Quan 2001.

Methods	Randomised, double‐blind parallel placebo controlled trial. Duration: 96 weeks. Measurements taken at week 4, 12 and every 12 weeks thereafter. Multicentre: 49 CF centres.
Participants	474 children randomised, 410 completed the trial. 60 participants withdrew from the trial, 472 (out of 474) had follow‐up data. The ITT population was 470. Age: range 6 ‐ 10 years (mean age 8.4 years). Disease status: FVC > 85% predicted.
Interventions	Treatment: 2.5 mg rhDNase once daily (n = 239). Control: placebo once daily (n = 235).
Outcomes	Pulmonary function (FEV1, FVC) and exacerbations, deaths, adverse events, change in weight for age.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised by computer, stratifying by centre using a permuted block design.
Allocation concealment (selection bias)	Low risk	Carried out by a pharmacy.
Blinding (performance bias and detection bias) All outcomes	Low risk	Described as double blind, no further details.
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT approach was used. 60 participants withdrew from the trial, 472 (out of 474) had follow‐up data. The ITT population was 470.
Selective reporting (reporting bias)	Unclear risk	Measurements taken at week 4, 12 and every 12 weeks thereafter. The end of trial results were reported.
Other bias	Low risk	None identified.