Hemoglobin SC Disease
Conditions
Keywords
Hemoglobin SC disease, hydroxyurea, quality of life, viscosity, red cell density
Brief summary
Sickle cell disease (SCD), specifically hemoglobin SC disease (HbSC), is a subtype of sickle cell disease with typically higher hemoglobin and milder or later disease complications. Sickle cell disease is a disorder in which red blood cells (RBCs) are abnormally shaped. This can result in painful episodes, serious infections, and damage to body organs. One medication used to treat sickle cell disease is hydroxyurea. Hydroxyurea therapy offers significant benefits for infants, children, and adolescents with sickle cell anemia. These include a reduction in the frequency of pain crises and acute chest syndrome (inflammation of the lungs). Hydroxyurea has been given to many HbSC patients but HbSC patients were not included in the large clinical trials used to test hydroxyurea in SCD, so less is known about how HbSC patients respond to hydroxyurea. The purpose of this research study is to see if hydroxyurea, a medication given to many children with the most common type of sickle cell, those who are homozygous for the sickle mutation (HbSS), helps children who have HbSC. The investigators will see if it helps by giving a questionaire when the medication is started, and then every two months at a clinic visit. The questionaire, called the Pediatric Quality of Life Inventory (PedsQL™) Sickle Cell Disease Module version 3.0, measures quality of life. The investigators will also see how hydroxyurea changes laboratory test numbers, and blood thickness.
Detailed description
To be eligible to participate in this study, patients must have HbSC disease, have experienced a sickle cell disease related complication, or have a score of 80 or lower on the PedsQL™ Sickle Cell Disease Module version 3.0. This questionnaire will be offered to all patients with HbSC seen in our clinic that consent to this study. If the patient is sexually active, they will be offered birth control. If the patient chooses not to initiate effective birth control, they will be tested at their scheduled vist with a urine pregnancy test. If the patient becomes pregnant they will be removed from the study. The maximum time patients will be on the study is 12 months after starting hydroxyurea therapy, with an option to participate in a 2 year observation study following the end of the study. Patients will be assessed in the clinic every two months after starting treatment. Hydroxyurea will be started at 10 mg/kg/day, and increased by 5 mg/kg/day at eight week intervals if needed to reach a maximum tolerated dose (MTD). The most common side effect of the drug is a drop in infection fighting cells, or white blood cells, so the medication will be started at a low dose and the dose will be increased only if it is safe to do so. Patients will be asked to allow the investigators to review information from their medical records at the start of the study, and throughout the study. If the patient would like to participate in the two year follow-up, their records will be reviewed during that period as well.
Interventions
Treat symptomatic HbSC patients to MTD on hydroxyurea, and assess for clinical improvement using the PedsQL™ Sickle Cell Disease Module version 3.0 after 6 months at MTD, compared to entrance scores
Sponsors
Study design
Eligibility
Inclusion criteria
1. Diagnosis of HbSC disease 2. Score equal or lower than 80 on the PedsQL™ Sickle Cell Disease Module version 3.0 3. Have experienced a sickle cell disease related complication
Exclusion criteria
1. Failure to meet inclusion criteria. 2. Hydroxyurea usage in the last 3 months. 3. Chronic RBC transfusion therapy. 4. Packed red blood cell transfusion in the last 3 months (temporary exclusion). 5. Pregnancy, or refusal to use medically effective birth control if female and sexually active.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in PedsQL SCDM | 6 months | Mean change in PedsQL™ Sickle Cell Disease Module version 3.0 score after achieving MTD compared with baseline. PedsQL™ Sickle Cell Disease Module version 3.0 scores are on a 100 point scale ranging from 0 to 100 with higher values indicating better quality of life. PedsQL: pediatric qulaity of life |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in HVR at 225s-1 | up to 7 months | Change in hematocrit viscosity ratio at 225s |
| DRBC | up to 7 months | Change in percent dense red blood cells |
| Change in HbF | up to 7 months | Change in fetal hemaglobin |
| Change in MCV | up to 7 months | Change in mean corpuscular volume |
