Kiniksa Pharmaceuticals International, plc Stock Compensation Disclosure

11.           Share-Based Compensation

As part of the Redomiciliation, Kiniksa International assumed the sponsorship of, and all rights and obligations of Kiniksa Bermuda under Kiniksa Bermuda’s equity compensation plans, which include the 2018 Plan, the 2015 Plan, and the 2018 ESPP.

2018 Incentive Award Plan

In May 2018, the Company’s board of directors and shareholders approved the 2018 Incentive Award Plan (the “2018 Plan”), which became effective on May 23, 2018. The 2018 Plan provides for the grant of incentive share options, nonqualified share options, share appreciation rights, restricted shares, dividend equivalents, restricted share units and other share- or cash- based awards. Upon the effectiveness of the 2018 Plan, the Company ceased granting awards under its 2015 Equity Incentive Plan (as amended, the “2015 Plan” together with the 2018 Plan, the “Plans”).

A total of 4,466,500 Class A ordinary shares were initially reserved for issuance under the 2018 Plan. The number of Class A ordinary shares that may be issued under the 2018 Plan will automatically increase on each January 1, beginning in 2019 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2028, equal to the lesser of (1) 4% of the Class A ordinary shares outstanding (on an as-converted basis) on the final day of the immediately preceding calendar year and (2) a smaller number of Class A ordinary shares

determined by the Company’s board of directors. As of December 31, 2025, 5,621,352 shares remained available for future grant. On January 1, 2026, the Class A ordinary shares issuable pursuant to the 2018 Plan increased by 3,051,742 shares, equal to 4% of the as-converted Class A ordinary shares outstanding on December 31, 2025. The Class A ordinary shares underlying any awards issued under the 2018 Plan or the 2015 Plan that on or after the effective date of the 2018 Plan expire, lapse unexercised or are terminated, exchanged for cash, surrendered, repurchased, canceled without having been fully exercised, or forfeited under the 2018 Plan or the 2015 Plan will be added back to the Class A ordinary shares available for issuance under the 2018 Plan.

2015 Equity Incentive Plan

Until May 23, 2018 (the effective date of the 2018 Plan), the 2015 Plan provided for the Company to grant incentive share options, nonqualified share options, share grants and other share-based awards to employees and non-employees to purchase the Company’s Class A ordinary shares. On the effective date of the 2018 Plan, the Company ceased granting awards under the 2015 Plan. At that time, the 4,691,213 Class A ordinary shares subject to outstanding awards under the 2015 Plan remained reserved for issuance under the plan pursuant to such awards and the 92,170 Class A ordinary shares that had been available for future grant under the 2015 Plan were no longer authorized and reserved for issuance or available for future grant under the 2015 Plan.

As of December 31, 2025, there were 618,561 Class A ordinary shares subject to outstanding awards under the 2015 Plan and reserved for issuance thereunder pursuant to such awards. The 2015 Plan continues to govern the terms and conditions of the outstanding awards granted under it. Class A ordinary shares subject to awards granted under the 2015 Plan that expire, lapse unexercised or are terminated, exchanged for cash, surrendered, repurchased, canceled without having been fully exercised, or forfeited become available for issuance under the 2018 Plan.

The exercise price for share options granted under the 2015 Plan was determined by the Company’s board of directors. All incentive share options granted to any person possessing 10% or less of the total combined voting power of all classes of shares could not have an exercise price of less than 100% of the fair market value of the Class A ordinary shares on the grant date. All incentive share options granted to any person possessing more than 10% of the total combined voting power of all classes of shares could not have an exercise price of less than 110% of the fair market value of the Class A ordinary shares on the grant date. The option term for incentive share options could not be greater than 10 years. Incentive share options granted to persons possessing more than 10% of the total combined voting power of all classes of shares could not have an option term of greater than five years. The vesting period for equity-based awards was determined by the board of directors, which was generally four to six years. For awards granted to employees and non-employees with four year vesting terms, 25% of the option vests on the first anniversary of the grant date and the remaining shares vest equally each month for three years thereafter. For awards granted to employees with six year vesting terms, 16% of the option vests on the first anniversary of the grant date and the remaining shares vest based on a predetermined vesting schedule for five years thereafter.

