Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 171

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 171
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 SION-109
were achieved with single and multiple doses.

A PK summary of SION-719 is shown in Figures 14 and 15 below.
The observed PK was consistent with twice daily (“BID”) dosing.

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Figure 14. Preliminary Phase 1 PK Summary for SION-719in the SAD Portion of the Trial

(Each solid line shows mean concentration data from a dosing cohort. Dotted lines represent average PK concentration exposure targets that have the potential, based on our preclinical CFHBE model, to provide clinically meaningful benefit, if SION-719 is administered in a proprietary dual combination with either SION-2222 or SION-109, or as an add-on to SOC.)

Figure 15. Preliminary Phase 1 PK Summary for SION-719in the MAD Portion of the Trial

(Each solid line shows mean concentration data from a dosing cohort on Day 10. Dotted lines represent average PK concentration exposure targets that have the potential, based on our preclinical CFHBE model, to provide clinically meaningful benefit, if SION-719 is administered in a proprietary dual combination with either SION-2222 or SION-109, or as an add-on to SOC.)

127

Interim Phase 1 Trial Data for SION-451

As of January 14, 2025, over 70 healthy subjects have been dosed in the Phase 1 clinical trial of SION-451. The
trial was designed to enroll eight subjects, randomized 3:1 active:placebo, in each dosing cohort. Four SAD cohorts have been completed, evaluating single doses of 75 mg, 150 mg, 300 mg and 450 mg. Two additional SAD cohorts have completed
dosing with 75 mg or 25 mg with food to provide a preliminary assessment of the effect of food on PK. Three MAD cohorts have been completed, evaluating 75 mg, 150 mg and 300 mg of SION-451 twice daily over 10
dosing days. We plan to continue enrolling healthy subjects in the trial. All data remain blinded to individual subject treatment assignment.

SION-451 was generally well tolerated at all dose levels administered based on interim Phase 1 clinical data as of the data cutoff date of January 14,
2025. There were no SAEs, and most TEAEs were mild to moderate (Grade 1 or Grade 2). No TEAEs led