GUGGENHEIM 3RD ANNUAL HEALTHCARE INNOVATION CONFERENCE - SIONNA THERAPEUTICS INC

Explicit Guidance:

• Cash Runway: Extended cash runway through the second half of 2029, ending Q2 with $268 million in cash to support dual-combo clinical execution.
• Study Initiation: The Phase 2 Ascension CF proof-of-concept study is scheduled to initiate in the first quarter of the coming year (Q1).
• Study Readout: No specific timeframe provided for top-line data from the Phase 2 study; timing will be determined post-initiation based on enrollment pace.
• Study Design: The upcoming Phase 2 Ascension CF study is an open-label, 28-day dosing trial in homozygous patients switching from Trikafta to the dual combination; primary endpoint is sweat chloride reduction.

Business-Segment Outlook:

• Asset Strategy: Pivot to a two-drug dual combination strategy (NBD1 stabilizer 451 + TMD1 corrector 2222) to replace the failed four-drug add-on approach with Trikafta.
• Efficacy Targets: Expectation to achieve CFTR function equivalent to or better than Vertex's triple-combination standard of care, with a target product profile (TPP) of clinical superiority and a minimum product profile (MPP) of equivalency.
• Phase Development: Post-Phase 2 Ascension CF, the path includes a dual-combination dose-ranging study followed by a Phase 3 pivotal trial aiming for approval of F508del patients (including both homozygous and heterozygous).
• Molecule Selection: 451 (NBD1) selected for higher exposures and 2222 (TMD1) selected for optimized once-daily dosing profile, avoiding the PK interactions observed with the previous 719/Trikafta combination.

Market and Competitive Outlook:

• Competitive Landscape: Acknowledges Vertex's pipeline progress (e.g., VX-828/Version 3.5/4.0) but maintains that current competitor data (e.g., Aleq/Trek-like results) does not fundamentally alter Siona's opportunity given the unique NBD1 mechanism.
• Differentiation Strategy: Positions the two-drug NBD1 combination as a unique alternative to three-drug regimens, aiming to drive "fully normal" CFTR function that competitors may not achieve.
• Market Position: Asserts leadership in the NBD1 modulator space with a strong asset portfolio and expects NBD1 to become a core component of the future CF treatment armamentarium.

Macro / Industry Outlook:

• Regulatory Strategy: Planning deep engagement with regulators ahead of Phase 3 to design a straightforward pivotal study; potential study designs include non-inferiority or superiority trials depending on Phase 2 data outcomes.
• Patient Population: Focus remains on the F508del cohort at launch, with plans to expand to heterozygous populations in later phases; no specific macroeconomic or currency impact discussed.

Strategic Initiatives:

• Portfolio Restructuring: Company has been resized to prioritize clinical investments in the 451-2222 dual combination, effectively pausing the four-drug strategy.
• New Clinical Studies: Launch of Phase 2 Ascension CF study in Q1; subsequent development of dose-ranging and pivotal Phase 3 studies.
• Assay Optimization: Applying post-hoc learnings from the Precision CF failure regarding "anti-synergy" and biological channel regulation to refine future assay interpretations and study designs.
• M&A/Partnerships: None mentioned; focus is on internal execution of the dual-combo strategy.

Risks and Headwinds to Outlook:

• Clinical Failure Risk: The Phase 2 Ascension CF study must demonstrate efficacy to restore conviction in the NBD1 hypothesis; failure would undermine the entire strategic pivot.
• Unpredictable Biology: Acknowledgment that the anti-synergy seen with the four-drug combination was complex and patient-variable; while the two-drug combo avoids the specific PK interaction, biological synergy remains a hypothesis.
• Study Design Uncertainty: Specifics on patient numbers, study completion dates, and the final design of the Phase 3 pivotal trial (non-inferiority vs. superiority) are currently TBD pending Phase 2 data.
• Enrollment and Execution: Future guidance on study timelines depends on the speed of patient enrollment and site readiness post-initiation.

Management Tone on the Future:

• Confidence Level: High confidence in the scientific viability of the NBD1 target and the dual-combo strategy despite the recent "disappointing" Precision CF readout; views the new path as "putting us in a very good position."
• Pivot Narrative: Frame the Precision CF failure as a valuable learning experience that clarified a complex PK/biological interaction, leading to a more optimized two-drug regimen.
• Conviction: Explicitly states that the "fundamental hypothesis hasn't changed" and that the company remains "excited about the next chapter."
• Financial Stability: Tone is reassuring regarding liquidity, citing an "extremely strong cash situation" that de-risks the near-to-mid-term clinical execution.

Miscellaneous:

• Prior Guidance: The company previously held a strong conviction in the four-drug combination; this conviction was not abandoned but refined based on data showing anti-synergy.
• Dosing Regimen: The dual combination will utilize 451 on a twice-daily (BID) basis and 2222 on a once-daily (QD) basis.
• Study Population: The Phase 2 Ascension CF study will exclusively enroll homozygous patients who are stable on Trikafta and switch directly to the dual combination without a washout period.