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Important: This site presents data from the FDA Adverse Event Reporting System (FAERS). A report does not mean the drug caused the event. Full disclaimer.

RILONACEPT: 843 Adverse Event Reports & Safety Profile

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843
Total FAERS Reports
14 (1.7%)
Deaths Reported
65
Hospitalizations
843
As Primary/Secondary Suspect
3
Life-Threatening
2
Disabilities
Kiniksa Pharmaceuticals (UK...
Manufacturer
Prescription
Status

Route: SUBCUTANEOUS · Manufacturer: Kiniksa Pharmaceuticals (UK), Ltd. · FDA Application: 125249 · HUMAN PRESCRIPTION DRUG · FDA Label: Available

First Report: 2010 · Latest Report: 20250722

What Are the Most Common RILONACEPT Side Effects?

#1 Most Reported
Injection site erythema
112 reports (13.3%)
#2 Most Reported
Chest pain
98 reports (11.6%)
#3 Most Reported
Product dose omission issue
94 reports (11.2%)

All RILONACEPT Side Effects by Frequency

Side Effect Reports % of Total Deaths Hosp.
Injection site erythema 112 13.3% 0 3
Chest pain 98 11.6% 0 8
Product dose omission issue 94 11.2% 0 5
Injection site pain 73 8.7% 0 2
Fatigue 70 8.3% 0 4
Off label use 63 7.5% 1 8
Pain 63 7.5% 0 3
Injection site pruritus 57 6.8% 0 2
Injection site rash 57 6.8% 0 1
Pericarditis 57 6.8% 0 12
Dyspnoea 53 6.3% 1 7
Injection site reaction 53 6.3% 0 0
Drug ineffective 51 6.1% 0 6
Arthralgia 41 4.9% 0 0
Nausea 40 4.7% 0 1
Chest discomfort 39 4.6% 0 4
Injection site swelling 38 4.5% 0 1
Injection site mass 36 4.3% 0 1
Malaise 36 4.3% 0 2
Headache 34 4.0% 0 1

Who Reports RILONACEPT Side Effects? Age & Gender Data

Gender: 68.2% female, 31.8% male. Average age: 51.9 years. Most reports from: US. View detailed demographics →

Is RILONACEPT Getting Safer? Reports by Year

YearReportsDeathsHosp.
2010 1 0 0
2012 1 0 1
2014 2 0 0
2015 4 0 0
2016 5 0 3
2017 5 0 0
2018 3 0 1
2019 2 0 0
2020 5 0 0
2021 83 1 4
2022 56 0 5
2023 104 1 10
2024 176 3 12
2025 68 0 8

View full timeline →

What Is RILONACEPT Used For?

IndicationReports
Pericarditis 497
Product used for unknown indication 228
Cryopyrin associated periodic syndrome 24
Still's disease 21
Pericarditis constrictive 11
Familial cold autoinflammatory syndrome 10
Pericardial disease 10
Juvenile idiopathic arthritis 7
Pericardial effusion 6
Blau syndrome 5

RILONACEPT vs Alternatives: Which Is Safer?

RILONACEPT vs RILPIVIRINE RILONACEPT vs RILUZOLE RILONACEPT vs RIMABOTULINUMTOXINB RILONACEPT vs RIMEGEPANT RILONACEPT vs RIOCIGUAT RILONACEPT vs RIPRETINIB RILONACEPT vs RISANKIZUMAB RILONACEPT vs RISANKIZUMAB-RZAA RILONACEPT vs RISDIPLAM RILONACEPT vs RISEDRONATE

Official FDA Label for RILONACEPT

Official prescribing information from the FDA-approved drug label.

Drug Description

Rilonacept is a dimeric fusion protein consisting of the ligand-binding domains of the extracellular portions of the human interleukin-1 receptor component (IL-1R1) and IL-1 receptor accessory protein (IL-1RAcP) linked in-line to the Fc portion of human IgG1. Rilonacept has a molecular weight of approximately 251 kDa. Rilonacept is expressed in recombinant Chinese hamster ovary (CHO) cells. ARCALYST is supplied in single-dose vials containing a sterile, white to off-white lyophilized powder. Each vial of ARCALYST is to be reconstituted with 2.3 mL of Sterile Water for Injection, USP. A volume of up to 2 mL can be withdrawn, which is designed to deliver 160 mg for subcutaneous administration only. The resulting solution is viscous, clear, colorless to pale yellow, and essentially free from particulates. Each vial contains 220 mg rilonacept. After reconstitution, each vial contains rilonacept (80 mg/mL), glycine (10 mg/mL), histidine (46 mM), L-arginine (50 mM), polyethylene glycol 3350 (30 mg/mL), and sucrose (20 mg/mL) at a pH of 6.5. No preservatives are present.

FDA Approved Uses (Indications)

AND USAGE ARCALYST (rilonacept) is an interleukin-1 blocker indicated for: Treatment of Cryopyrin-Associated Periodic Syndromes (CAPS), including Familial Cold Autoinflammatory Syndrome (FCAS), and Muckle-Wells Syndrome (MWS) in adults and children 12 years and older ( 1.1 , 14.1 ) Maintenance of remission of Deficiency of Interleukin-1 Receptor Antagonist (DIRA) in adults and pediatric patients weighing 10 kg or more ( 1.2 , 14.2 ) Treatment of recurrent pericarditis (RP) and reduction in risk of recurrence in adults and children 12 years and older ( 1.3 , 14.3 )

1.1 Cryopyrin-Associated Periodic Syndromes, Familial Cold Autoinflammatory Syndrome and Muckle-Wells Syndrome ARCALYST ® (rilonacept) is an interleukin-1 blocker indicated for the treatment of Cryopyrin-Associated Periodic Syndromes (CAPS), including Familial Cold Autoinflammatory Syndrome (FCAS), and Muckle-Wells Syndrome (MWS) in adults and pediatric patients 12 years and older.

