FcRn blocker therapies for generalized myasthenia gravis
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Criteria and authorization requirements for medical benefit use of FcRn blockers (Imaavy, Rystiggo, Vyvgart, Vyvgart Hytrulo) to treat generalized myasthenia gravis (gMG) in specified antibody-positive patients; affects prescribers and prior authorization reviewers.
Imaavy (nipocalimab-aahu) was added for intravenous (IV) administration and listed among applicable drug products administered by a healthcare professional.
Revised list of concomitant drug products patients must not be receiving in combination with Imaavy, Rystiggo, Vyvgart, and Vyvgart Hytrulo to include CD19-directed cytolytic antibodies and to update FcRn blocker examples.
Coverage criteria for Vyvgart and Vyvgart Hytrulo were revised; removed criterion requiring a minimum 50-day interval between treatment cycles.
Coverage Criteria for FcRn Blockers
inv-01: Imaavy Initial Therapy
Imaavy (nipocalimab-aahu) is medically necessary when ALL of the following are met:
For Medicare reviews, refer to CMS section.
inv-02: Imaavy Continuation Therapy
Imaavy continuation is allowed when ALL of the following are met:
Documentation of MG-ADL change and IST status required in records.
inv-03: Rystiggo Initial Therapy
Rystiggo (rozanolixizumab-noli) is medically necessary when ALL of the following are met:
inv-04: Rystiggo Continuation Therapy
Rystiggo continuation is allowed when ALL of the following are met:
inv-05: Vyvgart Initial and Continuation Therapy
Vyvgart (efgartigimod alfa-fcab) and Vyvgart Hytrulo are medically necessary when ALL of the following are met:
For Medicare reviews, refer to CMS section.
inv-06: Vyvgart / Vyvgart Hytrulo initial therapy for refractory gMG
Covered when ALL of the following are met:
Medicare reviews refer to CMS section.
inv-07: Vyvgart / Vyvgart Hytrulo continuation for gMG
Covered when ALL of the following are met:
Continuation requires documentation of sustained benefit; reauthorization ≤ 12 months.
inv-08: Vyvgart Hytrulo initial therapy for CIDP
Vyvgart Hytrulo is medically necessary for CIDP when ALL of the following are met:
Electrodiagnostic specifics provided in policy.
For Medicare reviews, refer to CMS section.
inv-09: Vyvgart Hytrulo continuation for CIDP
Covered when ALL of the following are met:
Dosing per US FDA label and prescribed by/with neurologist; reauthorization for no more than 12 months.
inv-10: Imaavy (nipocalimab-aahu) Initial Therapy
Covered when ALL of the following are met
Referenced drug classes/examples provided in policy.
inv-11: Imaavy Continuation Therapy
Covered when ALL of the following are met
Documentation of MG-ADL and IST changes required.
inv-12: CIDP (efgartigimod alfa + hyaluronidase) Evidence and Diagnostic Criteria
Clinical trial and diagnostic context
Electrodiagnostic numeric cutoffs provided in policy.
Use of FcRn blockers in combination with certain other immunomodulatory agents is explicitly excluded. Specifically, patients must not be receiving these FcRn blocker products in combination with a CD19-directed cytolytic antibody (e.g., Uplizna/inebilizumab), a complement inhibitor (e.g., eculizumab, ravulizumab, zilucoplan), another FcRn blocker (examples include Rystiggo, Vyvgart, Vyvgart Hytrulo, Imaavy), or an immune globulin (e.g., Hizentra, Privigen, Gammagard).
Rystiggo has an operational timing restriction: doses must not be administered sooner than 63 days from the start of the previous treatment cycle. This interval is reiterated for continuation requests and should be checked during prior authorization and refill reviews to ensure dosing cadence meets the policy requirement.
In summary, combination use of FcRn blockers with the following classes is disallowed: CD19-directed cytolytic antibodies, complement inhibitors, other FcRn blockers, and immune globulins. The policy lists specific examples for each class (e.g., Uplizna; eculizumab, ravulizumab, zilucoplan; Imaavy, Rystiggo, Vyvgart, Vyvgart Hytrulo; Hizentra, Privigen, Gammagard) and prior authorization reviews should flag any concurrent therapy from these groups as noncompliant with coverage criteria.
Policy revisions update the combination-exclusion language to explicitly include Imaavy (nipocalimab-aahu) among FcRn blocker examples and to add CD19-directed cytolytic antibodies to the prohibited-concomitant list. These operational changes affect prior authorization checks and should be used when verifying that a patient is not receiving any prohibited agent concurrently with the requested therapy.
Requests that propose initiating or continuing FcRn blocker therapy without the required prior therapy history, or that document concurrent use of any excluded agents, are not supported by the policy and are subject to denial. Reviewers should cite the absence of documented failures of required immunosuppressive therapies or the presence of a prohibited concomitant agent when issuing an operational denial.
