Persistency of Biologic Therapies for Plaque Psoriasis in 2 Large Community Practices

Background: Biologics have transformed the management of moderate to severe psoriasis. The persistency of biologics lacks real-world data. Objectives: To quantify drug survival of infliximab (IFX), adalimumab (ADA), etanercept (ETA), and ustekinumab (UST) and to identify potential factors affecting drug survival. Methods: An observational, retrospective 2-centre study consisting of 906 patients from private practices in Ontario between July 2003 and June 13, 2016, was conducted, including patients with plaque psoriasis receiving commercial treatment with ADA, ETA, IFX, and UST. Paper and electronic records of each patient were reviewed. Results: Median survival times for UST, IFX, ADA, and ETA were respectively, in months, 68, 23, 33, and 28. Female sex was determined to be a statistically significant positive predictor of drug survival. Our study was consistent with the literature in that UST had the highest survival rate compared to the other biologics, and the shape of our drug survival curve suggested that loss of drug efficacy is a stochastic occurrence. Compared to other studies, our data exhibited lower survival rates at various time points for all the biologics studied, and female sex did not predict drug survival in other studies. We also investigated potential reasons for differences in biologic survival times between different practices; the main differentiator was drug dosage, as higher dosages were associated with greater survival. Conclusion: UST has a higher drug survival rate than ADA, ETA, and IFX, as observed in other studies. When practice patterns are compared, dosage difference is the main factor that may cause differing survival rates.