Golimumab will be administered as a SC injection.

Placebo will be administered as a SC injection.

MDA defines a satisfactory state of disease activity that includes the 5 domains of PsA (joint symptoms, skin psoriasis, participant's assessment of pain and disease activity, physical function, and enthesitis). Participants are classified as achieving MDA if they fulfilled 5 of 7 outcome measures: tender joint count <=1; swollen joint count <=1; PASI <=1 or BSA <=3%; participant's pain VAS score of <=15; participant's global disease activity VAS (arthritis and psoriasis) score of <=20; HAQ-DI score <=0.5; and tender entheseal points <=1.

The PASI is a system used for assessing and grading the severity of psoriatic lesions and their response to therapy. The PASI produces a numeric score that can range from 0 (no psoriasis) to 72. Higher scores indicate more severe disease. A PASI 90 response is defined as >=90% 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. The PASI produces a numeric score that can range from 0 (no psoriasis) to 72. Higher scores indicate more severe disease. A PASI 100 response is defined as 100% improvement in PASI score from baseline.

IGA psoriasis response is defined as an IGA psoriasis score of 0 (cleared) or 1 (minimal) and >=2 grade reduction from baseline. 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, each using a 5-point scale: using 0 (no evidence), 1 (minimal), 2 (mild), 3 (moderate), and 4 (severe) scale. The IGA score of psoriasis is based upon the average of induration, erythema, and scaling scores. The participant's psoriasis is assessed as cleared (0), minimal (1), mild (2), moderate (3), or severe (4).

HAQ-DI score assess functional status of participant. It is 20 question instrument that assess degree of difficulty a person has in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and activities of daily living). Responses in each functional area are scored from 0=indicating no difficulty, to 3=indicating inability to perform a task in that area. Total HAQ score is average of the computed categories scores ranging from 0-3 where 0=least difficulty and 3=extreme difficulty. Lower scores are indicative of better functioning. Negative change from baseline indicates improvement of physical function.

Enthesitis will be assessed using the Leeds Enthesitis Index (LEI), a tool developed to assess enthesitis in participants with PsA and evaluates the presence (score of 1) or absence (score of 0) of pain by applying local pressure to the following entheses: left and right lateral epicondyle humerus, left and right medial femoral condyle, and left and right achilles tendon insertion. The enthesitis index score is a total score of the 6 evaluated sites from 0 (0 sites with tenderness) to 6 (worst possible score; 6 sites with tenderness). A LEI score of 0 at a post baseline visit indicates resolution of enthesitis when baseline LEI >0.

The presence and severity of dactylitis is assessed in both hands and feet using a scoring system from 0 to 3 (0-no dactylitis, 1-mild dactylitis, 2-moderate dactylitis, and 3-severe dactylitis) for each digit. The results are summed to produce a final score ranging from 0 to 60. Higher score indicates more severe dactylitis. Resolution of dactylitis is defined as a dactylitis score of 0 with the baseline dactylitis score >0.

SF-36 is a multi-domain instrument with 36 items to evaluate the health status and quality of life. It included 8 subscales (physical functioning, physical role functioning, bodily pain, general health perception, vitality, social functioning, emotional role functioning, and mental health), which yielded a PCS with score range 0-100 (higher score-better quality of life) and a Mental Component Summary (MCS) with score range 0-100 (higher score-better quality of life) in addition to subscale scores. The PCS scores are normalized to a mean of 50 and standard deviations of 10, based upon general US population norms. A positive change indicates improvement while a negative change indicates worsening of health status and quality of life.

Percentage of participants with AEs, SAEs, and reasonably related AEs will be assessed. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. SAE is any AE that results in: death, persistent or significant disability/incapacity, requires inpatient hospitalization or prolongation of existing hospitalization, is life-threatening experience, is a congenital anomaly/birth defect, and suspects transmission of any infectious agent via a medicinal product. Reasonably related AEs are those AEs which are judged related to study treatment by the investigator.

Percentage of participants with AEs leading to discontinuation of study intervention will be reported.

Percentage of participants with infections will be reported.

Percentage of participants with injection-site reactions will be reported. An injection-site reaction is any adverse reaction at a subcutaneous (SC) study intervention injection-site.

Serum guselkumab and golimumab concentration will be measured.

Percentage of participants with antibodies to guselkumab or golimumab will be reported.