NCT02313922.

Study characteristics
Methods	RCT, placebo‐controlled, double‐blind trial Date of study: August 2014 ‐ October 2016 Location: China (19 centres) Phase 4
Participants	Randomised: 466 participants Inclusion criteria Adults of both sexes, ≥ 18 years of age Patients who had a diagnosis of moderate‐to‐severe plaque psoriasis for ≥ 6 months Patients with an affected body surface area ≥ 10% and a PASI score > 10 at screening and baseline Patients who had failed to respond to a systemic therapy except methotrexate and were candidates for systemic therapy in the opinion of the investigator Patients who agreed to take means of contraception during the trial and 6 months after if they had reproductive potential Exclusion criteria Patients with guttate, erythrodermic,pustular psoriasis or drug‐induced psoriasis or other skin diseases that may interfere with evaluation Recent infection or opportunistic infections, active TB, hepatitis B and so on Liver and kidney dysfunction Other serious, progressive, uncontrolled disorders of vital organs and systems (including cardiovascular, liver, lung and kidney), other autoimmune diseases, cancer, HIV infection, which are not suitable for participation in the study of the disease History of significant methotrexate toxicity or total cumulative methotrexate exposure > 1000 mg (unless grade IIIb liver injury has not occurred) Use of UVB therapy, topical ciclosporin or calcineurin inhibitors, class III through VII topical corticosteroids (permitted on the scalp, axillae, and/or groin), or topical vitamin A or D analogues within 14 days of screening Psoralen or UVA therapy, systemic psoriasis therapy (including methotrexate), oral retinoids, class I or II topical corticosteroids, dithranol, cyclophosphamide, sulfasalazine, or intravenous or oral calcineurin inhibitors within 28 days of screening Patients were excluded if they had received a tumour necrosis factor (TNF) blocking agent or other biologics within 3 months or interleukin (IL)‐12 or IL‐23 inhibitors within 6 months of study initiation Baseline characteristics N = 466, mean age of 43 years and 76% men Dropouts and withdrawals 24/466 (5.15%): Methotrexate group (13), Placebo group (11) AEs: Methotrexate group (4), Placebo group (5) Lost to follow‐up: Methotrexate group(6), Placebo group (5) Withdrawal of consent: Methotrexate group(2), Placebo group (1) Did not meet eligibility criteria: Methotrexate group(1), Placebo group (0)
Interventions	Intervention A. Methotrexate (initial dose of 7.5 mg/week to a maximum dose of 15 mg/week or the maximum tolerated dose within 8 weeks), n = 233 Control intervention B. Placebo, n = 233 Co‐intervention: etanercept (50 mg subcutaneously once weekly)
Outcomes	At week 24 Primary outcome PASI 75 Secondary outcomes PASI 90, PASI 50 at weeks 12 and 24 PASI 75 at weeks 12 Patient’s Global Assessment (PtGA) and static Physician’s Global Assessment (sPGA) at weeks 12 and 24 DLQI at weeks 12 and 24 AEs
Notes	Funding "This research was supported by Zhejiang Public Walfare Technology Research Project (Grant number: LGF20H110002). Med‐ ical Health Science and Technology Project of Zhejiang Provincial Health Commission (Grant Number: 2018KY088) and 3SBIO INC." Conflict of interest "The authors declare that they have no conflict of interest."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote:""All eligible patients were randomly assigned by a random number created by a computer‐generated coding system to receive either the combination of rhTNFR‐Fc and MTX (combination group) or rhTNFR‐Fc plus placebo (monotherapy group)."
Allocation concealment (selection bias)	Unclear risk	Quote:"Then patients were randomized 1:1 to receive 50 mg rhTNFR‐Fc subcutaneously once weekly and oral MTX (from an initial dose of 7.5 mg/week to a maximum dose of 15 mg/week or the maximum tolerated dose within 8 weeks) or receive rhT‐ NFR‐Fc (as that in combination group) and a matched placebo (as MTX in combination group) for 24 weeks." Comment: no description of the method used to guarantee allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote:"This was a multicentre, randomized, double‐blind, placebo‐controlled trial of rhTNFR‐Fc..." Comment: no description of the method used to guarantee allocation blinding of participants and personnel
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote:"This was a multicentre, randomized, double‐blind, placebo‐controlled trial of rhTNFR‐Fc..." Comment: no description of the method used to assess the primary outcome
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Dealing with missing data:no information on how were handled missing data Quote:"Efficacy analysis was performed using the intent‐to‐treat principle, in which all randomized patients who received any part of the study medication treatment and received at least one evaluation of therapeutic effectiveness were included in the analysis. All results of the efficacy analysis were analysed in the full analysis set (FAS). Safety was analysed in a safety analysis set (SAS), which included all patients who had received at least 1 dose of the study drug." Randomised 466; analysed 466
Selective reporting (reporting bias)	Low risk	Comment: the protocol for the study was available on ClinicalTrials.gov (NCT02313922). The prespecified outcomes and those mentioned in the Methods section appeared to have been reported. No results are posted on ClinicalTrials.gov.