Yartemlea (narsoplimab-wuug) for TA-TMA
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Medical policy governing coverage and authorization criteria for Yartemlea (narsoplimab-wuug) for treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) in patients aged 2 years and older for Blue Cross of Idaho members.
New policy added to Prescription Drug section specifying that intravenously administered Yartemlea (narsoplimab-wuug) may be considered medically necessary when specified criteria are met for TA-TMA.
Coverage Criteria for Yartemlea (narsoplimab-wuug)
Initial Therapy — Covered when ALL of the following are met
Covered when ALL of the following are met:
Continuation Therapy — Covered when ALL of the following are met
Covered when ALL of the following are met:
Initial coverage stance — Covered when ALL of the following are met
Covered when ALL of the following are met
Full criteria set appears elsewhere in the policy.
The drug has a known safety concern for infectious complications. Yartemlea carries warnings for serious infections including sepsis, viral infections, pneumonia, bacteremia, fungal infections, gastroenteritis, respiratory tract infections, and urosepsis. If administered to a patient with an active infection, the patient should be closely monitored for worsening infection and treated promptly.
No specific exclusions are listed in the provided document fragment. The codes and coding guidance note that inclusion or exclusion of a code in the document does not itself determine coverage — benefit determinations remain subject to the member-specific benefit plan and the formal written coverage position.
Requests for Yartemlea that do not meet the policy's stated initiation or continuation criteria may be denied. Typical reasons for denial include failure to document age ≥ 2 years, lack of documented TA-TMA diagnosis or post‑HSCT status, insufficient diagnostic confirmation (no biopsy or fewer than the required diagnostic features), failure to rule out alternative diagnoses, lack of specialist involvement or consultation, or a requested quantity that exceeds the policy limit (see dosing/quantity limits).
Within the text fragment provided there are no explicit statements listing conditions as not medically necessary. Coverage guidance emphasizes that determinations depend on whether the initiation and continuation criteria are satisfied and on member-specific plan terms.
Initial Therapy Details and Requirements
Initial Therapy Details — initial therapy criteria and dosing/limits
Dosing and limits are per Dosing Information and Limits to treatment sections.
Initial therapy — 1 top-level node
Detailed criteria are provided in the Initial Therapy block elsewhere in the policy.
Criteria for Continuing Therapy
Continuation of Therapy — continuation may be approved when prior initiation criteria were met and patient shows clinical benefit
Continuation may be approved when prior initiation criteria were met and patient shows clinical benefit:
See Dosing Information and Limits to treatment for dosing and quantity limits.
Continuation therapy — 1 top-level node
See full policy for detailed continuation criteria.
Quantity Limits and Dosing
Coding and Billing Information
| No codes listed |
| C9399 | Unclassified drugs or biologicals |
| M31.11 | Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (TA-TMA) |
| XW03357 | Introduction of narsoplimab monoclonal antibody into a peripheral vein |
| XW04357 | Introduction of narsoplimab monoclonal antibody into a central vein |
| C9399 | Unclassified drugs or biologicals |
| M31.11 | Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (TA-TMA) |
| XW03357 | Introduction of narsoplimab monoclonal antibody into a peripheral vein |
| XW04357 | Introduction of narsoplimab monoclonal antibody into a central vein |
Prior Authorization, Documentation, and Provider Responsibilities
Prior authorization required — demonstrate initiation or continuation criteria (age ≥2 years and confirmed TA‑TMA)
Submit a prior authorization request demonstrating the patient meets the policy's initiation or continuation criteria, including that the patient is at least 2 years of age and has a documented diagnosis of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) with post‑HSCT status and diagnostic confirmation per policy.
- Age ≥ 2 years required (Initial Treatment I).
- Documented diagnosis of TA-TMA and that the patient is post‑HSCT (Initial Treatment II–III).
- Provide evidence of diagnostic confirmation (histology or ≥4 diagnostic features) and that requested quantity does not exceed 24 vials/12 weeks.
Prior authorization required — IV Yartemlea requires prior auth and is medically necessary when criteria met
Prior authorization is required for intravenous Yartemlea (narsoplimab‑wuug); when the specified initiation or continuation criteria are met the therapy is considered medically necessary for TA‑TMA.
