Narsoplimab

Narsoplimab-wuug inhibits MASP-2, the effector enzyme of the lectin pathway of the complement system, blocking lectin-dependent activation of complement component 3 (C3) and C4 without affecting the classical and alternative pathways of complement. In hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), MASP-2 inhibition is thought to prevent lectin pathway-mediated cellular injury, including endothelial cell injury in small blood vessels.

• YARTEMLEA is indicated for the treatment of adult and pediatric patients 2 years of age and older with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA). YARTEMLEA is a MASP-2 inhibitor indicated for the treatment of adult and pediatric patients 2 years of age and older with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA).

• None None ( 4 )contraindicated

Weight (kg) Recommended Dosage Greater than or equal to 50 kg 370 mg given as an intravenous infusion over 30 minutes once weekly. Increase frequency to twice weekly if there is inadequate improvement in TA-TMA signs and symptoms. ( 2.1 ) Less than 50 kg 4 mg/kg given as an intravenous infusion over 30 minutes once weekly. Increase frequency to twice weekly if there is inadequate improvement in TA-TMA signs and symptoms. ( 2.1 ) See Full Prescribing Information for instructions on preparation and administration. ( 2.2 , 2.3 , 2.4 , 2.5 ) 2.1 Recommended Dosage The recommended dosage of YARTEMLEA is provided in Table 1 . Table 1: Recommended Dosage of YARTEMLEA in Adult and Pediatric Patients Two Years of Age and Older with TA-TMA Weight (kg) Recommended Dosage Greater than or equal to 50 kg 370 mg given as an intravenous infusion over 30 minutes once weekly. Increase frequency to twice weekly if there is inadequate improvement in TA-TMA signs and symptoms. Less than 50 kg 4 mg/kg given as an intravenous infusion over 30 minutes once weekly. Increase frequency to twice weekly if there is inadequate improvement in TA-TMA signs and symptoms. If a dose is missed, administer the dose as soon as possible. Thereafter, resume dosing at the regular scheduled time. 2.2 Important Preparation and Administration Instructions Administer diluted YARTEMLEA as an intravenous infusion through a polyvinyl chloride (PVC) or PVC-lined infusion line with a 0.2-micron polyethersulfone (PES) in-line filter and a polyurethane catheter.

Serious infections: Monitor patients for signs/symptoms and treat appropriately. ( 5.1 ) 5.1 Serious Infections Serious and life-threatening infections have occurred in patients treated with YARTEMLEA. Serious infections, independent of causality, were reported in 36% (10/28) of patients with TA-TMA receiving YARTEMLEA in clinical trials. These infections included sepsis, viral infections, pneumonia, bacteremia, fungal infection, gastroenteritis, respiratory tract infection and urosepsis. If YARTEMLEA is administered to patients with active infections, monitor closely for signs and symptoms of worsening infection and treat promptly.

The following clinically significant adverse reactions are described elsewhere in the labeling: Serious Infections [see Warnings and Precautions ( 5.1 )] Most common adverse reactions (incidence > 20% and independent of causality) are viral infections, sepsis, hemorrhage, diarrhea, vomiting, nausea, neutropenia, pyrexia, fatigue and hypokalemia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Omeros Corporation at 1-844-YARTEM1 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety data described in this section reflect exposure to YARTEMLEA in the TA-TMA Study in which 28 adult patients received YARTEMLEA. In total, 24 patients received YARTEMLEA at a dose of 4 mg/kg intravenously once weekly for 4 or 8 weeks and 4 patients received 370 mg intravenously weekly for 8 weeks [see Clinical Studies ( 14 )] . The median duration of treatment with YARTEMLEA was 8 weeks (range: 2 to 16.4 weeks). Serious adverse reactions were reported in 61% of patients receiving YARTEMLEA. Serious adverse reactions in > 5% of patients who received YARTEMLEA included acute kidney injury, confusional state, acute respiratory failure, neutropenic sepsis, septic shock, pulmonary edema, and vomiting. Fatal adverse reactions occurred in 7% of patients, including neutropenic sepsis and septic shock.

8.1 Pregnancy Risk Summary The available data on the use of YARTEMLEA during pregnancy are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. In animal reproduction studies, narsoplimab-wuug was administered subcutaneously and intravenously twice weekly to pregnant mice and rabbits during organogenesis at dose exposures up to 22 and 91-fold, respectively, the human exposure at the maximum recommended human dose (MRHD) based on area under the concentration-time curve (AUC). There were no adverse effects observed in the absence of maternal toxicity (see Data ) . The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Transport of endogenous IgG antibodies across the placenta increases as pregnancy progresses and peaks during the third trimester. Therefore, it is expected that YARTEMLEA, following administration, will be present in infants exposed in utero during the third trimester.

