Sionna Therapeutics Reports Third Quarter 2026 Financial Results

Sionna expects its cash to fund operations into the second half of 2029 after workforce reductions and other cost-saving measures.

Rhea-AI Summary

Sionna Therapeutics (SION) reported a wider third-quarter 2026 net loss while advancing its SION-451 + SION-2222 cystic fibrosis combination toward Phase 2.

Net loss was $32.4 million, versus $20.3 million a year earlier. Research and development expenses rose to $22.0 million from $16.0 million; administrative expenses increased to $12.8 million from $7.8 million. Cash, cash equivalents and marketable securities totaled $249.8 million at September 30, with operations expected to be funded into the second half of 2029.

Sionna plans to begin the AscenSION CF Phase 2 proof-of-concept trial in the first quarter of 2027. The combination met Phase 1 safety, tolerability and drug-exposure objectives. SION-719 failed its Phase 2a key activity endpoint and will not advance as an add-on to standard care. A September workforce reduction affected approximately 46% of staff.

6 points · 0 major

NegativeiHow this balance works

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1 major · 16 points

Hollow bars mark forward-looking points. How the balance works

Positive

• Moderate point. Forward-looking: it has not happened yet and may not happen.SION-451 + SION-2222 Phase 2 initiation is planned for the first quarter of 2027.
• Moderate pointSION-451 + SION-2222 achieved Phase 1 safety, tolerability and drug-exposure objectives in healthy volunteers.
• Moderate point. Forward-looking: it has not happened yet and may not happen.Cash runway is expected to fund operations into the second half of 2029.
• Minor pointPost hoc SION-719 analysis showed up to -8.6 mmol/L mean placebo-adjusted sweat chloride reduction, excluding three participants.
• Minor pointLaboratory combinations improved CFTR protein trafficking and function up to wild-type levels in both tested donor groups.
• Minor pointCost-saving measures were implemented in September 2026 to focus resources and extend operating runway.

Negative

• Major pointSION-719 Phase 2a missed its key activity endpoint; development as an add-on to standard care stopped.
• Moderate pointApproximately 46% workforce reduction was implemented in September 2026.
• Moderate pointThird-quarter net loss widened to $32.418 million from $20.278 million in 2025.
• Moderate pointCash, cash equivalents and marketable securities fell to $249.797 million from $310.302 million at December 31, 2025.
• Minor pointThird-quarter loss per share widened to $0.72 from $0.46 in 2025, basic and diluted.

11 minor points

• Minor pointThird-quarter research and development expenses rose to $22.025 million from $16.044 million in 2025.
• Minor pointThird-quarter administrative expenses increased to $12.794 million from $7.761 million in 2025.
• Minor pointThird-quarter interest income declined to $2.407 million from $3.456 million in 2025.
• Minor pointNine-month net loss widened to $89.083 million from $54.828 million in 2025.
• Minor pointNine-month loss per share widened to $1.98 from $1.43 in 2025, basic and diluted.
• Minor pointNine-month research and development expenses rose to $62.852 million from $45.095 million in 2025.
• Minor pointNine-month administrative expenses increased to $34.036 million from $20.275 million in 2025.
• Minor pointNine-month interest income declined to $7.814 million from $10.123 million in 2025.
• Minor pointWorking capital declined to $212.108 million from $229.707 million at December 31, 2025.
• Minor pointTotal assets declined to $263.261 million from $325.953 million at December 31, 2025.
• Minor pointStockholders’ equity declined to $240.524 million from $306.833 million at December 31, 2025.

Key Figures

Cash and marketable securities: $249.8 million Cash runway: Into the second half of 2029 Net loss: $32.4 million vs. $20.3 million +5 more

Cash and marketable securities

$249.8 million

As of September 30, 2026

Cash runway

Into the second half of 2029

Company expectation based on current cash position

Net loss

$32.4 million vs. $20.3 million

Third quarter 2026 vs. third quarter 2025

R&D expenses

$22.0 million vs. $16.0 million

Third quarter 2026 vs. third quarter 2025

G&A expenses

$12.8 million vs. $7.8 million

Third quarter 2026 vs. third quarter 2025

Workforce reduction

Approximately 46%

Implemented in September 2026 alongside other cost-saving measures

Phase 2 trial initiation

First quarter of 2027

Planned start of the AscenSION CF proof-of-concept trial

Placebo-adjusted sweat chloride reduction

Up to -8.6 mmol/L

Post hoc analysis of SION-719 added to Trikafta, excluding three participants with dosing non-adherence

