Thrombotic MicroangiopathiesPhase 2NCT05855083
Efficacy and Safety Study of Narsoplimab in Pediatric Patients With High-Risk Hematopoietic Stem Cell Transplant TMA
A Phase 2 study testing Biological: narsoplimab in people with Thrombotic Microangiopathies and Hematopoietic Stem Cell Transplantation, run by Omeros Corporation at 16 sites in 5 countries.
Trial summary
The purpose of this study is to evaluate the safety and efficacy of narsoplimab in pediatric patients with thrombotic microangiopathies (TMA) following hematopoietic stem cell transplant (HSCT). Read more about this study
- Who is it for?
- Ages 28 days to 17 years
- Conditions the study is for
- Thrombotic Microangiopathies, Hematopoietic Stem Cell Transplantation
- What is being tested?
- Biological: narsoplimab
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 16 sitesin 5 countries
- Study dates
- 1 May 2023to Dec 2025
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 28 days to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- Age at least 28 days and less than 18 years prior to informed consent (Visit 0).
- Have informed consent from at least one parent or legal guardian as required by local law and regulation. Patient informed consent will be required if the patient has reached the local legal age of majority.
- Assent from patients as required by local law and regulation.
- Have received an allogeneic hematopoietic stem cell transplant for the treatment of benign or malignant disease.
- Have a diagnosis of HSCT-TMA defined as meeting both of the following criteria:
- Platelet count < 50,000/mL or a decrease in platelet count > 50% from the highest value obtained following transplant.
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- Evidence of microangiopathic hemolysis (presence of schistocytes, serum lactate dehydrogenase [LDH] > upper limit of normal ([ULN], or haptoglobin < lower limit of normal [LLN])
- Have at least one of the following HSCT-TMA high-risk criteria:
- HSCT-TMA persistence > 2 weeks following modification of calcineurin inhibitors or sirolimus OR
- Have evidence of high-risk HSCT-TMA defined as at least one of the following:
- Spot protein/creatinine ratio > 2 mg/mg
- Serum creatinine > 1.5 x the creatinine level prior to TMA development
- Biopsy-proven gastrointestinal TMA
- TMA-related neurological abnormality
- Pericardial or pleural effusion without alternative explanation
- Pulmonary hypertension without alternative explanation
- Have Grade III or Grade IV graft-versus-host disease (GVHD) or, in the opinion of the Investigator, risk for development of Grade III or Grade IV GVHD if immunosuppression were to be modified
- Have elevated serum C5b-9 (> 244 ng/mL)
- If sexually active and of childbearing potential (for female pediatric patients, defined as starting at onset of menses), must agree to practice a highly effective method of birth control throughout study drug treatment and for at least 12 weeks after the last dose of study drug, such method of birth control defined as one that results in a low failure rate (i.e., less than 1% per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some intrauterine devices, sexual abstinence (abstinence is acceptable when it is in line with the patient's preferred and usual lifestyle and is defined as complete abstinence of sexual intercourse, not periodic abstinence or withdrawal), or vasectomized partner.
- Male patients must be willing to avoid fathering children for at least 12 weeks following the last dose of study medication.
Who cannot join
- All treatments for HSCT-TMA are allowed except eculizumab, ravulizumab, and defibrotide within 3 months prior to informed consent, unless failure of therapy can be documented.
- Patients may not be on eculizumab, ravulizumab, or defibrotide for any indication at screening.
- Have Shiga toxin-producing Escherichia coli haemolytic uraemic syndrome (STEC-HUS). Test results obtained within 28 days prior to informed consent may be used.
- Have ADAMTS13 activity < 10%. Test results obtained within 28 days prior to informed consent may be used.
- Have a severe, uncontrolled systemic bacterial or fungal infection requiring antimicrobial therapy, or a severe uncontrolled viral infection (as determined by the investigator); prophylactic antimicrobial therapy administered as standard of care is allowed.
- Have malignant hypertension (blood pressure [BP] > 99th percentile plus 5 mmHg with bilateral hemorrhages or "cotton-wool" exudates on fundoscopic examination).
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- Due to conditions other than HSCT-TMA, have a poor prognosis with a life expectancy of less than 3 months in the opinion of the Investigator.
- If pregnant or lactating.
- Have received treatment with an investigational drug or device within 4 weeks of entering study.
- Have abnormal liver function tests defined as alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 5 times ULN within 28 days prior to informed consent.
- Have a positive test by antigen or polymerase chain reaction (PCR) for human immunodeficiency virus (HIV), if negative within 28 days prior to informed consent, the test does not need to be repeated.