Metabolism

The PK profile of narsoplimab-wuug has been characterized in healthy subjects and in patients. PK of narsoplimab-wuug is less than dose-proportional for 2 and 4 mg/kg weekly IV dosing, with an accumulation ratio ranging from 1.02 to 1.75 at 4 mg/kg IV weekly dosing.

There is no known antidote for YARTEMLEA and YARTEMLEA is not dialyzable. If an overdose occurs, institute general supportive measures. Consider contacting the Poison Help line (1-800-222-1222) or a medical toxicologist for additional overdose management recommendations.

• Dec 23, 2025BLABLA761152Omeros Corp

1. 1Thrombotic Microangiopathy321%
2. 2Disease Recurrence214%
3. 3Drug Ineffective214%
4. 4Gastrointestinal Haemorrhage214%
5. 5Hypertension214%
6. 6Respiratory Failure214%
7. 7Thrombocytopenia214%
8. 8Acute Kidney Injury17.1%
9. 9Acute Respiratory Distress Syndrome17.1%
10. 10Acute Respiratory Failure17.1%
11. 11Allogenic Stem Cell Transplantation17.1%
12. 12Blood Creatinine Increased17.1%
13. 13Bone Marrow Failure17.1%
14. 14Candida Infection17.1%
15. 15Cardiac Arrest17.1%

The 8 most recently updated of 8 ClinicalTrials.gov registrations naming Narsoplimab as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Safety Study of IgAN, LN, MN, & C3 Glomerulopathy Including Dense Deposit Disease Treated With OMS721
  Terminated · Phase 2 · Interventional · 31 enrolled · Omeros Corporation
  NCT02682407updated 2026-03-30
• I-SPY COVID-19 TRIAL: An Adaptive Platform Trial for Critically Ill Patients
  Active not recruiting · Phase 2 · Interventional · 1,500 enrolled · QuantumLeap Healthcare Collaborative
  NCT04488081updated 2026-03-16
• Single Patient Expanded Access Treatment Plan For The Investigational Product Narsoplimab
  Approved for marketing · Expanded access · Omeros Corporation
  NCT04247906updated 2026-03-05
• Safety and Efficacy Study of OMS721 in Patients With Atypical Hemolytic Uremic Syndrome
  Terminated · Phase 3 · Interventional · 6 enrolled · Omeros Corporation
  NCT03205995updated 2025-12-10
• Study of the Safety and Efficacy of OMS721 in Patients With Immunoglobulin A (IgA) Nephropathy
  Terminated · Phase 3 · Interventional · 360 enrolled · Omeros Corporation
  NCT03608033updated 2025-12-09
• Efficacy and Safety Study of Narsoplimab in Pediatric Patients With High-Risk Hematopoietic Stem Cell Transplant TMA
  Recruiting · Phase 2 · Interventional · 18 enrolled · Omeros Corporation
  NCT05855083updated 2025-03-25
• Safety and Efficacy Study of OMS721 in Patients With Thrombotic Microangiopathies
  Completed · Phase 2 · Interventional · 58 enrolled · Omeros Corporation
  NCT02222545updated 2024-08-28
• OMS721 Compassionate Use in Patients With Thrombotic Microangiopathy
  Available · Expanded access · Michal Nowicki
  NCT02355782updated 2015-04-15

Frequently asked questions

How does Narsoplimab work?

Narsoplimab-wuug inhibits MASP-2, the effector enzyme of the lectin pathway of the complement system, blocking lectin-dependent activation of complement component 3 (C3) and C4 without affecting the classical and alternative pathways of complement. In hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), MASP-2 inhibition is thought to prevent lectin pathway-mediated cellular injury, including endothelial cell injury in small blood vessels.

What is Narsoplimab used for?

According to FDA labeling, Narsoplimab carries indications including: YARTEMLEA is indicated for the treatment of adult and pediatric patients 2 years of age and older with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA). YARTEMLEA is a MASP-2 inhibitor indicated for the treatment of adult and pediatric patients 2 years of age and older with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA).. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Narsoplimab?

Narsoplimab is classified as Antibody-Receptor Interactions, Complement Inhibitors, Decreased Complement Activity.

What are the brand names for Narsoplimab?

Narsoplimab is marketed under brand names including Yartemlea.

What are the contraindications for Narsoplimab?

Narsoplimab labeling lists contraindications including: None None ( 4 ). Always consult the full prescribing information and a clinician.