Study to Determine Safety and Efficacy of B244 in Subjects With Episodic Migraine

Inclusion Criteria: * Males and Females, 18 to 65 years of age. * In good general health as determined by a thorough medical history and physical examination, and vital signs. * At least a 1-year history of migraine with or without aura that began before the age of 50 years old and consistent with a diagnosis of migraine with or without aura according to the International Classification of Headache Disorders, 3rd edition, beta version. * Experiences 4-14 migraine days per month and 3-14 migraine attacks per month and no more than 14 headache days per month (including migraine and non-migraine headache days) in the 3 months prior to screening. * Experiences 4-14 migraine headache days per month during the baseline period. * Ability and willingness to abstain from taking medications not allowed by the protocol or administering any foreign substance intranasally. * Ability and willingness to complete a migraine-history diary from screening to treatment with study drug and a migraine-treatment diary from prevention treatment through the remainder of the follow-up period. Exclusion Criteria: * Headache on greater than 14 days/month in any of the three months (90 days) preceding entry into the study. * Use of acute migraine-specific medications (e.g., ergotamine, triptan) on more than 10 days per month in the previous 3 months and during study. * Use of intranasal migraine medications during study. * Use of any intranasally administered over-the-counter product or nasal irrigation (e.g., neti pot) during study. * Opioids/barbiturates used on more than 4 days per month in the previous 3 months and throughout the duration of the study. * Use of analgesics (including acetaminophen, nonsteroidal anti-inflammatory drugs \[NSAIDs\], acetylsalicylic acid, or combination analgesics) for migraine and non-migraine headaches on more than 14 days per month in the - Use of migraine prevention medication within two months prior to study and throughout the duration of the study. * Botulinum toxin injection within 3 months prior to screening or during study. * Anti-CGRP monoclonal antibody (e.g., erenumab, fremanezumab, galcanezumab, and eptinezumab) injection or infusion within 4 months prior to screening or during study. * Small molecule anti-CGRP medications in the 30 days prior to the screening visit. * Use of systemic antibiotics during study. * Pregnancy or breast-feeding. * Female of childbearing potential not using adequate contraceptive measures. * Inability to give informed consent. * History of neurological, psychiatric, or any other medical condition that in the opinion of the investigator may compromise the subject's ability to safely participate in the study. * Subjects with any significant clinical abnormalities which may interfere with study participation. * Prior use of AO+ Mist. * Subjects with immunodeficiencies, nasal lesions, nasal polyps, or sinus infections. * Subjects who have participated in an investigational drug trial in the 30 days prior to the screening visit. * Inability to maintain at least 80% diary compliance during the study from baseline to follow-up.