Sionna Therapeutics, Inc. (SION)·Q4 2024 Earnings Summary

Executive Summary

• Sionna reported Q4 2024 and FY 2024 results highlighting increased R&D as Phase 1 programs for NBD1 stabilizers SION-719 and SION-451 progressed; Q4 net loss was $15.8M and FY net loss was $61.7M, reflecting pipeline advancement and in-licensing costs .
• Management reaffirmed near-term clinical catalysts: Phase 1 topline data for SION-719 and SION-451 expected in 1H 2025; initiation of a Phase 2a POC trial (NBD1 stabilizer + SOC) and combination MAD trials (NBD1 stabilizer + complementary modulator) in 2H 2025, with topline readouts in mid‑2026 .
• Balance sheet strengthened by an upsized IPO in Feb-2025 ($219M gross; ~$199.6M net), extending cash runway into 2028, positioning the company to execute on Phase 2 plans without near-term financing risk .
• Strategic update: Completion of Phase 1 for SION-109 in Dec-2024 and in-licensing of three CFTR modulators from AbbVie (galicaftor SION‑2222, navocaftor SION‑3067, SION‑2851) broaden dual-combo options around the NBD1 anchor mechanism .

What Went Well and What Went Wrong

• What Went Well

  • Phase 1 progress: MAD dosing completed for SION-451; final MAD cohort for SION-719 planned; both agents generally well tolerated, achieving target exposures supportive of clinical benefit potential as dual‑combo or SOC add‑on .
  • Pipeline breadth and optionality increased: phase-complete SION‑109 and in‑licensed galicaftor/navocaftor/SION‑2851 support multiple dual-combo paths with NBD1 stabilizers .
  • Capital and runway: IPO proceeds extend cash runway into 2028, enabling execution of the clinical roadmap to mid‑2026 readouts without near-term raise .

• What Went Wrong

  • Operating loss widened YoY: Q4 operating expenses rose to $18.1M (vs $12.6M), with R&D up on clinical execution and in‑process R&D charges tied to AbbVie assets; net loss increased to $15.8M (vs $11.9M) .
  • No product revenue; P&L remains driven by R&D/G&A with reliance on financing and partnership capital ahead of pivotal efficacy data .
  • Estimate comparison unavailable this quarter due to S&P Global access limits, constraining beat/miss analysis vs consensus (to be updated when accessible) [GetEstimates error].

Financial Results

Quarterly P&L (USD Millions, except per-share) — Q4 YoY

Annual P&L (USD Millions, except per-share)

Selected Balance Sheet (USD Millions)

Notes:

• No product revenue reported; financials reflect operating expenses and other income only, consistent with clinical‑stage status .
• FY 2024 R&D includes $13.6M in‑process R&D tied to AbbVie program licensing (cash/non‑cash components) .

KPIs / Operating Metrics

• Phase 1 status: SION‑451 MAD complete; SION‑719 final MAD cohort planned; both agents generally well tolerated; topline data expected 1H 2025 .
• Complementary modulator SION‑109 Phase 1 completed Dec‑2024; target exposures achieved with multiple doses .
• Liquidity runway into 2028 post‑IPO (net IPO proceeds ~$199.6M not included in 12/31/24 cash) .

Guidance Changes

† Based on Q4 press release/10‑K disclosures; earlier quarter earnings materials were not available in our document set for comparison .

Earnings Call Themes & Trends

Note: We did not locate a Q4 2024 earnings call transcript; thematic tracking below reflects management disclosures in the Q4 press release and 10‑K Business discussion.

Management Commentary

• “2024 was an excellent year for Sionna including strong clinical execution across multiple programs... encouraging interim Phase 1 data for SION‑719 and SION‑451... achieved target exposures—reinforcing their potential to deliver meaningful clinical benefits for people with CF.” — Mike Cloonan, President & CEO .
• “We successfully completed an upsized IPO... extends our cash runway into 2028 and provides financial and strategic flexibility.” — Mike Cloonan, President & CEO .
• Pipeline timing reiterated: Phase 1 topline in 1H 2025; Phase 2a add‑on to SOC and combination MAD starts in 2H 2025; topline for both in mid‑2026 .

Q&A Highlights

• Not disclosed in the Q4 materials we reviewed (press release and 10‑K); no Q4 2024 earnings call transcript was found in our document set .

Estimates Context

• EPS and revenue consensus from S&P Global were not retrievable due to a temporary access limit; therefore, beat/miss analysis vs Wall Street consensus is unavailable for this quarter. Values to be refreshed once access resumes (S&P Global).

Key Takeaways for Investors

• Near‑term catalysts in 1H 2025 (Phase 1 topline for SION‑719/451) and 2H 2025 (start of Phase 2a add‑on to SOC and combination MAD trials) create multiple shots on goal into mid‑2026 readouts .
• Safety/tolerability and target exposures achieved in Phase 1 to date de‑risk transition into patient studies, a key gating item for CFTR modulators .
• In‑licensed assets (galicaftor, navocaftor, SION‑2851) expand dual‑combo options and accelerate proprietary combination development around the NBD1 anchor .
• Strengthened balance sheet (IPO) extends runway into 2028, reducing financing overhang through initial Phase 2 data cycles .
• Competitive bar is high (Vertex ~$11B CFTR revenue; Alyftrek approval), but NBD1 stabilization addresses a domain not targeted by current SOC and has shown >1.5x CFTR activity improvement vs ETI at Emax in preclinical CFHBE models, supporting differentiation potential if translated clinically .
• Risk factors remain typical for clinical‑stage biotech (trial execution, translation from preclinical to clinical, regulatory), with management explicitly acknowledging these in risk disclosures .

Appendix: Additional Context

• Q4/FY 2024 operating expense increases were driven by direct program spend and recognition of $13.6M in in‑process R&D from AbbVie in‑licensing (cash and non‑cash components) .
• Cash, cash equivalents and marketable securities were $168.0M at 12/31/24, excluding ~$199.6M net IPO proceeds received in Feb‑2025; pro forma cash supports operations into 2028 per management .