Kiniksa Pharmaceuticals (KNSA) 10-Q 4 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 30, 2023
Document information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2023
Entity File Number	001-38492
Entity Registrant Name	Kiniksa Pharmaceuticals, Ltd.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1327726
Entity Address, Address Line One	Clarendon House
Entity Address, Address Line Two	2 Church Street
Entity Address, City or Town	Hamilton
Entity Address, Country	BM
Entity Address, Postal Zip Code	HM11
City Area Code	808
Local Phone Number	451-3453
Title of 12(b) Security	Class A Common Shares
Trading Symbol	KNSA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001730430
Amendment Flag	false
Common Shares
Document information
Entity Common Stock, Shares Outstanding		69,899,510
Class A common shares
Document information
Entity Common Stock, Shares Outstanding		34,970,866
Class B common shares
Document information
Entity Common Stock, Shares Outstanding		1,795,158
Class A1 common shares
Document information
Entity Common Stock, Shares Outstanding		17,075,868
Class B1 common shares
Document information
Entity Common Stock, Shares Outstanding		16,057,618

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 80,618	$ 122,715
Short-term investments	106,876	67,893
Accounts receivable, net	7,424	12,660
Contract asset		7,656
Inventory	23,425	21,599
Prepaid expenses and other current assets	13,157	10,537
Total current assets	231,500	243,060
Property and equipment, net	1,393	1,658
Operating lease right-of-use assets	5,228	5,385
Other long-term assets	2,323	5,824
Intangible asset, net	18,000	18,250
Deferred tax assets	184,418	185,495
Total assets	442,862	459,672
Current liabilities:
Accounts payable	1,391	7,899
Accrued expenses	20,885	30,112
Deferred revenue	6,495
Operating lease liabilities	3,482	3,301
Other current liabilities	4,334	5,754
Total current liabilities	36,587	47,066
Non-current liabilities:
Non-current deferred revenue	12,163	12,000
Non-current operating lease liabilities	2,133	2,618
Other long-term liabilities	1,884	1,839
Total liabilities	52,767	63,523
Commitments and contingencies (Note 13)
Shareholders' equity:
Additional paid-in capital	894,325	888,120
Accumulated other comprehensive income	55	44
Accumulated deficit	(504,304)	(492,034)
Total shareholders' equity	390,095	396,149
Total liabilities and shareholders' equity	442,862	459,672
Class A common shares
Shareholders' equity:
Common stock value	9	9
Class B common shares
Shareholders' equity:
Common stock value	1	1
Class A1 common shares
Shareholders' equity:
Common stock value	5	5
Class B1 common shares
Shareholders' equity:
Common stock value	$ 4	$ 4

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Class A common shares
Common stock, par value (in dollars per share)	$ 0.000273235	$ 0.000273235
Common stock, shares issued (in shares)	34,886,136	34,750,560
Common stock, shares outstanding (in shares)	34,886,136	34,750,560
Class B common shares
Common stock, par value (in dollars per share)	$ 0.000273235	$ 0.000273235
Common stock, shares issued (in shares)	1,813,457	1,813,457
Common stock, shares outstanding (in shares)	1,813,457	1,813,457
Class A1 common shares
Common stock, par value (in dollars per share)	$ 0.000273235	$ 0.000273235
Common stock, shares issued (in shares)	17,075,868	17,075,868
Common stock, shares outstanding (in shares)	17,075,868	17,075,868
Class B1 common shares
Common stock, par value (in dollars per share)	$ 0.000273235	$ 0.000273235
Common stock, shares issued (in shares)	16,057,618	16,057,618
Common stock, shares outstanding (in shares)	16,057,618	16,057,618

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue:
Product revenue, net	$ 48,345	$ 32,189
Costs and operating expenses:
Research and development	15,172	20,817
Selling, general and administrative	29,045	22,218
Total operating expenses	59,541	55,508
Loss from operations	(11,196)	(23,319)
Other income	1,832	34
Loss before income taxes	(9,364)	(23,285)
Provision for income taxes	(2,906)	(1,925)
Net loss	$ (12,270)	$ (25,210)
Net loss per share attributable to common shareholders, basic	$ (0.18)	$ (0.36)
Net loss per share attributable to common shareholders, diluted	$ (0.18)	$ (0.36)
Weighted average common shares outstanding, basic	69,751,697	69,136,901
Weighted average common shares outstanding, diluted	69,751,697	69,136,901
Comprehensive loss:
Net loss	$ (12,270)	$ (25,210)
Other comprehensive loss:
Unrealized gain (loss) on short-term investments and currency translation adjustments, net of tax	11	(37)
Total other comprehensive gain (loss)	11	(37)
Total comprehensive loss	(12,259)	(25,247)
Product revenue, net
Revenue:
Product revenue, net	42,659	22,189
Costs and operating expenses:
Cost of goods sold	7,036	4,219
Collaboration expenses	8,288	8,254
License and collaboration revenue
Revenue:
Product revenue, net	$ 5,686	$ 10,000

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Balance at the beginning of the period at Dec. 31, 2021	$ 18	$ 860,482	$ (66)	$ (675,397)	$ 185,037
Balance at the beginning of the period (in shares) at Dec. 31, 2021	69,060,403
Changes in equity
Issuance of Class A common shares under incentive award plans	$ 1	422			423
Issuance of Class A common shares under incentive award plans (in shares)	210,720
Share-based compensation expense		6,031			6,031
Unrealized gain (loss) on short-term investments and currency translation adjustments			(37)		(37)
Net loss				(25,210)	(25,210)
Balance at the end of the period at Mar. 31, 2022	$ 19	866,935	(103)	(700,607)	166,244
Balance at the end of the period (in shares) at Mar. 31, 2022	69,271,123
Balance at the beginning of the period at Dec. 31, 2022	$ 19	888,120	44	(492,034)	396,149
Balance at the beginning of the period (in shares) at Dec. 31, 2022	69,697,503
Changes in equity
Issuance of Class A common shares under incentive award plans		90			90
Issuance of Class A common shares under incentive award plans (in shares)	135,576
Share-based compensation expense		6,115			6,115
Unrealized gain (loss) on short-term investments and currency translation adjustments			11		11
Net loss				(12,270)	(12,270)
Balance at the end of the period at Mar. 31, 2023	$ 19	$ 894,325	$ 55	$ (504,304)	$ 390,095
Balance at the end of the period (in shares) at Mar. 31, 2023	69,833,079

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (12,270)	$ (25,210)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	596	656
Share-based compensation expense	6,115	6,031
Non-cash lease expense	841	735
Amortization of premiums and accretion of discounts on short-term investments	(1,061)	164
Loss on disposal of property and equipment	175
Deferred income taxes	1,077
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,634)	(3,932)
Accounts receivable, net	5,236	(25,455)
Inventory	(1,826)	(9,548)
Contract asset	7,656
Other long-term assets	3,268	2,755
Accounts payable	(6,508)	1,515
Accrued expenses and other current liabilities	(10,647)	4,085
Operating lease liabilities	(988)	(643)
Deferred revenue	6,658	12,000
Other long-term liabilities	45	1
Net cash used in operating activities	(4,267)	(36,846)
Cash flows from investing activities:
Purchases of property and equipment	(24)
Purchases of short-term investments	(52,896)	(30,223)
Proceeds from the maturities of short-term investments	15,000	7,500
Net cash used in investing activities	(37,920)	(22,723)
Cash flows from financing activities:
Proceeds from issuance of Class A common shares under incentive award plans and employee share purchase plan	510	992
Payments in connection with Common Stock tendered for employee tax obligations	(420)	(569)
Net cash provided by financing activities	90	423
Net decrease in cash and cash equivalents	(42,097)	(59,146)
Cash and cash equivalents at beginning of period	122,715	122,470
Cash and cash equivalents at end of period	80,618	$ 63,324
Supplemental information:
Cash paid for income taxes	3,196
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use asset obtained in exchange for operating lease obligation	$ 684

