Abstract Disclosure: S. Martin: Other; Self; Employee of RTI Health Solutions, an independent nonprofit research organization retained by Regeneron Pharmaceuticals, Inc. to conduct this research. Compensis unconnected to the studies they work on. K. Kosa: Other; Self; Employee of RTI Health Solutions, an independent nonprofit research organization retained by Regeneron Pharmaceuticals, Inc. to conduct this research. Compensis unconnected to the studies they work on. S. Podgrabinska: Employee; Self; Regeneron Pharmaceuticals. Stock Owner; Self; Regeneron Pharmaceuticals. A. Garg: Consulting Fee; Self; Aegerion Pharmaceuticals, Regeneron Pharmaceuticals, Third Rock ventures, Kyttaro, Cello Health, Health Advances. Grant Recipient; Self; Aegerion Pharmaceuticals, Pfizer, Inc., Regeneron Pharmaceuticals, Amryt, Ionis Pharmaceuticals Inc. E.A. Oral: Consulting Fee; Self; Regeneron Pharmaceuticals, Third Rock Ventures, Rejuvenate Inc. Grant Recipient; Self; Regeneron Pharmaceuticals, Amryt Pharmaceuticals, Ionis Pharmaceuticals Inc., Gemphire Therapeutics. Other; Self; Amryt Pharmaceuticals, Novo Nordisk, Rhythm Pharmaceuticals, Fractyl Laboratories, GI Dynamics. I. Yildirim Simsir: None. R.J. Brown: Other; Self; Regeneron Pharmaceuticals. S. Ozen: None. O. Pagovich: Employee; Self; Regeneron Pharmaceuticals. Stock Owner; Self; Regeneron Pharmaceuticals. D. Srinivasan: Employee; Self; Regeneron Pharmaceuticals. Stock Owner; Self; Regeneron Pharmaceuticals. R.J. Sanchez: Employee; Self; Regeneron Pharmaceuticals. Stock Owner; Self; Regeneron Pharmaceuticals. Background: Generalized lipodystrophy (GLD) is characterized by near-total lack of adipose tissue and, consequently, low levels of serum leptin. Mibavademab (REGN4461) is an investigational human monoclonal agonist antibody of the leptin receptor. As part of the phase 2, randomized, double-blind, placebo-controlled study (NCT04159415) of mibavademab, we conducted exit interviews to gather patient experience data specific to GLD and changes experienced during the study. Methods: Between week 52-54, experienced interviewers conducted 45-minute in-depth, semi structured, qualitative phone interviews to understand their GLD-related symptoms/signs, perceptions of any improvements experienced during the study as well as the importance of these improvements. Results: Interviews were conducted with 5 females and 2 males, with a mean age of 19.4 (range:15-23). Most participants reported experiencing hunger-related symptoms (n=6), pain, extreme body temperature sensations (n=5 for each), and fatigue or sleep problems (n=4 for each) prior to them starting the study. While we were interested in symptoms, many participants also reported clinical signs, such as enlarged/fatty liver and hyperglycemia (n=5 for each). Pain was most frequently reported as the most bothersome symptom (n=3) prior to the study. All participants who reported having hunger, pain, extreme body temperatures, hyperglycemia, and fatigue before the study reported improvements after 52 weeks of treatment. Participants generally indicated more than a minimal amount of change. For example, of the 5 participants who reported hunger as a symptom prior to the study and who were asked about the amount of change, all reported either “some” (n=1) or “a lot” of improvement (n=4). Participants, overall, rated each improvement, except body temperature as “very important.” Improvements in extreme body temperature were generally rated by participants as “somewhat important.” When asked which of the reported improvements were most important, changes in hyperglycemia was most frequently reported (n=4) followed by improvements in enlarged or fatty liver (n=2) and pain and hunger (n=1 each). All participants reported they were satisfied (n=2) or very satisfied (n=5) with the study treatment. Conclusions: All participants who reported symptoms of hunger, pain, fatigue, and extreme body temperature, or the clinical biomarker of hyperglycemia before entering the study reported improvements in each of these after treatment. In addition, all participants reported being either satisfied or very satisfied with treatment. This qualitative research provides insight into the patient experience for individuals with GLD and provides an opportunity to further understand and complement the clinical trial results. Presentation: 6/1/2024