ModifiedCentenePolicy CP.PHAR.411

Clinical Policy: Amifampridine (Firdapse)

Policy governs medical necessity criteria, dosing, and authorization requirements for amifampridine (Firdapse) for members of Centene-affiliated health plans across Commercial, HIM, and Medicaid lines of business, primarily for treatment of Lambert-Eaton myasthenic syndrome (LEMS).

Policy Summary

PayerCentene

PolicyAmifampridine (Firdapse) therapy for Lambert-Eaton myasthenic syndrome

Policy CodePolicy CP.PHAR.411

Change TypeMaterial revisions to approval duration and dosing/quantity controls

Effective Date01.22.19

Next Review Date

Key ActionPrior authorization required with documentation of diagnosis, confirmatory testing, neurologist involvement, age ≥6, baseline muscle strength assessment, absence of seizure history, and dose within plan limits.

SourceLink

POLICY UPDATE CHANGES

Revised initial approval duration from 6 to 12 months and added requirement that request does not exceed health plan-approved quantity limit, if applicable.

Modified maximum dose per updated prescribing information.

Added requirement that member does not have a history of seizures as use is contraindicated and applied to continued therapy.

Initial approval duration was revised from 6 to 12 months.

Age ≥ 6minimum FDA-approved and covered age

100 mg/daymax daily dose (≥45 kg)

50 mg/daymax daily dose (<45 kg)

12 monthsapproval duration

Commercial, HIM, Medicaidlines of business

Coverage Criteria

Initial Therapy

Initial Therapy — Covered when ALL of the following are met for Initial Approval (Lambert-Eaton Myasthenic Syndrome).

ALL of the following

Diagnosis of Lambert-Eaton Myasthenic Syndrome (LEMS).
- Repetitive Nerve Stimulation (RNS) testing showing reproducible post-exercise increase in compound muscle action potential (CMAP) amplitude of at least 60 percent compared with pre-exercise baseline value or a similar increment on high-frequency repetitive nerve stimulation without exercise.
- If member is unable to complete RNS testing, positive anti-P/Q type voltage-gated calcium channel (VGCC) antibody blood test.
Prescribed by or in consultation with a neurologist or neuromuscular specialist.
Age ≥ 6 years.
Documentation of a baseline clinical muscle strength assessment (examples include but are not limited to the Quantitative Myasthenia Gravis (QMG) score, triple-timed up-and-go test (3TUG), Timed 25-foot Walk test (T25FW)).
Member does not have a history of seizures.
Request does not exceed health plan-approved quantity limit, if applicable.
- Adults and pediatrics weighing ≥ 45 kg: 100 mg (10 tablets) per day.
- Pediatrics weighing < 45 kg: 50 mg (5 tablets) per day.

Continuation Therapy

Continuation Therapy — Covered when ALL of the following are met for Continued Therapy (LEMS).

ALL of the following

Member meets one of the following: currently receiving medication via Centene benefit or previously met initial approval criteria; or member is currently receiving medication and is enrolled in a state and product with continuity of care regulations (refer to state specific addendums for CC.PHARM.03A and CC.PHARM.03B).
Member is responding positively to therapy as evidenced by clinical muscle strength assessments (examples include but are not limited to the QMG score, 3TUG test, T25FW test).
Member does not have a history of seizures.
Request does not exceed health plan-approved quantity limit, if applicable.

Other/Off-label

Other/Off-label — Other diagnoses/indications.

ANY of the following

- For drugs on the formulary (commercial, health insurance marketplace) or PDL (Medicaid), refer to the no coverage criteria policy for the relevant line of business: CP.CPA.190 for commercial, HIM.PA.33 for health insurance marketplace, and CP.PMN.255 for Medicaid.
- For drugs NOT on the formulary (commercial, health insurance marketplace) or PDL (Medicaid), refer to the non-formulary policy for the relevant line of business: CP.CPA.190 for commercial, HIM.PA.103 for health insurance marketplace, and CP.PMN.16 for Medicaid.
If the requested use (e.g., diagnosis, age, dosing regimen) is NOT specifically listed under section III (Diagnoses/Indications for which coverage is NOT authorized) AND criterion 1 above does not apply, refer to the off-label use policy for the relevant line of business: CP.CPA.09 for commercial, HIM.PA.154 for health insurance marketplace, and CP.PMN.53 for Medicaid.

III. Diagnoses/Indications for which coverage is NOT authorized: Non‑FDA approved indications, which are not addressed in this policy, are not authorized unless there is sufficient documentation of efficacy and safety according to the off‑label use policies (CP.CPA.09 for commercial, HIM.PA.154 for health insurance marketplace, and CP.PMN.53 for Medicaid) or applicable evidence of coverage documents.

For Medicaid members, when state Medicaid coverage provisions conflict with the coverage provisions in this clinical policy, state Medicaid coverage provisions take precedence. Please refer to the state Medicaid manual for any coverage provisions pertaining to this clinical policy.

Non‑FDA approved indications that are not addressed in this policy are not authorized unless sufficient documentation of efficacy and safety is provided per the referenced off‑label use policies: CP.CPA.09 (commercial), HIM.PA.154 (health insurance marketplace), CP.PMN.53 (Medicaid).

Coding and Dosing

Product availability (strength)NDC

NDC unspecific

Tablet: 10 mg (product availability)

inv-08: Maximum daily dose — Adults and pediatrics ≥45 kg: 100 mg/day; Pediatrics <45 kg: 50 mg/day.

