UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 12, 2019

Kiniksa Pharmaceuticals, Ltd.

(Exact name of Registrant as Specified in Its Charter)

Kiniksa Pharmaceuticals, Ltd.

Clarendon House

2 Church Street

Hamilton HM11, Bermuda
(808) 451-3453

(Address, zip code and telephone number, including area code of principal executive offices)

Kiniksa Pharmaceuticals Corp.

100 Hayden Avenue

Lexington, MA, 02421

(781) 431-9100

(Address, zip code and telephone number, including area code of agent for service)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions

o                                    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o                                    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                                    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                                    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  x

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.   x

Item 2.02. Results of Operations and Financial Condition.

On August 12, 2019, Kiniksa Pharmaceuticals, Ltd. (the “Company”) issued a press release announcing financial results for the quarter ended June 30, 2019. A copy of the press release is furnished with this Current Report on Form 8-K as Exhibit 99.1.

The information contained in this Item 2.02 of this Current Report on Form 8-K and Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, regardless of any general incorporation language in such filing and except as expressly provided by specific reference in such filing.

Item 7.01. Regulation FD.

On August 12, 2019, the Company issued a press release announcing interim data from its repeated-single-dose Phase 1b clinical trial of KPL-716 in subjects with moderate-to-severe atopic dermatitis. A copy of the press release and a slide-deck containing interim data from the trial are furnished with this Current Report on Form 8-K as Exhibits 99.2 and 99.3, respectively.

The information contained in this Item 7.01 of this Current Report on Form 8-K and Exhibits 99.2 and 99.3 shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, regardless of any general incorporation language in such filing and except as expressly provided by specific reference in such filing.

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Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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Exhibit 99.1

Kiniksa Reports Second Quarter 2019 Financial Results and Highlights Recent Corporate and Pipeline Activity

—  Rilonacept pivotal Phase 3 study dosing patients in the U.S., Australia, Israel and Italy; expect to present final Phase 2 data this year —

— Mavrilimumab global Phase 2 study dosing patients in fifteen countries —

— KPL-716 repeated-single-dose Phase 1b interim data showed rapid and sustained anti-pruritic effect throughout the 12-week treatment period; no meaningful difference from placebo on other efficacy endpoints specific to atopic dermatitis —

— Enrollment in KPL-716 Phase 2a in prurigo nodularis progressing; first patients dosed in exploratory Phase 2 study in diseases characterized by chronic pruritus—

HAMILTON, BERMUDA — August 12, 2019 — Kiniksa Pharmaceuticals, Ltd. (Nasdaq: KNSA) (“Kiniksa”), a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients with significant unmet medical need, today reported second quarter 2019 financial results and highlighted recent corporate and pipeline activity.

“Kiniksa is advancing a pipeline of autoimmune and autoinflammatory product candidates based on validated mechanisms or strong biologic rationale and focused on rare diseases,” said Sanj K. Patel, Chief Executive Officer and Chairman of the Board of Kiniksa. “Enrollment in our clinical trials continues to progress across our portfolio, and interim KPL-716 repeated-single-dose data support our ongoing Phase 2 development in prurigo nodularis and diseases characterized by chronic pruritus. Additionally, we look forward to clinical readouts from multiple programs over the next twelve months, starting later this year with final data from our rilonacept Phase 2 study.”

Clinical-Stage Pipeline Activity

Rilonacept (IL-1α and IL-1β cytokine trap)

·                  Kiniksa is advancing rilonacept for the potential treatment of recurrent pericarditis, a painful and debilitating autoinflammatory cardiovascular disease.

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·                  Kiniksa is enrolling RHAPSODY, a randomized-withdrawal (RW) design, pivotal Phase 3 clinical trial of rilonacept in subjects with recurrent pericarditis in the U.S., Australia, Israel and Italy. The primary efficacy endpoint is time-to-first-adjudicated pericarditis-recurrence in the RW period. Top-line data are expected in the second half of 2020.