Previous Earnings Reports

1 past event · Latest: Aug 06

Same Type 1 event

1. Aug 06

   Earnings report

   24h Move

   +4.8%

   Phase 1 SION-451 dual-combination work preceded the current Phase 2 advancement.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

pharmacokinetics, cftr, open-label, post hoc

4 terms

pharmacokinetics medical

"The trial will assess sweat chloride, safety, and pharmacokinetics (PK)"

Pharmacokinetics is the study of how a substance, such as a drug or chemical, moves through and is processed by the body over time. It tracks how it is absorbed, distributed, broken down, and eventually eliminated. For investors, understanding pharmacokinetics helps gauge the effectiveness, safety, and potential risks of new medications or treatments, which can influence a company’s success and valuation in the healthcare industry.

cftr medical

"SION-2222 (galicaftor) is a transmembrane domain 1 (TMD1)-directed CFTR corrector."

CFTR is a gene that makes a protein acting like a tiny gate in cell membranes to control the flow of salt and water; when the gate works properly it helps keep mucus thin and organs functioning. Investors care because mutations in CFTR drive serious diseases and create demand for diagnostics, drugs and long-term treatment revenue; progress or setbacks in therapies, approvals or patents directly affect company value.

open-label medical

"The open-label trial will evaluate participants with CF homozygous for F508del"

Open-label describes a situation where everyone involved in a study or process knows the full details, such as who is receiving a treatment or intervention. For investors, understanding whether a project or product is open-label helps gauge the level of transparency and potential biases, influencing trust and decision-making. It’s like knowing whether a test or experiment is conducted openly or behind closed doors.

post hoc technical

"Post hoc analyses excluding three participants with drug exposures"

Post hoc means “after the fact” and describes conclusions or analyses made only after seeing results rather than set up beforehand. Investors should treat post hoc findings like noticing a pattern after the game has been played — they can suggest possibilities but are prone to coincidence or bias and often require rigorous, preplanned testing to be trusted. Overreliance on post hoc reasoning can lead to bad bets or misreading a company’s prospects.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Advancing SION-451 + SION-2222 dual combination to AscenSION CF Phase 2 proof-of-concept trial, expected to initiate in the first quarter of 2027

Clinical and nonclinical data presented at 2026 NACFC support advancement of SION-451 + SION-2222 and the potential of NBD1 stabilizer combinations to benefit a broad population of people with CF

Strong cash position of $249.8 million as of September 30, 2026, expected to fund operations into the second half of 2029

WALTHAM, Mass., Nov. 10, 2026 (GLOBE NEWSWIRE) -- Sionna Therapeutics, Inc. (Nasdaq: SION), a clinical-stage biopharmaceutical company on a mission to develop novel medicines for cystic fibrosis (CF), today reported financial results for the third quarter ended September 30, 2026, and provided a business update.

“During the third quarter, we established a focused path forward for Sionna centered on SION-451 + SION-2222, our proprietary, NBD1-anchored dual combination,” said Mike Cloonan, President and Chief Executive Officer of Sionna. “We believe the findings from the PreciSION CF post hoc analyses, together with the dual combination’s favorable Phase 1 results, support advancing the dual combination into the next phase of development. With our resources focused on developing this program and cash runway expected into the second half of 2029, we are well-positioned to execute our strategy to deliver new treatment options for people with CF.”

Pipeline Updates

• SION-451 + SION-2222 Dual Combination Advancing into AscenSION CF Phase 2 proof-of-concept: Sionna plans to initiate the AscenSION CF Phase 2 proof-of-concept (POC) trial in the first quarter of 2027. SION-451 is an NBD1 stabilizer and SION-2222 (galicaftor) is a transmembrane domain 1 (TMD1)-directed CFTR corrector. The open-label trial will evaluate participants with CF homozygous for F508del treated with SION-451 + SION-2222 for 28 days after switching from Trikafta®. The trial will assess sweat chloride, safety, and pharmacokinetics (PK), and its design will incorporate key learnings from PreciSION CF related to dosing adherence and sweat chloride variability. SION-451 + SION-2222 was selected as the dual combination based on the totality of the clinical, PK, and nonclinical data, including achievement of the safety, tolerability, and PK objectives in the Phase 1 healthy volunteer trial.
• Completed Comprehensive Analysis of SION-719 PreciSION CF: As previously announced, the PreciSION CF Phase 2a trial of SION-719 added to Trikafta did not achieve its key activity endpoint, and Sionna is not advancing SION-719 as an add-on to standard of care. Post hoc analyses excluding three participants with drug exposures consistent with dosing non-adherence showed a mean placebo-adjusted sweat chloride reduction of up to -8.6 mmol/L when SION-719 was added to Trikafta, which Sionna believes is indicative of NBD1 biological activity. The analyses also identified other potential confounding factors related to the complex interaction of SION-719 combined with Trikafta that may have blunted the additional benefit of NBD1 stabilization. These findings, together with results from the Phase 1 dual combination trial, informed the decision to advance SION-451 + SION-2222 and the design of the AscenSION CF trial.
• Presented Clinical and Nonclinical Data at 2026 North American Cystic Fibrosis Conference: In October 2026, Sionna presented clinical and nonclinical data in an oral presentation and poster at the North American Cystic Fibrosis Conference (NACFC) in Atlanta, Georgia. The oral presentation summarized the previously disclosed post hoc analyses of PreciSION CF and the rationale for advancing SION-451 + SION-2222 into AscenSION CF. The poster evaluated the effects of Sionna’s NBD1 stabilizers, SION-451 and SION-719, in combination with complementary CFTR modulators, including SION-2222 and SION-109, in primary CF human bronchial epithelial cells from donors with either two copies of F508del or one copy of F508del and a null CFTR mutation. Across both donor groups, the NBD1 stabilizer-based combinations demonstrated improved CFTR trafficking and function up to wild-type levels, supporting their potential to benefit a broad population of people with CF.
  
