(1) For adults with plaque psoriasis, after failure of topical symptomatic 
treatments and PUVA therapy, several systemic immunosuppressive agents are 
acceptable for severe disease: methotrexate, then ciclosporin, and possible a 
TNF alpha antagonist (etanercept, etc.); (2) Ustekinumab is an inhibitor of 
interleukins 12 and 23, which are believed to be implicated in the onset of 
psoriasis. It is authorized in the European Union for patients who fail to 
respond to conventional systemic treatments; (3) In one trial with a low level 
of evidence (single-blind), 2 subcutaneous injections of ustekinumab at an 
interval of 4 weeks appeared to be statistically more effective than 
twice-weekly subcutaneous injections of etanercept for 12 weeks. More patients 
achieved a 75% reduction in the score most widely used to evaluate the extent 
and intensity of plaque psoriasis lesions (PASI score): about 71% versus 57%. 
The results beyond this period have not been reported; (4) Two randomised, 
double-blind, placebo-controlled trials in a total of 1996 patients showed that 
at least two-thirds of patients treated with ustekinumab achieved at least a 75% 
reduction in their PASI score versus fewer than 4% with placebo; (5) In animal 
studies, interleukin 12 and 23 inhibitors cause cancer. There is therefore a 
high risk of cancer developing during prolonged treatment with ustekinumab; (6) 
The main adverse effects identified in clinical trials include infections, 
injection-site reactions, psychological disorders and development of 
anti-ustekinumab antibodies; (7) There is insufficient follow-up to evaluate the 
cardiac risks associated with ustekinumab; (8) As maintenance therapy, 
ustekinumab is administered as one subcutaneous injection every 12 weeks. This 
practical advantage compared to TNF alpha antagonists must be weighed against 
the risks inherent in prolonged immunosuppression; (9) In summary, for 
symptomatic relief of patients whose psoriasis poses major problems despite 
treatment with methotrexate or ciclosporin, in the absence of a better 
alternative, it is better to use a TNF alpha antagonist and to avoid exposing 
patients to the risks associated with ustekinumab, particularly its carcinogenic 
risk.