Study of Guselkumab in Skin of Color Participants With Moderate-to-severe Plaque and/or Scalp Psoriasis

Cohort A: Percentage of Participants who Achieve IGA Score of Cleared (0) at Week 16

Percentage of participants with IGA score 0 (cleared) will be reported. The IGA documents the investigator's assessment of the participant's psoriasis at a given time point. Overall lesions are graded for induration, erythema, and scaling. The participant's psoriasis is assessed as cleared (0), minimal (1), mild (2), moderate (3), or severe (4).

Time frame: Week 16

Cohort A: Percentage of Participants who Achieve PASI 100 Response at Week 16

A PASI 100 response is defined as 100% improvement in PASI score from baseline. The PASI is a system used for assessing and grading the severity of psoriatic lesions and their response to therapy. In the PASI system, the body is divided into 4 regions: head, trunk, upper, and lower extremities. Each of these areas is assessed separately for the percentage of the area involved, which translates to a numeric score that ranges from 0 (indicates no involvement) to 6 (90% to 100% involvement), and for erythema, induration, and scaling, which are each rated on a scale of 0 (none) to 4 (severe). The PASI produces a numeric score that can range from 0 to 72. A higher score indicates more severe disease.

Time frame: Week 16

Cohort A: Change from Baseline in PASI Score at Week 16

Change from baseline in PASI score at Week 16 will be reported. The PASI is a system used for assessing and grading the severity of psoriatic lesions and their response to therapy. In the PASI system, the body is divided into 4 regions: head, trunk, upper, and lower extremities. Each of these areas is assessed separately for the percentage of the area involved, which translates to a numeric score that ranges from 0 (indicates no involvement) to 6 (90% to 100% involvement), and for erythema, induration, and scaling, which are each rated on a scale of 0 (none) to 4 (severe). The individual scores are multiplied by a weighted factor for each body region; the sum of these scores gives the total PASI score. The PASI produces a numeric score that can range from 0 to 72. A higher score indicates more severe disease.

Time frame: Baseline and Week 16

Cohort A: Change from Baseline in Body Surface Area (BSA) at Week 16

Change from baseline in BSA at Week 16 will be reported. The BSA is a measurement of involved skin over the whole body. The overall BSA affected by psoriasis is estimated based on the participant's handprint (defined as the entire palmar surface of the hand including fingers).

Time frame: Baseline and Week 16

Cohort A: Time to >=90% Reduction in PASI Score

Time to \>=90% reduction in PASI score will be reported which is defined as time to achieve \>=90% improvement in PASI. The PASI is a system used for assessing and grading the severity of psoriatic lesions and their response to therapy. In the PASI system, the body is divided into 4 regions: head, trunk, upper, and lower extremities. Each of these areas is assessed separately for the percentage of the area involved, which translates to a numeric score that ranges from 0 (indicates no involvement) to 6 (90% to 100% involvement), and for erythema, induration, and scaling, which are each rated on a scale of 0 (none) to 4 (severe). The PASI produces a numeric score that can range from 0 to 72. A higher score indicates more severe disease.

Time frame: Up to Week 16

Cohorts A and B: Change from Baseline in Dermatology Life Quality Index (DLQI) Score at Week 16

Change from baseline in DLQI score at Week 16 will be reported. The DLQI is a dermatology specific quality of life instrument designed to assess the impact of dermatologic disease on a participant's quality of life (QoL). It is a 10 item patient-reported outcome(s) (PRO) questionnaire that, in addition to evaluating overall QoL, can be used to assess 6 different aspects that may affect QoL: symptoms and feelings, daily activities, leisure, work or school performance, personal relationships, and treatment. The DLQI produces a numeric score that can range from 0 to 30. A higher score indicates more severe disease.

Time frame: Baseline and Week 16

Cohort A: Percentage of Participants who Achieve >= 4-point Reduction (Improvement) from Baseline in the Psoriasis Symptom and Sign Diary (PSSD) Itch Score at Week 16, Among Participants with Baseline PSSD Itch >= 4 at Baseline

Percentage of participants who achieve \>=4-point reduction (improvement) from baseline in PSSD itch score at Week 16 among participants with baseline PSSD itch \>=4 at baseline will be reported. The PSSD includes PRO questionnaires designed to measure the severity of psoriasis symptoms and signs for the assessment of treatment benefits. The participants are asked to answer the questions thinking about either the last 24 hours (24-hour recall version) or the last 7 days (7 days recall version). Both versions include 11 items covering symptoms (itch, pain, stinging, burning and skin tightness) and participant observable signs (skin dryness, cracking, scaling, shedding or flaking, redness and bleeding) using 0 to 10 numerical rating scales for severity. Two subscores will be derived, each ranging from 0-100: the psoriasis symptom score and the psoriasis sign score. A higher score indicates more severe disease.