  

Corporate Update

• Implemented Workforce Reduction and Cost-Saving Measures: In September 2026, following a comprehensive review of its operations, Sionna implemented a workforce reduction of approximately 46% and other cost-saving measures to focus resources on advancing SION-451 + SION-2222 and extend its operating runway.
  
  

Financial Results for the Quarter Ended September 30, 2026

Research and Development Expenses: Research and development expenses were $22.0 million for the third quarter of 2026, compared to $16.0 million for the third quarter of 2025. This increase was primarily driven by development expenses incurred during the period, personnel-related costs, including stock-based compensation expenses, and restructuring related costs associated with the workforce reduction.

General and Administrative Expenses: General and administrative expenses were $12.8 million for the third quarter of 2026, compared to $7.8 million for the third quarter of 2025. This increase was primarily due to personnel-related costs, including stock-based compensation expenses, and restructuring related costs associated with the workforce reduction.

Net Loss: Net loss was $32.4 million for the third quarter of 2026, compared to a net loss of $20.3 million for the third quarter of 2025. 

Cash and Cash Equivalents: Cash, cash equivalents and marketable securities totaled $249.8 million as of September 30, 2026. Sionna expects its current cash position to fund operations into the second half of 2029. 

About Sionna Therapeutics 

Sionna Therapeutics is a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for cystic fibrosis (CF) by developing novel medicines that improve the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Sionna’s goal is to deliver differentiated medicines for people living with CF that can restore their CFTR function to as close to normal as possible by directly stabilizing CFTR’s nucleotide binding domain 1 (NBD1), which Sionna believes is central to potentially unlocking meaningful improvements in clinical outcomes and quality of life for people with CF. For more information about Sionna, visit www.sionnatx.com.

Sionna intends to use its Investor Relations website as a means of disclosing material nonpublic information and for complying with its disclosure obligations under Regulation FD. Accordingly, investors should monitor Sionna’s Investor Relations website, in addition to following Sionna’s press releases, SEC filings, public conference calls, presentations, and webcasts.