| Change in MCHC | up to 7 months | Change in mean corpuscular hemoglobin concentration |
| Change in HVR at 45s-1 | up to 7 months | Change in hematocrit to viscosity ratio (HVR) at 45s-1 at follow-up versus baseline. This is a measure of oxygen carrying capacity, as a higher hematocrit with lower viscosity indicates ability to deliver oxygen without slowed blood flow due to high viscosity or blood thickness. Higher values are associated with improvement. |
| Change in ARC | up to 7 months | Change in absolute reticulocyte count |
| Change in ANC | up to 7 months | Change in absolute neutrophil count |
| Change in LDH | up to 7 months | Change in lactate dehydrogenase |
| Change in UB Levels | up to 7 months | Change in unconjugated bilirubin levels |
| Change in Hb | up to 7 months | Change in hemoglobin |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Hydroxyurea hydroxyurea (HU) at 10 mg/kg daily | 32 |
| Total | 32 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Physician Decision | 14 |
| Overall Study | Protocol closed early | 4 |
Baseline characteristics
| Characteristic | Hydroxyurea |
|---|---|
| Age, Categorical <=18 years | 32 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 0 Participants |
| Age, Continuous | 11 years STANDARD_DEVIATION 3.5 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 31 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| PedsQLTM 3.0 SCD Module score | 54.9 units on a scale STANDARD_DEVIATION 20.4 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 31 Participants |
| Race (NIH/OMB) More than one race | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 0 Participants |
| Region of Enrollment United States | 32 participants |
| Sex: Female, Male Female | 13 Participants |
| Sex: Female, Male Male | 19 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 32 |
| other Total, other adverse events | 0 / 32 |
| serious Total, serious adverse events | 0 / 32 |
Outcome results
Change in PedsQL SCDM
Mean change in PedsQL™ Sickle Cell Disease Module version 3.0 score after achieving MTD compared with baseline. PedsQL™ Sickle Cell Disease Module version 3.0 scores are on a 100 point scale ranging from 0 to 100 with higher values indicating better quality of life. PedsQL: pediatric qulaity of life
Time frame: 6 months
Population: Participants who achieved MTD of hydroxyureq per protocol with observed PEDSQL scores at 6-months and baseline (study entry).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in PedsQL SCDM | 5.7 Score on PedsQL 3.0 SCD Module | Standard Deviation 15.5 |
Change in ANC
Change in absolute neutrophil count
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in ANC | -0.24 10^3 cells/uL | Standard Deviation 0.82 |
Change in ARC
Change in absolute reticulocyte count
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in ARC | 0.01 10^3 cells/uL | Standard Deviation 0.025 |
Change in Hb
Change in hemoglobin
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in Hb | -0.62 percent | Standard Deviation 0.59 |
Change in HbF
Change in fetal hemaglobin
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in HbF | -0.47 percent | Standard Deviation 0.94 |
Change in HVR at 225s-1
Change in hematocrit viscosity ratio at 225s
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in HVR at 225s-1 | 0.11 au | Standard Deviation 0.83 |
Change in HVR at 45s-1
Change in hematocrit to viscosity ratio (HVR) at 45s-1 at follow-up versus baseline. This is a measure of oxygen carrying capacity, as a higher hematocrit with lower viscosity indicates ability to deliver oxygen without slowed blood flow due to high viscosity or blood thickness. Higher values are associated with improvement.
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in HVR at 45s-1 | 0.083 au | Standard Deviation 0.72 |
Change in LDH
Change in lactate dehydrogenase
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in LDH | -21.7 percent | Standard Deviation 52.48 |
Change in MCHC
Change in mean corpuscular hemoglobin concentration
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in MCHC | 0.33 percent | Standard Deviation 0.43 |
Change in MCV
Change in mean corpuscular volume
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in MCV | -6.2 fL | Standard Deviation 2.3 |
Change in UB Levels
Change in unconjugated bilirubin levels
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | Change in UB Levels | -0.1 percent | Standard Deviation 0.28 |
DRBC
Change in percent dense red blood cells
Time frame: up to 7 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Hydroxurea | DRBC | 1.93 percentage of dense red blood cells | Standard Deviation 20.6 |