# Sionna Therapeutics

Startup profile on Capital Atlas: https://capitalatlas.ai/startups/sionna-therapeutics

- Industry: Biotechnology
- Headquarters: Waltham, US
- Website: www.sionnatx.com/
- Total disclosed funding: $293M
- Latest round: Series C (Mar 6, 2024)
- Investors on record: 12

## About

Established in 2019, and based in Massachusetts, US, Sionna Therapeutics is a clinical-stage company developing novel small molecule therapies targeting the genetic mutation affecting cystic fibrosis (CF) patients. In March 2024, the firm raised USD 182 million in Series C funding led by investor Patient Square Capital, with participation from returning investors RA Capital Management, OrbiMed Advisors, TPG, Atlas Venture, Cystic Fibrosis Foundation, T. Rowe Price, and Q Healthcare Holdings, LLC. Other investors Viking Global Investors, Perceptive Advisors, and other investors also participated in the round. As of 2024, the company is headed by its CEO Mike Cloonan. Sionna offers a range of innovative small compounds that are intended to fix CFTR protein abnormalities. The TMD1, ICL4, and NBD1 domains are the targets of these compounds and are necessary for CFTR function. The company's therapies aim to offer treatment options for cystic fibrosis (CF) patients. The company plans to use the March 2024 funding to progress the clinical testing of new small compounds for cystic fibrosis. In February 2025, Sionna Therapeutics, Inc. raised USD 190.59 million in an IPO, selling 10.59 million shares at USD 18 per share, within the expected USD 16-18 range, on the Nasdaq Global Select Market under the ticker symbol "SION". Sionna Therapeutics, Inc. has granted the underwriters a 30-day option to purchase up to an additional 1.59 million shares of common stock as part of the listing. Following the transaction, RA Capital Management retained a 21.9% minority stake, TPG retained a 13.1% minority stake, Atlas Venture retained an 8.5 minority stake, OrbiMed Advisors retained a 7.4% minority stake, and Viking Global Investors retained a 2.2% minority stake in Sionna Therapeutics, Inc., respectively. 

The company plans to use the February 2025 funding to to complete Phase 1 clinical trials, conduct a Phase 2a proof of concept trial, perform preclinical and early clinical activities for a dual combination of nucleotide-binding domain 1 stabilizer and complementary modulator, initiate and progress a Phase 2b dose-ranging clinical trial, continue manufacturing scale-up for late-stage clinical trials, support research and development activities, and allocate the remainder to working capital and general corporate purposes.

## Funding rounds

- Series C, Mar 6, 2024, $182M — Atlas Venture, OrbiMed Advisors, TPG, Viking Global Investors, Cystic Fibrosis Foundation, RA Capital Management, Perceptive Advisors, T Rowe Price Advisory Services, Patient Square Capital, Q Healthcare Holdings, LLC
- Series B, Apr 19, 2022, $111M — Atlas Venture, OrbiMed Advisors, T Rowe Price, TPG, Qatar Investment Authority, RA Capital Management, Cystic Fibrosis Foundation, Q Healthcare Holdings, LLC

## Investors

- Atlas Venture (https://capitalatlas.ai/funds/atlas-venture) — Series B, Series C
- OrbiMed Advisors (https://capitalatlas.ai/funds/orbimed-advisors) — Series B, Series C
- T Rowe Price (https://capitalatlas.ai/funds/t-rowe-price) — Series B
- TPG (https://capitalatlas.ai/funds/tpg) — Series B, Series C
- Qatar Investment Authority (https://capitalatlas.ai/funds/qatar-investment-authority) — Series B
- RA Capital Management (https://capitalatlas.ai/funds/ra-capital-management) — Series B, Series C
- Cystic Fibrosis Foundation — Series B, Series C
- Q Healthcare Holdings, LLC — Series B, Series C
- Viking Global Investors (https://capitalatlas.ai/funds/viking-global-investors) — Series C
- Perceptive Advisors (https://capitalatlas.ai/funds/perceptive-advisors) — Series C
- T Rowe Price Advisory Services — Series C
- Patient Square Capital (https://capitalatlas.ai/funds/patient-square-capital) — Series C