A year-long treatment with onabotulinumtoxin A (OnabotA) may effectively and safely reduce the number of monthly headaches in individuals with chronic migraine, particularly individuals with unilateral pain, according to a study published in the European Journal of Neurology.1,2
In a letter to the journal editor addressing comments on the publication, the study authors emphasized the fact that their main finding —that unilateral pain in chronic migraine may represent a predictive factor for responsiveness to OnabotA — is particularly the case in patients in whom treatment is initiated early (ie, within 1 month of chronic migraine onset).1 Lower headache-related pain intensity and disability at baseline were also found to be associated with more efficient migraine prophylaxis with OnabotA; however, this was not “discussed in detail,” the researchers pointed out.
The study authors emphasized: “We believe that the presence of unilateral pain identifies in a better way patients diagnosed with ‘pure’ migraines, with less tensional component and therefore with a higher likelihood of being responders to OnabotA.”2
The results are consistent with a 2017 study in which patients with chronic migraine and predominantly unilateral vs bilateral pain — as well as scalp allodynia and pericranial muscle tenderness — showed greater response to OnabotA.3
“We consider that ‘pure’ migraineurs (ie, those with unilateral pain and autonomic symptoms) as well as early treatment in [chronic migraine] could be two elements with a high predictive value in terms of effectiveness when OnabotA treatment is applied in patients with [chronic migraine],” concluded the study authors.