Persistence rates and medical costs of biological therapies for psoriasis treatment in Japan: a real-world data study using a claims database

Background: Biological therapies (BTs) including infliximab (IFX), adalimumab (ADL), secukinumab (SCK) and ustekinumab (UST) are approved in Japan for the treatment of psoriasis. Although the persistence rates and medical costs of BTs treatment have been investigated in multiple foreign studies in recent years, few such studies have been conducted in Japan and the differences between patients who adhered to treatment and those who did not have not been reported. This study is aimed at investigating the persistence rates and medical costs of BTs in the treatment of psoriasis in Japan, using the real-world data from a large-scale claims database. Methods: Claims data from the JMDC database (August 2009 to December 2016) were used for this analysis. Patient data were extracted using the ICD10 code for psoriasis and claims records of BT injections. Twelve-month and 24-month persistence rates of BTs were estimated by Kaplan-Meier methodology, and 12-month-medical costs before and after BT initiation were compared between persistent and non-persistent patient groups at 12 months. Results: A total of 205 psoriasis patients treated with BTs (BT-naive patients: 177) were identified. The 12-month/24month persistence rates for ADL, IFX, SCK, and UST in BT-naive patients were 46.8% +/- 16.6%/46.8 +/- 16.6%, 53.0% +/- 14.9%/41.0% +/- 15.5%, 55.4%/55.4% (95% CI not available) and 79.4% +/- 9.9%/71.9% +/- 12.2%, respectively. Statistically significant differences in persistence were found among different BT treatments, and UST was found to have the highest persistence rate. The total medical costs during the 12 months after BT initiation in BT-naive patients were (in 1000 Japanese Yen): 2218 for ADL, 3409 for IFX, 465 for SCK, 2824 for UST (average: 2828). Compared with the 12-month persistent patient group, the total medical costs in the persistent group was higher (Delta:+ 118), but for some medications such as IFX or UST cost increases were lower for persistent patients. Conclusions: UST was found to have the highest persistence rate among all BTs for psoriasis treatment in Japan. The 12-month medical costs after BT initiation in the persistent patient group may not have increased as much as in the non-persistent patient group for some medications.