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2023
Nature of the Business and Basis of Presentation
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Kiniksa Pharmaceuticals, Ltd. (the “Company”) is a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical need. The Company’s immune-modulating assets, ARCALYST, KPL-404 and mavrilimumab, are based on strong biologic rationale or validated mechanisms, target a spectrum of underserved cardiovascular and autoimmune conditions and offer the potential for differentiation. The Company is subject to risks and uncertainties common to small commercial stage companies in the biopharmaceutical industry and global health, societal, economic and market conditions, including the Company’s dependence on third parties, including contract research organizations and contract manufacturing organizations, the Company’s limited experience obtaining regulatory approvals, the potential failure of the Company to successfully complete research and development of its current or future product candidates, the potential inability of the Company to adequately protect its technology, potential competition, the uncertainty that any current or future product candidates will obtain necessary government regulatory approval, that ARCALYST will continue to be commercially viable and whether any of the Company’s current or future product candidates, if approved, will be commercially viable. Such risks and uncertainties may be subject to substantial and uncertain changes, which may cause significant disruption to the Company’s business and operations, preclinical studies and clinical trials, the business and operations of the third parties with whom the Company conducts business and the national and global economies, all of which may have material impacts on the Company’s business, financial condition and results of operations. Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries, Kiniksa Pharmaceuticals Corp. (“Kiniksa US”), Primatope Therapeutics, Inc. (“Primatope”) and Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”) as well as the subsidiaries of Kiniksa UK, Kiniksa Pharmaceuticals (Germany) GmbH (“Kiniksa Germany”), Kiniksa Pharmaceuticals (France) SARL (“Kiniksa France”), and Kiniksa Pharmaceuticals GmbH (“Kiniksa Switzerland”), after elimination of all significant intercompany accounts and transactions. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the recognition of revenue, the accrual for research and development expenses, the valuation of our deferred tax assets and the valuation of share-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Unaudited Interim Consolidated Financial Information The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial information. The accompanying unaudited consolidated financial statements do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the “2022 Form 10-K”). The Company’s accounting policies are described in the Notes to Consolidated Financial Statements in the Company’s 2022 Form 10-K and updated, as necessary, in this report. The accompanying year-end consolidated balance sheet was derived from audited financial statements but does not include all disclosures required by GAAP. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2023 and the results of its operations for the three months ended March 31, 2023 and 2022, the changes in its shareholders’ equity for the three months ended March 31, 2023 and 2022 and its cash flows for the three months ended March 31, 2023 and 2022. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods or any future year or period. Liquidity The Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the consolidated financial statements are issued. As of March 31, 2023, the Company had an accumulated deficit of $504,304. During the three months ended March 31, 2023, the Company reported net loss of $12,270 and used $4,267 cash in operating activities. As of March 31, 2023, the Company had cash, cash equivalents and short-term investments of $187,494. Based on its current operating plan, the Company expects that its cash, cash equivalents and short-term investments will be sufficient to fund its operations and capital expenditure requirements for at least twelve months from the issuance date of these consolidated financial statements. The future viability of the Company beyond that point is dependent on its ability to fund its operations through sales of ARCALYST and/or raise additional capital, as needed. If the Company is unable to grow sales of ARCALYST in future periods, the Company would need to seek additional financing through public or private securities offerings, debt financings, or other sources, which may include licensing, collaborations or other strategic transactions or arrangements. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing on terms acceptable to the Company, if at all. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its commercialization efforts, research and development programs for product candidates or product portfolio expansion, which could adversely affect its business prospects, or the Company may be unable to continue operations. ​ Recently Adopted Accounting Pronouncements ​

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	3 Months Ended
	Mar. 31, 2023
Fair Value of Financial Assets and Liabilities
Fair Value of Financial Assets and Liabilities	2 Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: ● Level 1—Quoted prices in active markets for identical assets or liabilities. ● Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. ● Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The following tables present information about the Company’s financial instruments measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ ​ as of March 31, 2023 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents — money market funds ​ $ 51,481 ​ $ — ​ $ — ​ $ 51,481 Cash equivalents — U.S. Treasury notes ​ ​ — ​ ​ 1,000 ​ ​ — ​ ​ 1,000 Short-term investments — U.S. Treasury notes ​ ​ — ​ ​ 106,876 ​ ​ — ​ ​ 106,876 ​ ​ $ 51,481 ​ $ 107,876 ​ $ — ​ $ 159,357 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ ​ as of December 31, 2022 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents — money market funds ​ $ 20,929 ​ $ — ​ $ — ​ $ 20,929 Cash equivalents — U.S. Treasury notes ​ ​ — ​ ​ 15,009 ​ ​ — ​ ​ 15,009 Short-term investments — U.S. Treasury notes ​ ​ — ​ ​ 67,893 ​ ​ — ​ ​ 67,893 ​ ​ $ 20,929 ​ $ 82,902 ​ $ — ​ $ 103,831 ​ During the three months ended March 31, 2023 and the year ended December 31, 2022, there were no transfers between Level 1, Level 2 and Level 3. The money market funds were valued using quoted prices in active markets, which represent a Level 1 measurement in the fair value hierarchy. The Company’s cash equivalents and short-term investments as of March 31, 2023 and December 31, 2022 included U.S. Treasury notes, which are not traded on a daily basis and, therefore, represent a Level 2 measurement in the fair value hierarchy at each period end. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Credit ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ Losses ​ Value March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents — U.S. Treasury notes ​ $ 1,000 ​ $ — ​ $ — ​ $ — ​ $ 1,000 Short-term investments — U.S. Treasury notes ​ ​ 106,848 ​ ​ 29 ​ ​ (1) ​ ​ — ​ ​ 106,876 ​ ​ $ 107,848 ​ $ 29 ​ $ (1) ​ $ — ​ $ 107,876 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Credit ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ Losses ​ Value December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents — U.S. Treasury notes ​ $ 15,006 ​ $ 3 ​ $ — ​ $ — ​ $ 15,009 Short-term investments — U.S. Treasury notes ​ ​ 67,891 ​ ​ 6 ​ ​ (4) ​ ​ — ​ ​ 67,893 ​ ​ $ 82,897 ​ $ 9 ​ $ (4) ​ $ — ​ $ 82,902 ​ As of March 31, 2023, we consider the unrealized losses in our investment portfolio to be temporary in nature and not due to credit losses. We have the ability to hold such investments until recovery of the fair value. We utilize the specific identification method in computing realized gains and losses. We had no realized gains and losses on our available-for-sale securities for the three months ended March 31, 2023 or 2022.

Product Revenue, Net

Product Revenue, Net	3 Months Ended
	Mar. 31, 2023
Product Revenue, Net
Product Revenue, Net	3. Product Revenue, Net Product revenue, net, from sales of ARCALYST was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2023 ​ 2022 Product revenue, net ​ $ 42,659 ​ $ 22,189 ​ The following table summarizes balances and activity in each of the product revenue allowance and reserve categories for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Government ​ ​ ​ ​ ​ ​ Adjustments ​ Rebates ​ Returns ​ Total Balance at December 31, 2022 ​ $ 1,464 ​ $ 2,084 ​ $ 351 ​ $ 3,899 Current provisions relating to sales in the current year ​ ​ 3,239 ​ ​ 1,800 ​ ​ 96 ​ ​ 5,135 Adjustments relating to prior years ​ ​ (72) ​ ​ 46 ​ ​ — ​ ​ (26) Payments/returns relating to sales in the current year ​ ​ (2,120) ​ ​ (402) ​ ​ — ​ ​ (2,522) Payments/returns relating to sales in the prior years ​ ​ (1,392) ​ ​ (1,230) ​ ​ (39) ​ ​ (2,661) Balance at March 31, 2023 ​ $ 1,119 ​ $ 2,298 ​ $ 408 ​ $ 3,825 ​ Total revenue-related reserves as of March 31, 2023 and December 31, 2022, included in our consolidated balance sheets, are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Components of accounts receivable ​ $ (175) ​ $ (304) Components of other current liabilities ​ ​ 4,000 ​ ​ 4,203 Total revenue-related reserves ​ $ 3,825 ​ $ 3,899 ​ Primarily all of the Company’s trade accounts receivable arise from product revenue in the United States due from the Company’s third party logistics provider. ​

Inventory

Inventory	3 Months Ended
	Mar. 31, 2023
Inventory
Inventory	4. Inventory Inventory consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Raw materials ​ $ — ​ $ — Work-in-process ​ 13,517 ​ 6,312 Finished Goods ​ ​ 9,908 ​ ​ 15,287 ​ ​ $ 23,425 ​ $ 21,599 ​

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2023
Property and Equipment, Net
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Furniture, fixtures and vehicles ​ $ 224 ​ $ 224 Computer hardware and software ​ 345 ​ 345 Leasehold improvements ​ ​ 3,931 ​ ​ 3,931 Lab equipment ​ ​ 4,017 ​ ​ 4,017 Construction in progress ​ 24 ​ — Total property and equipment ​ ​ 8,541 ​ ​ 8,517 Less: Accumulated depreciation ​ (7,148) ​ (6,859) Total property and equipment, net ​ $ 1,393 ​ $ 1,658 ​ Depreciation expense was $289 and $359 during the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023 and December 31, 2022, $198 and $226, respectively, of our property and equipment, net was in the United Kingdom.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2023
Intangible Assets
Intangible Assets	6. Intangible Assets Intangible assets, net of accumulated amortization, impairment charges and adjustments as of March 31, 2023 and December 31, 2022 are summarized in the following table. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of March 31, 2023 ​ As of December 31, 2022 ​ ​ Estimated ​ ​ ​ Accumulated ​ ​ ​ ​ ​ Accumulated ​ ​ ​ life Cost Amortization Net ​ Cost Amortization Net Regulatory milestone ​ 20 years ​ $ 20,000 ​ $ 2,000 ​ $ 18,000 ​ $ 20,000 ​ $ 1,750 ​ $ 18,250 ​ ​ ​ ​ $ 20,000 ​ $ 2,000 ​ $ 18,000 ​ $ 20,000 ​ $ 1,750 ​ $ 18,250 ​

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2023
Accrued Expenses
Accrued Expenses	7. Accrued Expenses Accrued expenses consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Accrued research and development expenses ​ $ 2,896 ​ $ 8,378 Accrued employee compensation and benefits ​ ​ 5,644 ​ ​ 11,213 Accrued collaboration expenses ​ ​ 8,288 ​ ​ 7,522 Accrued legal, commercial and professional fees ​ 3,988 ​ 2,866 Other ​ 69 ​ 133 ​ ​ $ 20,885 ​ $ 30,112 ​

