Question explored with the scientific record
Conversation so far
- 1 Why is Ajovy available only in 225mg syringes? Why is there no 175mg, for example? How did the drug manufacturer arrive at that dose and can I see that data? What dose ranges did they test?
- 2 What does it imply if an adult can take Ajovy 225mg every two months instead of monthly? does it imply the 225mg dose is an overshoot for this particular person? if the half-life is 30 days and the drug works great for 60 days, what do we learn from that?
- 3 Do any guidelines address stretching Ajovy dosing beyond 30 days?
- 4 Are there any studies on dosing at 45 or 60 days for Ajovy?
- 5 what are the long-term impacts of mAbs?
Answered on this page ↓
what are the long-term impacts of mAbs?
The short version: the evidence shows Ajovy helps many people for up to two years, but long-term safety beyond that is simply not established.
The strongest long-term data comes from a 2025 real-world study of 165 patients. Monthly migraine days fell by about 7 days at 3 months and about 10 days at 24 months [1]. About 58 in 100 people were still on the drug at two years [1]. Adverse events were mostly injection-site reactions, affecting about 13 in 100 people, with about 2 in 100 stopping due to side effects [1].
The pivotal trials only ran 12 weeks [2]. A systematic review of those trials found serious adverse events in about 1 in 100 people, judged unrelated to the drug [3]. But the review itself notes the trials had short follow-up and homogeneous populations [3]. No retrieved study tracks patients beyond 24 months. No study compares long-term users to a genuinely untreated group.
The mechanism deserves attention. These antibodies block CGRP, a peptide involved in blood vessel dilation and pain signaling [5]. One exploratory study found galcanezumab lowered several inflammatory cytokines, including TNF-alpha and IL-1 beta, at least transiently [6]. What that means for years of continuous immune modulation is unknown. The drug has a half-life of about 30 to 39 days, so it stays in the body for months after the last injection [4].
| Outcome | 12 weeks | 24 months |
|---|---|---|
| Migraine day reduction | about 7 days [1] | about 10 days [1] |
| Still on treatment | not reported | about 58 in 100 [1] |
| Injection-site reactions | common [2] | about 13 in 100 [1] |
My call: Ajovy clearly reduces migraine burden for up to two years in many people, but the evidence does not establish safety beyond that window, and the immune effects of years of CGRP blockade have not been studied. Confidence: moderate for benefit, low for long-term safety.
Sources used 6
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A real-world study of the efficacy and tolerability of fremanezumab in migraine patients with a median follow-up of 14 months
In a single-center retrospective cohort of 165 migraine patients, fremanezumab significantly reduced monthly migraine days through 24 months, with comparable efficacy for monthly and quarterly dosing and greater treatment persistence with quarterly dosing.
DOI: 10.1186/s42466-025-00395-y -
Fremanezumab for prophylaxis of migraine in adults
Fremanezumab, an anti-CGRP monoclonal antibody, significantly reduced monthly migraine and headache days versus placebo in phase 3 trials of episodic and chronic migraine and was well tolerated.
DOI: 10.1002/psb.1818 -
Efficacy and Safety of Fremanezumab in the Preventive Treatment of Migraine: A Systematic Review of Randomized Clinical Trials
This systematic review found that fremanezumab significantly reduced migraine frequency and produced clinically meaningful response rates, with a low rate of treatment-unrelated serious adverse events, though trials had short follow-up and homogeneous populations.
DOI: 10.46979/rbn.v61i4.69673 -
A phase 1 study to assess the pharmacokinetics, safety, and tolerability of fremanezumab doses (225 mg, 675 mg and 900 mg) in Japanese and Caucasian healthy subjects
Single fremanezumab doses (225, 675, 900 mg) showed similar pharmacokinetics and safety in healthy Japanese and Caucasian subjects, with no anti-drug antibodies.
DOI: 10.1177/0333102418771376 -
Antigens and Antibodies in Disease With Specifics About CGRP Immunology
A clinically oriented review outlining CGRP immunology, IgG structure/function, monoclonal antibody production, and the development and immunogenicity considerations of anti-CGRP therapies (erenumab, fremanezumab, galcanezumab, and eptinezumab) for migraine.
DOI: 10.1111/head.13409 -
Could galcanezumab modulate inflammatory cytokines? A single-centre exploratory study
Interictal cytokine profiling across episodic migraine, chronic migraine, and healthy controls reveals distinct inflammatory signatures, and galcanezumab treatment in episodic migraine is associated with a transient decrease in several cytokines, implying CGRP modulates neuroinf…
DOI: 10.1007/s00415-026-13706-3