Long-Term Side Effects of Fremanezumab
Fremanezumab has a favorable long-term safety profile with minimal serious adverse effects, with the most common side effects being injection site reactions and nasopharyngitis. 1, 2
Common Side Effects
- Injection site reactions (pain, erythema, induration, and pruritus) are the most frequently reported adverse events, occurring in up to 24% of patients 2
- Nasopharyngitis is common, reported in up to 64% of patients in long-term studies 2
- Upper respiratory tract infections may occur as a common side effect 3
- Mild adverse events including headache, nausea, fatigue, and dizziness have been reported 1
Immunogenicity
- Anti-drug antibody (ADA) development is rare, with only 1.6% of patients developing ADAs in clinical trials 1
- Among those who develop antibodies, approximately 0.9% develop neutralizing antibodies 1
- The incidence of anti-drug antibody development remains low (2.4%) even with long-term treatment 2
- Fremanezumab shows a very low incidence of adverse drug antibodies compared to other CGRP antagonists 4
Cardiovascular Considerations
- Unlike erenumab (another CGRP antagonist), fremanezumab has not been associated with development or worsening of hypertension in post-marketing studies 3
- Although there were theoretical concerns about vasoconstriction with CGRP antagonists, these have not been confirmed clinically 5
- Long-term cardiovascular effects require ongoing monitoring as CGRP is involved in multiple biological activities in the human body 6
Pregnancy and Breastfeeding
- There is a pregnancy exposure registry monitoring outcomes in women exposed to fremanezumab during pregnancy 1
- No adequate data exist on developmental risks associated with use during pregnancy 1
- Animal studies at doses resulting in plasma levels greater than those expected clinically did not show adverse developmental effects 1
- No data are available on the presence of fremanezumab in human milk or its effects on breastfed infants 1
Discontinuation and Tolerability
- Discontinuation rates due to adverse events are low (approximately 4%) in long-term studies 2
- Unlike some traditional migraine preventives, fremanezumab does not require tapering when discontinuing 5
- The medication can be safely continued throughout perioperative periods without interruption 5
Potential Immune System Effects
- Post-marketing reports have identified rare cases of anaphylactic reactions and angioedema 1
- These hypersensitivity reactions are included in the FDA label warnings and precautions 1
Long-Term Efficacy and Safety
- Studies following patients for up to 12 months have shown sustained efficacy with no evidence of tolerance or worsening side effect profiles 2
- Long-term treatment (6+ months) demonstrates continued reduction in migraine days without new safety concerns 7
- The long half-life of fremanezumab may improve patient compliance but also means effects persist longer after discontinuation 1, 6
Special Considerations
- Safety and effectiveness have not been established in pediatric patients 1
- Clinical studies did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently 1
- As a monoclonal antibody, fremanezumab is not associated with liver toxicity and is not expected to interact with other medications 6
Clinical Monitoring Recommendations
- Regular monitoring for injection site reactions is recommended, though these are typically mild and self-limiting 2
- Unlike some other migraine preventives, fremanezumab does not require routine laboratory monitoring 6
- Patients should be educated about potential hypersensitivity reactions and when to seek medical attention 1