Duration of Galcanezumab Treatment
Galcanezumab should be continued for 6-12 months, with efficacy assessed at 3-6 months, followed by a trial discontinuation to determine if ongoing preventive therapy remains necessary. 1
Initial Treatment Duration and Assessment Timeline
Efficacy should be assessed after 3-6 months of galcanezumab treatment, as therapeutic benefits may not be immediately apparent and require adequate time to manifest. 1
Treatment can be paused after 6-12 months of successful response to determine if preventive therapy can be discontinued, thereby minimizing unnecessary drug exposure and cost. 1
In clinical trials, galcanezumab demonstrated sustained efficacy and safety for up to 12 months of continuous treatment in patients with both episodic and chronic migraine. 2, 3
Evidence for Long-Term Treatment
A 12-month open-label extension study showed that patients with chronic migraine maintained a mean reduction of 8.0-9.0 monthly migraine headache days from baseline through month 12, with 57% achieving ≥50% response rates. 3
Long-term treatment with galcanezumab for 12 months was safe and well-tolerated, with only 5% of patients discontinuing due to adverse events and 81% completing the full 12-month treatment period. 3
In episodic migraine, galcanezumab 120 mg reduced monthly migraine headache days by 4.3 days compared to 2.3 days with placebo over 6 months of treatment. 4
Treatment Algorithm for Duration
For Migraine Prevention:
- Months 0-3: Initiate galcanezumab 120 mg monthly (with 240 mg loading dose) and monitor for initial response. 3
- Months 3-6: Assess efficacy; if inadequate response, consider dose adjustment to 240 mg monthly or alternative preventive therapy. 1, 3
- Months 6-12: Continue treatment if achieving therapeutic benefit (≥50% reduction in migraine days). 1, 3
- After 12 months: Attempt treatment discontinuation to assess ongoing need for preventive therapy. 1
For Cluster Headache (Episodic):
- Galcanezumab 240 mg (two 120 mg injections) should be administered during the cluster period, with median time to 100% reduction in attacks occurring at 17 days. 5
- Most patients with episodic cluster headache require only one dose of galcanezumab per cluster period, with only 10.8% requiring a second dose. 5
- Galcanezumab is specifically recommended against for chronic cluster headache. 6
Important Considerations and Pitfalls
Do not continue galcanezumab indefinitely without reassessment—the goal is to minimize drug exposure while maintaining therapeutic benefit. 1
Avoid premature discontinuation before 3 months, as some patients may require this duration to demonstrate full therapeutic response. 1
Monitor for injection site reactions (most common adverse event), which typically do not require treatment discontinuation. 2, 4
The annual cost of galcanezumab ranges from $7,071 to $22,790, making periodic reassessment of ongoing need particularly important from both clinical and economic perspectives. 1
Unlike some other preventive medications, galcanezumab can be discontinued without tapering and does not require interruption during perioperative periods. 1