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2023
Share-Based Compensation
Share-Based Compensation	8. Share-Based Compensation The Company maintains several equity compensation plans, including the 2018 Incentive Award Plan (the “2018 Plan”), 2018 Employee Share Purchase Plan (the “2018 ESPP”), and Rilonacept Long-Term Incentive Plan (“RLTIP”) which was approved under the 2018 Plan. Upon the effectiveness of the 2018 Plan, the Company ceased granting awards under its 2015 Equity Incentive Plan (as amended, the “2015 Plan” and together with the 2018 Plan, the “Plans”). 2015 Plan As of March 31, 2023, there were 1,951,667 Class A common shares subject to outstanding awards under the 2015 Plan and reserved for issuance thereunder pursuant to such awards. 2018 Plan In May 2018, the Company’s board of directors and shareholders approved 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 (“RSUs”) and other share- or cash- based awards. Pursuant to the 2018 Plan’s evergreen provision, the number of shares available for future issuance under the 2018 Plan, as of January 1, 2023, increased by 2,787,900 Class A common shares. As of March 31, 2023, 6,877,727 shares remained available for future grant under the 2018 Plan. 2018 ESPP In December 2022, the Company’s board of directors resolved not to increase the number of Class A common shares reserved for issuance under the 2018 ESPP. As of March 31, 2023, 562,890 Class A common shares were available for future issuance under the 2018 ESPP. ​ ​ ​ ​ ​ Options Share option activity under the Plans is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of ​ Average ​ ​ Shares ​ Exercise Price Outstanding as of December 31, 2022 10,144,618 ​ $ 13.36 Granted 46,200 ​ $ 13.91 Exercised (14,859) ​ $ 7.56 Forfeited (90,973) ​ $ 15.79 Outstanding as of March 31, 2023 10,084,986 ​ $ 13.35 Share options exercisable as of March 31, 2023 5,982,120 ​ $ 13.61 Share options unvested as of March 31, 2023 4,102,866 ​ $ 12.96 ​ As of March 31, 2023, total unrecognized compensation expense related to the unvested share option awards was $31,910 which is expected to be recognized over a weighted average remaining period of 2.51 years. ​ Restricted Share Units ​ Beginning in March 2021, the Company began granting RSUs with service conditions (“Time-Based RSUs”) to eligible employees as part of its equity incentive compensation. 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. During the years ended December 31, 2020 and 2019, the Company granted the first RSU awards (“First RLTIP RSU Awards”) as part of the RLTIP to eligible employees. During the year ended December 31, 2021, the FDA Milestone (as defined in RLTIP) was achieved (the date of such achievement, the “Achievement Date”) and (1) the number of Class A common shares issuable under the First RLTIP RSU Awards were determined in accordance with the RLTIP and vested in one installment in March 2022, and (2) the Company granted a second set of RSU awards to eligible employees on the Achievement Date with respect to a number of shares determined in accordance with the RLTIP, which vested in one installment in March 2023. During the three months ended March 31, 2023 and 2022, the Company recognized compensation expense of $1,529 and $619, respectively, related to RSUs including those granted in connection with the RLTIP. The following table summarizes RSU activity, including the RSUs issued under the RLTIP for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested RSUs as of December 31, 2022 ​ 1,742,401 ​ $ 12.76 Granted ​ 69,045 ​ $ 13.91 Vested ​ (115,907) ​ $ 20.15 Forfeited ​ (39,462) ​ $ 11.86 Unvested RSUs as of March 31, 2023 ​ 1,656,077 ​ $ 12.31 ​ As of March 31, 2023, total unrecognized compensation cost related to the RSU awards was $16,991 which is expected to be recognized over a weighted average remaining period of 3.06 years. Share-Based Compensation Share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2023 2022 Cost of goods sold ​ $ 286 ​ $ 180 Research and development expenses ​ ​ 1,444 ​ ​ 1,976 Selling, general and administrative expenses ​ 4,385 ​ 3,875 ​ ​ $ 6,115 ​ $ 6,031 ​

Out-Licensing Agreements

Out-Licensing Agreements	3 Months Ended
	Mar. 31, 2023
Out-Licensing Agreements
Out-Licensing Agreements	9. Genentech License Agreement In August 2022, the Company entered into a license agreement (the “Genentech License Agreement”) with Genentech, Inc. and F. Hoffmann-La Roche Ltd (collectively, “Genentech”), pursuant to which the Company granted Genentech exclusive worldwide rights to develop, manufacture and commercialize vixarelimab and related antibodies (each, a “Genentech Licensed Product”). The Genentech License Agreement became effective on September 12, 2022 (the “Genentech Effective Date”). Under the Genentech License Agreement, the Company received an upfront payment of $80,000 for the license. In the first quarter of 2023, following the Company’s last delivery of certain drug supplies to Genentech, the Company received an additional $20,000 payment. In addition, the Company will be eligible to receive up to approximately $600,000 in contingent payments, including specified development, regulatory and sales-based milestones, before fulfilling the Company’s upstream financial obligations. The Company will also be eligible to receive tiered percentage royalties on a Genentech Licensed Product-by-Genentech Licensed Product basis ranging from low-double digits to mid-teens on annual net sales of each Genentech Licensed Product, subject to certain customary reductions, with an aggregate minimum floor, before fulfilling the Company’s upstream financial obligations. Royalties will be payable on a Genentech Licensed Product-by-Genentech Licensed Product and country-by-country basis until the latest to occur of the expiration of certain patents that cover a Genentech Licensed Product, the expiration of regulatory exclusivity for such Genentech Licensed Product, or the tenth anniversary of first commercial sale of such Genentech Licensed Product in such country. Pursuant and subject to the terms of the Genentech License Agreement, Genentech has the exclusive worldwide right to conduct development and commercialization activities for Genentech Licensed Products at its sole cost. Notwithstanding the foregoing, the Company is responsible, at its sole cost, for continuing to conduct and finalize its Phase 2b clinical trial assessing the efficacy, safety and tolerability of vixarelimab in reducing pruritis in prurigo nodularis. Accounting for the Genentech License Agreement As of the Genentech Effective Date, the Company identified the following performance obligations in the Genentech License Agreement: (i) the delivery of the exclusive license for vixarelimab; (ii) an initial drug supply delivery; (iii) a drug product resupply delivery; and (iv) completion of the Phase 2b clinical trial for vixarelimab. The Company determined the transaction price at the inception of the Genentech License Agreement which consists of the $80,000 upfront payment. The Company determined that the $20,000 variable consideration related to the delivery of the initial drug supply and drug product resupply was no longer constrained during the fourth quarter of 2022, as the Company determined that it could assert it was not probable that a significant reversal in the amount of cumulative revenue recognized would occur. The Company met the initial drug supply and drug product resupply obligation in the first quarter of 2023 and has received the related $20,000 payment. As noted above, the Company identified four performance obligations in the Genentech License Agreement: (i) the delivery of the exclusive license for vixarelimab; (ii) an initial drug supply delivery; (iii) a drug product resupply delivery; and (iv) completion of the Phase 2b clinical trial for vixarelimab. The selling price of each performance obligation in the Genentech License Agreement was determined based on the Company’s standalone selling price with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the transaction price to each of the four performance obligations noted above. ​ ​ ​ ​ Performance Obligation ​ Method of Recognition Exclusive license for vixarelimab ​ Point in time; upon transfer of the license to Genentech, as control of the license was transferred on the Genentech Effective Date and Genentech could begin to use and benefit from the license on that date. Initial drug supply delivery ​ Point in time upon delivery. Drug product resupply delivery ​ Point in time upon delivery. Completion of the phase 2b clinical trial for vixarelimab ​ Over time; using the cost-to-cost input method, which is believed to best depict the transfer of control to the customer. Under the cost-to-cost input method, the percent of completion is based on the ratio of actual costs incurred as of the period end to the total estimated costs. Revenue is recorded as a percentage of the allocated transaction price times the percent of completion. ​ The Company recognized $5,686 of collaboration