Subject: Firdapse SGM 2803-A P2025

Drug

FIRDAPSE  (amifampridine)

Policy:

Indications

The indications below including FDA-approved indications and compendial uses are considered a covered benefit provided that all the approval criteria are met and the member has no exclusions to the prescribed therapy.

FDA-Approved Indications¹

Treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults and pediatric patients 6 years of age and older.

All other indications are considered experimental/investigational and not medically necessary.

Documentation

Submission of either of the following diagnostic tests is necessary to initiate the prior authorization review:

• Electromyography (EMG) showing compound muscle action potential (CMAP)
• Anti-P/Q type voltage-gated calcium channel antibody test

Prescriber Specialties

This medication must be prescribed by or in consultation with a neurologist, oncologist, or a physician who specializes in the treatment of LEMS.

Exclusions

Coverage will not be provided for members with a history of seizures.²

Coverage Criteria

Lambert-Eaton Myasthenic Syndrome (LEMS)^1-4

Authorization of 6 months may be granted for treatment of Lambert-Eaton myasthenic syndrome (LEMS) when both of the following criteria are met:

• Diagnosis is confirmed by either of the following:
  • EMG showing compound muscle action potential (CMAP) that increased at least 2-fold after maximum voluntary contraction of the tested muscle.
  • A positive anti-P/Q type voltage-gated calcium channel antibody test.
• Member has proximal muscle weakness.

Continuation of Therapy

Authorization of 12 months may be granted for continued treatment in members requesting reauthorization for LEMS who are responding to therapy (i.e., there is stability or improvement in symptoms relative to the natural course of LEMS).

Place of Service:

Outpatient

The above policy is based on the following references:

1. Firdapse [package insert]. Coral Gables, FL: Catalyst Pharmaceuticals, Inc.; May 2024.
2. Oh SJ, Scherbakova N, Kostera-Pruszczyk A, et al; LEMS Study Group. Amifampridine phosphate (Firdapse®) is effective and safe in a phase 3 clinical trial in LEMS. Muscle Nerve. 2016;53(5):717-25. doi: 10.1002/mus.25070
3. Shieh P, Sharma K, Kohrman B, Oh SJ. Amifampridine phosphate (Firdapse) is effective in a confirmatory phase 3 clinical trial in LEMS. J Clin Neuromuscul Dis. 2019; 20(3):111-119. doi: 10.1097/CND.0000000000000239
4. Wiendl H, Abicht A, Chan A, et al: Guideline for the management of myasthenic syndromes. Ther Adv Neurol Disord. 2023;16:1-31. Doi: 10.1177/17562864231213240

Copyright Aetna Inc. All rights reserved. Pharmacy Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.

January 20, 2026