Relationship between incidence of secondary failure and antibody formation to infliximab in Japanese psoriasis patients

Secondary failure of infliximab may develop in the treatment of psoriasis. We examined 102 patients treated with infliximab in our hospital and analyzed the association between treatment failure and the psoriasis activity severity index (PASI) score at the initial administration, age of onset, disease duration, and body weight. Primary treatment failure occurred in 8 patients (7.8%). Maximum effects occurred at 22 weeks among all treated patients. Secondary treatment failure occurred in 25 patients (24.5%) at a mean of 54 weeks after treatment. Effective (non-failure) cases tended to have a PASI score <20, <20 or >50 years of age at onset, and for >10 years of disease duration. And we set a secondary failure existence to objective variable. Analysis with multiple logistic regression showed that there are significant difference in PASI score between failure and non-failure cases. It suggested that these factors are important toward preventing secondary failure of infliximab. We further analyzed the blood concentration of antibody to infliximab (ATI) in 47 patients treated with infliximab. Among these 47 patients, 16 (34.0%) exhibited ATI positivity, and ATI appeared at a mean of 20.2 weeks (0–38 weeks). ATI levels were measured in 18 of the 25 patients with secondary failure. Of these 18 patients, 11 (61.1%) exhibited ATI positivity, and the ATI positivity occurred at a mean of 15.5 weeks. Furthermore, among the seven patients with primary failure in whom ATI was assessed, four patients (57.1%) were ATI-positive. ATI appeared relatively early, at 14.5 weeks. Therefore, examination of ATI at an early time-point may predict secondary failure in Japanese (Asian) patients.