Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 183

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 183
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100 mg, 200 mg, 400 mg QD) over 29 days. |

| • |     | Galicaftor was generally well-tolerated in this trial. The majority of reported treatment-emergent AEs were mild or                                                                                                                                       
 moderate in severity. A total of four SAEs were reported (two after galicaftor, two after placebo) in two subjects in the pooled placebo and one subject in the galicaftor 100 mg QD treatment group, respectively. The three subjects experienced one or 
 two events of infective pulmonary exacerbation of CF, all of which were considered not related to trial drug.                                                                                                                                             |

| • |     | Sweat chloride levels, lung function (ppFEV1) and CFQ-R were also                                                                                                                                                                                       
 assessed as secondary endpoints. Mean sweat chloride concentrations decreased dose-dependently with increasing doses of galicaftor, with a maximum decrease observed in the 200 mg QD treatment group on days 15 and 29, with statistically significant 
 LS means differences compared to placebo of -11.2 (95% CI, -19.1; -3.3; p=0.0062) and -15.8 (95% CI, -23.2; -8.3; p<0.0001) mmol/L, respectively. After termination of the trial drug, mean sweat chloride concentrations returned to baseline values   
 in all treatment groups. Percent predicted FEV1 and CFQ-R did not significantly improve in any group.                                                                                                                                                   |

| • |     | Trial GLPG-2222-CL-201 was a Phase 2 trial conducted by Galapagos in Europe and Australia that evaluated the safety and                                                                   
 tolerability and the effect on CFTR function (sweat chloride), lung function (ppFEV1) and CFQ-R of galicaftor in 37 CF patients that were heterozygous for F508del and a gating mutation, 
 receiving ivacaftor. The trial was completed in August 2017.                                                                                                                              |

| • |     | Two doses of galicaftor were tested in this trial (150 mg or 300 mg QD) over 29 days. |

| • |     | Galicaftor was well-tolerated in this trial. Most treatment-emergent AEs were mild in severity, and there were no SAEs. |

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| • |     | Changes from baseline in sweat chloride