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Sionna Therapeutics Launches with $111 Million Series B Financing to Advance Pipeline of Novel Small Molecules with the Potential to Fully Restore CFTR Function in Cystic Fibrosis

– Company advancing first-in-class portfolio of molecules targeting correction of NBD1, the key unique mechanism that could enable full restoration of function of ΔF508-CFTR in cystic fibrosis –

– Potential for two IND submissions within the next 12 months including the first novel program targeting NBD1 –

– Strong management team of respected industry leaders with deep experience in cystic fibrosis and rare disease drug development and commercialization –

Boston, MA, April 19, 2022 — Sionna Therapeutics, a life sciences company founded in 2019 to develop highly effective and differentiated treatments for cystic fibrosis (CF), today announced the official launch of the company and the closing of a $111 million Series B financing. The round was led by OrbiMed with participation from funds advised by T. Rowe Price Associates, Inc., Q Healthcare Holdings, LLC., a wholly owned subsidiary of QIA, the sovereign wealth fund of Qatar, and previous investors including RA Capital, TPG’s The Rise Fund, Atlas Venture, and the Cystic Fibrosis Foundation. Sionna has raised approximately $150 million to date.

Sionna is advancing a pipeline of first-in-class small molecules designed to fully restore the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein that is defective in CF, by stabilizing CFTR’s first nucleotide-binding domain (NBD1). The leading cause of CF is the genetic mutation ΔF508 that affects NBD1 stability and CFTR function.

In clinically predictive in vitro CF models, Sionna’s NBD1-targeted small molecules, in combination with other complementary modulators, have demonstrated the potential to normalize folding, maturation, and stability of the CFTR protein affected by the ΔF508 genetic mutation. This allows proper trafficking of CFTR to the cell surface and normal regulation of the flow of ions and water. By fully restoring CFTR function for patients with the ΔF508 genetic mutation to levels seen in cells of people without CF, Sionna’s pipeline has the potential to deliver best-in-class efficacy and optimal clinical benefit for people with CF.

“NBD1 is a well-known and researched target, but it has been considered undruggable until now. Based on our focused efforts and continued progress on NBD1, we see the potential to normalize CFTR function in the vast majority of people with CF,” said Mike Cloonan, President and Chief Executive Officer of Sionna Therapeutics. “Our mission at Sionna is to significantly improve the health and quality of life for people who continue to suffer from the life-long consequences and burden of living with CF. With this financing, our strong syndicate, and our experienced and talented team, we are excited to launch Sionna and are focused on advancing the first compounds from our differentiated pipeline into the clinic.”

CF is a serious, potentially fatal genetic disease caused by a mutation in the CFTR gene that leads to a buildup of mucus in the lungs and airways, impaired pancreatic function and other organ dysfunction that can have a significant and often severe impact on health and life expectancy. There are over 100,000 people living with CF around the world[i],[ii], an estimated 90 percent of whom have the genetic mutation ΔF508 that occurs within the NBD1 domain of CFTR. This mutation causes NBD1 to unfold at body temperature and impairs CFTR function. Despite the availability of currently approved treatments and the significant progress made on other targets within CFTR, most people with ΔF508 do not achieve full CFTR function. NBD1 is essential to normalize the function of CFTR and the production of healthy, freely flowing mucus in the airways, digestive system, and other organs.

The company plans to advance development of a franchise of small molecules targeting NBD1 and complementary modulators, including NBD1’s interface with the intracellular loop 4 (ICL4) region and the transmembrane domain 1 (TMD1) of CFTR. Sionna plans to submit Investigational New Drug applications (IND) for its first NBD1 targeted program, SION-638, and for its lead ICL4 program, SION-109, within the next 12 months.

Experienced Leadership Team and Board of Directors

Sionna Therapeutics is led by industry veterans with deep experience in CF and rare disease drug development and commercialization, including:

  • Mike Cloonan, President and Chief Executive Officer
    Mr. Cloonan brings two decades of biopharma leadership experience including his most recent experience as the Chief Operating Officer for Sage Therapeutics and previously the Senior Vice President, U.S. Commercial at Biogen.
  • Charlotte McKee, M.D., Chief Medical Officer
    Dr. McKee brings more than two decades of clinical trial and drug development experience and served as Vice President of Clinical Development in CF at Vertex Pharmaceuticals where she led development and approvals across their currently marketed modulator franchise.
  • John Macor, Ph.D., Chief Scientific Officer
    Dr. Macor brings to Sionna more than 35 years of successful drug discovery experience. Most recently he was the Global Head of Integrated Drug Discovery at Sanofi.
  • Elena Ridloff, Chief Financial Officer
    Ms. Ridloff brings more than two decades of experience in finance and the life sciences industry, most recently serving as Executive Vice President and Chief Financial Officer for Acadia Pharmaceuticals.
  • Greg Hurlbut, Ph.D., Co-founder, Senior Vice President, Discovery Research
    Dr. Hurlbut has focused on the discovery of transformative therapies for rare pulmonary and protein conformational diseases, previously serving as Head of Protein Conformational Disease and Rare Pulmonary Disease Research at Sanofi Genzyme.
  • Mark Munson, Ph.D., Co-founder, Vice President, Medicinal Chemistry
    Dr. Munson has nearly 30 years of experience creating biopharmaceutical drugs, most recently serving as U.S. Head of Medicinal Chemistry at Sanofi.

Board of Directors

  • Josh Resnick, M.D., Chair, Managing Director, RA Capital
  • Bruce Booth, D.Phil., Partner, Atlas Venture
  • Mike Cloonan, President & CEO, Sionna Therapeutics
  • Lucian Iancovici, M.D., Managing Director, TPG Life Sciences Innovation
  • Adam Rosenberg, J.D., Venture Partner, RA Capital
  • Peter Thompson, M.D., Partner, OrbiMed

About Sionna Therapeutics

Sionna Therapeutics is a life sciences company dedicated to developing highly effective and differentiated treatments for cystic fibrosis (CF) by normalizing the function of CFTR, the key protein associated with disease progression in CF. Building on over a decade of extensive research on the genetic mutations associated with CF and founded in 2019, Sionna is advancing a pipeline of small molecules engineered to correct ΔF508, the most common mutation that affects the CFTR protein. The company has a first-in-class portfolio of programs targeting correction of NBD1, the key and unique mechanism to enable full restoration of ΔF508-CFTR function, and complementary programs targeting ICL4 and TMD1 domains. Sionna’s pipeline has the potential to deliver best-in-class efficacy and reach previously unachievable levels of long-term benefit for people with CF. For information about Sionna visit sionnatx.com.


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[i] CF Registry data collected from: US; Europe; Australia; Canada; Brazil; New Zealand; South Africa (Epidemiological estimates were calculated by summing patient registry data from all available CF patient registries; data was grown from year of data publication to 2021 in all major CF markets using growth rates in patient registry reports; the CF prevalence is extremely low in Asian countries and likely under-diagnosed, with a lack of centralized registries).

[ii] Singh M, Rebordosa C, Bernholz J, Sharma N. Epidemiology and genetics of cystic fibrosis in Asia: In preparation for the next-generation treatments. Respirology. 2015 Nov;20(8):1172-81. doi: 10.1111/resp.12656. Epub 2015 Oct 6. PMID: 26437683.