• Pain free response [ Time Frame: 30 minutes, 1 hour, 1.5 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Pain relief response. [ Time Frame: 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Sustained pain relief response. [ Time Frame: 24 hours, 48 hours ] [ Designated as safety issue: No ]
• Time to headache recurrence. [ Time Frame: Up to 48 hours after study drug administration. ] [ Designated as safety issue: No ]
• Change in nausea. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Change in phonophobia. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Change in photophobia. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Change in vomiting. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: No ]
• Sustained pain free response [ Time Frame: 24 hours, 48 hours ] [ Designated as safety issue: No ]

• Pain free response [ Time Frame: 30 minutes, 1 hour, 1.5 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Pain relief response. [ Time Frame: 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Sustained pain relief response. [ Time Frame: 24 hours, 48 hours ] [ Designated as safety issue: Yes ]
• Time to headache recurrence. [ Time Frame: Up to 48 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Change in nausea. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Change in phonophobia. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Change in photophobia. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Change in vomiting. [ Time Frame: Pre-dose, 30 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours and 4 hours after study drug administration. ] [ Designated as safety issue: Yes ]
• Sustained pain free response [ Time Frame: 24 hours, 48 hours ] [ Designated as safety issue: Yes ]

This is a Phase 2, multicenter, randomized, double-blind, placebo and active comparator-controlled study of LY2590443 in approximately 200 subjects with migraines.

• Drug: LY2590443
• Drug: Placebo injection
• Drug: Sumatriptan
• Drug: Placebo capsule

Inclusion Criteria:

• Male and female subjects between the ages of 18 and 65 years, inclusive.
• Subjects who have migraine headaches, with or without aura (diagnosis according the International Classification of Headache Disorders-II), for at least 1 year.
• Subjects who have had 2-8 migraine attacks on average per month for the last 3 months (but less than 15 headache days per month).
• Subjects who are willing and able to comply with the study schedule and requirements.
• Subjects who speak, read and understand English sufficiently well and are willing to provide written informed consent.
• Subjects who in the opinion of the principal investigator are in good general health.
• Venous access should be sufficient to allow blood sampling as per protocol.

Exclusion Criteria:

• Subjects who do not or may not tolerate 5HT1 agonist treatments, with known hypersensitivity to sumatriptan (as discussed with the investigator).
• Female subjects who have a positive pregnancy test at screening or pre- dose evaluation, or are breastfeeding.
• History or presence of significant medical illnesses as determined by the investigator.
• Subjects with a current clinical diagnosis of major psychiatric disease.
• Regular use of known drugs of abuse; use of opiates for migraine rescue (no more than two times per month) is permissible.
• Blood donation of 500mL or greater of whole blood products within 4 weeks of study commencement, during the study, or 4 weeks following the study.
• Investigator site personnel directly affiliated with this study and their immediate families. Immediate family is defined as a spouse, parent, child or sibling, whether biological or legally adopted.
• Consumption of more than three units of alcohol per day where one unit is defined as a 12 oz beer, 4 oz wine, or 2 oz of alcohol spirit liquor.
• Are unwilling or unable to comply with the use of a diary to directly record data from the subject.