Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 143

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 143
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                                      |      |                         | 1,399 |     |      |   |    93 |     |        | 1,306 |
| Total general and administrative expenses              |      | $                       | 9,707 |     |      | $ | 6,767 |     | $      | 2,940 |

General and administrative expenses increased by $2.9 million to $9.7 million for the year ended December 31, 2023, from $6.8 million for the year ended December 31, 2022. The increase in general and administrative expenses was primarily due to:

| • |     | $1.4 million increase in personnel-related (including stock-based compensation) due to an increase in headcount; |

| • |     | $1.3 million increase in facility expenses due to the commencement of the Waltham Lease (as defined below) in January 
 2023; and                                                                                                             |

103

| • |     | $0.2 million increase in professional services and fees primarily due to an increase in consulting and audit fee 
 costs.                                                                                                           |

Interest Income Interest income increased by $1.7 million to $2.8 million for the year ended December 31, 2023, from $1.1 million for the year ended December 31, 2022, primarily driven by increased interest income and the amortization of discounts on our investment activity. Other Income Other income for the year ended December 31, 2023 was $0.3 million, driven by sublease income in connection with our subleasing agreement which was entered into during the year ended December 31, 2023. Liquidity and Capital Resources Sources of Liquidity Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from operations. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we advance the clinical development of our product candidates and any future product candidates. As such, we expect our research and development and general and administrative costs will continue to increase significantly, including the costs associated with operating as a public company following the completion of this offering. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity or debt financings or strategic agreements. To date, we have funded our operations primarily from the sale of proceeds of preferred stock. As of September 30, 2024, we had received aggregate net proceeds of