Efficacy and Safety Study of Narsoplimab in Pediatric Patients With High-Risk Hematopoietic Stem Cell Transplant TMA

March 24, 2025 updated by: Omeros Corporation

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).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
18

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Expanded Access

Expanded Access

A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration (FDA). Also called compassionate use. There are different expanded access types.
Available

Available

  • Available: Expanded access is currently available for this investigational treatment, and patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.
  • No longer available: Expanded access was available for this intervention previously but is not currently available and will not be available in the future.
  • Temporarily not available: Expanded access is not currently available for this intervention but is expected to be available in the future.
  • Approved for marketing: The intervention has been approved by the U.S. Food and Drug Administration for use by the public.
 outside the clinical trial. See expanded access record.

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Omeros Clinical Trial Information
  • Phone Number: 206-676-5000
  • Email: ctinfo@omeros.com

Study Locations

  • Germany
      • Halle, Germany
        • Not yet recruiting
        • Omeros Investigational Site
      • Hanover, Germany
        • Not yet recruiting
        • Omeros Investigational Site
  • Israel
      • Haifa, Israel
        • Not yet recruiting
        • Omeros Investigational Site
      • Jerusalem, Israel
        • Not yet recruiting
        • Omeros Investigational Site
      • Ramat Gan, Israel
        • Not yet recruiting
        • Omeros Investigational Site
      • Tel Aviv, Israel
        • Not yet recruiting
        • Omeros Investigational Site
  • Netherlands
      • Utrecht, Netherlands
        • Not yet recruiting
        • Omeros Investigational Site
  • Spain
      • Pamplona, Spain
        • Recruiting
        • Omeros Investigational Site
  • United States
    • California
      • San Diego, California, United States, 92024
        • Recruiting
        • Omeros Investigational Site
    • Florida
      • Gainesville, Florida, United States, 32608
        • Not yet recruiting
        • Omeros Investigational Site
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Not yet recruiting
        • Omeros Investigational Site
    • Missouri
      • Saint Louis, Missouri, United States, 63104
        • Recruiting
        • Omeros Investigational Site
    • New York
      • New York, New York, United States, 10065
        • Not yet recruiting
        • Omeros Investigational Site
      • Valhalla, New York, United States, 10595
        • Recruiting
        • Omeros Investigational Site
    • Texas
      • Houston, Texas, United States, 77030
        • Not yet recruiting
        • Omeros Investigational Site
    • Washington
      • Seattle, Washington, United States, 98105
        • Not yet recruiting
        • Omeros Investigational Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age at least 28 days and less than 18 years prior to informed consent (Visit 0).
  2. 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.
  3. Assent from patients as required by local law and regulation.
  4. Have received an allogeneic hematopoietic stem cell transplant for the treatment of benign or malignant disease.

  5. 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.
    • Evidence of microangiopathic hemolysis (presence of schistocytes, serum lactate dehydrogenase [LDH] > upper limit of normal ([ULN], or haptoglobin < lower limit of normal [LLN])

  6. 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)
  7. 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.
  8. Male patients must be willing to avoid fathering children for at least 12 weeks following the last dose of study medication.

Exclusion Criteria:

  1. 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.

    a. Patients may not be on eculizumab, ravulizumab, or defibrotide for any indication at screening.

  2. Have Shiga toxin-producing Escherichia coli haemolytic uraemic syndrome (STEC-HUS). Test results obtained within 28 days prior to informed consent may be used.
  3. Have ADAMTS13 activity < 10%. Test results obtained within 28 days prior to informed consent may be used.
  4. 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.
  5. Have malignant hypertension (blood pressure [BP] > 99th percentile plus 5 mmHg with bilateral hemorrhages or "cotton-wool" exudates on fundoscopic examination).
  6. 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.
  7. If pregnant or lactating.
  8. Have received treatment with an investigational drug or device within 4 weeks of entering study.
  9. Have abnormal liver function tests defined as alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 5 times ULN within 28 days prior to informed consent.
  10. 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.
  11. 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.
  12. Have a known hypersensitivity to any constituent of the product.
  13. Presence of any condition that the Investigator believes would put the patient at risk.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Narsoplimab single arm-treatment
Narsoplimab 4 mg/kg
Drug: Biological: narsoplimab
Treatment with narsoplimab 4 mg/kg will be administered
Other Names:
  • Narsoplimab

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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
100 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of participants with treatment-emergent adverse events assessed by CTCAE v5.0
Time Frame: 52 weeks
Number and percentage of patients with treatment-emergent adverse events will be summarized by MedDRA system organ class and preferred term
52 weeks
Percentage of patients meeting protocol definition of clinical response
Time Frame: 52 weeks
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)
52 weeks
52 week survival rate following high-risk HSCT-TMA diagnosis
Time Frame: 52 weeks
Percentage of patients alive at 52 weeks following the diagnosis of high-risk HSCT-TMA
52 weeks
Overall survival following the diagnosis of high-risk HSCT-TMA
Time Frame: 52 weeks
Median overall survival (days) following the diagnosis of high-risk HSCT-TMA by Kaplan-Meier estimate
52 weeks
Pharmacokinetics (PK) of multiple-dose administration of OMS721
Time Frame: 52 weeks
PK parameters including maximum concentration and minimum (trough) concentration
52 weeks
Presence of anti-drug antibody (ADA)
Time Frame: 52 weeks
Number and percentage of patient with at least one ADA positive sample
52 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Omeros Corporation

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 1, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 6, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 2, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 11, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 25, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 24, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • OMS721-HCT-002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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