Sionna Therapeutics Appoints Caroline Stark Beer as Chief Business Officer

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 announced the appointment of Caroline Stark Beer, MBA, as its Chief Business Officer (CBO).

"We are delighted to welcome Caroline to our executive team at such a pivotal stage for Sionna," said Mike Cloonan, President and Chief Executive Officer of Sionna. "Caroline's exceptional experience, leadership, and value creation mindset will enhance our corporate development efforts as we continue to advance toward our goal of delivering innovative and transformative therapies for people living with CF."

Caroline brings over 20 years of experience in the life science industry to her role with Sionna. She was most recently CBO at Jnana Therapeutics until Jnana's sale to Otsuka Pharmaceutical. Caroline led the team responsible for corporate and business development, alliance management, legal contracts, new product planning, and communications. Before Jnana, she spent over a decade at Alnylam Pharmaceuticals; in her final role there, she served as VP of Business Development. During this time, she led the formation of a variety of high-impact partnerships including a 5-year collaboration with Regeneron Pharmaceuticals to discover and develop new RNA interference (RNAi) therapeutics. Prior to Alnylam, Caroline served in business development at Amicus Therapeutics and started her career as a strategy consultant at Bain & Company. Caroline received her MBA from the MIT Sloan School of Management and a Bachelor of Economics from Duke University.

"I believe that the most meaningful growth happens in organizations where scientific excellence and business strategy work seamlessly together while focusing on the patient as the North-Star. Sionna embodies this approach, which is why I'm thrilled to join the company," said Caroline. "I look forward to helping Sionna execute on its mission, striving toward enhanced options for CF patients."

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 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 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 innovative and transformative treatment options to CF patients. 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; 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
Adam Daley
CG Life
212.253.8881
adaley@cglife.com

Investor Contact
Juliet Labadorf
ir@sionnatx.com