Pain clinical trials are notoriously complex and often inefficient in demonstrating efficacy, even for known efficacious treatments. A major issue is the difficulty in the a priori identification of specific phenotypes to include in the study population. Recent work has identified the extent of widespread pain as an important determinant of the likelihood of response to therapy, but it has not been tested in clinical trials for the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS). We explored this hypothesis using data from 3 previously published trials testing treatments for IC/BPS, which suggested modest benefits but did not meet a priori primary outcome statistical significance criteria. Importantly, these studies also collected symptom questionnaire data that allowed us to retrospectively identify participants with and without widespread pain. Analyzing the treatment by the degree of widespread pain revealed a difference in outcome and statistical significance level for each trial. Participants with predominately local pain (ie, limited widespread pain symptoms) responded to therapy targeting local symptoms, whereas those with widespread pain did not. Alternatively, participants with widespread pain beyond their local pelvic pain responded to more centrally acting treatments. Our results suggest that differentiating patients based on widespread vs more localized pain is a key consideration for designing future clinical trials for conditions with variable pain profiles, such as IC/BPS and potentially other pain-based syndromic disorders.
Pain. 2024 Nov 05 [Epub ahead of print]
John T Farrar, Kenneth T Locke, J Quentin Clemens, James W Griffith, Steven E Harte, Ziya Kirkali, Karl J Kreder, John N Krieger, H Henry Lai, Robert M Moldwin, Chris Mullins, Bruce D Naliboff, Michel A Pontari, Larissa V RodrÃguez, Anthony J Schaeffer, Andrew Schrepf, Alisa Stephens-Shields, Siobhan Sutcliffe, Bayley J Taple, David A Williams, J Richard Landis
Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States., Department of Urology, University of Michigan Medical School, Ann Arbor, MI, United States., Department of Medical Social Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States., Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States., National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States., Department of Urology, Roy J and Lucille A Carver College of Medicine, The University of Iowa, Iowa City, IA, United States., Department of Urology, University of Washington School of Medicine, Seattle, WA, United States., Department of Urology, Washington University School of Medicine, St. Louis, MO, United States., Department of Urology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Lake Success, NY, United States., Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, United States., Department of Urology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States., Department of Urology, New York-Presbyterian/Weill Cornell Medical Center, New York, NY, United States., Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States., Department of Surgery, Washington University School of Medicine, St. Louis, MO, United States., Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States., Department of Psychology, University of Michigan Medical School, Ann Arbor, MI, United States.