Required documentation for authorization — supply diagnostic, post‑HSCT, confirmation, and evaluation details
Include documentation with the authorization request showing TA‑TMA diagnosis, post‑HSCT status, diagnostic confirmation (histology or at least four diagnostic features), evaluation/management of alternative diagnoses and TA‑TMA triggers, specialist involvement, and requested quantity consistent with dosing limits.
- Diagnostic confirmation: histological evidence of microangiopathy OR presence of ≥4 diagnostic features (e.g., anemia, thrombocytopenia, elevated LDH, schistocytes, hypertension, elevated sC5b‑9, renal dysfunction such as rUPCR ≥ 1 mg/mg).
- Documentation that alternative diagnoses have been ruled out and TA‑TMA triggers have been evaluated and are being managed.
- Evidence the prescriber is a specialist or that a specialist was consulted, and that the requested quantity does not exceed 24 vials for 12 weeks.
Coding/documentation guidance — align codes with benefit plan; listed codes for reference
Ensure coding and claim documentation align with the member's benefit plan and this medical policy; the policy provides codes for reference but inclusion does not guarantee coverage or reimbursement.
Denial risk — requests not meeting initiation/continuation criteria may be denied
Requests that do not meet the policy's initiation or continuation criteria may be denied; this includes failures such as age <2 years, insufficient diagnostic confirmation, not post‑HSCT, lack of specialist involvement, or requested quantity exceeding limits.
- Denials may be issued if diagnostic confirmation (histology or ≥4 features) is not provided.
- Denials may be issued if requested quantity exceeds 24 vials per 12 weeks.
Coverage subject to benefit plan — codes do not guarantee coverage or reimbursement
Inclusion of a code in the policy's coding section does not guarantee member coverage or provider reimbursement; coverage determinations remain subject to the member‑specific benefit plan and policy terms.
- Verify member benefit plan documentation and any additional terms or requirements before assuming coverage.
- Codes provided are for general reference and may not be all‑inclusive.
Provider action — document specialist prescriber or specialist consultation
For authorization, ensure the prescriber is a specialist in the patient's diagnosis (e.g., hematologist) or document that a specialist consultation has occurred as required by the policy.
- Specialist involvement is listed as a required element (Initial Treatment VII).
- If the prescriber is not a specialist, include consult notes documenting specialist input.
Provider action — verify and document dosing and quantity limits before authorization
Confirm and document that the requested quantity and proposed dosing conform to policy limits (maximum 24 vials for a 12‑week course and dosing per weight: 4 mg/kg IV once weekly if <50 kg; 370 mg IV once weekly if ≥50 kg).
- Dosing: <50 kg = 4 mg/kg IV weekly; ≥50 kg = 370 mg IV weekly; increase to twice weekly if inadequate improvement.
- Quantity limit: 24 vials for 12 weeks (initial treatment limit).
Place of Service and Administration
Infusion: IV administration (FDA‑approved); site not restricted
IV administration is the approved route of administration for Yartemlea; the policy does not restrict specific infusion site of care in the provided text.
- Yartemlea is the FDA‑approved IV monoclonal antibody for TA‑TMA in patients 2 years and older.
- No site‑of‑care restriction is specified in the policy fragment.
Infusion place of service and ICD‑10‑PCS coding guidance
Place of service for infusion may be outpatient or inpatient; ICD‑10‑PCS procedure codes reference introduction of narsoplimab into a peripheral or central vein for coding purposes.
- Place of service listed includes outpatient and inpatient settings.
- ICD‑10‑PCS codes: XW03357 (peripheral vein) and XW04357 (central vein) are provided for reference.
Definitions and Terminology
Background on Yartemlea (narsoplimab-wuug)
Yartemlea (narsoplimab-wuug) is a humanized monoclonal antibody that functions as a MASP-2 inhibitor. By inhibiting mannan-binding lectin-associated serine protease‑2 (MASP‑2), it blocks activation of the lectin pathway of complement (reducing downstream C3/C4 activation), which is intended to prevent endothelial injury implicated in hematopoietic stem cell transplant‑associated thrombotic microangiopathy (TA‑TMA). The agent is FDA‑approved for adults and pediatric patients aged 2 years and older for this indication.
Policy Revision History
New policy added to the Prescription Drug section; Blue Cross of Idaho adopted the policy effective 2026-09-01 for intravenous Yartemlea (narsoplimab-wuug) for TA-TMA.
Policy became effective for coverage of intravenously administered Yartemlea (narsoplimab-wuug) when specified criteria are met for TA-TMA.
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