# EDGAR Filing Document

**Accession Number:** 0002036042
**File Stem:** 0001628280-26-044263
**Filing Date:** 2026-6
**Character Count:** 5701
**Document Hash:** a0d23f0783657311da8c1f3a64006f2e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-044263.hdr.sgml**: 20260618

**ACCESSION NUMBER**: 0001628280-26-044263

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 11

**CONFORMED PERIOD OF REPORT**: 20260617

**ITEM INFORMATION**: Submission of Matters to a Vote of Security Holders

**FILED AS OF DATE**: 20260618

**DATE AS OF CHANGE**: 20260618

**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:** 261102511

**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-20260617

**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): June 17, 2026**

__________________________

**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.)** |

---

**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:

---

| | | |
|:---|:---|:---|
| **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 |

---

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 5.07&nbsp;&nbsp;&nbsp;&nbsp;Submission of Matters to a Vote of Security Holders.**

On June 17, 2026, Sionna Therapeutics, Inc. (the "Company") held its Annual Meeting of Stockholders, at which a quorum was present. There were 45,142,330 shares of the Company's common stock outstanding as of the record date of April 21, 2026.

The following are the voting results for the proposals considered and voted upon at the meeting, which are described in detail in the Company's Definitive Proxy Statement filed with the Securities and Exchange Commission on April 27, 2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.To elect four nominees as Class II directors: H. Edward Fleming, Jr., M.D., Marcella Kuhlman Ruddy, M.D., Peter A. Thompson, M.D., and Joanne Louise Viney, Ph.D., each to hold office until the Company's Annual Meeting of Stockholders in 2029.

---

| | | | |
|:---|:---|:---|:---|
| **Nominee** | **Votes For** | **Votes Withheld** | **Broker Non-Votes** |
| H. Edward Fleming, Jr. | 42,168,569 | 40,021 | 1,084,330 |
| Marcella Kuhlman Ruddy | 40,270,279 | 1,938,311 | 1,084,330 |
| Peter A. Thompson | 39,862,185 | 2,346,405 | 1,084,330 |
| Joanne Louise Viney | 41,931,706 | 276,884 | 1,084,330 |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.To ratify the appointment of Deloitte & Touche LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2026.

---

| | | |
|:---|:---|:---|
| **Votes For** | **Votes Against** | **Abstentions** |
| 43,291,215 | 1,198 | 507 |

---

Based on the foregoing votes, each of the nominees was elected as a Class II director and the appointment of Deloitte & Touche LLP was ratified.

------

**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.

---

| | | |
|:---|:---|:---|
| | | Sionna Therapeutics, Inc. |
| Date: June 18, 2026 | By: | /s/ Jennifer Fitzpatrick |
|  | Name: | Jennifer Fitzpatrick |
|  | Title: | Chief Legal Officer |

---