- Patient or one or more of the patient's parents or legal guardians are is an employee or an immediate family member of Omeros, the Clinical Research Organization (CRO), an Investigator, or a study staff member.
- Have a known hypersensitivity to any constituent of the product.
- Presence of any condition that the Investigator believes would put the patient at risk.
Trial locations and contacts
16 sites in 5 countries. Contact the study team or a site near you to ask about taking part.
16 sites in 5 countries
United States8 sites, 8 recruiting
- Not yet recruiting
Omeros Investigational Site
Boston, Massachusetts, 02215
- Not yet recruiting
Omeros Investigational Site
Gainesville, Florida, 32608
- Not yet recruiting
Omeros Investigational Site
Houston, Texas, 77030
- Not yet recruiting
Omeros Investigational Site
New York, New York, 10065
- Recruiting
Omeros Investigational Site
San Diego, California, 92024
- Not yet recruiting
Omeros Investigational Site
Seattle, Washington, 98105
- Recruiting
Omeros Investigational Site
St Louis, Missouri, 63104
- Recruiting
Omeros Investigational Site
Valhalla, New York, 10595
Israel4 sites, 4 recruiting
- Not yet recruiting
Omeros Investigational Site
Haifa
- Not yet recruiting
Omeros Investigational Site
Jerusalem
- Not yet recruiting
Omeros Investigational Site
Ramat Gan
- Not yet recruiting
Omeros Investigational Site
Tel Aviv
Germany2 sites, 2 recruiting
- Not yet recruiting
Omeros Investigational Site
Halle
- Not yet recruiting
Omeros Investigational Site
Hanover
Netherlands1 site, 1 recruiting
- Not yet recruiting
Omeros Investigational Site
Utrecht
About this study
Official title: A Phase 2 Study Evaluating the Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Narsoplimab in Pediatric Patients (28 Days to ≤ 18 Years of Age.) With High-Risk Hematopoietic Stem Cell Transplant Thrombotic Microangiopathy
The purpose of this study is to evaluate the safety and efficacy of narsoplimab in pediatric patients with thrombotic microangiopathies (TMA) following hematopoietic stem cell transplant (HSCT).
Read the detailed description
This is a Phase 2, uncontrolled, single-dosing regimen study in pediatric patients from 28 days to less than 18 years of age with high risk HSCT-TMA. At least 4 patients will be required from each of 3 age cohorts:
28 days to <2 years of age, 2 years to <12 years of age, and 12 years to <18 years of age.
Treatment will be for 8 weeks and patients will be followed for up to 52 weeks.
- Being tested
- Biological: narsoplimab
- Keywords
- TMA, HSCT, Pediatric, BMT, OMS721, Narsoplimab
- Medical subject headings
- Thrombotic Microangiopathies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Biological: narsoplimabDrug
Also called Narsoplimab
Treatment with narsoplimab 4 mg/kg will be administered
| Study group | Role | What they receive |
|---|---|---|
| Narsoplimab single arm-treatment | Experimental | Narsoplimab 4 mg/kg Receives: Drug: Biological: narsoplimab |
What is being measured
The primary outcome is the main question the study is designed to answer.
100-day survival rate following high-risk HSCT-TMA diagnosis.
Percentage of patients alive at 100 days following the diagnosis of high-risk HSCT-TMA
Measured: 100 days
Secondary outcomes (6)
Number of participants with treatment-emergent adverse events assessed by CTCAE v5.0
Number and percentage of patients with treatment-emergent adverse events will be summarized by MedDRA system organ class and preferred term
Measured: 52 weeks
Percentage of patients meeting protocol definition of clinical response
A responder is defined as a patient with HSCT-TMA who demonstrates improvement in laboratory TMA markers (platelet count and LDH) and clinical benefit (either improvement in organ function or reduction in transfusion burden)
Measured: 52 weeks
52 week survival rate following high-risk HSCT-TMA diagnosis
Percentage of patients alive at 52 weeks following the diagnosis of high-risk HSCT-TMA
Measured: 52 weeks
Overall survival following the diagnosis of high-risk HSCT-TMA
Median overall survival (days) following the diagnosis of high-risk HSCT-TMA by Kaplan-Meier estimate
Measured: 52 weeks
Pharmacokinetics (PK) of multiple-dose administration of OMS721
PK parameters including maximum concentration and minimum (trough) concentration
Measured: 52 weeks
Presence of anti-drug antibody (ADA)
Number and percentage of patient with at least one ADA positive sample
Measured: 52 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 May 2023
- Study start1 May 2023
- Primary completionDec 2025 (estimated)
- Study completionDec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Thrombotic MicroangiopathiesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Omeros Corporation
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05855083
- Sponsor's protocol ID
- OMS721-HCT-002
- Status last verified
- Mar 2025
- First submitted
- 6 Apr 2023
- Last updated
- 25 Mar 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
- Expanded access
- Available
Study at a glance
From the registry record, last updated by the sponsor on 25 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2 Study Evaluating the Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Narsoplimab in Pediatric Patients (28 Days to ≤ 18 Years of Age.) With High-Risk Hematopoietic Stem Cell Transplant Thrombotic Microangiopathy
- ClinicalTrials.gov ID
- NCT05855083
- Acronym / sponsor ID
- OMS721-HCT-002
- Keywords
- TMA, HSCT, Pediatric, BMT, OMS721, Narsoplimab
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- Omeros CorporationIndustry (pharma, biotech, devices)
- Study start
- 1 May 2023 (actual)
- Primary completion
- Dec 2025 (estimated)
- Study completion
- Dec 2025 (estimated)
- First posted
- 11 May 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to evaluate the safety and efficacy of narsoplimab in pediatric patients with thrombotic microangiopathies (TMA) following hematopoietic stem cell transplant (HSCT).