revenue during three months ended March 31, 2023 under the Genentech License Agreement related to the license, completed portion of the Phase 2b clinical trial for vixarelimab, and materials delivered. The Company expects to recognize the remaining deferred revenue associated with the Genentech License Agreement over the remaining portion of the Phase 2b clinical trial for vixarelimab. Huadong Collaboration Agreements In February 2022 (the “Effective Date”), the Company entered into two collaboration and license agreements (each, a “Huadong Collaboration Agreement” and together, the “Huadong Collaboration Agreements”) with Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (“Huadong”), pursuant to which the Company granted Huadong exclusive rights to develop and commercialize rilonacept and develop, manufacture and commercialize mavrilimumab (each, a “Huadong Licensed Product” and together, the “Huadong Licensed Products”) in the following countries: People’s Republic of China, Hong Kong SAR, Macao SAR, Taiwan Region, South Korea, Indonesia, Singapore, The Philippines, Thailand, Australia, Bangladesh, Bhutan, Brunei, Burma, Cambodia, India, Laos, Malaysia, Maldives, Mongolia, Nepal, New Zealand, Sri Lanka, and Vietnam (collectively, the “Huadong Territory”). Under the Huadong Collaboration Agreements, the Company received a total upfront cash payment of $22,000, which includes $12,000 for the Huadong Territory license of rilonacept and $10,000 for the Huadong Territory license of mavrilimumab. The Company will be eligible to receive up to approximately $70,000 in payments for rilonacept, and up to approximately $576,000 in payments for mavrilimumab, including specified development, regulatory and sales-based milestones. Huadong will also be obligated to pay the Company tiered percentage royalties on a Huadong Licensed Product-by-Huadong Licensed Product basis ranging from the low-teens to low-twenties on annual net sales of each Huadong Licensed Product in the Huadong Territory, subject to certain reductions tied to rilonacept manufacturing costs and certain other customary reductions, with an aggregate minimum floor. Royalties will be payable on a Huadong Licensed Product-by-Huadong Licensed Product and country-by-country or region-by-region basis until the later of (i) 12 years after the first commercial sale of the applicable Huadong Licensed Product in such country or region in the Huadong Territory, (ii) the date of expiration of the last valid patent claim of the Company’s patent rights or any joint collaboration patent rights that covers the applicable Huadong Licensed Product in such country or region in the Huadong Territory, and (iii) the expiration of the last regulatory exclusivity for the applicable Huadong Licensed Product in such country or region in the Huadong Territory. The Company concluded that the Huadong Collaboration Agreements should not be combined and treated as a single arrangement for accounting purposes as the Huadong Collaboration Agreements were negotiated separately with separate and distinct commercial objectives, the amount of consideration in one Huadong Collaboration Agreement is not dependent on the price or performance of the other Huadong Collaboration Agreement, and the goods and services promised in the Huadong Collaboration Agreements are not a single performance obligation. Accounting for the Mavrilimumab Huadong Collaboration Agreement As of the Effective Date, the Company identified the following performance obligations in the mavrilimumab Huadong Collaboration Agreement: delivery of (i) exclusive license for mavrilimumab in the Huadong Territory and (ii) clinical manufacturing supply of certain materials for mavrilimumab products in the Huadong Territory. The Company determined the transaction price at the inception of the mavrilimumab Huadong Collaboration Agreement which includes $10,000, consisting of the upfront payment. The Company also includes an estimate of variable consideration associated with the clinical manufacturing supply of certain materials when those materials are shipped. The Company determined that any variable consideration related to development and regulatory milestones is deemed fully constrained and therefore excluded from the transaction price due to the high degree of uncertainty and risk associated with these potential payments, as the Company determined that it could not assert that it was probable that a significant reversal in the amount of cumulative revenue recognized will not occur. The Company also determined that royalties and sales milestones relate solely to the licenses of intellectual property. Revenue related to these royalties and sales milestones will only be recognized when the associated sales occur, and relevant thresholds are met, under the sales or usage-based royalty exception of Topic 606. The Company recognizes revenue for the license performance obligations at a point in time, that is upon transfer of the license to Huadong. As control of the license was transferred on the Effective Date and Huadong could begin to use and benefit from the license, the Company recognized $10,000 of collaboration revenue during the year ended December 31, 2022 under the mavrilimumab Huadong Collaboration Agreement. The Company will recognize revenue for the clinical manufacturing supply obligations at a point in time, that is upon each delivery of the supply to Huadong. ​ Accounting for the Rilonacept Huadong Collaboration Agreement As of the Effective Date, the Company identified one performance obligation in the rilonacept Huadong Collaboration Agreement: the exclusive license for rilonacept and clinical and commercial manufacturing obligations for rilonacept products in the Huadong Territory. Huadong cannot exploit the value of the exclusive license for rilonacept products in the Huadong Territory without receipt of supply as the exclusive license for rilonacept products in the Huadong Territory does not convey to Huadong the right to manufacture and therefore the Company has combined the exclusive license for rilonacept products in the Huadong Territory and the manufacturing obligations into one performance obligation. The Company determined the transaction price at the inception of the rilonacept Huadong Collaboration Agreement which includes $12,000, consisting of the upfront payment. The Company also includes an estimate of variable consideration associated with the clinical and commercial manufacturing supply of certain materials when those materials are shipped. The Company determined that any variable consideration related to development and regulatory milestones, sales milestones and royalties are deemed fully constrained and therefore excluded from the transaction price due to the high degree of uncertainty and risk associated with these potential payments, as the Company determined that it could not assert that it was probable that a significant reversal in the amount of cumulative revenue recognized will not occur. Royalties and sales milestones will be recognized as the Company delivers the commercial manufactured product to Huadong. Any changes in estimates may result in a cumulative catch-up based on the number of units of manufactured product delivered. ​ The Company recognizes revenue for the single performance obligation in the rilonacept Huadong Collaboration Agreement consisting of the exclusive license for rilonacept and clinical and commercial manufacturing obligations for rilonacept products in the Huadong Territory at a point in time, upon which control of materials are transferred to Huadong for each delivery of the associated materials. The Company currently expects to recognize the revenue over the life of the agreement. This estimate considers the timing of development and commercial activities under the rilonacept Huadong Collaboration Agreement and may be reduced or increased based on changes in the various activities. ​ The Company has not recognized any revenue under the rilonacept Huadong Collaboration Agreement for the three months ended March 31, 2023 as there has been no delivery of materials under the rilonacept Huadong Collaboration Agreement to date. The transaction price of $11,931 is recorded in non-current deferred revenue and $69 is recorded in current deferred revenue, based upon timing of anticipated future shipments. ​ The following table summarizes the Company’s contract assets and contract liabilities in connection with license and collaboration agreements for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ Revenue ​ ​ ​ Balance at End ​ ​ Beginning of Period ​ Additions ​ Recognized ​ Reclassification ​ of Period Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Genentech vixarelimab ​ $ 7,656 ​ $ — ​ $ — ​ $ (7,656) ​ $ — Contract Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Genentech vixarelimab ​ $ — ​ $ 20,000 ​ $ (5,686) ​ $ (7,656) ​ $ 6,658 Huadong rilonacept ​ ​ 12,000 ​ ​ — ​ ​ — ​ ​ — ​ ​ 12,000 Total Contract Liabilities ​ $ 12,000 ​ $ 20,000 ​ $ (5,686) ​ $ (7,656) ​ $ 18,658 ​

