Kiniksa Pharmaceuticals International, plc - Deed of Waiver

Kiniksa Pharmaceuticals International, plc entered into a deed of waiver with Baker Bros. Advisors LP, representing Baker Brothers Life Sciences, L.P. and 667, L.P. (the Shareholders). The Shareholders have waived their rights to convert Class A1 or Class B1 ordinary shares into Class A or Class B ordinary shares if, after conversion, they would beneficially own more than 49.9% of the Company's outstanding voting rights. This waiver is irrevocable and unconditional and is intended to prevent the Shareholders from exceeding this ownership threshold. The deed can only be amended or terminated with a 75% shareholder vote, unless the amendment adds new shareholders or additional restrictions on conversion rights. The agreement, dated May 21, 2026, is governed by English law.