A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Subcutaneously Administered Guselkumab for the Treatment of Chronic Plaque Psoriasis in Pediatric Participants

Inclusion Criteria:

• Have a diagnosis of chronic plaque-type psoriasis for at least 6 months (with orwithout psoriatic arthritis [PsA]), prior to first administration of studyintervention, defined as having at screening and baseline, Investigator GlobalAssessment (IGA) greater than or equal to (>=) 3, Psoriasis Area and Severity Index (PASI) >=12, >=10% body surface area (BSA) involvement and at least one of thefollowing: very thick lesions, clinically relevant facial, genital, or hand/ footinvolvement, PASI>=20, >20% BSA involvement, or IGA=4

• Be a candidate for phototherapy or systemic treatment of plaque psoriasis (eithernaive or history of previous treatment)

• Have plaque psoriasis considered by the investigator as inadequately controlled withphototherapy and/or topical therapy after an adequate dose and duration of therapy

• Be considered, in the opinion of the investigator, a suitable candidate foretanercept therapy, according to their country's approved Enbrel product labeling

• Be otherwise healthy on the basis of physical examination, medical history, andvital signs performed at screening. Any abnormalities, must be consistent with theunderlying illness in the study population and this determination must be recordedin the participant's source documents and initialed by the investigator

• Must have acceptable evidence of immunity to varicella and measles, mumps, andrubella (MMR), which includes any one of the following: documentation ofage-appropriate vaccination that includes both doses of each vaccine (unless localguidelines specify otherwise) or documentation of past infection by a healthcareprovider or in the absence of previous 2 criteria, participants must have positiveprotective antibody titers to these infection prior to the first administration ofstudy intervention. For participants who have not completed the recommendedvaccination schedule for varicella and MMR, and the subsequent vaccination fallswithin the next 4 years, an accelerated vaccination schedule must be completed priorto study enrollment if available and required or strongly recommended for thelocation. If varicella or MMR vaccines are utilized, it is necessary for 2 weeks toelapse between the vaccination and receipt of study intervention

Exclusion Criteria:

• Currently has nonplaque forms of psoriasis (example, erythrodermic, guttate, orpustular)

• Has current drug-induced psoriasis (example, a new onset of psoriasis or anexacerbation of psoriasis from beta blockers, calcium channel blockers, or lithium)

• Has previously received guselkumab or etanercept

• Has a history of chronic or recurrent infectious disease, including but not limitedto chronic renal infection, chronic chest infection (example, bronchiectasis),recurrent urinary tract infection (recurrent pyelonephritis or chronic non-remittingcystitis), fungal infection (mucocutaneous candidiasis), or open, draining, orinfected skin wounds or ulcers

• Has a known history of lymphoproliferative disease, including lymphoma; a history ofmonoclonal gammopathy of undetermined significance (MGUS); or signs and symptomssuggestive of possible lymphoproliferative disease, such as lymphadenopathy orsplenomegaly