Phenotype Variability in Interstitial Cystitis Clinical Trial Recruitment.

Importance: There is a need to understand phenotype-specific therapies for interstitial cystitis/bladder pain syndrome (IC/BPS) at the clinical trial level to move beyond trial-and-error treatment approaches.

Objective: The objective of this study was to characterize IC/BPS clinical trials that incorporate patient phenotype into the eligibility criteria in accordance with the American Urological Association (AUA) guidelines.

Study design: Registered IC/BPS clinical trials were identified from ClinicalTrials.gov. Trials were included if they enrolled patients with IC/BPS and addressed pain-related outcomes. Trials were assessed for phenotype recognition and categorized by intervention type, funding source, and registration date relative to the AUA's 2015 IC/BPS guidelines for initial phenotype recognition.

Results: Out of 170 trials, 37 (21.8%) included phenotype stratification. The majority focused on bladder-centric presentations. Men were underrepresented in IC/BPS clinical trials. Phenotypic stratification was more frequently reported in industry-funded trials compared with those without industry support (40.5% vs 16.5%, P =0.0031). Trials registered after the 2015 AUA guideline update showed greater phenotype inclusion, though this was not statistically significant (26.6% vs 15.8%). Therapeutic trials comprised the majority of trials. Stratification appeared more often in physical therapy and psychosocial trials at 40% and in drug studies at 34.3%. Intravesical instillation and injection trials showed lower rates at 19.6% and 13.0%, respectively.

Conclusions: Failure to incorporate IC/BPS phenotypes into trial design limits the ability to evaluate treatments within the context of real-world symptom variability. Bridging this methodological gap is essential to ensure that clinical research supports the development of more targeted and effective therapies.