Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 279

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 279
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 Opportunity II, LLC is the general partner of Atlas Venture Associates Opportunity II, L.P. The members of Atlas 
 Venture Associates Opportunity II, LLC collectively make investment decisions on behalf of Atlas Venture Associates Opportunity II, LLC. Dr. Booth is a member of Atlas Venture Associates Opportunity II, LLC. Each of AVOF II, Atlas Venture           
 Associates Opportunity II, L.P., and Atlas Venture Associates Opportunity II, LLC may be deemed to beneficially own the shares held by AVOF II. Dr. Booth expressly disclaims beneficial ownership of the shares owned by AVOF II, except to the         
 extent of his pecuniary interest therein, if any. The address for each of these entities and individuals is 300 Technology Square, 8th Floor, Cambridge, MA 02139.                                                                                       |

| (2) | Consists of (i) 2,560,951 shares of common stock issuable upon the conversion of Series B preferred stock held by                                                                                                                                         
 OrbiMed Private Investments VIII, LP (“OPI VIII”) and (ii) 2,048,760 shares of common stock issuable upon the conversion of Series C preferred stock held by OPI VIII. OrbiMed Capital GP VIII LLC (“GP VIII”) is the general                             
 partner of OPI VIII. OrbiMed Advisors LLC (“OrbiMed Advisors”) is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting power and investment power over the securities               
 held by OPI VIII and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, 
 each of whom disclaims beneficial ownership of the shares held by OPI VIII. The address for each of these entities and individuals is 601 Lexington Avenue, 54th Floor, New York, NY 10022.                                                               |

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| (3) | Consists of (i) 1,284,000 shares of common stock held by RA Capital Healthcare Fund, L.P. (“RACHF”), (ii)                                                                                                                                               
 819,153 shares of common stock issuable upon the conversion of Series Seed preferred stock held by RACHF, (iii) 1,229,830 shares of common stock issuable upon the conversion of Series A preferred stock held by RACHF, (iv)