# EDGAR Filing Document

**Accession Number:** 0002036042
**File Stem:** 0002036042-25-000044
**Filing Date:** 2025-8
**Character Count:** 20749
**Document Hash:** 18a0d7293ec97c2134bb70429ee117ef
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0002036042-25-000044.hdr.sgml**: 20250811

**ACCESSION NUMBER**: 0002036042-25-000044

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 13

**CONFORMED PERIOD OF REPORT**: 20250811

**ITEM INFORMATION**: Results of Operations and Financial Condition

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20250811

**DATE AS OF CHANGE**: 20250811

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Sionna Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0002036042
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42504
- **FILM NUMBER:** 251200146

**BUSINESS ADDRESS:**
- **STREET 1:** 21 HICKORY DRIVE, SUITE 500
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
- **BUSINESS PHONE:** 617-819-2020

**MAIL ADDRESS:**
- **STREET 1:** 21 HICKORY DRIVE, SUITE 500
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451

?xml version='1.0' encoding='ASCII'? sion-20250811

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

__________________________

**FORM 8-K**

__________________________

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d)**

**of the Securities Exchange Act of 1934**

**Date of Report (date of earliest event reported): August 11, 2025**

__________________________

**SIONNA THERAPEUTICS, INC.**

**(Exact name of registrant as specified in its charter)**

__________________________

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| | | |
|:---|:---|:---|
| **Delaware** | **001-42504** | **84-2801521** |
| **(State or other jurisdiction<br>of incorporation)** | **(Commission<br>File Number)** | **(I.R.S. Employer<br>Identification No.)** |

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**SIONNA THERAPEUTICS, INC.**

**21 Hickory Drive, Suite 500**

**Waltham, MA02451**

**(Address of principal executive offices, including zip code)**

**617-819-2020**

**(Registrant's telephone number, including area code)**

**Not Applicable**

**(Former Name or Former Address, if Changed Since Last Report)**

__________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading<br>Symbol(s)** | **Name of each exchange<br>on which registered** |
| Common Stock, $0.001 par value per share | SION | The Nasdaq Global Market |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ⌧

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. □

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**Item 2.02&nbsp;&nbsp;&nbsp;&nbsp;Results of Operations and Financial Condition.**

On August 11, 2025, Sionna Therapeutics, Inc. issued a press release announcing its financial results and business highlights for the quarter ended June 30, 2025. The full text of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information set forth under this Item 2.02 and in Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933 or the Exchange Act, except as expressly set forth by specific reference in such filing.

**Item 9.01&nbsp;&nbsp;&nbsp;&nbsp;Financial Statements and Exhibits.**

(d) Exhibits

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| | |
|:---|:---|
| 99.1 | <u>[Press Release of Sionna Therapeutics, Inc. dated](sion2q25earningsrelease_fi.htm)[August 11](sion2q25earningsrelease_fi.htm)[, 2025.](sion2q25earningsrelease_fi.htm)</u> |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

---

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**SIGNATURE** 

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | |
|:---|:---|:---|
| | | Sionna Therapeutics, Inc. |
| Date: August 11, 2025 | By: | /s/ Jennifer Fitzpatrick |
|  | Name: | Jennifer Fitzpatrick |
|  | Title: | Chief Legal Officer |

---

## Exhibit 99.1

**Sionna Therapeutics Reports Second Quarter 2025 Financial Results**

*Announced Positive Phase 1 data for SION-719 and SION-451 demonstrating both first-in-class NBD1 stabilizers were generally well tolerated and exceeded pharmacokinetic targets*

*Initiation of Phase 2a proof-of-concept trial of SION-719 as an add-on to standard of care in cystic fibrosis patients is on track for the second half of 2025 with topline data expected in mid-2026*

*Advancement of Phase 1 healthy volunteer trial of SION-451 in two proprietary dual combinations is on track for the second half of 2025 with topline data expected in mid-2026*

*Maintained strong cash position with approximately $337.3 million in cash and cash equivalents, expected to fund operations into 2028*

**Waltham, Mass., August 11, 2025 (GLOBE NEWSWIRE)** – Sionna Therapeutics, Inc. (Nasdaq: SION), a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for cystic fibrosis (CF) by developing novel medicines that normalize the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, today reported financial results for the quarter ended June 30, 2025, and provided a business update.

