NCT06439082 · Novartis Pharmaceuticals
A Study to Investigate the Efficacy and Safety of Crizanlizumab (5 mg/kg) Compared With Placebo in Adolescent and Adult Sickle Cell Disease Patients Who Experience Frequent Vaso-Occlusive Crises (SPARKLE)
(SPARKLE)
What this study is about
A phase III, multi-center, randomly assigned, compared against an inactive treatment, where neither patients nor doctors know which treatment is given study to assess effectiveness and safety of crizanlizumab (5 mg/kg) versus placebo, with or without hydroxyurea/hydroxycarbamide therapy, in adolescent and adult Sickle Cell Disease patients with frequent vaso-occlusive crises.
View original scientific description
A phase III, multi-center, randomized, placebo-controlled, double-blind study to assess efficacy and safety of crizanlizumab (5 mg/kg) versus placebo, with or without hydroxyurea/hydroxycarbamide therapy, in adolescent and adult Sickle Cell Disease patients with frequent vaso-occlusive crises.
Interventions
BIOLOGICAL
Crizanlizumab
Crizanlizumab is supplied in single use 10 mL glass vials at a concentration of 10 mg/mL. One vial contains 100 mg of crizanlizumab. This is a concentrate for solution for IV infusion.
DRUG
Placebo
Placebo is supplied in single use 10 mL glass vials at a concentration of 0 mg/mL. This is a concentrate for solution for IV infusion.
Primary outcome measures
Annualized rate of VOCs that are healthcare professional (HCP)-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) in each treatment arm
Time frame: 1 year
Vaso oclusive crisis (VOC) is defined as a pain crisis (acute onset of pain for which there is no other medically determined explanation other than vaso-occlusion) lasting for at least 4 hours which is treated as per local guidelines with standard of care therapy used to treat VOC. Acute chest syndrome (ACS), priapism and hepatic or splenic sequestration will be considered VOC in this study. VOCs included are those HCP-managed in a healthcare facility and HCP-managed via remote consultation. Annualized rate of VOC events = (Number of VOC events \* 365)/(number of days in the observation period). Observation period = time from date of randomization to minimum of (last dose date until treatment discontinuation + 27 days, date of initiation or discontinuation of HU/HC or L-Glutamine (or other therapies such as Voxelotor and erythropoietin therapies to treat SCD and/or to prevent/reduce VOCs), date of randomization + 365 days).
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Participants must be aged 12 years and older on the day of signing informed consent. Adolescents include participants aged 12 to \<18 years old and adults include participants aged 18 years and older.
- Confirmed diagnosis of SCD by Hb electrophoresis or high-performance liquid chromatography (HPLC) (performed locally or by central laboratory if not available locally). All SCD genotypes are eligible.
- Experienced 4 to 12 VOCs (refer to Section 8.3.1 for study definition of VOC) that are HCP-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) within the 12 months prior to the screening visit. Baseline VOCs are determined by medical history and are required to be documented at source.
- If the participant is on HU/HC, they must be taking it for at least 6 months and at stable dose for at least 3 months prior to the Screening visit and plan to continue taking it at the same dose and schedule until at least the participant has reached 52 weeks of the planned study treatment. Participants who have initiated HU/HC 6-12 months prior to the screening visit must have evidence of insufficient control of acute pain despite initiation. These participants must have a cumulative of 4-12 VOCs in the 12 months prior to the screening period, with at least 2 during the last 6 months while on HU/HC. If receiving erythropoietin stimulating agent, the participant must have been receiving the drug for at least 6 months prior to screening visit and plan to continue taking the drug at the same dose and schedule until the participant has reached 52 weeks of the planned study treatment. Participants who have not been receiving HU/HC, and/or erythropoietin stimulating agent must not have received it for at least 6 months prior to screening visit. Key
Exclusion criteria
- Fewer than 4 or more than 12 VOCs that are HCP-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) within the 12 months prior to screening visit as determined by medical history and documented at source.
- History of stem cell transplant and/or gene therapy.
- Received blood products within 30 days prior to Week 1 Day 1 dosing.
- Any documented history of a clinical stroke or intracranial hemorrhage, or an uninvestigated neurologic finding within the past 12 months before screening visit. Silent infarct only present on imaging is not excluded.
- Participating in a chronic transfusion program (pre-planned series of transfusions for prophylactic purposes) and/or planning to undergo an exchange transfusion during the duration of the study; episodic transfusion in response to worsened anemia or VOC is permitted.
- Contraindication or hypersensitivity to any drug or metabolites from similar class as study drug or to any excipients of the study drug formulation. History of severe hypersensitivity reaction to other monoclonal antibodies, which in the opinion of the investigator may pose an increased risk of serious infusion reaction.
Where
- Birmingham, Alabama
- Orange, California
- Washington D.C., District of Columbia
- Jacksonville, Florida
- Augusta, Georgia
- Riverdale, Georgia
- Chicago, Illinois
- Louisville, Kentucky
- Baltimore, Maryland
- Flowood, Mississippi
- The Bronx, New York
- Greenville, North Carolina
And 4 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Oct 15, 2026 · Source of record for eligibility and locations