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Table of Contents ( Mark One ) ㅁ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number : 001-38492 Kiniksa Pharmaceuticals , Ltd. ( Exact name of registrant as specified in its charter ) Bermuda ( State or other jurisdiction of incorporation or organization ) Title of each class Class A Common Shares Kiniksa Pharmaceuticals , Ltd. Clarendon House 2 Church Street Hamilton HM11 , Bermuda + ( 44 ) 808-189-6257 ( Address , zip code and telephone number , including area code of principal executive offices ) Kiniksa Pharmaceuticals Corp. 100 Hayden Avenue Lexington , MA , 02421 ( 781 ) 431-9100 ( Address , zip code and telephone number , including area code of agent for service ) N / A ( Former name , former address and former fiscal year , if changed since last report ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) KNSA 98-1327726 ( I.R.S. Employer Identification Number ) Name of each exchange on which registered The Nasdaq Global Select Market Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes No Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes No □ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer " , " smaller reporting company " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Large Accelerated Filer Accelerated Filer Non - accelerated Filer Smaller Reporting Company Emerging Growth Company If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No The aggregate market value of the voting and non - voting common equity held by non - affiliates of the Registrant , based on the closing price of the common shares on The Nasdaq Global Select Market on June 30 , 2020 , was approximately $ 712.6 million . As of January 31 , 2021 , there were 68,232,304 common shares outstanding in aggregate , comprised of : 31,922,546 Class A common shares , par value $ 0.000273235 per share 2,227,614 Class B common shares , par value $ 0.000273235 per share 18,024,526 Class A1 common shares , par value $ 0.000273235 per share 16,057,618 Class B1 common shares , par value $ 0.000273235 per share DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive proxy statement for its 2021 Annual Meeting of Shareholders , which the registrant intends to file with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days after the end of the registrant's fiscal year ended December 31 , 2020 , are incorporated by reference into Part III of this Annual Report on Form 10 - K .