·                  Kiniksa expects to present final data from an open-label Phase 2 clinical trial of rilonacept in different pericarditis populations later this year.

·                  Kiniksa continues to advance its launch readiness activities for rilonacept through expansion of its commercial and medical affairs teams, generation of evidence on unmet need and disease burden, and research and education with payers, physicians and advocacy groups.

Mavrilimumab (monoclonal antibody inhibitor targeting GM-CSFRα)

·                  Kiniksa is advancing mavrilimumab for the potential treatment of giant cell arteritis (GCA), a chronic inflammatory disease of medium-large blood vessels.

·                  Kiniksa is enrolling a global Phase 2 proof-of-concept clinical trial of mavrilimumab in subjects with GCA in fifteen countries. The primary efficacy endpoint is time-to-first-flare. Top-line data are expected in the second half of 2020.

KPL-716 (monoclonal antibody inhibitor of signaling through OSMRβ)

·                  Kiniksa announced interim data today from a repeated-single-dose Phase 1b clinical trial of KPL-716 in subjects with moderate-to-severe atopic dermatitis. The data showed a rapid and sustained reduction in pruritus throughout the 12-week treatment period. There was no meaningful benefit of repeated-single-doses of KPL-716 on other efficacy endpoints specific to atopic dermatitis, including Eczema Area and Severity Index (EASI) and Scoring Atopic Dermatitis (SCORAD). There were no serious adverse events. However, there were more atopic dermatitis flares in the KPL-716 treated population versus placebo. All flares were successfully managed with topical corticosteroids. KPL-716 was otherwise well-tolerated by all subjects. Kiniksa has no current plan to invest in atopic dermatitis development.

·                  Kiniksa is advancing KPL-716 for the potential treatment of a variety of pruritic diseases, including prurigo nodularis, a chronic inflammatory skin condition.

·                  Kiniksa is enrolling a Phase 2a clinical trial of KPL-716 in subjects with prurigo nodularis. The primary efficacy endpoint is percent change from baseline in weekly

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average Worst-Itch Numeric Rating Scale (WI-NRS). Top-line data are expected in the first half of 2020.

·                  Kiniksa is enrolling an exploratory Phase 2 clinical trial in diseases characterized by chronic pruritus. The trial is designed to identify chronic pruritic conditions where signaling through oncostatin M receptor beta (OSMRβ) may be playing a role and to investigate the efficacy, safety and tolerability of KPL-716 in reducing the moderate-to-severe pruritus experienced by these subjects. Kiniksa expects to provide interim data from this study on a cohort-by-cohort basis throughout 2020.

Preclinical Pipeline Activity

·                  Kiniksa is progressing its preclinical activities with KPL-404, a monoclonal antibody inhibitor of the CD40 co-stimulatory receptor in diseases characterized by T-cell-dependent, B-cell-mediated pathology. Kiniksa expects to file an investigational new drug (IND) application with the U.S. Food and Drug Administration (FDA) later this year.

·                  Kiniksa is evaluating the progression of KPL-045, a monoclonal antibody inhibitor of the CD30 ligand co-stimulatory molecule, based on preclinical data from the program in the context of the company’s portfolio.

Third Quarter 2019 Scientific Conferences

·                  Kiniksa plans to present at the following scientific conferences in the third quarter of 2019:

·                  European Society of Cardiology (ESC) in September 2019; rilonacept Phase 3 methods.

·                  American College of Epidemiology (ACE) in September 2019; retrospective claims analysis of recurrent pericarditis epidemiology in the U.S.

·                  European Society for Dermatological Research (ESDR) in September 2019; preclinical data analyzing expression of OSMRβ in chronic pruritic diseases.

Financial Results

·                  For the second quarter of 2019, Kiniksa reported a net loss of $37.2 million, compared to a net loss of $20.3 million for the second quarter of 2018.

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·                  Total operating expenses for the second quarter of 2019 totaled $39.3 million compared to $21.5 million for the second quarter of 2018. Non-cash share-based compensation expense totaled $3.5 million for the second quarter of 2019, compared to $1.1 million for the second quarter of 2018.

