NCT02672852.

Study characteristics
Methods	RCT, placebo‐controlled, double‐blind study Date of study: February 2016 ‐ July 2018 Location: worldwide Phase 3
Participants	Randomised: 507 participants Inclusion criteria Men or women Women of childbearing potential must be ready and willing to use highly effective methods of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly Age ≥ 18 years at screening Diagnosis of chronic plaque psoriasis (with or without psoriatic arthritis) ≥ 6 months before the first administration of study drug. Duration of diagnosis may be reported by the patient Stable moderate‐severe chronic plaque psoriasis with or without psoriatic arthritis at both screening and baseline (randomisation); Have an involved BSA ≥ 10%, PASI ≥ 12 a sPGA score of ≥ 3 Must be a candidate for systemic therapy or phototherapy for psoriasis treatment, as assessed by the investigator Signed and dated written informed consent prior to admission to the study and performance of any study procedures in accordance with GCP and local legislation Exclusion criteria: Non‐plaque forms of psoriasis (including guttate, erythrodermic, or pustular); current drug‐induced psoriasis (including a new onset of psoriasis or an exacerbation of psoriasis from beta blockers, calcium channel blockers, or lithium); active ongoing inflammatory diseases other than psoriasis and psoriatic arthritis that might confound trial evaluations according to the investigator's judgement Previous exposure to ABBV‐066 Currently enrolled in another investigational study or < 30 days (from screening) since completing another investigational study Use of any restricted medication as noted or any drug considered likely to interfere with the safe conduct of the study Major surgery performed within 12 weeks prior to randomisation or planned within 12 months after screening (e.g. hip replacement, removal aneurysm, stomach ligation) Known chronic or relevant acute infections such as active TB, HIV, or viral hepatitis Any documented active or suspected malignancy or history of malignancy within 5 years prior to screening, except appropriately‐treated basal cell carcinoma or squamous cell carcinoma of the skin or in situ carcinoma of uterine cervix Evidence of a current or previous disease (including chronic alcohol or drug abuse), medical condition other than psoriasis, surgical procedure (i.e. organ transplant), medical examination finding (including vital signs and ECG), or laboratory value at the screening visit outside the reference range that in the opinion of the Investigator is clinically significant and would make the study participant unable to adhere to the protocol or to complete the trial, compromise the safety of the patient, or compromise the quality of the data History of allergy/hypersensitivity to a systemically administered biologic agent or its excipients Women who are pregnant, nursing, or who plan to become pregnant while in the trial Previous enrolment in this trial Dropouts and withdrawals 7/507 (1.4%) Risankizumab group (4), Placebo group (3) Lost to follow‐up: Risankizumab group (1), Placebo group (2) Disease worsening: Risankizumab group (1), Placebo group (0) Withdrawal by participant: Risankizumab group (1), Placebo group (1) AEs: Risankizumab group (0), Placebo group (1)
Interventions	Intervention A. Risankizumab 150 mg by subcutaneous injection at Weeks 0 and 4, n = 407 Control intervention B. Placebo by subcutaneous injection at Weeks 0 and 4, n = 100
Outcomes	At week 16 Primary composite outcome PASI 90 PGA 0/1 Secondary outcomes PASI 75 at weeks 16 and 52 PASI 90 at weeks 52 PGA 0/1 at weeks 52
Notes	Funding: AbbVie, Boehringer Ingelheim Conflict of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote (ClinicalTrials.gov and study protocol/statistical analysis plan): "This is a confirmatory, multinational, multicenter, randomized, double‐blind, placebo controlled, study... During Visit 2 and after the patient’s eligibility has been confirmed, the treatment will be assigned via Interactive Response Technology (IRT). To facilitate the use of the IRT, the Investigator will receive all necessary instructions." Comment: probably done
Allocation concealment (selection bias)	Low risk	Quote (ClinicalTrials.gov and study protocol/statistical analysis plan): "This is a confirmatory, multinational, multicenter, randomized, double‐blind, placebo controlled, study... During Visit 2 and after the patient’s eligibility has been confirmed, the treatment will be assigned via Interactive Response Technology (IRT). To facilitate the use of the IRT, the Investigator will receive all necessary instructions." Comment: probably done
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote (ClinicalTrials.gov and study protocol/statistical analysis plan): "Injections should be at least 2 cm. apart and should not be close to a vein. The injection sites should avoid sites of psoriasis involvement as well as sites where the skin is tender, bruised, erythematous, or indurated, and should be alternated to other areas for subsequent doses. Injections will be given in a double blind fashion with each patient receiving 2 injections of BI 655066 or matching placebo administered within approximately 5 minutes at each dosing visit as indicated in the Flow Charts" Comment: probably done
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote (ClinicalTrials.gov and study protocol/statistical analysis plan): "Injections should be at least 2 cm. apart and should not be close to a vein. The injection sites should avoid sites of psoriasis involvement as well as sites where the skin is tender, bruised, erythematous, or indurated, and should be alternated to other areas for subsequent doses. Injections will be given in a double blind fashion with each patient receiving 2 injections of BI 655066 or matching placebo administered within approximately 5 minutes at each dosing visit as indicated in the Flow Charts" Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dealing with missing data: Quote (statistical analysis plan): "The NRI will be the primary approach in the analyses of categorical variables." ITT results on ClinicalTrials.gov
Selective reporting (reporting bias)	Low risk	Comment: the protocol for the study was available on ClinicalTrials.gov (NCT02672852) The prespecified outcomes and those mentioned in the Methods section appeared to have been reported