Detailed description
This is a Phase 2, uncontrolled, single-dosing regimen study in pediatric patients from 28 days to less than 18 years of age with high risk HSCT-TMA. At least 4 patients will be required from each of 3 age cohorts:
28 days to <2 years of age, 2 years to <12 years of age, and 12 years to <18 years of age.
Treatment will be for 8 weeks and patients will be followed for up to 52 weeks.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Narsoplimab single arm-treatment | Experimental | Drug: Biological: narsoplimabNarsoplimab 4 mg/kg |
Who may qualify
- Ages
- 28 days to 17 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (20 listed)
- Age at least 28 days and less than 18 years prior to informed consent (Visit 0).
- Have informed consent from at least one parent or legal guardian as required by local law and regulation. Patient informed consent will be required if the patient has reached the local legal age of majority.
- Assent from patients as required by local law and regulation.
- Have received an allogeneic hematopoietic stem cell transplant for the treatment of benign or malignant disease.
- Have a diagnosis of HSCT-TMA defined as meeting both of the following criteria:
Key exclusion criteria (14 listed)
- All treatments for HSCT-TMA are allowed except eculizumab, ravulizumab, and defibrotide within 3 months prior to informed consent, unless failure of therapy can be documented.
- Have Shiga toxin-producing Escherichia coli haemolytic uraemic syndrome (STEC-HUS). Test results obtained within 28 days prior to informed consent may be used.
- Have ADAMTS13 activity < 10%. Test results obtained within 28 days prior to informed consent may be used.
- Have a severe, uncontrolled systemic bacterial or fungal infection requiring antimicrobial therapy, or a severe uncontrolled viral infection (as determined by the investigator); prophylactic antimicrobial therapy administered as standard of care is allowed.
- Have malignant hypertension (blood pressure [BP] > 99th percentile plus 5 mmHg with bilateral hemorrhages or "cotton-wool" exudates on fundoscopic examination).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Biological: narsoplimabAlso: NarsoplimabTreatment with narsoplimab 4 mg/kg will be administered | Drug | Narsoplimab single arm-treatment |
Primary outcome
100-day survival rate following high-risk HSCT-TMA diagnosis.
Time frame: 100 days
Percentage of patients alive at 100 days following the diagnosis of high-risk HSCT-TMA
6 secondary outcomes
Number of participants with treatment-emergent adverse events assessed by CTCAE v5.0
Time frame: 52 weeks
Percentage of patients meeting protocol definition of clinical response
Time frame: 52 weeks
52 week survival rate following high-risk HSCT-TMA diagnosis
Time frame: 52 weeks
Overall survival following the diagnosis of high-risk HSCT-TMA
Time frame: 52 weeks
Pharmacokinetics (PK) of multiple-dose administration of OMS721
Time frame: 52 weeks
Presence of anti-drug antibody (ADA)
Time frame: 52 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Mar 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
16 sites in 5 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Biological: narsoplimab in people with Thrombotic Microangiopathies and Hematopoietic Stem Cell Transplantation, run by Omeros Corporation at 16 sites in 5 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 20 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 25 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 16 sites in United States, Israel, Germany, Netherlands, Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Omeros Clinical Trial Information (206-676-5000, ctinfo@omeros.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
100-day survival rate following high-risk HSCT-TMA diagnosis. (time frame: 100 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Mar 2025.