The policy revisions specifically removed a prior 50-day interval requirement for Vyvgart/Vyvgart Hytrulo cycles and standardized the prohibited-concomitant therapy lists across agents. Operationally, this means reviewers should no longer enforce a 50-day minimum interval for Vyvgart products but must continue to enforce updated combination-exclusion checks that now list CD19-directed cytolytic antibodies and revised FcRn blocker examples.
Billing and Diagnosis Codes
| G61.81 | Chronic inflammatory demyelinating polyneuritis. |
| G70.00 | Myasthenia gravis without (acute) exacerbation. |
| G70.01 | Myasthenia gravis with (acute) exacerbation. |
| No codes listed |
Provider Requirements and Prior Authorization
Imaavy prior authorization requirements
Prior authorization is required for initial Imaavy (nipocalimab) therapy. Submit complete medical records (chart notes, laboratory values, antibody test results, MG-ADL score, MGFA classification, prior therapy history) to support the request. Initial approvals will be for up to 12 months.
- Imaavy requests must include documentation of diagnosis of generalized myasthenia gravis (gMG).
- Provide positive serologic testing for anti-AChR or anti-MuSK antibodies when applicable.
- Include MGFA clinical classification and baseline MG-ADL total score.
Requests missing required documentation (diagnosis, antibody testing, MGFA class, MG-ADL)
Requests lacking required diagnostic documentation risk denial. Ensure submission includes chart notes confirming diagnosis, antibody testing results, MGFA class, baseline MG-ADL score, and prior treatment history.
- Missing antibody testing, MG-ADL, or MGFA classification may result in denial.
- Document that the patient has not failed prior course of the same agent when applicable.
Use of listed FcRn blockers and other agents in combination prohibited
Imaavy must not be given in combination with other listed FcRn blockers or certain other immunotherapies. Concurrent use with these agents is prohibited and may result in denial.
- Do not combine Imaavy with other FcRn blockers (examples: Rystiggo/rozanolixizumab, Vyvgart/efgartigimod alfa-fcab, Vyvgart Hytrulo).
- Concurrent administration with CD19-directed cytolytic antibodies, complement inhibitors, or immune globulin is also prohibited.
Concurrent therapy exclusion
Concurrent therapy exclusion: Imaavy must not be used concurrently with CD19-directed cytolytic antibodies, complement inhibitors, other FcRn blockers, or immune globulin. Requests indicating concurrent use will be operationally denied.
- Examples of excluded agents: Uplizna (inebilizumab), eculizumab, Ultomiris (ravulizumab), Zilbrysq (zilucoplan), Hizentra, Privigen, Gammagard.
Submit medical records (chart notes, laboratory values, MG-ADL, MGFA, prior therapy history)
Submit full medical records to support initial and continuation requests. Include chart notes, laboratory tests, documented antibody results, MG-ADL scores (baseline and on-therapy), MGFA classification, and detailed prior therapy history including durations and outcomes.
- Initial requests: diagnosis confirmation, antibody positivity, MGFA class, baseline MG-ADL, prior immunosuppressant trial history (agents, durations, outcomes).
- Continuation requests: on-treatment MG-ADL demonstrating ≥2 point improvement or maintenance from baseline, documentation of symptom reduction, and evidence of maintenance/reduction/discontinuation of baseline immunosuppressive therapy.
For continuation, submit records demonstrating ≥2 point MG-ADL improvement (or maintenance) and IST changes
For continuation of Imaavy, submit records demonstrating clinical improvement or maintenance. Required evidence includes objective MG-ADL change, reduction in signs/symptoms, and immunosuppressant dosing changes consistent with response.
- Continuation approval requires demonstration of at least a 2-point improvement (reduction) in MG-ADL from pre-treatment baseline, or maintenance of prior benefit.
- Also submit notes showing reduction in MG signs/symptoms and maintenance/reduction/discontinuation of baseline IST. Addition or escalation of IST or need for rescue therapy while on Imaavy is considered treatment failure.
Clinical Background and Mechanism
Generalized myasthenia gravis (gMG) is an antibody-mediated neuromuscular disorder in which pathogenic IgG autoantibodies impair neuromuscular transmission. FcRn blockers (agents such as efgartigimod, nipocalimab, rozanolixizumab) bind the neonatal Fc receptor (FcRn) and reduce circulating IgG levels, thereby lowering pathogenic autoantibody concentrations. This mechanism underpins the clinical rationale for using FcRn blockers in antibody-positive gMG and informs policy requirements linking treatment eligibility to antibody status, baseline severity (e.g., MG-ADL ≥ 5, MGFA class II–IV), and prior therapy failure pathways.
Definitions and Clinical Scales
Policy Revision History
Policy retitled and updated to add Imaavy (nipocalimab-aahu) for intravenous (IV) administration and revise the list of applicable drug products administered by a healthcare professional.
Revised the list of drug products patients must not be receiving in combination with Rystiggo, Vyvgart, Vyvgart Hytrulo, and Imaavy to add CD19-directed cytolytic antibodies and update FcRn blocker examples (including Imaavy in FcRn blocker lists).
Removed the coverage criterion that required a minimum 50-day interval between Vyvgart or Vyvgart Hytrulo treatment cycles.
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