Time frame: Week 16

Cohorts A and B: Percentage of Participants who Achieve a PSSD Symptom Score of 0 at Week 16, Among Randomized Participants with Baseline PSSD Symptom Score >=1

Percentage of participants who achieve a PSSD symptom score of 0 at Week 16 among randomized participants with baseline PSSD symptom score \>=1 will be reported. The PSSD includes PRO questionnaires designed to measure the severity of psoriasis symptoms and signs for the assessment of treatment benefits. The participants are asked to answer the questions thinking about either the last 24 hours (24-hour recall version) or the last 7 days (7 days recall version). Both versions include 11 items covering symptoms (itch, pain, stinging, burning and skin tightness) and participant observable signs (skin dryness, cracking, scaling, shedding or flaking, redness and bleeding) using 0 to 10 numerical rating scales for severity. Two subscores will be derived, each ranging from 0-100: the psoriasis symptom score and the psoriasis sign score. A higher score indicates more severe disease.

Time frame: Week 16

Cohorts A and B: Change from Baseline in PSSD Symptom Score at Week 16

Change from baseline in PSSD symptom score at Week 16 will be reported. The PSSD includes PRO questionnaires designed to measure the severity of psoriasis symptoms and signs for the assessment of treatment benefits. The participants are asked to answer the questions thinking about either the last 24 hours (24-hour recall version) or the last 7 days (7 days recall version). Both versions include 11 items covering symptoms (itch, pain, stinging, burning and skin tightness) and participant observable signs (skin dryness, cracking, scaling, shedding or flaking, redness and bleeding) using 0 to 10 numerical rating scales for severity. Two subscores will be derived, each ranging from 0-100: the psoriasis symptom score and the psoriasis sign score. A higher score indicates more severe disease.

Time frame: Baseline and Week 16

Cohort B: Percentage of Participants who Achieve ss-IGA Score of Absence of Disease (0) at Week 16

Percentage of participants with ss-IGA score 0 (absence of disease) will be reported. The ss-IGA instrument is used to evaluate the disease severity of scalp psoriasis. The lesions are assessed in terms of the clinical signs of redness, thickness, and scaliness which are scored as: absence of disease (0), very mild disease (1), mild disease (2), moderate disease (3), and severe disease (4).

Time frame: Week 16

Cohort B: Change from Baseline in Scalp Surface Area (SSA) at Week 16

Change from baseline in SSA at Week 16 will be reported. The SSA is a measurement of involved skin on the scalp. The overall SSA affected by psoriasis will be estimated based on the participant's thumb.

Time frame: Baseline and Week 16

Cohort B: Percentage of Participants who Achieve PSSI 100 Response at Week 16

A PSSI 100 response is defined as 100% reduction in PSSI score from baseline. The PSSI measures the extent of psoriasis involvement and the severity of erythema, infiltration, and desquamation of the scalp. Involved scalp area is measured on a scale from 0 (0% of scalp involved) to 6 (90-100% of scalp involved), clinical symptoms are each rated from 0 (absent) to 4 (severest possible). Involvement and severity of psoriasis for the PSSI is scored by physicians using a scale from 0 to 72, where 0=no psoriasis, and higher scores indicating more severe disease.

Time frame: Week 16

Cohort B: Change from Baseline in PSSI Score at Week 16

Change from baseline in PSSI score at Week 16 will be reported. The PSSI measures the extent of psoriasis involvement and the severity of erythema, infiltration, and desquamation of the scalp. Involved scalp area is measured on a scale from 0 (0% of scalp involved) to 6 (90-100% of scalp involved), clinical symptoms are each rated from 0 (absent) to 4 (severest possible).The PSSI total score is a composite score derived from the sum of the scores for erythema, induration and desquamation multiplied by the score for the extent of scalp area involved (percent of scalp involved). Involvement and severity of psoriasis for the PSSI is scored by physicians using a scale from 0 to 72, where 0=no psoriasis, and higher scores indicating more severe disease.

Time frame: Baseline and Week 16

Cohort B: Time to >=90% Reduction in PSSI Score

Time to \>=90% reduction in PSSI score will be reported which is defined as time to achieve \>=90% improvement in PSSI. The PSSI measures the extent of psoriasis involvement and the severity of erythema, infiltration, and desquamation of the scalp. Involvement and severity of psoriasis for the PSSI is scored by physicians using a scale from 0 to 72, where 0=no psoriasis, and higher scores indicating more severe disease.

Time frame: Up to Week 16

Cohort B: Percentage of Participants with >= 4 Point Reduction (Improvement) from Baseline in the Scalp Itch NRS Score at Week 16, Among Participants with Baseline Scalp Itch >=4 at Baseline

Percentage of participants with \>=4 point reduction (improvement) from baseline in scalp itch NRS score, among participants with scalp itch \>=4 at baseline will be reported. The scalp itch NRS is a single-item scale that asks participants to rate the severity of their scalp itching due to psoriasis by considering their worst level of itching over the past 24 hours. The participants will be asked to assess scalp itch and select a number on a scale of 0-10, where "0" represents no scalp itch, and "10" represents the worst imaginable scalp itch.

Time frame: Week 16

Cohorts A and B: Number of Participants with Adverse Events (AEs)

An adverse event (AE) is any untoward medical event that occurs in a participant administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product.

Time frame: Up to Week 116

Cohorts A and B: Number of Participants with Serious Adverse Events (SAEs)

SAE is an adverse event resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly/birth defect; suspected transmission of any infectious agent via a medicinal product or medically important.

Time frame: Up to Week 116