Malmström 1999.

Methods	Study design: multicentre, prospective, randomised clinical trial Number of study centres: 12 Study dates: 1987–1992, follow‐up of 10 years Participants randomly assigned: 261
Participants	Inclusion criteria: people with stage Ta, grades 1–3 or stage T1, grades 1 and 2 tumours with ≥ 3 tumour effects during the prior 18 months people with stage T1, grade 3 and people with primary or concomitant dysplasia or carcinoma Exclusion criteria: previous or ongoing intravesical treatment with MMC, BCG or radiotherapy, chemotherapy during the prior 6 months any secondary malignancy except treated Cis of the uterine cervix or basal cell carcinoma of the skin ongoing corticosteroid therapy leukocytes < 3000/mL, thrombocytes < 100,000/mL untreated urinary tract infection, urethral stricture preventing cystoscopy, active tuberculosis, pregnancy Karnofsky performance index < 50
Interventions	Group A: MMC 40 mg dissolved in 50 mL phosphate buffer (pH 7.4) Group B: BCG (Danish strain 1331) 120 mg containing 1 × 109 cfu, dissolved in 50 mL saline Procedure: therapy begun 1–3 weeks after TUR or biopsies, and was given weekly for 6 weeks, then monthly for up to 1 year and every 3 months during year 2; treatment cross‐over for people with stage Ta, grades 1–3 or stage T1, grades 1 and 2 disease if tumour relapsed at 2 consecutive follow‐up visits. Cross‐over was performed at initial relapse in people with stage T1, grade 3 tumour, and if cytology and biopsies showed malignancy after 6 months of treatment in people with stage Cis disease or dysplasia.
Outcomes	Recurrence‐free survival, progression‐free survival, overall survival
Funding sources	No information on funding in the first study publication reported. The later publications referred to governmental funding sources.
Declarations of interest	No information on declaration of interests in the first study publication. In the publication of 1999, 1 author reported "financial interest and/or other relationship with Statens Serum Institute;" in the publication of 2007, the authors declared no conflicts of interests.
Notes	Supported by Grant 2323‐Bg5‐09XBB from the Swedish Cancer Society. First author declared financial interest or other relationship with Statens Serum Institute, or both.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: no information
Allocation concealment (selection bias)	Low risk	Comment: randomisation via centralised procedure.
Blinding of participants and personnel (performance bias) all outcomes	High risk	Comment: no information on blinding. We assumed that there was no blinding and that the outcomes might have been influenced by differences in performance due to a lack of blinding.
Blinding of outcome assessment (detection bias) overall survival	Low risk	Comment: no information on blinding. We assumes that there was no blinding but that the absence of blinding did not affect this objective outcome.
Blinding of outcome assessment (detection bias) recurrence and progression free survival	Low risk	Quote: "Immunostaining evaluation was performed blindly, without knowledge of clinical history, by 2 observers (K. W. and C. B.) in collaboration over a conference microscope." (for the 5‐year outcome paper). Comment: we assumed there was low risk for this item.
Blinding of outcome assessment (detection bias) serious and non‐serious adverse effects	Low risk	Quote: "Immunostaining evaluation was performed blindly, without knowledge of clinical history, by 2 observers (K. W. and C. B.) in collaboration over a conference microscope." (for the 5‐year outcome paper). Comment: we assumed there was low risk for this item.
Blinding of outcome assessment (detection bias) quality of life	Unclear risk	Outcome not reported.
Incomplete outcome data (attrition bias) Survival outcomes	Low risk	Comment: 125/130 participants in the MMC group and 125/131 (95%) in the BCG group were included in the analyses.
Incomplete outcome data (attrition bias) Adverse effect outcomes	Low risk	Comment: 125/130 participants in the MMC group and 125/131 (95%) in the BCG group were included in the analyses.
Incomplete outcome data (attrition bias) Quality of life outcomes	Unclear risk	Outcome not reported.
Selective reporting (reporting bias)	Unclear risk	Comment: no study protocol available.
Other bias	Low risk	Comment: we assumed that there was no risk for other bias.