·                  As of June 30, 2019, the company had cash, cash equivalents and short-term investments of $287.4 million and no outstanding debt.

Financial Guidance

·                  Kiniksa expects that its cash, cash equivalents and short-term investments will fund its current operating plan into 2021.

About Kiniksa

Kiniksa is a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical need. Kiniksa has a pipeline of product candidates across various stages of development, focused on autoinflammatory and autoimmune conditions. For more information, please visit www.kiniksa.com.

About Rilonacept

Rilonacept is a weekly, subcutaneously-injected, recombinant fusion protein that blocks interleukin-1α (IL-1α) and interleukin 1β (IL-1β) signaling. Rilonacept was discovered and developed by Regeneron Pharmaceuticals, Inc. (Regeneron) and is approved by the FDA under the brand name ARCALYST® for the treatment of Cryopyrin-Associated Periodic Syndromes (CAPS), which includes Familial Cold Autoinflammatory Syndrome and Muckle-Wells Syndrome. IL-1 blockade may interfere with immune response to infections. Serious, life-threatening infections have been reported in patients taking ARCALYST. ARCALYST should be discontinued if a patient develops a serious infection. Taking ARCALYST with TNF inhibitors is not recommended because this may increase the risk of serious infections. Kiniksa exclusively licensed rilonacept from Regeneron for recurrent pericarditis and certain other indications. Rilonacept in recurrent pericarditis is an investigational drug.

About Mavrilimumab

Mavrilimumab is an investigational fully-human monoclonal antibody that is designed to antagonize granulocyte macrophage colony stimulating factor (GM-CSF) signaling by binding to the alpha subunit of the GM-CSF receptor. Kiniksa’s lead indication for mavrilimumab is giant cell arteritis, an inflammatory disease of blood vessels.

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About KPL-716

KPL-716 is an investigational fully-human monoclonal antibody that targets OSMRβ, which mediates signaling of interleukin-31 (IL-31) and oncostatin M (OSM), two key cytokines implicated in pruritus, inflammation and fibrosis. Kiniksa believes KPL-716 to be the only monoclonal antibody in development that targets both pathways simultaneously.

About KPL-404

KPL-404 is an investigational humanized monoclonal antibody that is designed to inhibit the CD40-CD40-ligand interaction, a key T-cell co-stimulatory signal critical for B-cell maturation and immunoglobulin class switching. Dysregulation of the CD40-CD40L pathway has been implicated in multiple autoimmune disease pathologies such as Systemic Lupus Erythematosus, Rheumatoid Arthritis, Sjogren’s Syndrome and Grave’s Disease.

About KPL-045

KPL-045 is an investigational fully-human monoclonal antibody that is designed to inhibit the CD30-CD30 ligand interaction, a co-stimulatory signal involved in activating and sustaining memory T-cells.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward looking statements by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these identifying words.  All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding: plans and timing to advance our product candidates; proposed indications for the investigation of our product candidates; plans and timing to report or present interim, final and top-line clinical trial, pre-clinical and other data; our conclusions from interim pre-clinical and clinical trial data for KPL-716; plans and timing for the submission of investigational new drug and other applications and submissions to regulatory authorities; and expected timeframe for funding our operating plan with current cash, cash equivalents and short-term investments.

These forward-looking statements are based on management’s current plans, estimates or expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance

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or achievements expressed or implied by the forward-looking statements, including without limitation, the following: potential delays or difficulty in enrollment of patients in, and activation of sites for, our clinical trials; potential complications in coordinating among requirements, regulations and guidelines of regulatory authorities across a number of jurisdictions for our global clinical trials; potential amendments to our clinical trial protocols initiated by us or required by regulatory authorities; potential delays or difficulty in completing our clinical trials; potential undesirable side effects caused by our product candidates; our potential inability to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities or otherwise producing negative, inconclusive or commercially uncompetitive results; potential for changes between final data and any preliminary, interim and “top-line” data we announce; impact of additional data from us or other companies; our potential inability to replicate in later clinical trials positive results from our earlier clinical trials; drug substance and/or drug product shortages caused by issues at our third-party manufacturers’ facilities; our reliance on certain third parties as the sole source of supply of the drug substance and drug products used in our product candidates; our reliance on third parties to conduct our research, pre-clinical studies, clinical trials, and other trials for our product candidates; we face substantial competition; and our ability to attract and retain qualified personnel.

