• The response rate at 2 hours post-dose such that the percentage of subjects whose migraine pain-intensity score is none [0] or mild [1] at 2 hours post-dose, after a baseline pain intensity of moderate [2] or severe [3]
  

• Pain-free rate at 2 hours post-dose
  
• Response rate up to 48 (±24) hours post-dose
  
• Recurrence rate of migraine headache within 24 hours post dose
  
• Time to recurrence of migraine within 24 hours post-dose
  
• Area under the migraine pain curve in visual analogue scale (VAS) 0 4 hours post-dose
  
• VAS pain reduction: peak pain reduction in VAS score 0-4 hours post-dose
  
• Presence of nausea/vomiting, sensitivity to sound/light, skin sensitivity (cutaneous allodynia), intracranial sensitivity
  
• Brush allodynia
  
• Muscle tenderness
  
• Functional disability
  
• Use of rescue medication
  
• Time to meaningful pain relief
  
• Global Subject Impression (GSI)
  

Migraine, the most common cause of recurrent severe or disabling headache, is diagnosed on the basis of a clinical history of intermittent headache with autonomic, constitutional, and neurologic disturbances.

Many antiepileptic drugs (AEDs) have demonstrated efficacy as acute and/or prophylaxis therapy for migraine, even though the mechanism of action of the various AEDs is poorly understood.

NPS 1776, isovaleramide, is a neutral aliphatic amide. The mechanism by which NPS 1776 exerts its therapeutic actions in nonclinical animal models of disease is unclear. The same is true for many antiepileptics on the market today. NPS 1776 does not appear to bind directly to various CNS receptor centers, although it shows a broad range of anticonvulsant activity in multiple animal models of seizures. This broad profile of anticonvulsant activity is similar to that of valproic acid (VPA), and may also predict NPS 1776 efficacy in the treatment of migraine.