Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 157

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 157
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), a TMD1-directed corrector, which has recently completed a Phase 1 clinical trial.                                                                                                                                                           |

| • |     | Build upon our NBD1-centric CF franchise through a data-driven dual combination path. Our strategy is to                                                                                                                                               
 advance multiple NBD1 stabilizers and complementary compounds through Phase 1 development, with the goal of selecting the combinations with the best potential, based on human data. Following the selection of our lead NBD1 stabilizer, we intend to 
 begin MAD trials in healthy volunteers evaluating galicaftor and/or SION-109 in combination with our lead NBD1 stabilizer to assess the safety, tolerability and PK of each combination, with the goal of                                              
 developing proprietary combination therapies that provide clinically meaningful benefit to CF patients. Based on the results of these trials, we plan to select the most promising lead proprietary dual combination to advance into Phase 2b          
 dose-ranging trials in patients with CF.                                                                                                                                                                                                               |

| • |     | Fortify our CF franchise through continued research efforts and utilization of the translational CFHBE model. Our                                                                                                                                         
 goal is to build a CF franchise anchored by our NBD1 stabilizers and remain focused on our mission to deliver clinically meaningful benefit to CF patients. The CFHBE model has been highly predictive of clinical outcomes for approved CFTR modulators, 
 and our application of the model provides a key translational roadmap for us to prioritize compounds for further evaluation. We believe the model allows us to determine the target exposure needed to achieve a desired level of clinical activity, such 
 as the level of improvement in a patient’s forced expiratory volume in one second (“FEV1”), a measure of lung function, and sweat chloride level, the clinical biomarker of CFTR                                                                          
 function. We intend to invest in research activities and leverage insights from the model in our pursuit of delivering additional differentiated product candidates that meaningfully impact the lives of CF patients and facilitate our company’s        
 long-term growth. We also intend to opportunistically consider strategic in-licensing opportunities to maximize the value of our pipeline.                                                                                                                |

Our Company’s History and Our Team Sionna was founded in 2019 to continue to explore novel approaches to treating CF by targeting NBD1. Our co-founders,Greg Hurlbut, Ph.D., and Mark Munson, Ph.D., spent over a decade extensively researching the NBD1 target as research leaders at Sanofi SA (f/k/a Sanofi Genzyme) (“San