These and other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (“SEC”) on May 7, 2019 and our other reports subsequently filed with the SEC could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s plans, estimates, or expectations as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release.

ARCALYST® is a registered trademark of Regeneron Pharmaceuticals, Inc.

Every Second Counts!™

Kiniksa Investor and Media Contact

Mark Ragosa

(781) 430-8289

mragosa@kiniksa.com

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KINIKSA PHARMACEUTICALS, LTD.

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except share and per share amounts)

(Unaudited)

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KINIKSA PHARMACEUTICALS, LTD.

SELECTED CONSOLIDATED BALANCE SHEET DATA

(In thousands)

(Unaudited)

(1) We define working capital as current assets less current liabilities.

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Exhibit 99.2

Kiniksa Announces Interim Data from KPL-716 Repeated-Single-Dose Phase 1b Clinical Trial

- Rapid and sustained anti-pruritic effect shown throughout the 12-week treatment period -

- No meaningful difference from placebo on other efficacy endpoints specific to atopic dermatitis -

- Data support focused development of KPL-716 in prurigo nodularis and diseases characterized by chronic pruritus -

HAMILTON, BERMUDA — August 12, 2019 — Kiniksa Pharmaceuticals, Ltd. (Nasdaq: KNSA) (“Kiniksa”), a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients with significant unmet medical need, today announced interim repeated-single-dose Phase 1b clinical data for KPL-716, an investigational fully-human monoclonal antibody that targets oncostatin M receptor beta (OSMRβ). In this clinical trial, weekly subcutaneous (SC) doses of KPL-716 resulted in a rapid and sustained reduction in pruritus throughout the 12-week treatment period but also a higher rate of atopic dermatitis flares. The results support Kiniksa’s ongoing development of KPL-716 in a Phase 2a clinical trial for prurigo nodularis and an exploratory Phase 2 clinical trial in diseases characterized by chronic pruritus.

“Data from the repeated-single-dose Phase 1b study of KPL-716 showed a rapid reduction in pruritus,” said Sanj K. Patel, Chief Executive Officer and Chairman of the Board of Kiniksa. “Our focus for KPL-716 continues to be on prurigo nodularis as well as select chronic pruritic conditions, and we have no current plans to invest in atopic dermatitis. Considering the anti-pruritic effect in this repeated-single-dose study, we are pursuing an earlier readout from our Phase 2a prurigo nodularis clinical trial.”

The repeated-single-dose Phase 1b clinical trial used a weekly 360 mg SC dose in a randomized, double-blind, placebo-controlled design in order to evaluate safety and exploratory disease response markers. The 360 mg SC dose was intended to replicate

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and extend exposures from the prior single-ascending-dose Phase 1b clinical trial where an early signal of efficacy was observed in reducing pruritus after a single 7.5 mg/kg intravenous dose.

In the repeated-single-dose Phase 1b clinical trial, 43 subjects with moderate-to-severe atopic dermatitis were enrolled and randomized 1:1 to KPL-716 or placebo once weekly for 12 weeks. There was a seven-day wash out period of all other therapies before treatment, and topical corticosteroids were not allowed throughout the 12-week treatment period. Rescue medication was available for atopic dermatitis flares throughout the study.

In an interim analysis of the data through the 12-week treatment period, KPL-716 showed a rapid and sustained reduction in Worst-Itch Numeric Rating Scale (WI-NRS) in subjects with moderate-to-severe atopic dermatitis:

·                  Mean change from baseline in weekly-average WI-NRS at Week 1 was -28.1% in KPL-716 recipients compared to -6.8% in placebo recipients.

