| Ciprofloxacin DPI | Placebo | p-value | |
| Baseline total subjects | 60 | 63# | 0.220¶ |
| No sputum/clear | 5 (8.3) | 7 (11.1) | |
| Yellow | 29 (48.3) | 23 (36.5) | |
| Green | 25 (41.7) | 28 (44.4) | |
| Rust | 1 (1.7) | 5 (7.9) | |
| End of treatment | 49 | 52 | 0.026¶, 0.029+ |
| No sputum/clear | 12 (24.5) | 9 (17.3) | |
| Yellow | 31 (63.3) | 26 (50.0) | |
| Green | 5 (10.2) | 17 (32.7) | |
| Rust | 1 (2.0) | 0 | |
| 4-week follow-up | 40 | 37 | 0.494¶, 0.609+ |
| No sputum/clear | 10 (25.0) | 5 (13.5) | |
| Yellow | 16 (40.0) | 22 (59.5) | |
| Green | 11 (27.5) | 9 (24.3) | |
| Rust | 3 (7.5) | 1 (2.7) |
Data are presented as n or n (%), unless otherwise stated. DPI: dry powder for inhalation. #: no sputum information was available for one patient; ¶: based on Cochran–Mantel–Haenszel test with ridit scores test stratified by centre/cluster of centre; +: based on Cochran–Mantel–Haenszel test with ridit scores test stratified by centre/cluster of centre and baseline sputum colour.