The primary objective is to evaluate the safety of long-term treatment with NP101 as assessed by:

• Subject self-examination skin irritation scores
• Adverse events
• Changes in vital signs and ECG parameters

The secondary objective is to evaluate the long term efficacy of NP101 as assessed by:

• Headache pain free at two hours after patch activation for all initial acute migraine attacks treated with NP101
• Headache pain relief at two hours after patch activation for all initial acute migraine attacks treated with NP101
• Nausea free at two hours after patch activation for all initial acute migraine attacks treated with NP101
• Phonophobia free at two hours after patch activation for all initial acute migraine attacks treated with NP101
• Photophobia free at two hours after patch activation for all initial acute migraine attacks treated with NP101
• Migraine free at two hours after patch activation for all initial acute migraine attacks treated with NP101

This study will use an open-label design to assess the long term safety of NP101 (sumatriptan iontophoretic transdermal patch).

Subjects who continue to be in good health (use of a triptan or use of an NP101 patch is not contraindicated) and received treatment (patch activation) with the study patch for a qualifying migraine under study NP101-007 will be considered eligible for enrollment into the open-label study. Subjects will be expected to remain in the study for up to 12 months.

Inclusion Criteria:

• Subject was previously enrolled in study NP101-007 and treated (patch activation) a qualifying migraine.
• Subject will be judged to be in good health, based upon the results of a medical history, physical examination, vital signs, and ECG. Subjects will not have any clinically significant abnormal vital signs or ECG parameters in order to qualify for enrollment. ECG must be done at enrollment for NP101-008 unless ECG for the Final Visit of study NP101-007 was conducted within 30 days.
• Female subjects of childbearing potential (not surgically sterile or 2 years post menopausal) must have a negative pregnancy test at enrollment.

Exclusion Criteria:

• Subject has less than two potential skin application sites.
• Subject has clinically significant abnormal vital signs or ECG parameters or had an adverse event while participating in NP101-007 that would preclude the continued treatment with the NP101 patch.
• Subject has had changes in their medical history or medication use that would preclude their use of sumatriptan as per the approved Imitrex® product Prescribing Information (PI) or their safe use of NP101 as per the NP101 Investigator's Brochure.
• Subject has or plans to start, stop, change treatment or dose of any of the following within 3 months prior to the subject's study Enrollment date and through the Final Visit: anxiolytics, lithium and other mood stabilizers such as valproate, carbamazepine or lamotrigine, hypnotics or antipsychotics.
• Subject has taken non-triptan serotonergic drugs including selective serotonin reuptake inhibitor (SSRI), serotonin and norepinephrine reuptake inhibitor (SNRI), tricyclic antidepressants (TCAs), monoamine oxidase inhibitor (MAOI) or preparations containing St. John's Wort within 1 month prior to enrollment and/or is planning to start any of these medications during the study (through Final Visit).
• Female subjects who are pregnant, breast feeding, or of childbearing potential, and are not using or are unwilling to use an effective form of contraception during the study and for a period of 30 days following Final Visit. Acceptable methods of contraception include barrier method with spermicide, intrauterine device (IUD), steroidal contraceptive (oral, transdermal, implanted or injected) or abstinence. If the exclusive male partner is surgically sterile, this will be acceptable.
• Subject has participated in a clinical study within 30 days of enrollment (excluding NP101-007) or is planning to participate in another clinical study for the duration of NP101-008.