"We are pleased with the progress we've made this past quarter, underscored by the encouraging tolerability and PK data from the Phase 1 trials of our first-in-class NBD1 stabilizers, SION-719 and SION-451," said Mike Cloonan, President and Chief Executive Officer of Sionna. "These data reinforce our confidence in advancing both NBD1 stabilizers into the next stages of development. We are preparing to initiate the Phase 2a proof-of-concept trial of SION-719 as an add-on to standard of care and the Phase 1 trial of SION-451 in dual combinations this year and look forward to sharing topline results from both studies in mid-2026. Supported by a clear development plan and a strong financial position, we are excited to be advancing CF therapies that have the potential to make a meaningful difference for people affected by the disease."

**<u>Pipeline Updates</u>**

***NBD1 Stabilizers***

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Positive Phase 1 Results for SION-719 and SION-451:** In June 2025, Sionna announced positive Phase 1 data for its first-in-class nucleotide binding domain 1 (NBD1) stabilizers, SION-719 and SION-451. The randomized, double-blind, placebo-controlled trials enrolled over 200 healthy volunteers and evaluated each compound's safety, tolerability, and pharmacokinetics (PK) across single and multiple ascending dose cohorts. Both NBD1 stabilizers were generally well tolerated and exceeded target exposure levels that Sionna believes, based on its cystic fibrosis human bronchial epithelial (CFHBE) model, have the potential to deliver clinically meaningful benefit as add-on therapies to standard of care (SOC) or in proprietary dual combinations with complementary modulators. These data reinforce Sionna's decision to progress SION-719 and SION-451 to the next phases of development.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Phase 2a Proof-of-Concept Trial with SION-719:** Sionna is on track to progress SION-719 into a proof-of-concept (POC) trial in the second half of 2025 evaluating the compound as an add-on to SOC in CF patients, with topline data anticipated in mid-2026. The trial is designed to demonstrate the unique mechanism of NBD1 stabilization and the potential opportunity to drive improved CFTR function beyond the current SOC, as defined by sweat chloride. The midazolam

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drug-drug interaction study to confirm SION-719 can be dosed in combination with the SOC according to its label has initiated and is on track to be completed prior to initiation of the Phase 2a trial.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Phase 1 Dual Combination Trial with SION-451 and Complementary Modulators:** Sionna is on track to advance a Phase 1 healthy volunteer trial evaluating SION-451 in combination with SION-2222 (galicaftor), a transmembrane domain 1 (TMD1)-directed CFTR corrector, and with SION-109, an intracellular loop 4 (ICL4)-directed CFTR corrector, in the second half of 2025. Topline data are anticipated in mid-2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Preclinical Data Presented at 48**<sup>th</sup> **European Cystic Fibrosis Conference:** In June 2025, Sionna presented preclinical data at the European Cystic Fibrosis Society's (ECFS) 48<sup>th</sup> Annual Conference demonstrating that Sionna's NBD1 stabilizers, in dual combinations with proprietary complementary modulators, enable full correction of F508del-CFTR in CF models. Sionna believes that these findings highlight the strong mechanistic rationale and the synergy of its dual combination approach to restoring CFTR function, suggesting the potential for these dual combinations to produce meaningful clinical outcomes and improved quality of life for people with CF.

**<u>Financial Results for the Quarter Ended June 30, 2025</u>**

**Research and Development Expenses:** Research and development expenses were $15.4 million for the second quarter of 2025, compared to $8.2 million for the second quarter of 2024. This increase was mainly driven by direct program spend to support Sionna's clinical pipeline.

**General and Administrative Expenses:** General and administrative expenses were $6.5 million for the second quarter of 2025, compared to $3.1 million for the second quarter of 2024. This increase was primarily due to personnel-related costs, including stock-based compensation, and professional fees.

**Net Loss:** Net loss was $18.1 million for the second quarter of 2025, compared to a net loss of $8.6 million for the second quarter of 2024.

**Cash and Cash Equivalents:** Cash, cash equivalents and marketable securities totaled $337.3 million as of June 30, 2025. Sionna continues to expect its current cash position to fund operations into 2028.

**About Sionna Therapeutics** 

<br> 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 normalize 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 dramatic improvements in clinical outcomes and quality of life for people with CF. Leveraging more than a decade of the co-founders' research on NBD1, Sionna is advancing a pipeline of small molecules engineered to correct the defects caused by the F508del genetic mutation, which resides in NBD1. Sionna is also developing a portfolio of complementary CFTR modulators that are designed to work synergistically with its NBD1 stabilizers to improve CFTR function. For information about Sionna, visit <u>www.sionnatx.com</u>.

