BACKGROUND & AIMS: Regulatory assessments of drug risks do not routinely 
consider patient preferences, despite evidence that some patients are willing to 
accept increased side-effect risk in exchange for therapeutic benefits. The aim 
of this study is to estimate the willingness of Crohn's disease (CD) patients to 
accept life-threatening adverse event risks in exchange for CD symptom relief.
METHODS: Patients with CD completed choice-format conjoint trade-off tasks 
involving hypothetical treatments with varying efficacy and risk levels. The 
treatment features included daily symptoms and activity limitations, serious 
complications (fistulas, abscesses, bowel obstructions), time between flare-ups, 
oral steroid use and risk of 3 serious adverse events (SAEs) known to be 
associated with CD treatment (progressive multifocal leukoencephalopathy (PML), 
serious infections, and lymphoma). The mean maximum acceptable annual risk (MAR) 
for each of the SAEs was calculated for various levels of clinical benefit.
RESULTS: Daily symptom severity was the most important factor in treatment 
preferences. Higher MAR was observed for trade-off tasks involving higher levels 
of clinical benefit. The MAR was similar across the 3 SAEs. For improvements 
from severe daily symptoms to remission and from moderate daily symptoms to 
remission, the MARs ranged from 0.69% to 0.81% and from 0.39% to 0.55%, 
respectively.
CONCLUSIONS: Patients with CD have well-defined preferences among treatment 
attributes and are willing to accept tradeoffs among attributes. The patients 
indicated they are willing to accept elevated SAE risks in exchange for clinical 
efficacy. The perspective of the patients on the benefit versus risk balance can 
assist in making treatment and regulatory decisions.