License and Acquisition Agreeme

License and Acquisition Agreements	3 Months Ended
	Mar. 31, 2023
License and Acquisition Agreements
License and Acquisition Agreements	10. License and Acquisition Agreements Biogen Asset Purchase Agreement In September 2016, the Company entered into an asset purchase agreement (the “Biogen Agreement”) with Biogen MA Inc. (“Biogen”) to acquire all of Biogen’s right, title and interest in and to certain assets used in or relating to vixarelimab and other antibodies covered by certain patent rights, including patents and other intellectual property rights, clinical data, know-how, and clinical drug supply. In addition, Biogen granted the Company a non-exclusive, sublicensable, worldwide license to certain background patent rights related to the vixarelimab program. The Company is obligated to use commercially reasonable efforts to develop and commercialize such acquired products. Under the Biogen Agreement, the Company is obligated to make milestone payments to Biogen of up to $179,000 upon the achievement of specified clinical and regulatory milestones in multiple indications in various territories, of which $165,000 remains as of March 31, 2023. Additionally, the Company could be obligated to make up to an aggregate of up to $150,000 of payments upon the achievement of specified annual net sales milestones and to pay tiered royalties on escalating tiers of annual net sales of licensed products starting in the high single-digit percentages and ending below the teens. The Company also agreed to pay certain obligations under third party contracts retained by Biogen that relate to the vixarelimab program. Under these retained contracts, the Company paid a one-time upfront sublicense fee and is obligated to pay insignificant annual maintenance fees as well as clinical and regulatory milestone payments of up to an aggregate of $1,575. The Biogen Agreement will terminate upon the expiration of all payment obligations with respect to the last product in all countries in the territory. The Company has the right to terminate the agreement with 90 days’ prior written notice. Both parties may terminate by mutual written consent or in the event of material breach of the agreement by the other party that remains uncured for 90 days (or 30 days for payment-related breaches). In July 2017, the Company and Biogen entered into Amendment No. 1 to the Biogen Agreement, which clarified the scope of the antibodies subject to the Biogen Agreement. In August 2022, the Company entered into Amendment No. 2 to the Biogen Agreement (the “Second Biogen Amendment”). Pursuant to the terms of the Second Biogen Amendment, commencing on the effective date of the Genentech License Agreement, certain defined terms in the Biogen Agreement were amended, including “Net Sales”, “Indication”, “Product”, “Combination Product” and “Valid Claim”. In addition, the tiered royalty rates to be paid by the Company to Biogen increased by an amount equal to less than one percent. Upon the termination or expiration of the Genentech License Agreement, the amendments to the terms of the Biogen Agreement, as set forth in the Second Biogen Amendment, will terminate and all terms of the Biogen Agreement will revert to the version of such terms in effect as of immediately prior to the effective date of the Genentech License Agreement. During the three months ended March 31, 2023, the Company did not record any research and development expense in connection with the Biogen Agreement. Beth Israel Deaconess Medical Center License Agreement In 2019, the Company exercised the call option under the stock purchase option agreement with Primatope and acquired all of the outstanding securities of Primatope (the “Primatope Acquisition”). As a result of the Primatope Acquisition, the Company acquired the rights to an exclusive license to certain intellectual property rights controlled by Beth Israel Deaconess Medical Center, Inc. (“BIDMC”) to make, use, develop and commercialize KPL-404 (the “BIDMC Agreement”). Under the BIDMC Agreement, the Company is solely responsible for all development, regulatory and commercial activities and costs. The Company is also responsible for costs related to filing, prosecuting and maintaining the licensed patent rights. Under the BIDMC Agreement, the Company is obligated to pay an insignificant annual maintenance fee as well as clinical and regulatory milestone payments of up to an aggregate of $1,200 to BIDMC. The Company is also obligated to pay a low single-digit royalty on annual net sales of products licensed under the agreement. During the three months ended March 31, 2023 and 2022, the Company did not record any research and development expense in connection with the BIDMC Agreement. Regeneron License Agreement In September 2017, the Company entered into a license agreement (the “Regeneron Agreement”) with Regeneron Pharmaceuticals, Inc. (“Regeneron”), pursuant to which the Company has been granted an exclusive license under certain intellectual property rights controlled by Regeneron to develop and commercialize ARCALYST worldwide, excluding the Middle East and North Africa, for all indications other than those in oncology and local administration to the eye or ear. Upon receiving positive data in RHAPSODY, the Company’s pivotal Phase 3 clinical trial of ARCALYST, Regeneron transferred the biologics license application (“BLA”) for ARCALYST to the Company. In March 2021, when the FDA granted approval of ARCALYST for the treatment of recurrent pericarditis and reduction in risk of recurrence in adults and children 12 years and older, the Company assumed the sales and distribution of ARCALYST for Cryopyrin-Associated Periodic Syndromes and Deficiency of Interleukin-1 Receptor Antagonist in the United States. ​ The Company evenly splits profits on sales of ARCALYST with Regeneron, where profits are determined after deducting from net sales of ARCALYST certain costs related to the manufacturing and commercialization of ARCALYST. Such costs include but are not limited to (i) the Company’s cost of goods sold for product used, sold or otherwise distributed for patient use by the Company; (ii) customary commercialization expenses, including the cost of the Company’s field force, and (iii) the Company’s cost to market, advertise and otherwise promote ARCALYST, with such costs identified in subsection (iii) subject to specified limits.  To the extent permitted in accordance with the Regeneron Agreement, the fully-burdened costs incurred by each of the Company and Regeneron in performing (or having performed) the technology transfer of the manufacturing process for ARCALYST drug substance will also be deducted from net sales of ARCALYST to determine profit. The Company also evenly splits with Regeneron any proceeds received by the Company from any licensees, sublicensees and distributors in consideration for the sale, license or other disposition of rights with respect to ARCALYST, including upfront payments, milestone payments and royalties. For the three months ended March 31, 2023 and 2022, the Company recognized $8,288 and $8,254 respectively, of expenses related to the profit sharing agreement presented within collaboration expenses. The Company recorded $6,000 of profit sharing expense during the three months ended March 31, 2022, related to the rilonacept Huadong Collaboration Agreement. ​ Pursuant to the Regeneron Agreement, during the year ended December 31, 2021, the Company entered into a commercial supply agreement under which Regeneron agreed to manufacture product for the Company’s clinical and commercial use. The commercial supply agreement terminates upon the termination of the Regeneron Agreement or the date of completion of the transfer of technology related to the manufacture of ARCALYST. During the three months ended March 31, 2023 and 2022, the Company did not incur any research and development expense related to the purchase of drug materials under the clinical supply agreement. The Company’s inventory balance as of March 31, 2023 and December 31, 2022, of $23,425 and $21,599, respectively, were purchased under the commercial supply agreement. As of March 31, 2023, the Company had non-cancelable purchase commitments under the commercial supply agreement (see Note 13). The Regeneron Agreement will expire when the Company is no longer developing or commercializing any licensed product under the Regeneron Agreement. Either party may terminate the agreement upon the other party’s insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured for 90 days (or 30 days for payment related breaches). Regeneron has the right to terminate the agreement if the Company suspends its development or commercialization activities for a consecutive 12 month period or does not grant a sublicense to a third party to perform such activities, or if the Company challenges any of the licensed patent rights. The Company may terminate the agreement at any time with one year’s written notice. The Company may also terminate the agreement with three months’ written notice if the licensed product is determined to have certain safety concerns. MedImmune License Agreement In December 2017, the Company entered into a license agreement (as amended from time to time, the “MedImmune Agreement”) with MedImmune, Limited (“MedImmune”), pursuant to which MedImmune granted the Company an exclusive, sublicensable, worldwide license to certain intellectual property rights to make, use, develop and commercialize mavrilimumab. Under the MedImmune Agreement, the Company also acquired reference rights to relevant manufacturing and regulatory documents and MedImmune’s existing supply of mavrilimumab drug substance and product. The Company is obligated to use commercially reasonable efforts to develop and commercialize the licensed products. The Company is obligated to make clinical, regulatory and initial sales milestone payments of up to $72,500 in aggregate for the first two indications, of which $57,500 remain as of March 31, 2023. In addition, the Company is obligated to make clinical and regulatory milestone payments of up to $15,000 in the aggregate for each subsequent indication. In July 2020, the Company entered into an amendment to the MedImmune Agreement to establish a new coronavirus field and defer the payment of certain development and regulatory milestones as applied to the new coronavirus field. The Company is obligated to make milestone payments to MedImmune of up to $85,000 upon the achievement of annual net sales thresholds up to, but excluding, $1,000,000 in annual net sales as well as additional milestone payments aggregating up to $1,100,000 upon the achievement of additional specified annual net sales thresholds starting at $1,000,000 and higher. The Company has also agreed to pay tiered royalties on escalating tiers of annual net sales of licensed products starting in the low double-digit percentages and ending at twenty percent. Royalty rates are subject to reductions upon certain events. ​ The Company is solely responsible for all development, manufacturing, and commercial activities and costs of the licensed products, including clinical studies or other tests necessary to support the use of a licensed product. The Company is also responsible for costs related to the filing, prosecution and maintenance of the licensed patent rights. The MedImmune Agreement will expire upon the expiration of the royalty term in the last country for the last indication, as defined in the agreement. Either party may terminate the agreement upon the other party’s insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured for 90 days. MedImmune has the right to terminate the agreement if the Company challenges any of the licensed patent rights. The Company may terminate the agreement at any time upon 90 days’ prior written notice. During the three months ended March 31, 2023 and 2022, the Company did not record research and development expense in connection with milestone payments due under the MedImmune Agreement.

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2023
Net Loss per Share
Net Loss per Share	​ 11. Net Loss per Share The rights, including the liquidation and dividend rights, of the holders of Class A, Class B, Class A1 and Class B1 common shares are identical, except with respect to voting, transferability and conversion (see the Notes to Consolidated Financial Statements to our Form 10-K Basic and diluted net loss attributable to common shareholders was calculated as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2023 2022 Numerator: ​ ​ ​ ​ Net loss attributable to common shareholders ​ $ (12,270) ​ $ (25,210) Denominator: ​ ​ Weighted-average shares outstanding - basic and diluted ​ 69,751,697 ​ 69,136,901 Basic and dilute net loss per share ​ $ (0.18) ​ $ (0.36) ​ ​ ​ ​ ​ ​ ​ ​ The Company’s potentially dilutive securities, which include options and unvested RSUs, have been excluded from the computation of diluted net loss per share attributable to common shareholders as the effect would be to reduce the net loss per share attributable to common shareholders. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common shareholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common shareholders for the periods indicated because including them would have had an anti-dilutive effect: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ March 31, ​ 2023 2022 Share options to purchase common shares ​ 10,084,986 ​ ​ 8,789,357 Unvested RSUs ​ 1,656,077 ​ ​ 665,770 Total anti-dilutive shares ​ 11,741,063 ​ ​ 9,455,127 ​

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Taxes
Income Taxes	12. Income Taxes The Company is an exempted company incorporated under the laws of Bermuda. Under the current laws of Bermuda, income tax is not charged or levied on an exempted company’s income. As a result, the Company has not recorded any income tax benefits from losses incurred in Bermuda during each reporting period, and no net operating loss carryforwards will be available to the Company for those losses. The Company’s wholly owned U.S. subsidiaries, Kiniksa US and Primatope, are subject to federal and state income taxes in the United States. The Company’s wholly owned subsidiary Kiniksa UK, and its wholly owned subsidiaries, Kiniksa Germany, Kiniksa France, and Kiniksa Switzerland are subject to taxation in their respective countries. Certain of the Company’s subsidiaries, primarily Kiniksa US, operate under cost plus arrangements. ​ Although Bermuda has no corporate income tax the Company’s income tax rate for the three months ended March 31, 2023 is due to Kiniksa UK’s and Kiniksa US’s income subject to taxation in each of their respective countries. Income tax provision for the three months ended March 31, 2023 was $2,906. The provision for income taxes is primarily driven by income earned in the UK and U.S. offset in part by tax benefits from Foreign Derived Intangible Income (“FDII”) deduction and U.S. federal and state research and development credits. ​ While the Company still maintains a full valuation allowance on its U.S. deferred tax assets as of March 31, 2023, based on current U.S. forecasted income, it is reasonably possible that the Company will release its valuation allowance on its U.S. deferred tax assets within one year. ​ Management regularly reassesses the valuation allowance on the Company’s deferred income tax assets. Valuation allowances require an assessment of both positive and negative evidence when determining whether it is more likely than not that the Company will be able to recover its deferred tax assets. Such assessment is required on a jurisdiction-by-jurisdiction basis. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. ​ A number of countries have begun to enact legislation to implement the Organization for Economic Cooperation and Development's ("OECD") international tax framework. The Company is currently monitoring these developments and is in the process of evaluating the potential impact on its results of operations. ​

