An Efficacy and Safety Study of CNTO1959 (Guselkumab) in the Treatment of Participants With Generalized Pustular Psoriasis or Erythrodermic Psoriasis

"Participants will receive 50 milligram (mg) guselkumab subcutaneously at Weeks 0, 4 and 12. At Week 16 through the study end (Week 52) participants who are defined Very much improved or Much improved in Clinical Global Impression (CGI) will continue to receive guselkumab 50 mg every 8 weeks from Week 20 to the study end (Week 52). At each visit timing from Week 20, participants who are defined No change or Worsened in CGI will receive guselkumab 100 mg and continue 100 mg every 8 weeks dosing until the study end (Week 52). Participants who are defined Minimally improved in CGI will also receive guselkumab 100 mg only if the investigator considers that it is necessary."