·                  Mean change from baseline in weekly-average WI-NRS at Week 12 was -55.0% in KPL-716 recipients compared to -30.9% in placebo recipients.

·                  52.6% of KPL-716 recipients demonstrated a ≥ 4-point reduction in weekly-average WI-NRS at Week 12 compared to 26.3% of placebo recipients.

There was no meaningful benefit of repeated-single-doses of KPL-716 on other efficacy endpoints specific to atopic dermatitis, including Eczema Area and Severity Index (EASI) and Scoring Atopic Dermatitis (SCORAD).

There were no serious adverse events. However, there were more atopic dermatitis flares in the KPL-716-treated population versus placebo (47.6% versus 4.5%) through the 12-week treatment period; all subjects who experienced a flare were successfully managed with topical corticosteroids. KPL-716 was otherwise well-tolerated by all subjects.

“We believe the data from the repeated-single-dose Phase 1b study show that KPL-716 has the potential to treat a spectrum of pruritic diseases which involve signaling through OSMRβ,” said John F. Paolini, MD, PhD, Chief Medical Officer of Kiniksa. “The pharmacokinetic data are consistent with our prior modeling and support the testing of lower and less frequent dosing.”

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Kiniksa is enrolling a Phase 2a clinical trial of KPL-716 in subjects with prurigo nodularis. The primary efficacy endpoint is percent change from baseline in weekly average WI-NRS. Top-line data are expected in the first half of 2020.

Kiniksa is enrolling an exploratory Phase 2 clinical trial in diseases characterized by chronic pruritus. The trial is designed to identify chronic pruritic conditions where signaling of OSMRβ may be playing a role and to investigate the efficacy, safety and tolerability of KPL-716 in reducing the moderate-to-severe pruritus experienced by these subjects. Kiniksa expects to provide interim data from this study on a cohort-by-cohort basis throughout 2020.

About KPL-716

KPL-716 is an investigational fully-human monoclonal antibody that targets OSMRβ, which mediates signaling of interleukin-31 (IL-31) and oncostatin M (OSM), two key cytokines implicated in pruritus, inflammation and fibrosis. Kiniksa believes KPL-716 to be the only monoclonal antibody in development that targets both pathways simultaneously.

About Kiniksa

Kiniksa is a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical need. Kiniksa has a pipeline of product candidates across various stages of development, focused on autoinflammatory and autoimmune conditions. For more information, please visit www.kiniksa.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward looking statements by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these identifying words.  All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding: plans and timing to advance our product candidates; plans and timing to report or present interim, final and top-line clinical trial, pre-clinical and other data; proposed indications for the investigation of our product candidates; and our conclusions from interim pre-clinical and clinical trial data for KPL-716.

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These forward-looking statements are based on management’s current plans, estimates or expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including without limitation, the following: potential delays or difficulty in enrollment of patients in, and activation of sites for, our KPL-716 clinical trials; potential complications in coordinating among requirements, regulations and guidelines of regulatory authorities across jurisdictions for our KPL-716 clinical trials; potential amendments to our KPL-716 clinical trial protocols initiated by us or required by regulatory authorities; changes between final data and any preliminary or  interim data we present; our potential inability to replicate in later clinical trials, including our Phase 2a clinical trial and exploratory Phase 2 clinical trial of KPL-716, the positive preliminary or interim data from our pre-clinical and earlier clinical trials; potential impact of additional data from us or other companies; potential undesirable side effects caused by KPL-716; our potential inability to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities; and our reliance on third parties to manufacture KPL-716 and to conduct research, clinical trials and/or certain regulatory activities for KPL-716.

These and other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the period ended March 31, 2019, filed with the Securities and Exchange Commission (“SEC”) on May 7, 2019 and our other reports subsequently filed with the SEC, could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s plans, estimates or expectations as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release.

Every Second Counts!™

Kiniksa Investor and Media Contact

Mark Ragosa

(781) 430-8779

mragosa@kiniksa.com

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Exhibit 99.3