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies License Agreements The Company entered into license agreements with various parties under which it is obligated to make contingent and non-contingent payments (see Note 10). Manufacturing Commitments The Company entered into a commercial supply agreement with Regeneron to provide both clinical supply and commercial product (see Note 10). The Company entered into agreements with several CMOs to provide the Company with preclinical and clinical trial materials. As of March 31, 2023, the Company had committed to minimum payments under these agreements totaling $11,743 all of which are due within one year. Indemnification Agreements The Company is not aware of any claims under indemnification arrangements that are expected to have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of March 31, 2023 or December 31, 2022. Legal Proceedings The Company is not a party to any material litigation and does not have contingency reserves established for any litigation liabilities.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries, Kiniksa Pharmaceuticals Corp. (“Kiniksa US”), Primatope Therapeutics, Inc. (“Primatope”) and Kiniksa Pharmaceuticals (UK), Ltd. (“Kiniksa UK”) as well as the subsidiaries of Kiniksa UK, Kiniksa Pharmaceuticals (Germany) GmbH (“Kiniksa Germany”), Kiniksa Pharmaceuticals (France) SARL (“Kiniksa France”), and Kiniksa Pharmaceuticals GmbH (“Kiniksa Switzerland”), after elimination of all significant intercompany accounts and transactions.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the recognition of revenue, the accrual for research and development expenses, the valuation of our deferred tax assets and the valuation of share-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.
Unaudited Interim Consolidated Financial Information	Unaudited Interim Consolidated Financial Information The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial information. The accompanying unaudited consolidated financial statements do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the “2022 Form 10-K”). The Company’s accounting policies are described in the Notes to Consolidated Financial Statements in the Company’s 2022 Form 10-K and updated, as necessary, in this report. The accompanying year-end consolidated balance sheet was derived from audited financial statements but does not include all disclosures required by GAAP. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2023 and the results of its operations for the three months ended March 31, 2023 and 2022, the changes in its shareholders’ equity for the three months ended March 31, 2023 and 2022 and its cash flows for the three months ended March 31, 2023 and 2022. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods or any future year or period.
Liquidity	Liquidity The Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the consolidated financial statements are issued. As of March 31, 2023, the Company had an accumulated deficit of $504,304. During the three months ended March 31, 2023, the Company reported net loss of $12,270 and used $4,267 cash in operating activities. As of March 31, 2023, the Company had cash, cash equivalents and short-term investments of $187,494. Based on its current operating plan, the Company expects that its cash, cash equivalents and short-term investments will be sufficient to fund its operations and capital expenditure requirements for at least twelve months from the issuance date of these consolidated financial statements. The future viability of the Company beyond that point is dependent on its ability to fund its operations through sales of ARCALYST and/or raise additional capital, as needed. If the Company is unable to grow sales of ARCALYST in future periods, the Company would need to seek additional financing through public or private securities offerings, debt financings, or other sources, which may include licensing, collaborations or other strategic transactions or arrangements. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing on terms acceptable to the Company, if at all. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its commercialization efforts, research and development programs for product candidates or product portfolio expansion, which could adversely affect its business prospects, or the Company may be unable to continue operations.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value of Financial Assets and Liabilities
Schedule of financial assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ ​ as of March 31, 2023 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents — money market funds ​ $ 51,481 ​ $ — ​ $ — ​ $ 51,481 Cash equivalents — U.S. Treasury notes ​ ​ — ​ ​ 1,000 ​ ​ — ​ ​ 1,000 Short-term investments — U.S. Treasury notes ​ ​ — ​ ​ 106,876 ​ ​ — ​ ​ 106,876 ​ ​ $ 51,481 ​ $ 107,876 ​ $ — ​ $ 159,357 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ ​ as of December 31, 2022 Using: ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ Cash equivalents — money market funds ​ $ 20,929 ​ $ — ​ $ — ​ $ 20,929 Cash equivalents — U.S. Treasury notes ​ ​ — ​ ​ 15,009 ​ ​ — ​ ​ 15,009 Short-term investments — U.S. Treasury notes ​ ​ — ​ ​ 67,893 ​ ​ — ​ ​ 67,893 ​ ​ $ 20,929 ​ $ 82,902 ​ $ — ​ $ 103,831 ​
Schedule of short-term investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Credit ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ Losses ​ Value March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents — U.S. Treasury notes ​ $ 1,000 ​ $ — ​ $ — ​ $ — ​ $ 1,000 Short-term investments — U.S. Treasury notes ​ ​ 106,848 ​ ​ 29 ​ ​ (1) ​ ​ — ​ ​ 106,876 ​ ​ $ 107,848 ​ $ 29 ​ $ (1) ​ $ — ​ $ 107,876 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Credit ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ Losses ​ Value December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents — U.S. Treasury notes ​ $ 15,006 ​ $ 3 ​ $ — ​ $ — ​ $ 15,009 Short-term investments — U.S. Treasury notes ​ ​ 67,891 ​ ​ 6 ​ ​ (4) ​ ​ — ​ ​ 67,893 ​ ​ $ 82,897 ​ $ 9 ​ $ (4) ​ $ — ​ $ 82,902

Product Revenue, Net (Tables)

Product Revenue, Net (Tables)	3 Months Ended
	Mar. 31, 2023
Product Revenue, Net
Schedule of product revenue, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2023 ​ 2022 Product revenue, net ​ $ 42,659 ​ $ 22,189 ​
Schedule of balances and activity of the product revenue allowance and reserve categories	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Government ​ ​ ​ ​ ​ ​ Adjustments ​ Rebates ​ Returns ​ Total Balance at December 31, 2022 ​ $ 1,464 ​ $ 2,084 ​ $ 351 ​ $ 3,899 Current provisions relating to sales in the current year ​ ​ 3,239 ​ ​ 1,800 ​ ​ 96 ​ ​ 5,135 Adjustments relating to prior years ​ ​ (72) ​ ​ 46 ​ ​ — ​ ​ (26) Payments/returns relating to sales in the current year ​ ​ (2,120) ​ ​ (402) ​ ​ — ​ ​ (2,522) Payments/returns relating to sales in the prior years ​ ​ (1,392) ​ ​ (1,230) ​ ​ (39) ​ ​ (2,661) Balance at March 31, 2023 ​ $ 1,119 ​ $ 2,298 ​ $ 408 ​ $ 3,825 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Components of accounts receivable ​ $ (175) ​ $ (304) Components of other current liabilities ​ ​ 4,000 ​ ​ 4,203 Total revenue-related reserves ​ $ 3,825 ​ $ 3,899 ​

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2023
Inventory
Schedule of inventory	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Raw materials ​ $ — ​ $ — Work-in-process ​ 13,517 ​ 6,312 Finished Goods ​ ​ 9,908 ​ ​ 15,287 ​ ​ $ 23,425 ​ $ 21,599

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2023
Property and Equipment, Net
Schedule of property and equipment, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Furniture, fixtures and vehicles ​ $ 224 ​ $ 224 Computer hardware and software ​ 345 ​ 345 Leasehold improvements ​ ​ 3,931 ​ ​ 3,931 Lab equipment ​ ​ 4,017 ​ ​ 4,017 Construction in progress ​ 24 ​ — Total property and equipment ​ ​ 8,541 ​ ​ 8,517 Less: Accumulated depreciation ​ (7,148) ​ (6,859) Total property and equipment, net ​ $ 1,393 ​ $ 1,658 ​

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Intangible Assets
Schedule of intangible assets, net of accumulated amortization, impairment charges, and adjustments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of March 31, 2023 ​ As of December 31, 2022 ​ ​ Estimated ​ ​ ​ Accumulated ​ ​ ​ ​ ​ Accumulated ​ ​ ​ life Cost Amortization Net ​ Cost Amortization Net Regulatory milestone ​ 20 years ​ $ 20,000 ​ $ 2,000 ​ $ 18,000 ​ $ 20,000 ​ $ 1,750 ​ $ 18,250 ​ ​ ​ ​ $ 20,000 ​ $ 2,000 ​ $ 18,000 ​ $ 20,000 ​ $ 1,750 ​ $ 18,250

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2023
Accrued Expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 2022 Accrued research and development expenses ​ $ 2,896 ​ $ 8,378 Accrued employee compensation and benefits ​ ​ 5,644 ​ ​ 11,213 Accrued collaboration expenses ​ ​ 8,288 ​ ​ 7,522 Accrued legal, commercial and professional fees ​ 3,988 ​ 2,866 Other ​ 69 ​ 133 ​ ​ $ 20,885 ​ $ 30,112

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Compensation
Schedule of share option activity under the Plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of ​ Average ​ ​ Shares ​ Exercise Price Outstanding as of December 31, 2022 10,144,618 ​ $ 13.36 Granted 46,200 ​ $ 13.91 Exercised (14,859) ​ $ 7.56 Forfeited (90,973) ​ $ 15.79 Outstanding as of March 31, 2023 10,084,986 ​ $ 13.35 Share options exercisable as of March 31, 2023 5,982,120 ​ $ 13.61 Share options unvested as of March 31, 2023 4,102,866 ​ $ 12.96 ​
Schedule of restricted share activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested RSUs as of December 31, 2022 ​ 1,742,401 ​ $ 12.76 Granted ​ 69,045 ​ $ 13.91 Vested ​ (115,907) ​ $ 20.15 Forfeited ​ (39,462) ​ $ 11.86 Unvested RSUs as of March 31, 2023 ​ 1,656,077 ​ $ 12.31
Schedule of share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2023 2022 Cost of goods sold ​ $ 286 ​ $ 180 Research and development expenses ​ ​ 1,444 ​ ​ 1,976 Selling, general and administrative expenses ​ 4,385 ​ 3,875 ​ ​ $ 6,115 ​ $ 6,031