Maximum daily dose — Adults and pediatrics ≥45 kg100 mg/day (10 tablets)

Maximum daily dose — Pediatrics <45 kg50 mg/day (5 tablets)

Dose escalation guidanceAdults/pediatrics ≥45 kg: start 15–30 mg/day in 3–5 divided doses; increase by 5 mg every 3–4 days to a maximum of 100 mg/day

inv-09: Maximum single dose — Adults/pediatrics ≥45 kg: 20 mg; Pediatrics <45 kg: 10 mg.

Maximum single dose — Adults/pediatrics ≥45 kg20 mg

Maximum single dose — Pediatrics <45 kg10 mg

Provider Actions and Authorization

Prior Authorization

Prior Authorization Required

Prior authorization is required. Provider must submit documentation (such as office chart notes, lab results or other clinical information) supporting that the member has met all approval criteria, including diagnosis and confirmatory testing. Prescriptions must be by or in consultation with a neurologist or neuromuscular specialist when applicable.

Prior authorization required with documentation of diagnosis and confirmatory testing.
Prescribed by or in consultation with a neurologist or neuromuscular specialist when indicated.

Prior Authorization

Initial Approval Duration

Initial approvals will be granted for up to 12 months. Requests must not exceed health plan‑approved quantity limits, if applicable.

Background

Amifampridine (Firdapse) is a potassium channel blocker approved for the treatment of Lambert‑Eaton myasthenic syndrome (LEMS) in patients aged ≥6 years. Diagnosis of LEMS is supported by electrophysiologic testing such as repetitive nerve stimulation demonstrating the characteristic post‑exercise increment in compound muscle action potential (CMAP) amplitude, or by positive anti‑P/Q‑type voltage‑gated calcium channel (VGCC) antibody testing when RNS cannot be completed. Baseline and follow‑up clinical assessments (for example, Quantitative Myasthenia Gravis [QMG] score, 3‑Timed Up and Go [3TUG], or Timed 25‑Foot Walk [T25FW]) are used to document muscle strength and response to therapy.

Definitions and Assessment Criteria

inv-19: RNS increment criteria — Repetitive Nerve Stimulation (RNS): reproducible post‑exercise increase in CMAP amplitude thresholds.

RNS increment diagnostic thresholdReproducible post-exercise increase in CMAP amplitude of at least 60% vs pre-exercise baseline

Supportive vs diagnostic rangesIncrements of 60–99% are strongly supportive; >100% is considered diagnostic

Alternative high-frequency RNSA similar increment on high-frequency RNS without exercise fulfills the criterion

inv-20: Clinical assessment tools — QMG, 3TUG, T25FW used to assess baseline and response.

Primary clinical assessment toolsQuantitative Myasthenia Gravis (QMG) score, triple-timed up-and-go test (3TUG), Timed 25-foot Walk test (T25FW)

QMG description

Policy Summary

PayerCentene

PolicyAmifampridine (Firdapse) therapy for Lambert-Eaton myasthenic syndrome

Policy CodePolicy CP.PHAR.411

Change TypeMaterial revisions to approval duration and dosing/quantity controls

Effective Date01.22.19

Next Review Date

SourceLink

On This Page

Adults and pediatrics weighing ≥ 45 kg: 100 mg (10 tablets) per day.

Pediatrics weighing < 45 kg: 50 mg (5 tablets) per day.

Dosing frequencyTotal daily dose divided into 3 to 5 doses

Initial approval duration: 12 months.
Request does not exceed health plan‑approved quantity limit, if applicable.

Step Therapy

Step / Redirect for Other Diagnoses

If the requested use is not listed under covered indications and the drug has had a recent label change (within the last 6 months) that is not yet reflected in this policy, follow the referenced formulary/non‑formulary or off‑label use policies for the applicable line of business.

Refer to CP.CPA.190 (commercial formulary) or HIM.PA.33/CP.PMN.255 as applicable for formulary covered drugs.
For non‑formulary drugs, refer to CP.CPA.190/HIM.PA.103/CP.PMN.16 as applicable.
If criterion 1 does not apply, refer to off‑label use policies: CP.CPA.09 (commercial), HIM.PA.154 (HIM), CP.PMN.53 (Medicaid).

Denial Risk

Denial Triggers / Contraindications

Requests for non‑FDA approved indications that lack sufficient documentation of safety and efficacy per the applicable off‑label use policies will be denied. Use is contraindicated in members with a history of seizures or hypersensitivity to amifampridine or another aminopyridine.

Non‑FDA indications require sufficient documentation per CP.CPA.09, HIM.PA.154, or CP.PMN.53.
Contraindicated: history of seizures; hypersensitivity to amifampridine or another aminopyridine.

Documentation Required

Required Documentation and Administrative Notes

Coverage decisions are subject to the member's coverage terms, conditions, exclusions, and limitations. Providers should ensure all required documentation is submitted to support the request and follow applicable state continuity of care rules when relevant.

Coverage subject to the member's evidence of coverage and contract terms.
If member is receiving therapy and continuity of care rules apply, refer to state‑specific addendums CC.PHARM.03A and CC.PHARM.03B.
Provider must submit supporting documentation (office notes, lab results, clinical assessments).

Physician-rated evaluation of 13 muscle function assessments (each 0–3); lower scores indicate better strength

3TUG and T25FW use3TUG and T25FW used as functional mobility measures to assess baseline and response to therapy

inv-21: Additional definition placeholder (no label) — miscellaneous definitional terms.

RNS abbreviation and definitionRNS = Repetitive Nerve Stimulation; diagnostic when CMAP amplitude increase >100% after exercise or high-frequency RNS

VGCC antibody noteP/Q-type VGCC antibody result is strongly suggestive of LEMS but not diagnostic alone; used when RNS cannot be completed

Policy context reminderClinical policy guides medical necessity and coverage decisions; providers must follow plan terms and documentation requirements