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

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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**<br>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 to CF patients; the initiation, timing, progress and results of Sionna's research and development programs, preclinical studies and clinical trials and studies, including the timing of the planned initiation of a Phase 2a proof-of-concept trial and Phase 1 healthy volunteer dual combination trial and the timing of topline data from these trials; the ability of clinical trials to demonstrate safety and efficacy of Sionna's product candidates; the ability of Sionna's preclinical studies to predict later clinical trial results and support Sionna's dual combination approach to restoring CFTR function; 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 planned and future clinical trials and studies; the company's ability to replicate positive results from earlier preclinical studies or clinical trials 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; regulatory developments in the United States and foreign countries; and general economic, industry and market conditions. These risks and uncertainties are described in the section entitled "Risk Factors" in Sionna's most recent Quarterly Report on Form 10-Q 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.

**Media Contact** <br> Adam Daley <br>CG Life <br>212.253.8881 <br><u>adaley@cglife.com</u>

**Investor Contact** <br> Juliet Labadorf <br><u>ir@sionnatx.com</u>

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| | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** |
| **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** | **Consolidated Statements of Operations** |
| **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** | **(In thousands, except per share data)** |
| **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** | **(unaudited)** |
| | **Three Months Ended** | **Three Months Ended** | **Three Months Ended** | **Three Months Ended** | **Six Months Ended** | **Six Months Ended** | **Six Months Ended** | **Six Months Ended** |
| | **June 30,** | **June 30,** | **June 30,** | **June 30,** | **June 30,** | **June 30,** | **June 30,** | **June 30,** |
|  | **2025** | **2025** | **2024** | **2024** | **2025** | **2025** | **2024** | **2024** |
| Operating expenses: |  |  |  |  |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Research and development | $15383 | 15383 | $8233 | 8233 | $29051 | 29051 | $18453 | 18453 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;General and administrative |  | 6523 |  | 3059 |  | 12514 |  | 5986 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total operating expenses |  | 21906 |  | 11292 |  | 41565 |  | 24439 |
| Loss from operations |  | (21906) |  | (11292) |  | (41565) |  | (24439) |
| Other income: |  |  |  |  |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Interest income |  | 3667 |  | 2566 |  | 6667 |  | 3698 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other income |  | 171 |  | 174 |  | 348 |  | 342 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total other income |  | 3838 |  | 2740 |  | 7015 |  | 4040 |
| Net loss | $(18068) | (18068) | $(8552) | (8552) | $(34550) | (34550) | $(20399) | (20399) |
| Net loss per share, basic and diluted | $(0.41) | (0.41) | $(2.71) | (2.71) | $(0.98) | (0.98) | $(6.54) | (6.54) |
| Weighted-average common shares outstanding, basic and diluted |  | 44116997 |  | 3159815 |  | 35404928 |  | 3121225 |

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| | | | | |
|:---|:---|:---|:---|:---|
| **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** | **Sionna Therapeutics, Inc.** |
| **Selected Consolidated Balance Sheet Data** | **Selected Consolidated Balance Sheet Data** | **Selected Consolidated Balance Sheet Data** | **Selected Consolidated Balance Sheet Data** | **Selected Consolidated Balance Sheet Data** |
| **(In thousands)** | **(In thousands)** | **(In thousands)** | **(In thousands)** | **(In thousands)** |
| **(Unaudited)** | **(Unaudited)** | **(Unaudited)** | **(Unaudited)** | **(Unaudited)** |
| | **June 30,** | **June 30,** | **December 31,** | **December 31,** |
|  | **2025** | **2025** | **2024** | **2024** |
| Cash, cash equivalents, and marketable securities | $337270 | 337270 | $168043 | 168043 |
| Working capital<sup>1</sup> |  | 259196 |  | 140573 |
| Total assets |  | 352048 |  | 185752 |
| Total stockholders' equity (deficit) |  | 336429 |  | (163713) |
| <sup>1</sup>Sionna defines working capital as current assets minus current liabilities. | <sup>1</sup>Sionna defines working capital as current assets minus current liabilities. | <sup>1</sup>Sionna defines working capital as current assets minus current liabilities. |  |  |

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