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

• JNJ-77242113 (Drug): JNJ-77242113 tablet will be administered orally.

Primary outcomes

• Percentage of Participants With Generalized Pustular Psoriasis (GPP) Who Experienced Treatment Success at Week 16 [Week 16]: Percentage of participants with GPP who experienced treatment success at Week 16 was reported. Treatment success for GPP was defined as at least "minimally improved" rating in Clinical Global Impression (CGI) scale for GPP based on Japanese Dermatological Association (JDA) total score. JDA severity index includes skin symptoms (area of erythema with pustules, total area of erythema, and area of edema; each scored 0-3) and systemic/laboratory findings (fever, white blood cell count, C-reactive protein, and serum albumin; each scored 0-2). JDA total score was sum of 2 assessments ranging from 0 (best) to 17 (worst). CGI ratings were defined as: 1=Very much improved (greater than or equal to \[>=\]3-point reduction in JDA total score), 2=Much improved (1-2-point reduction), 3=Minimally improved (no change in JDA total score, but >=20 percent (%) reduction in area of erythema with pustules or meaningful improvement in >=1 other parameter), 4=No change, 5=Worsened. Higher score = worsening.
• Percentage of Participants With Erythrodermic Psoriasis (EP) Who Experience Treatment Success at Week 16 [Week 16]: Percentage of participants with EP who experienced treatment success at Week 16 was reported. Treatment success for EP was defined as at least "minimally improved" rating in CGI scale for EP. The CGI scale is a clinician-rated 5-point scale with the following categories: 1 = Very much improved, 2 = Much improved, 3 = Minimally improved, 4 = No change, 5 = Worsened. Higher score indicated worsening.

Secondary outcomes

• Percentage of Participants With GPP Who Experienced Treatment Success Over Time Based on CGI Scale According to JDA Total Score [From baseline (Week 0) to Week 156]
• Percentage of Participants With EP Who Experienced Treatment Success Over Time Based on CGI Scale [From Baseline (Week 0) to Week 156]
• Change From Baseline in the Total Score of the Japanese Dermatological Association (JDA) Severity Index for GPP Over Time [From baseline (Week 0) up to Week 156]
• Change From Baseline in Severity Classification of JDA Severity Index for GPP Over Time [From baseline (Week 0) up to Week 156]
• Change From Baseline in the Body Surface Area (BSA) of Involvement of Lesion for EP Over Time [From baseline (Week 0) up to Week 156]
• Percentage of Participants Who Achieved an Investigator's Global Assessment (IGA) Score of Cleared (0) or Minimal (1) Over Time [Baseline (Week 0) up to Week 156]
• Percentage of Participants Who Achieved an IGA Score of Cleared (0) Over Time [Baseline (Week 0) up to Week 156]
• Percent Improvement From Baseline in Psoriasis Area and Severity Index (PASI) Over Time [From baseline (Week 0) up to Week 156]
• Change From Baseline in Dermatology Life Quality Index (DLQI) Score Over Time [From baseline (Week 0) up to Week 156]
• Percentage of Participants Who Achieved DLQI Score of 0 or 1 Over Time [Baseline (Week 0) up to Week 156]
• Change From Baseline in EuroQol-5 Dimension 5-Level (EQ-5D-5L) Over Time: Domain Scores [From baseline (week 0) up to Week 156]
• Change From Baseline in EQ-5D-5L Over Time: Visual Analog Scale (VAS) Scores [From baseline (Week 0) up to Week 156]
• Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Treatment-emergent Serious Adverse Events (TESAEs) [Baseline (Week 0) up to 160 weeks]

Sex: All, ages: 12 Years to any

Inclusion Criteria:

* The study participant has a diagnosis of generalized pustular psoriasis (GPP) or erythrodermic psoriasis (EP) at screening. For GPP, a diagnosis must be classified based on the criteria for diagnosis of GPP by the Japanese Dermatological Association (JDA); for EP, has a history of plaque-type psoriasis. In addition, has an involved body surface area (BSA) of lesion greater than or equal to (>=) 80 percent (%) at baseline
* Candidate for phototherapy or systemic treatment for psoriasis (either naive or history of previous treatment)
* A female participant of childbearing potential must have a negative highly sensitive serum pregnancy test (beta-human chorionic gonadotropin \[beta-hCG\]) at screening and have a negative urine pregnancy test at Week 0 prior to administration of study intervention
* A male participant must agree not to plan to father a child while enrolled in this study or within 90 days after the last dose of study intervention
* A male participant must agree not to donate sperm for the purpose of reproduction during the study and for a minimum of 90 days after receiving the last dose of study intervention

Exclusion Criteria:

* The study participant has a total score of JDA severity index for GPP >=14 at baseline 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 of severe, progressive, or uncontrolled liver, renal; cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, psychiatric, or metabolic 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 concomitant therapy and/or history/conditions of infections

Participant flow

Outcome results

• Percentage of Participants With Generalized Pustular Psoriasis (GPP) Who Experienced Treatment Success at Week 16 (Primary), Number, Percentage of participants: GPP: JNJ-77242113 200 mg QD 88.9 (51.8 to 99.7)
• Percentage of Participants With Erythrodermic Psoriasis (EP) Who Experience Treatment Success at Week 16 (Primary), Number, Percentage of participants: EP: JNJ-77242113 200 mg QD 100.0 (69.2 to 100.0)
• Percentage of Participants With GPP Who Experienced Treatment Success Over Time Based on CGI Scale According to JDA Total Score (Secondary)
• Percentage of Participants With EP Who Experienced Treatment Success Over Time Based on CGI Scale (Secondary)
• Change From Baseline in the Total Score of the Japanese Dermatological Association (JDA) Severity Index for GPP Over Time (Secondary)
• Change From Baseline in Severity Classification of JDA Severity Index for GPP Over Time (Secondary)
• Change From Baseline in the Body Surface Area (BSA) of Involvement of Lesion for EP Over Time (Secondary)
• Percentage of Participants Who Achieved an Investigator's Global Assessment (IGA) Score of Cleared (0) or Minimal (1) Over Time (Secondary)
• Percentage of Participants Who Achieved an IGA Score of Cleared (0) Over Time (Secondary)
• Percent Improvement From Baseline in Psoriasis Area and Severity Index (PASI) Over Time (Secondary)
• Change From Baseline in Dermatology Life Quality Index (DLQI) Score Over Time (Secondary)
• Percentage of Participants Who Achieved DLQI Score of 0 or 1 Over Time (Secondary)
• Change From Baseline in EuroQol-5 Dimension 5-Level (EQ-5D-5L) Over Time: Domain Scores (Secondary)
• Change From Baseline in EQ-5D-5L Over Time: Visual Analog Scale (VAS) Scores (Secondary)
• Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Treatment-emergent Serious Adverse Events (TESAEs) (Secondary)

Adverse events

Time frame: From Week 0 up to Week 24

Serious adverse events by term

Other adverse events by term

• Study Protocol (PDF, 2023-08-29)
• Statistical Analysis Plan (PDF, 2025-04-04)

• Janssen Pharmaceutical K.K., Japan Clinical Trial, Study director, Janssen Pharmaceutical K.K.