Calcitonin Gene-Related Peptide Blocker

Aka: Calcitonin Gene-Related Peptide Blocker, CGRP Monoclonal Antibody, CGRP Antagonist, Injectable Calcitonin Gene-Related Peptide Blocker, Injectable CGRP Inhibitor, Erenumab, Ajovy, Fremanezumab, Emgality, Galcanezumab, Aimovig, Eptinezumab, Vyepti

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II. Indications

  1. Migraine Prophylaxis if refractory to first-line agents

III. Mechanism

  1. Calcitonin Gene-Related Peptide (CGRP)
    1. CGRP is a neuropeptide that acts as a vasodilator and pain sensitization
    2. CGRP Is released by trigeminal Neurons in Migraine Headache, Cluster Headache and Trigeminal Neuralgia
  2. CGRP Inhibitors block CalcitoninGene-Related Peptide (CGRP)
    1. CGRP Monoclonal Antibody agents that are injectable
    2. Contrast with Gepants which are oral or intranasal agents that block CGRP
    3. Some agents target the CGRP Ligand (e.g. Eptinezumab, Fremanezumab, and Galcanezumab)
      1. Prevent binding to CGRP receptor
    4. Some agents target CGRP Receptor (e.g. Erenumab)
      1. Block Ligand binding to receptor site

IV. Medications

  1. See Rimegepant (Nurtec)
  2. Erenumab (Aimovig)
    1. Autoinjector once monthly in Abdomen, thigh, upper arm
    2. Start 70 mg, and may increase as needed to 140 mg
    3. Adverse Effects: Constipation, myalgias
  3. Fremanezumab (Ajovy)
    1. May give 225 mg prefilled syringe dose once monthly OR
    2. Give 675 mg (3 injections from prefilled syringes) once every 3 months
  4. Galcanezumab (Emgality)
    1. Once monthly injection via pen
    2. Load 240 mg once, then 120 mg monthly
    3. Adverse Effects: back pain, Dizziness, swelling, Nausea, Pharyngitis
  5. Eptinezumab (Vyepti)
    1. Dosed 100 mg infused IV over 30 minutes every 3 months
    2. Rapid peak plasma concentration reached shortly after infusion
      1. Migraine improvement onset within 1 hour of infusion
      2. Statistically SignificantMigraine improvement at 2 and 4 hours after infusion
    3. FDA approved for Migraine prevention
      1. Single infusion effective for 90 days of prophylaxis (Elimination Half-Life: 27 days)
    4. Consider for Migraine abortive care in acute, severe, refractory, Status Migrainosus >72 hours
      1. May be considered for emergency department use
      2. Single infusion effects persist for >48 hours
    5. References
      1. Carroll and LoVecchio (2026) Crit Dec Emerg Med 40(2): 36
      2. Ailani (2022) BMC Neurol 22(1):205 +PMID: 35659622 [PubMed]
      3. Ashina (2022) Lancet Neurol 21(7):597-607 +PMID: 35716692 [PubMed]

V. Adverse Effects

  1. Injection site mild reactions
  2. New onset or worsening Hypertension (Erenumab or Aimovig)
    1. Associated with 60 cases of systolic increase of 40 mmHg, diastolic increase of 30 mmHg
    2. Occurred within 1 week of first or second dose
    3. May be related to the blockade of CGRP which is a vasodilator
    4. Avoid in Uncontrolled Hypertension or significant Cardiovascular Risk
    5. Incorporate Home Blood Pressure Monitoring for the first few months after starting
    6. (2021) Presc Lett 28(4): 19-20
    7. Saely (2021) Headache 61(1):202-8 [PubMed]
  3. Hypersensitivity Reaction
    1. Eptinezumab (2.1%, severe in 0.4%, occurring during or within 1 hour of infusion)

VI. Efficacy

  1. Reduces migraine Incidence by 2 fewer Migraine days/month

VII. Disadvantages

  1. Limited safety data outside healthy patients without comorbidity at time of 2018 release
  2. Expensive: $6900 per year

VIII. References

  1. (2018) Presc Lett 25(8)
  2. (2018) Presc Lett 25(12): 70

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Cost: Medications

ajovy (on 1/1/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
AJOVY 225 MG/1.5 ML AUTOINJECT $427.41 per ml
AJOVY 225 MG/1.5 ML SYRINGE $429.27 per ml
emgality (on 1/1/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
EMGALITY 120 MG/ML PEN $631.97 per ml
EMGALITY 120 MG/ML SYRINGE $630.62 per ml
EMGALITY 300 MG DOSE (100 MG/ML X 3 SYRINGES) $524.70 per ml
aimovig (on 7/1/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
AIMOVIG 140 MG/ML AUTOINJECTOR $675.06 per ml
AIMOVIG 70 MG/ML AUTOINJECTOR $674.94 per ml
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information. GoodRx is another tool for finding lower drug prices.

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