<h3>Objective:</h3> Quantify the proportion of phase III galcanezumab study participants with episodic migraine (EM) and clinically meaningful improvement in the Migraine Disability Assessment (MIDAS) despite monthly migraine headache day (MHD) reduction <50%. <h3>Background:</h3> The American Headache Society (AHS) Consensus Statement states continued treatment with monoclonal antibodies (mAbs) to calcitonin gene-related peptide (CGRP) or its receptor is supported by either: 1) ≥50% MHD reduction or 2) clinically meaningful improvement in migraine-specific patient-reported outcome measures (eg. MIDAS). <h3>Design/Methods:</h3> Data were pooled for participants with EM treated with galcanezumab 120 or 240 mg versus placebo in EVOLVE-1, EVOLVE-2, and CONQUER phase III studies and who experienced >0% and <50% MHD reduction during the trial period. Clinically meaningful MIDAS improvement is defined by the AHS Consensus Statement as either 1) reduction of ≥5 points for baseline score 11–20 or 2) reduction of ≥30% for baseline score >20. <h3>Results:</h3> 1551 phase III study participants had a MHD improvement >0%, mean age was 41.5 (SD=11.4) years; 84.8% were female; baseline MHD frequency was: 9.2 (SD=2.9) days. Within this group, MHD improvement was <50% in 35.7% (n=276) and 41.2% (n=240) of treatment group participants and 64.3% (n=417) and 57.3% (n=340) of the placebo group participants at 3 months and 6 months respectively. Of this group with MHD improvement >0% and <50%, clinically significant MIDAS improvement was seen in 58.0% (n=160) of the treatment group participants versus 50.6% (n=211) for placebo at 3 months (OR 1.26, 95% CI [0.92, 1.73], p=0.144) and 62.5% (n=150) of treatment group participants versus 52.9% (n=180) for placebo at 6 months (OR 1.47, 95% CI [1.05, 2.06], p=0.024). <h3>Conclusions:</h3> In phase III galcanezumab trials, a majority of participants with EM who experienced >0% and <50% MHD reduction achieved clinically meaningful improvement in disability. At 6 months, this improvement is statistically superior to placebo. <b>Disclosure:</b> Dr. Vargas has received personal compensation for serving as an employee of Lilly USA. Dr. Vargas has received personal compensation in the range of $0-$499 for serving as an officer or member of the Board of Directors for ElevateMed. Dr. Vargas has stock in Eli Lilly. An immediate family member of Dr. Vargas has stock in Pfizer. Dr. Vargas has received personal compensation in the range of $500-$4,999 for serving as a Unaffiliated Neurotrauma Consultant with National Football League. Dr. Vargas has received personal compensation in the range of $10,000-$49,999 for serving as a Neurotrauma Consultant with National Association for Stock Car Auto Racing. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Amgen. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Axsome Therapeutics. Dr. Starling has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Lundbeck. Dr. Starling has received personal compensation in the range of $0-$499 for serving as a Consultant for Med-IQ. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Medscape. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Satsuma. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurolief. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbvie. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Everyday Health. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Allergan. Dr. Starling has received personal compensation in the range of $500-$4,999 for serving as a Consultant for WebMD. Dr. Nicholson has received personal compensation for serving as an employee of Eli Lilly & Company. Dr. Nicholson has stock in Eli Lilly & Company. Dr. Nicholson has received intellectual property interests from a discovery or technology relating to health care. Mrs. Polavieja has stock in Lilly. Mrs. Polavieja has received personal compensation in the range of $100,000-$499,999 for serving as a Biostatistician with Lilly. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Allergan. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Lilly. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novartis. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TEVA. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Lilly. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Teva. Zaza Katsarava, MD has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novartis. Lars Viktrup has received personal compensation for serving as an employee of Lilly. Lars Viktrup has received stock or an ownership interest from Lilly. Prof. Vincent has received personal compensation for serving as an employee of Eli Lilly and Company. Prof. Vincent has received stock or an ownership interest from Eli Lilly and Company. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Allergan/Abbvie. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Amgen. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biohaven. Dr. Lipton has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Eli Lilly. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Lundbeck. Dr. Lipton has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for GlaxoSmithKline. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Teva. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Vedanta. Dr. Lipton has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Merck. Dr. Lipton has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Satsuma. Dr. Lipton has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Eli Lilly. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Grifols. Dr. Lipton has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Allergan/Abbvie. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biohaven. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Eli Lilly. Dr. Lipton has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Lundbeck. Dr. Lipton has stock in Biohaven. Dr. Lipton has stock in Manistee. The institution of Dr. Lipton has received research support from Teva. The institution of Dr. Lipton has received research support from Amgen. The institution of Dr. Lipton has received research support from Allergan/Abbvie. The institution of Dr. Lipton has received research support from Gammacore. The institution of Dr. Lipton has received research support from Axsome. The institution of Dr. Lipton has received research support from Charleston Labs. The institution of Dr. Lipton has received research support from Eli Lilly. The institution of Dr. Lipton has received research support from Satsuma. The institution of Dr. Lipton has received research support from NIH . The institution of Dr. Lipton has received research support from NIH. The institution of Dr. Lipton has received research support from NINDS. The institution of Dr. Lipton has received research support from NIH. The institution of Dr. Lipton has received research support from NIA. The institution of Dr. Lipton has received research support from NIH. The institution of Dr. Lipton has received research support from NIA. The institution of Dr. Lipton has received research support from NIH. The institution of Dr. Lipton has received research support from Veterans Administration. The institution of Dr. Lipton has received research support from NIH. Dr. Lipton has received publishing royalties from a publication relating to health care.