Company: SION
Filing Date: 2025-05-12
Form Type: 10-Q
Source: 0002036042-25-000016
Chunk: 240

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-05-12
Form: 10-Q
Item: Part II, Item 8
Chunk 240
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 was declared effective by the SEC. The 2025 ESPP initially reserved 390,127 shares of common stock for future issuance and is subject to automatic increases in the number of shares of common stock reserved for future issuances in accordance with the evergreen provisions in the 2025 ESPP. Stock Option Activity The following table summarizes the Company’s common stock option activity for the three months ended March 31, 2025: Number ofCommonStockOptionsWeighted-AverageExercise PriceWeighted-AverageRemainingContractual TermAggregateIntrinsic Value(in years)(in thousands)Outstanding as of December 31, 20243,700,335$5.87 8.3$16,522 Granted1,949,58817.99 Exercised—— Cancelled or forfeited—— Outstanding as of March 31, 20255,649,923$10.05 8.7$16,993 Exercisable as of March 31, 20251,741,157$5.70 7.4$8,564 The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the estimated fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The weighted-average grant date fair value of options granted during the three months ended March 31, 2025, was $13.20. 

F-11

Table of Contents

Stock-Based Compensation Expense During the three months ended March 31, 2025, and 2024, the Company recorded stock-based compensation in the accompanying condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months EndedMarch 31,20252024Research and development expense$804 $279 General and administrative expense1,290 368 Total$2,094 $647 

As of March 31, 2025, there was $33.5 million of unrecognized stock-based compensation expense for common stock option awards that are expected to be recognized over a weighted average period of 3.1 years. As of March 31, 2025, the unrecognized stock-based compensation expense for restricted common stock awards is de minimis. 

10. Segment Information 

The following table presents segment net loss, including significant expense categories (in thousands):Three Months EndedMarch 31,20252024Research and development expenses:External research and