br>* Other names: Hydroxycarbamide;|
| Active Comparator: Fixed Dose<br>Fixed dose of Hydroxyurea, 20 mg/kg/day | Drug: Hydroxyurea<br>* Administered once a day in tablet form (100mg or scored 1000mg) for 24 months<br>* Other names: Hydroxycarbamide;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of children with average hemoglobin ≥9.0 g/dL or average HbF ≥20% | Proportion of children who achieve either an average hemoglobin ≥9.0 g/dL or an average HbF ≥20% after 24 months on study drug | Over 24 month period on study drug | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical malaria incidence | Clinical malaria is defined as a history of fever or measured axillary temperature ≥37.5 degrees, plus Plasmodium species on blood smear. | Over 24 month period on study drug | 
| Vaso-occlusive crises | SCA-related adverse events defined as: Pain event Dactylitis Acute chest syndrome | Over 24 month period on study drug | 
| Incidence of severe adverse events (SAE) | Death, hospitalization >7 days, life-threatening event | Over 24 month period on study drug | 
| Incidence of hematologic toxicities | Hematologic toxicities are defined as: Hemoglobin (Hb) <4.0g/dL Hb <6.0g/dL AND absolute reticulocyte count (ARC) <100 x 10E9/L Hb <7.0g/dL AND ARC <80 x 10E9/L Platelets <80 x 10E9/L Absolute neutrophil count (ANC) <1.0 x 10E9/L | Over 24 month period on study drug | 
| Cerebrovascular function | Transcranial Doppler blood vessel velocity to determine cerebrovascular function | At study treatment initiation then at 12 months and 24 months after study initiation | 
| Change in creatinine levels | Changes in creatinine level as a measure of renal function | Over 24 month period on study drug | 
| Change in cystatin C | Changes in cystatin C level as a measure of renal function | Over 24 month period on study drug | 
| Change in splenic function | Quantitative micronuclei [Howell Jolly bodies] measured by flow cytometry | Over 24 month period on study drug | 
| Change in height-for-age z-score | Change in height-for-age z-score | Over 24 month period on study drug | 
| Change in weight-for-age z-score | Change in weight-for-age z-score | Over 24 month period on study drug | 
| Change in weight-for-height z-score | Change in weight-for-height z-score | Over 24 month period on study drug | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hydroxyurea