2018 Employee Share Purchase Plan

In May 2018, the Company’s board of directors and shareholders approved the 2018 Employee Share Purchase Plan (the “2018 ESPP”), which became effective on May 23, 2018. A total of 670,000 Class A ordinary shares were initially reserved for issuance under the 2018 ESPP. The number of Class A ordinary shares that may be issued under the 2018 ESPP automatically increases on each January 1, beginning in 2019 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2028, equal to the lesser of (1) 1% of the Class A ordinary shares outstanding (on an as-converted basis) on the final day of the immediately preceding calendar year and (2) a smaller number of Class A ordinary shares determined by the Company’s board of directors, provided that no more than 6,420,000 Class A ordinary shares may be issued under the 2018 ESPP. In December 2025, the Company’s board of directors approved an increase as of January 1, 2026 of 110,000 Class A ordinary shares. As of December 31, 2025, 690,063 Class A ordinary shares were available for future issuance under the 2018 ESPP.

Restricted Share Units

RSUs represent the right to receive shares of the Company’s Class A ordinary shares upon vesting of the RSUs. The fair value of each RSU award is based on the closing price of the Company’s Class A ordinary shares on the date of grant.

Starting March 2021, the Company granted RSUs with service conditions (“Time-Based RSUs”) to eligible employees. The Time-Based RSUs vest 25% on each of the first, second, third and fourth anniversaries of the date of grant, subject to continued employment through such dates.

Market and Performance-Based Shares Units

In the second quarter of 2024, the Company began periodically granting performance-based restricted share units to certain employees under the 2018 Plan. The Company granted awards which are earned based upon the achievement of certain specified ARCALYST revenue targets (“Revenue PSUs”), and awards which are earned based upon the Company’s total shareholder return (“TSR”) relative to the performance of the members of the Nasdaq Biotechnology Index (“TSR PSUs”). The TSR PSUs and Revenue PSUs are subject to a three-year service period.

In addition, the Company from time-to-time grants performance-based restricted share units to certain eligible employees pursuant to the 2018 Plan that are earned based upon certain development and regulatory milestones (“Development PSUs” and, together with the Revenue PSUs and TSR PSUs, “PSUs”). The Company’s currently outstanding Development PSUs are subject to earnout percentages based upon the date of applicable milestone achievement.

The following table summarizes RSU and PSU activity for the year ended December 31, 2025:

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RSUs granted in 2024 and 2023 had weighted average grant date fair values of $22.19 and $15.13, respectively. PSUs granted in 2024 had a weighted average grant date fair value of $22.06. No PSUs were granted in 2023.

The total grant date fair values of RSUs that vested during the years ended December 31, 2025, 2024, and 2023 totaled $12,576, $9,495 and $5,635, respectively. No PSUs vested during the years ended December 31, 2025, 2024 and 2023.

Share Options

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The following table summarizes option activity for the year ended December 31, 2025:

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The aggregate intrinsic value of share options is calculated as the difference between the exercise price of the share options and the fair value of the Company’s ordinary shares for those share options that had exercise prices lower than the fair value of the Company’s ordinary shares.

The total intrinsic value of options exercised during the years ended December 31, 2025, 2024 and 2023, were $63,241, $19,235 and $2,595, respectively. The tax benefit arising on the exercise of stock options was $16,481 for the year ended December 31, 2025. The weighted-average grant-date fair value per share of share options granted during the years ended December 31, 2025, 2024 and 2023 was $17.61, $14.41 and $9.82, respectively.

Performance Share Options

Beginning in the second quarter of 2025, the Company began granting performance share options (“PSOs”) to certain eligible employees pursuant to the 2018 Plan representing the right to purchase shares of the Company’s Class A ordinary shares. Such PSOs vest, if at all, upon the achievement of certain specified development and regulatory milestones and are subject to earnout percentages based upon the date of applicable milestone achievement.

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No PSOs were exercised during the years ended December 31, 2025, 2024 and 2023. The weighted-average grant-date fair value per share of PSOs granted during the years ended December 31, 2025 was $14.17. No PSOs were granted during the years ended December 31, 2024 and 2023.

Option Valuation

The assumptions that the Company used to determine the grant-date fair value of share options granted to employees and directors from the 2018 Plan during the years ended December 31, 2025, 2024 and 2023 were as follows, presented on a weighted-average basis:

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During the years ended December 31, 2025, 2024 and 2023, the Company did not grant share options to non-employees.

As of December 31, 2025, total unrecognized compensation cost related to RSUs, Revenue PSUs, TSR PSUs, and share options was $90,372 which is expected to be recognized over a weighted average remaining period of 2.52 years. As of December 31, 2025, total unrecognized compensation cost related to outstanding Development PSUs and PSOs was $9,576 which will be recognized when the applicable milestones are deemed probable of achievement through the date the awards vests with a cumulative catch-up.

Share-Based Compensation

Share-based compensation expense was classified in the consolidated statements of operations and comprehensive income (loss) as follows:

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The tax benefit from share-based compensation recognized during the years ended December 31, 2025, 2024 and 2023, were $9,643, $7,976 and $7,433, respectively.