Out-Licensing Agreements (Table

Out-Licensing Agreements (Tables)	3 Months Ended
	Mar. 31, 2023
Out-Licensing Agreements
Schedule of identified performance obligations to recognize revenue	​ ​ ​ ​ Performance Obligation ​ Method of Recognition Exclusive license for vixarelimab ​ Point in time; upon transfer of the license to Genentech, as control of the license was transferred on the Genentech Effective Date and Genentech could begin to use and benefit from the license on that date. Initial drug supply delivery ​ Point in time upon delivery. Drug product resupply delivery ​ Point in time upon delivery. Completion of the phase 2b clinical trial for vixarelimab ​ Over time; using the cost-to-cost input method, which is believed to best depict the transfer of control to the customer. Under the cost-to-cost input method, the percent of completion is based on the ratio of actual costs incurred as of the period end to the total estimated costs. Revenue is recorded as a percentage of the allocated transaction price times the percent of completion.
Schedule of contract liabilities and contract assets in connection with license and collaboration agreements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ Revenue ​ ​ ​ Balance at End ​ ​ Beginning of Period ​ Additions ​ Recognized ​ Reclassification ​ of Period Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Genentech vixarelimab ​ $ 7,656 ​ $ — ​ $ — ​ $ (7,656) ​ $ — Contract Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Genentech vixarelimab ​ $ — ​ $ 20,000 ​ $ (5,686) ​ $ (7,656) ​ $ 6,658 Huadong rilonacept ​ ​ 12,000 ​ ​ — ​ ​ — ​ ​ — ​ ​ 12,000 Total Contract Liabilities ​ $ 12,000 ​ $ 20,000 ​ $ (5,686) ​ $ (7,656) ​ $ 18,658

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Net Loss per Share
Schedule of basic and diluted net loss attributable to common shareholders	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2023 2022 Numerator: ​ ​ ​ ​ Net loss attributable to common shareholders ​ $ (12,270) ​ $ (25,210) Denominator: ​ ​ Weighted-average shares outstanding - basic and diluted ​ 69,751,697 ​ 69,136,901 Basic and dilute net loss per share ​ $ (0.18) ​ $ (0.36) ​ ​ ​ ​ ​ ​ ​
Schedule of anti-dilutive securities excluded from the computation of diluted net loss per share attributable to common shareholders	​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ March 31, ​ 2023 2022 Share options to purchase common shares ​ 10,084,986 ​ ​ 8,789,357 Unvested RSUs ​ 1,656,077 ​ ​ 665,770 Total anti-dilutive shares ​ 11,741,063 ​ ​ 9,455,127

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Liquidity
Accumulated deficit	$ 504,304		$ 492,034
Net loss	12,270	$ 25,210
Cash used in operations	4,267	$ 36,846
Cash, cash equivalents and short-term investments	$ 187,494

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Assets:
Short-term investments	$ 107,876	$ 82,902
Short-term investments
Amortized Cost	107,848	82,897
Gross Unrealized Gains	29	9
Gross Unrealized Losses	(1)	(4)
Fair Value	107,876	82,902
Fair Value, Assets Transfers
Fair value of assets transferred from Level 1 to Level 2	0	0
Fair value of assets transferred from Level 2 to Level 1	0	0
Fair value of asset transfer into Level 3	0	0
Fair value of asset transfer out of Level 3	0	0
Securities in unrealized loss position	0		$ 0
U.S. Treasury Notes | Cash equivalents
Assets:
Short-term investments	1,000	15,009
Short-term investments
Amortized Cost	1,000	15,006
Gross Unrealized Gains		3
Fair Value	1,000	15,009
U.S. Treasury Notes | Short-term Investments
Assets:
Short-term investments	106,876	67,893
Short-term investments
Amortized Cost	106,848	67,891
Gross Unrealized Gains	29	6
Gross Unrealized Losses	(1)	(4)
Fair Value	106,876	67,893
Fair Value | Recurring basis
Assets:
Assets	159,357	103,831
Fair Value | Recurring basis | Money Market Funds
Assets:
Cash equivalents	51,481	20,929
Fair Value | Recurring basis | U.S. Treasury Notes
Assets:
Cash equivalents	1,000	15,009
Short-term investments	106,876	67,893
Short-term investments
Fair Value	106,876	67,893
Fair Value | Recurring basis | Level 1
Assets:
Assets	51,481	20,929
Fair Value | Recurring basis | Level 1 | Money Market Funds
Assets:
Cash equivalents	51,481	20,929
Fair Value | Recurring basis | Level 2
Assets:
Assets	107,876	82,902
Fair Value | Recurring basis | Level 2 | U.S. Treasury Notes
Assets:
Cash equivalents	1,000	15,009
Short-term investments	106,876	67,893
Short-term investments
Fair Value	$ 106,876	$ 67,893

Product Revenue, Net (Details)

Product Revenue, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Product revenue
Product revenue, net	$ 48,345	$ 32,189
Contractual Adjustments
Balance at beginning of period	1,464
Current provisions relating to sales in the current year	3,239
Adjustments relating to prior years	(72)
Payments/returns relating to sales in the current year	(2,120)
Payments/returns relating to sales in the prior years	(1,392)
Balance at end of period	1,119
Government Rebates
Balance at beginning of period	2,084
Current provisions relating to sales in the current year	1,800
Adjustments relating to prior years	46
Payments/returns relating to sales in current year	(402)
Payments/returns relating to sales in the prior years	(1,230)
Balance at end of period	2,298
Returns
Balance at beginning of period	351
Current provisions relating sales in the current year	96
Payments/returns relating to sales in the prior years	(39)
Balance at end of period	408
Total
Balance at beginning of period	3,899
Current provisions relating to sales in the current year	5,135
Adjustments relating to prior years	(26)
Payments/returns relating to sales in the current year	(2,522)
Payments/returns relating to sales in the prior years	(2,661)
Balance at end of period	3,825
Product revenue, net
Product revenue
Product revenue, net	$ 42,659	$ 22,189

Product Revenue, Net - Revenue

Product Revenue, Net - Revenue Related Reserves in Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Revenue-related reserves
Revenue-related reserves	$ 3,825	$ 3,899
Accounts receivable, net
Revenue-related reserves
Revenue-related reserves	(175)	(304)
Other current liabilities
Revenue-related reserves
Revenue-related reserves	$ 4,000	$ 4,203

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Inventory
Work-in-process	$ 13,517	$ 6,312
Finished goods	9,908	15,287
Total inventory	$ 23,425	$ 21,599

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Property and Equipment, Net
Total property and equipment	$ 8,541		$ 8,517
Less: Accumulated depreciation	(7,148)		(6,859)
Total property and equipment, net	1,393		1,658
Depreciation expense	289	$ 359
UK
Property and Equipment, Net
Total property and equipment, net	198		226
Furniture, fixtures, and vehicles
Property and Equipment, Net
Total property and equipment	224		224
Computer hardware and software
Property and Equipment, Net
Total property and equipment	345		345
Leasehold improvements
Property and Equipment, Net
Total property and equipment	3,931		3,931
Lab equipment
Property and Equipment, Net
Total property and equipment	4,017		$ 4,017
Construction in progress
Property and Equipment, Net
Total property and equipment	$ 24

Intangible Assets - Finite-live

Intangible Assets - Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Intangible Assets
Cost	$ 20,000	$ 20,000
Accumulated Amortization	2,000	1,750
Net	$ 18,000	18,250
Regulatory milestone
Intangible Assets
Estimated life	20 years
Cost	$ 20,000	20,000
Accumulated Amortization	2,000	1,750
Net	$ 18,000	$ 18,250

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accrued Expenses
Accrued research and development expenses	$ 2,896	$ 8,378
Accrued employee compensation and benefits	5,644	11,213
Accrued collaboration expenses	8,288	7,522
Accrued legal, commercial and professional fees	3,988	2,866
Other	69	133
Total accrued expenses	$ 20,885	$ 30,112

Share Based Compensation (Detai

Share Based Compensation (Details) - shares		3 Months Ended
	Jan. 01, 2023	Mar. 31, 2023	Dec. 31, 2022
Restricted Share Units (RSUs)
Share-based compensation
RSUs Granted		69,045
Stock options | Class A common shares
Share-based compensation
Shares outstanding (in shares)		10,084,986	10,144,618
Number of options granted		46,200
2018 Plan
Share-based compensation
Number of common shares available for future grant		6,877,727
2018 Plan | Class A common shares | Maximum
Share-based compensation
Additional shares authorized	2,787,900
2015 Plan | Class A common shares
Share-based compensation
Shares outstanding (in shares)		1,951,667
2018 ESPP | Class A common shares
Share-based compensation
Number of common shares available for future grant		562,890

Share-Based Compensation - Opti

Share-Based Compensation - Options (Details) - Class A common shares - Stock options	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of Shares
Outstanding, beginning of the period | shares	10,144,618
Granted | shares	46,200
Exercised | shares	(14,859)
Forfeited | shares	(90,973)
Outstanding, end of the period | shares	10,084,986
Options exercisable | shares	5,982,120
Options unvested | shares	4,102,866
Weighted Average Grant Date Fair Value
Outstanding, beginning of the period | $ / shares	$ 13.36
Granted | $ / shares	13.91
Exercised | $ / shares	7.56
Forfeited | $ / shares	15.79
Outstanding, end of the period | $ / shares	13.35
Options exercisable | $ / shares	13.61
Options unvested | $ / shares	$ 12.96

