A Phase 3 interventional study of Crizanlizumab and Placebo in Sickle Cell Disease, sponsored by Novartis Pharmaceuticals. Recruiting at 36 sites in 5 countries. Open to participants aged 12 Years to 100 Years. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by Novartis Pharmaceuticals (part of Novartis) · Phase 3, Interventional, and Treatment
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.
Study CSEG101A2303 (SPARKLE) is a Phase III, multicenter, randomized, double-blind study to assess efficacy and safety of crizanlizumab 5 mg/kg versus placebo, with or without hydroxyurea/ hydroxycarbamide therapy (HU/HC), in Sickle Cell Disease patients aged 12 years and older with frequent vaso-occlusive crises (4-12 events in 12 months prior to the screening visit).
Participants will be randomized in a 2:1 ratio to the crizanlizumab 5 mg/kg or placebo treatment arm. Central randomization will be stratified by concomitant HU/HC usage (yes/no) and region (South America, North America, and sub-Saharan Africa) at baseline.
104 studies on the registry are indexed under Vaso-Occlusive Crises; 31 are open to participants now.
This study's planned enrollment of 354 is above the median of 81 across 86 interventional studies indexed under Vaso-Occlusive Crises.
Browse Vaso-Occlusive Crises studies →Novartis Pharmaceuticals is the lead sponsor of 2,718 studies on the registry; 221 are open to participants now.
Of its 585 completed or terminated interventional studies of FDA-regulated products, 438 (75%) have results posted.
Compared within Vaso-Occlusive Crises, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Anemia, Sickle Cell. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Key Inclusion Criteria:
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:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive Crizanlizumab (SEG101) at 5.0 mg/kg and standard of care.
Biological: Crizanlizumab
Participants receive the placebo drug and standard of care.
Drug: Placebo
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.
Also known as: SEG101, Adakveo®, Ryverna®
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.
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
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).
Time frame: 1 year
The annualized rate of all VOCs including VOCs that are HCP-managed (either at a health care facility or via remote consultation) as well as those that are self-managed without recommendations from HCP during the event in each treatment arm
VOCs can be categorized as those HCP-managed in a healthcare facility, HCP-managed via remote consultation, or self-managed without recommendations from HCP during the event. Annualized rate of VOC events = (Number of VOC events \* 365)/(number of days in the observation period). To capture VOC events that are self-managed, and in order to avoid VOC recall bias and to make sure the pain events are captured in real-time, a cloud-based application will be used and setup an account for each participant.
Time frame: 1 year
Annualized rate of VOC by subtype of management in each treatment arm over the planned 52-week period.
Vaso oclusive crisis (VOC) is defined as a pain crisis lasting for at least 4 hours which is treated as per local guidelines with standard of care therapy. Acute chest syndrome (ACS), priapism and hepatic or splenic sequestration will be considered VOC in this study. VOCs can be categorized as those HCP-managed in a healthcare facility, HCP-managed via remote consultation, or self-managed without recommendations from HCP during the event. Annualized rate of VOC is the number of VOC events during a year period.
Time frame: 1 year
The time to first VOC that is HCP-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) between treatment arms.
VOC is defined as a pain crisis lasting for at least 4 hours which is treated as per local guidelines with standard of care therapy. 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. Time to first occurrence of VOC that is HCP-managed (either at a health care facility or via remote consultation) is defined as the time from the date of randomization to the date of the first occurrence of the VOC.
Time frame: 1 year
Proportion of participants free from VOCs that are HCP-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) in each treatment arm over the planned 52-week treatment period.
To assess the number of participants free from VOCs leading to healthcare visit. VOC is defined as a pain crisis lasting for at least 4 hours which is treated as per local guidelines with standard of care therapy. ACS, priapism and hepatic or splenic sequestration will be considered VOC in this study. A participant is free from VOC if they do not have a VOC crisis.
Time frame: 1 year
Duration of VOCs that are HCP-managed (including VOCs leading to management at a health care facility or those managed via remote consultation) in each treatment arm over the planned 52-week treatment period.
VOC is defined as a pain crisis lasting for at least 4 hours which is treated as per local guidelines with standard of care therapy. ACS, priapism and hepatic or splenic sequestration will be considered VOC in this study. Duration of HCP-managed VOC is defined as end date of the VOC - start date of the VOC + 1 day.
Time frame: 1 year
Number of participants with anti-SEG101 (crizanlizumab) antibodies (any time)
Immunogenicity: measurement of anti-drug antibodies (ADA) to crizanlizumab.
Time frame: 2 years
Incidence and severity of Adverse Events (AEs) and Serious Adverse Events (SAEs)
Incidence and severity of AEs and SAEs by treatment group, including changes in vital signs, electrocardiograms (ECGs), and laboratory results qualifying and reported as AEs.
Time frame: 2 years
Absolute change from baseline in hemoglobin
Assessment of safety of SEG101
Time frame: Baseline, 2 years
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Plan to share: Yes — Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com
Data sharing details ↗ · www.clinicalstudydatarequest.com
No publications or documents are linked to this record.
Started Oct 2024 (actual). Primary completion is estimated for Jul 2029, 56 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Crizanlizumab