A Study of JNJ-77242113 for the Treatment of Participants With Generalized Pustular Psoriasis or Erythrodermic Psoriasis

Inclusion Criteria:

• The study participant has a diagnosis of generalized pustular psoriasis (GPP) orerythrodermic psoriasis (EP) at screening. For GPP, a diagnosis must be classifiedbased on the criteria for diagnosis of GPP by the Japanese DermatologicalAssociation (JDA); for EP, has a history of plaque-type psoriasis. In addition, hasan involved body surface area (BSA) of lesion greater than or equal to (>=) 80percent (%) at baseline

• Candidate for phototherapy or systemic treatment for psoriasis (either naive orhistory of previous treatment)

• A female participant of childbearing potential must have a negative highly sensitiveserum pregnancy test (beta-human chorionic gonadotropin [beta-hCG]) at screening andhave a negative urine pregnancy test at Week 0 prior to administration of studyintervention

• A male participant must agree not to plan to father a child while enrolled in thisstudy or within 90 days after the last dose of study intervention

• A male participant must agree not to donate sperm for the purpose of reproductionduring the study and for a minimum of 90 days after receiving the last dose of studyintervention

Exclusion Criteria:

• The study participant has a total score of JDA severity index for GPP >=14 atbaseline if participants have a diagnosis of GPP

• The study participant has a differential diagnosis of the erythroderma (for example,erythroderma caused by lymphoma or drug eruption) other than EP

• The study participant has a history of or current diagnosis or signs or symptoms ofsevere, progressive, or uncontrolled liver, renal; cardiac, vascular, pulmonary,gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, psychiatric, ormetabolic disturbances

• The study participant has a history of amyloidosis

• Known allergies, hypersensitivity, or intolerance to JNJ-77242113 or its excipients

• The study participant who doesn't meet the criteria of prior/current concomitanttherapy and/or history/conditions of infections