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Shares and RSUs (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2023	Mar. 31, 2022
Share-based compensation
Share-based compensation expense		$ 6,115	$ 6,031
Restricted Share Units (RSUs)
Share-based compensation
Share-based compensation expense		$ 1,529	$ 619
Number of shares
Beginning of the period		1,742,401
Granted		69,045
Vested		(115,907)
Forfeited		(39,462)
End of the period		1,656,077
Weighted Average Fair Value at Issuance
Beginning of the period		$ 12.76
Granted		13.91
Vested		20.15
Forfeited		11.86
End of the period		$ 12.31
Time-based RSUs
Share-based compensation
Vesting percentage	25%

Share-Based Compensation - Clas

Share-Based Compensation - Classification of Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based compensation
Share-based compensation expense	$ 6,115	$ 6,031
Cost of goods sold
Share-based compensation
Share-based compensation expense	286	180
Research and development expenses
Share-based compensation
Share-based compensation expense	1,444	1,976
Selling, general and administrative expenses
Share-based compensation
Share-based compensation expense	4,385	3,875
Stock options
Share-based compensation
Total unrecognized compensation cost	$ 31,910
Expenses expected to be recognized over a weighted average remaining period	2 years 6 months 3 days
Restricted Share Units (RSUs)
Share-based compensation
Share-based compensation expense	$ 1,529	$ 619
Total unrecognized compensation cost	$ 16,991
Expenses expected to be recognized over a weighted average remaining period	3 years 21 days

Out-Licensing Agreements (Detai

Out-Licensing Agreements (Details) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Aug. 31, 2022 USD ($) item	Feb. 28, 2022 USD ($) item agreement	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Collaborative agreements
Product revenue, net			$ 48,345	$ 32,189
License and collaboration revenue
Collaborative agreements
Product revenue, net			5,686	$ 10,000
Collaboration Agreements | Huadong rilonacept
Collaborative agreements
Upfront payments received		$ 22,000
Number of agreements entered into | agreement		2
Term of agreement for royalty payments		12 years
Territory License - Rilonacept | Huadong rilonacept
Collaborative agreements
Upfront payments received		$ 12,000
Transaction price		$ 12,000
Number of performance obligations in an agreement | item		1
Payments to be received by the company upon the achievement of specified development, regulatory and sales milestones		$ 70,000
Territory License - Rilonacept | Huadong rilonacept | Non-current deferred revenue
Collaborative agreements
Transaction price			11,931
Territory License - Rilonacept | Huadong rilonacept | Current deferred revenue
Collaborative agreements
Transaction price			69
Territory License - Rilonacept | Huadong rilonacept | License and collaboration revenue
Collaborative agreements
Product revenue, net			0
Territory License - Mavrilimumab | Huadong rilonacept
Collaborative agreements
Upfront payments received		10,000
Transaction price		10,000
Payments to be received by the company upon the achievement of specified development, regulatory and sales milestones		$ 576,000
Territory License - Mavrilimumab | Huadong rilonacept | License and collaboration revenue
Collaborative agreements
Product revenue, net					$ 10,000
Worldwide License - Vixarelimab | Genentech
Collaborative agreements
Upfront payments received	$ 80,000
Payments to be received by the company upon delivery of certain materials			20,000
Milestone receipts	600,000
Transaction price	$ 80,000
Number of performance obligations in an agreement | item	4
Worldwide License - Vixarelimab | Genentech | License and collaboration revenue
Collaborative agreements
Product revenue, net			$ 5,686

Out-Licensing Agreements - Cont

Out-Licensing Agreements - Contract Assets and Liabilities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Contract Assets:
Balance at Beginning of Period	$ 7,656
Contract Liabilities:
Balance at Beginning of Period	12,000
Balance at End of Period	12,163
Collaboration Agreements
Contract Liabilities:
Balance at Beginning of Period	12,000
Additions	20,000
Revenue Recognized	(5,686)
Reclassification	(7,656)
Balance at End of Period	18,658
Territory License - Rilonacept | Huadong rilonacept
Contract Liabilities:
Balance at Beginning of Period	12,000
Balance at End of Period	12,000
Worldwide License - Vixarelimab | Genentech
Contract Assets:
Balance at Beginning of Period	7,656
Reclassification	(7,656)
Contract Liabilities:
Additions	20,000
Revenue Recognized	(5,686)
Reclassification	(7,656)
Balance at End of Period	$ 6,658

License and Acquisition Agree_2

License and Acquisition Agreements - Biogen Asset Purchase Agreement (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Aug. 31, 2022	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2023	Mar. 31, 2022
License and Acquisition Agreements
Uncured period which causes termination of the agreement, due to insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured		90 days
Notice period to terminate the agreement under payment-related breaches		30 days
Research and development				$ 15,172	$ 20,817
Maximum
License and Acquisition Agreements
Royalty rate increase (percentage)	1%
Asset Purchase Agreement | Biogen
License and Acquisition Agreements
Remaining milestone payments to be paid upon clinical and regulatory milestone achievement				$ 165,000
Maximum aggregate obligation to pay insignificant annual maintenance fees as well as clinical and regulatory milestone payments			$ 1,575
Notice period to terminate the agreement			90 days
Uncured period which causes termination of the agreement, due to insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured			90 days
Notice period to terminate the agreement under payment-related breaches			30 days
Asset Purchase Agreement | Biogen | Maximum
License and Acquisition Agreements
Milestone payment to be paid upon clinical and regulatory milestone achievement			$ 179,000
Milestone payment to be paid upon net sales milestone achievement			$ 150,000

License and Acquisition Agree_3

License and Acquisition Agreements - Beth Israel Deaconess Medical Center License Agreement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
License and Acquisition Agreements
Research and development	$ 15,172	$ 20,817
License Agreement | BIDMC
License and Acquisition Agreements
Research and development	0	$ 0
License Agreement | BIDMC | Maximum
License and Acquisition Agreements
Milestone payment to be paid upon clinical and regulatory milestone achievement	$ 1,200

License and Acquisition Agree_4

License and Acquisition Agreements - Regeneron License Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Sep. 30, 2017	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
License and Acquisition Agreements
Research and development		$ 15,172	$ 20,817
Uncured period which causes termination of the agreement, due to insolvency or bankruptcy or for material breach of the agreement by the other party that remains uncured	90 days
Notice period to terminate the agreement under payment-related breaches	30 days
Consecutive suspension of activities period for termination of agreement	12 months
Notice period to terminate the agreement	1 year
Notice period to terminate the agreement if products are having safety concerns	3 months
Intangible asset - Regulatory milestone		20,000		$ 20,000
Commercial product inventory		23,425		21,599
Regulatory milestone
License and Acquisition Agreements
Intangible asset - Regulatory milestone		20,000		20,000
Regeneron | License Agreement
License and Acquisition Agreements
Profit sharing recognized		8,288	8,254
Regeneron | License Agreement | Short-term liabilities
License and Acquisition Agreements
Profit sharing recognized			$ 6,000
Regeneron | Clinical Supply Agreement
License and Acquisition Agreements
Commercial product inventory		$ 23,425		$ 21,599

License and Acquisition Agree_5

License and Acquisition Agreements - MedImmune License Agreement (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Jul. 31, 2020	Sep. 30, 2017	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2017
License and Acquisition Agreements
Notice period to terminate the agreement by both parties for material breaches		90 days
Research and development			$ 15,172	$ 20,817
MedImmune | License Agreement
License and Acquisition Agreements
Remaining milestone payments to be paid upon clinical and regulatory milestone achievement			57,500
Annual net sales excluded from calculation of specified annual net sales thresholds	$ 1,000,000
Maximum percentage of royalty payable on annual net sales of licensed products	20%
Notice period to terminate the agreement by both parties for material breaches	90 days
Notice period to terminate the agreement	90 days
Research and development			$ 0	$ 0
Minimum | MedImmune | License Agreement
License and Acquisition Agreements
Additional specified annual net sales threshold for additional milestone payment.	$ 1,000,000
Maximum | MedImmune | License Agreement
License and Acquisition Agreements
Milestone payment to be paid upon specified milestone achievements for first two indications					$ 72,500
Milestone payment to be paid upon clinical and regulatory milestone achievement					$ 15,000
Milestone payment to be paid upon specified annual sales milestone achievements	85,000
Additional specified annual net sales threshold for additional milestone payment.	$ 1,100,000

Net Loss per Share (Details)

Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss attributable to common shareholders	$ (12,270)	$ (25,210)
Denominator:
Weighted-average basic shares outstanding	69,751,697	69,136,901
Effect of dilutive securities
Weighted-average diluted shares outstanding	69,751,697	69,136,901
Basic net loss per share	$ (0.18)	$ (0.36)
Diluted net loss per share	$ (0.18)	$ (0.36)

Net Loss per Share - Anti-Dilut

Net Loss per Share - Anti-Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of net loss per share	11,741,063	9,455,127
Share options to purchase common shares
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of net loss per share	10,084,986	8,789,357
Unvested RSUs
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of net loss per share	1,656,077	665,770

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Bermuda statutory income tax rate	0%
Net operating loss carryforwards - Bermuda	$ 0	$ 0
Income tax expense	$ 2,906	$ 1,925
Kiniksa US
Time period before release of valuation allowance	1 year

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Mar. 31, 2023 USD ($)
Manufacturing commitments
Non-cancelable purchase commitments	$ 11,743