Sionna Therapeutics (SION) Corporate presentation summary

Leadership and expertise

• Executive team and board have extensive experience in rare disease, biotech, and CF drug development.

• Founders and key scientists have backgrounds at Genzyme, Sanofi, Vertex, and other leading firms.

Scientific foundation and innovation

• Over 15 years of CFTR research, with origins in Genzyme and Sanofi, underpin the pipeline.

• Focus on stabilizing NBD1, a critical domain affected in ~90% of CF patients with the F508del mutation.

• NBD1 stabilization shown to restore CFTR half-life and function to wild-type levels in preclinical studies.

Pipeline and clinical progress

• Lead NBD1 stabilizers SION-719 and SION-451 advanced through successful Phase 1 trials, showing favorable PK and safety.

• SION-719 is being evaluated as an add-on to standard of care (SOC) in a Phase 2a POC trial; SION-451 is anchor for dual combinations.

• Dual combinations with complementary correctors (SION-2222, SION-109) are in Phase 1 trials, with topline data expected summer 2026.