X0306 4 2020-06-30 0 0001730430 Kiniksa Pharmaceuticals, Ltd. KNSA 0001263508 BAKER BROS. ADVISORS LP 860 WASHINGTON STREET 3RD FLOOR NEW YORK NY 10014 1 0 1 0 0001551139 667, L.P. 860 WASHINGTON STREET, 3RD FLOOR NEW YORK NY 10014 1 0 1 0 0001580575 Baker Bros. Advisors (GP) LLC 860 WASHINGTON STREET 3RD FLOOR NEW YORK NY 10014 1 0 1 0 0001363364 Baker Brothers Life Sciences LP 860 WASHINGTON STREET 3RD FLOOR NEW YORK NY 10014 1 0 1 0 0001087940 BAKER FELIX 860 WASHINGTON STREET 3RD FLOOR NEW YORK NY 10014 1 0 1 0 0001087939 BAKER JULIAN 860 WASHINGTON STREET, 3RD FLOOR NEW YORK NY 10014 1 0 1 0 Non-Qualified Share Option (right to buy) 25.48 2020-06-30 4 A 0 37520 0 A 2030-06-30 Class A Common Shares 37520 37520 I See Footnotes 18,760 non-qualified stock options ("Stock Options") exercisable solely into Class A common shares ("Class A Common Shares") of Kiniksa Pharmaceuticals, Ltd. (the "Issuer") each granted to Felix J. Baker, a managing member of Baker Bros. Advisors (GP) LLC (the "Adviser GP") and Dr. Stephen R. Biggar, a full time employee of Baker Bros. Advisors LP (the "Adviser") on June 30, 2020, pursuant to the Issuer's 2018 Incentive Award Plan. The Stock Options with a strike price of $25.48 vest in 12 equal monthly installments and expire 10 years from the date of grant. Felix J. Baker and Dr. Biggar serve on the board of directors of the Issuer (the "Board") as representatives of 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds"). Pursuant to the policies of the Adviser, Felix J. Baker and Dr. Biggar do not have a right to any of the Issuer's securities issued as part of their service on the Board and the Funds are entitled to an indirect proportionate pecuniary interest in the securities. The Funds each own an indirect proportionate pecuniary interest in the securities. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the Stock Options and any Class A Common Shares resulting from the exercise of Stock Options (i.e. no direct pecuniary interest). The Adviser serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. The Adviser GP is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds. Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose. Pursuant to agreements between Felix J. Baker, Dr. Biggar and the Adviser, the Adviser has voting and dispositive power over the Stock Options and any Class A Common Shares received as a result of the exercise of Stock Options. Felix J. Baker, a managing member of Baker Bros. Advisors (GP) LLC and Dr. Stephen R. Biggar, a full-time employee of Baker Bros. Advisors LP are directors of Kiniksa Pharmaceuticals, Ltd. (the "Issuer"). By virtue of their representation on the board of directors of the Issuer, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the reporting persons are deemed directors by deputization of the Issuer. By: Baker Bros. Advisors LP, Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing 2020-07-02 Baker Bros. Advisors LP, Mgmt. Co. and Inv. Adviser to 667, L.P., pursuant to authority granted by Baker Biotech Capital, L.P., GP to 667, L.P. Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing 2020-07-02 By: Baker Bros. Advisors (GP) LLC, Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing 2020-07-02 Baker Bros. Advisors LP, Mgmt. Co. and Inv. Adviser to BAKER BROTHERS LIFE SCIENCES, L.P., pursuant to authority granted by Baker Brothers Life Sciences Capital, L.P., GP to Baker Brothers Life Sciences, L.P., Name: Scott L. Lessing, Title: President /s/ 2020-07-02 /s/ Felix J. Baker 2020-07-02 /s/ Julian C. Baker 2020-07-02