Cautionary Note Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, implied and express statements about Sionna’s beliefs and expectations regarding: its goal of transforming the treatment paradigm for CF and providing clinically meaningful benefit for people with CF; the potential of Sionna’s product candidates, including the SION-451 + SION-2222 dual combination, to expand therapeutic options for people with CF, including the potential of NBD1 stabilizer combinations to benefit a broad population of people with CF; Sionna’s interpretation of the results of the PreciSION CF trial and the impact of potential confounding factors on the interpretation of those results; the potential for NBD1 stabilization to improve CFTR function and produce clinical benefit, including beliefs about NBD1 biological activity in PreciSION CF and the translatability of preclinical and in vitro assay data to clinical outcomes; the objectives, design, timing, initiation and conduct of the AscenSION CF Phase 2 proof-of-concept trial of SION-451 + SION-2222; the therapeutic potential, clinical benefits and safety of SION-451 + SION-2222; the ability of clinical trials to demonstrate safety and efficacy of Sionna’s product candidates; the ability of Sionna’s nonclinical studies or earlier clinical trials, including post hoc analyses of the PreciSION CF trial, to predict later clinical trial results; the expected benefits of Sionna’s workforce reduction and other cost-saving measures, including the ability to focus resources on advancing SION-451 + SION-2222 and to extend its operating runway; and financial projections and expectations regarding the time period in which Sionna’s capital resources will be sufficient to fund its anticipated operations, including cash runway, use of capital, expenses and other financial results. In some cases, the forward-looking statements can be identified by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by the forward-looking statements contained in this press release. Factors that could cause actual results to differ include, but are not limited to, risks and uncertainties inherent in the development of product candidates, including uncertainties concerning the initiation, timing, progress, and results of Sionna’s ongoing, planned and future clinical trials and studies; uncertainties in interpreting the PreciSION CF results and potential confounding factors; the inherent limitations of post hoc analyses, which are exploratory and may not reliably predict future outcomes; the risk that in vitro and preclinical data may not translate to clinical benefit; the risk that results observed with one compound may not be predictive of results with a different compound or combination; uncertainties in designing and conducting the AscenSION CF Phase 2 trial; Sionna’s ability to replicate positive results from earlier nonclinical studies or clinical trials, or results of post hoc analyses thereof, in current or future clinical trials; Sionna’s ability to demonstrate that its NBD1 stabilizers, complementary CFTR modulators, and any potential future product candidates are safe and effective for their proposed indications; the ability to obtain regulatory feedback or approvals; the ability to achieve anticipated restructuring savings and runway extension; the ability to retain key personnel and capabilities following the workforce reduction; the ability to secure sufficient funding; regulatory developments in the United States and foreign countries; the competitive landscape for CF treatments, including existing therapies; and general economic, industry and market conditions. These risks and uncertainties are described in the section entitled “Risk Factors” in Sionna’s most recent Annual Report on Form 10-K as well as any subsequent filings with the Securities and Exchange Commission. The events and circumstances reflected in the forward-looking statements may not be achieved or occur. In addition, any forward-looking statements represent Sionna’s views only as of today and should not be relied upon as representing its views as of any subsequent date. Sionna explicitly disclaims any obligation to update any forward-looking statements except as required by law. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.
  
Investor & Media Contact 
Juliet Labadorf 
ir@sionnatx.com 
media@sionnatx.com

Sionna Therapeutics, Inc.
Consolidated Statements of Operations
(In thousands, except per share data)
(Unaudited)
	Three Months Ended								Nine Months Ended
	September 30,								September 30,
	2026				2025				2026				2025
Operating expenses:
Research and development	$	22,025			$	16,044			$	62,852			$	45,095
General and administrative		12,794				7,761				34,036				20,275
Total operating expenses		34,819				23,805				96,888				65,370
Loss from operations		(34,819	)			(23,805	)			(96,888	)			(65,370	)
Other income:
Interest income		2,407				3,456				7,814				10,123
Other income (expense), net		(6	)			71				(9	)			419
Total other income		2,401				3,527				7,805				10,542
Net loss	$	(32,418	)		$	(20,278	)		$	(89,083	)		$	(54,828	)
Net loss per share, basic and diluted	$	(0.72	)		$	(0.46	)		$	(1.98	)		$	(1.43	)
Weighted-average common shares outstanding, basic and diluted		45,208,940				44,255,053				45,094,349				38,387,388

Sionna Therapeutics, Inc.
Selected Consolidated Balance Sheet Data
(In thousands)
(Unaudited)
		September 30,			December 31,
		2026			2025
Cash, cash equivalents, and marketable securities		$	249,797		$	310,302
Working capital1			212,108			229,707
Total assets			263,261			325,953
Total stockholders’ equity			240,524			306,833
1Sionna defines working capital as current assets minus current liabilities.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What were Sionna Therapeutics’ third-quarter 2026 financial results?

Sionna reported a $32.4 million net loss for the third quarter of 2026, compared with $20.3 million a year earlier. Research and development expenses were $22.0 million, and general and administrative expenses were $12.8 million.

When will Sionna begin the SION-451 + SION-2222 Phase 2 trial?

Sionna plans to initiate the AscenSION CF Phase 2 proof-of-concept trial in the first quarter of 2027. The program evaluates the SION-451 + SION-2222 dual combination for cystic fibrosis.

How will Sionna’s AscenSION CF trial evaluate SION-451 + SION-2222?

The open-label trial will treat participants with cystic fibrosis who have two copies of F508del for 28 days after switching from Trikafta. It will assess sweat chloride, safety and pharmacokinetics, meaning drug exposure in the body. Its design will incorporate lessons from PreciSION CF concerning dosing adherence and sweat chloride variability.

What limitations affected Sionna’s SION-719 post hoc analysis?

The analysis excluded three participants whose drug exposures were consistent with dosing non-adherence. It also identified potential confounding factors involving SION-719 combined with Trikafta that may have blunted the additional benefit of stabilizing NBD1, a domain of the CFTR protein. Sionna believes the post hoc findings indicate NBD1 biological activity.