1.2 Deficiency of IL-1 Receptor Antagonist ARCALYST is indicated for the maintenance of remission of Deficiency of Interleukin-1 Receptor Antagonist (DIRA) in adults and pediatric patients weighing at least 10 kg.

1.3 Recurrent Pericarditis ARCALYST is indicated for the treatment of recurrent pericarditis (RP) and reduction in risk of recurrence in adults and pediatric patients 12 years and older.

Dosage & Administration

AND ADMINISTRATION Administer by subcutaneous injection ( 2.1 ) CAPS, FCAS, MWS, and RP ( 2.2 ): Adults: – Loading dose: 320 mg, delivered as two 160 mg (2 mL) injections. – Maintenance dose: 160 mg (2 mL) injection once weekly. Pediatric patients 12 years to 17 years: – Loading dose: 4.4 mg/kg, up to a maximum of 320 mg, delivered as 1 or 2 injections (not to exceed 2 mL/injection). – Maintenance dose: 2.2 mg/kg, up to a maximum of 160 mg (2 mL) injection, once weekly. DIRA ( 2.3 ): Adults and pediatric patients weighing 10 kg or more: – 4.4 mg/kg up to a maximum of 320 mg, delivered as 1 or 2 injections (2 mL/injection) once weekly.

2.1 General Dosing Information ARCALYST is for subcutaneous use only.

2.2 Cryopyrin-Associated Periodic Syndromes, Familial Cold Autoinflammatory Syndrome, Muckle-Wells Syndrome and Recurrent Pericarditis Adults : Initiate treatment with a loading dose of 320 mg delivered as two, 2-mL subcutaneous injections of 160 mg each, administered on the same day at two different injection sites. Continue dosing with a once-weekly injection of 160 mg administered as a single, 2-mL subcutaneous injection. Pediatric patients 12 years to 17 years : Initiate treatment with a loading dose of 4.4 mg/kg, up to a maximum dose of 320 mg, administered as one or two subcutaneous injections, not to exceed single-injection volume of 2 mL per injection site. If the initial dose is given as two injections, administer on the same day at two different sites. Continue dosing with a once-weekly injection of 2.2 mg/kg, up to a maximum of 160 mg, administered as a single subcutaneous injection, up to 2 mL. If a once-weekly dose is missed, instruct the patient to administer the injection within 7 days from the missed dose and then resume the patient's original schedule. If the missed dose is not administered within 7 days, instruct the patient to administer the dose, starting a new schedule based on this date.

2.3 Deficiency of IL-1 Receptor Antagonist Adults : The recommended dose of ARCALYST is 320 mg, once weekly, administered as two subcutaneous injections on the same day at two different sites with a maximum single-injection volume of 2 mL. ARCALYST should not be given more often than once weekly. Pediatric patients weighing 10 kg or more : The recommended dose of ARCALYST is 4.4 mg/kg (up to a maximum of 320 mg), once weekly, administered as one or two subcutaneous injections with a maximum single-injection volume of 2 mL. If the dose is given as two injections, administer both on the same day, each one at a different site. When switching from another IL-1 blocker, discontinue the IL-1 blocker and begin ARCALYST treatment at the time of the next dose <span class="opacity-50 text-xs">[see Drug Interactions (7.1) ]</span> .

2.4 Preparation for Administration Reconstitute each single-dose vial of ARCALYST with 2.3 mL of preservative-free Sterile Water for Injection, USP (supplied separately) prior to subcutaneous administration of the drug.

2.5 Administration Using aseptic technique, withdraw 2.3 mL of preservative-free Sterile Water for Injection through an 18-gauge, 1- or 1½-inch needle attached to a 3-mL syringe and inject the preservative-free Sterile Water for Injection, USP, into the drug product vial for reconstitution. The needle and syringe used for reconstitution with preservative-free Sterile Water for Injection, USP, should then be discarded and should not be used for subcutaneous injections. After the addition of preservative-free Sterile Water for Injection, USP, reconstitute the vial contents by shaking the vial for approximately one minute and then allowing it to sit for one minute. The resulting 80mg/mL solution is sufficient to allow a withdrawal volume of up to 2 mL for subcutaneous administration. The reconstituted solution is viscous, clear, colorless to pale yellow, and free from particulates. Prior to injection, inspect the reconstituted solution for any discoloration or particulate matter. Discard the solution if either is observed. Using aseptic technique, withdraw the recommended dose volume, up to 2 mL (160 mg), of the solution with a new 18-gauge, 1- or 1½-inch needle attached to a new 3-mL syringe. For the subcutaneous injection, replace the needle with a new 26-gauge, ½-inch needle. EACH VIAL SHOULD BE USED FOR A SINGLE DOSE ONLY. Discard the vial after withdrawal of drug. After reconstitution, ARCALYST may be kept at room temperature, but keep it protected from light, and use the solution within three hours after reconstitution. Discard unused portions of ARCALYST. Rotate the sites for subcutaneous injection, such as the abdomen, thigh, or upper arm. Injections should never be administered at sites that are bruised, red, tender, or hard.

Contraindications

None. None. ( 4 )

Known Adverse Reactions

REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling.

Serious

Infections [see Warnings and Precautions (5.1) ] Risk of Malignancy [see Warnings and Precautions (5.2) ]

Hypersensitivity

Reactions [see Warnings and Precautions (5.3) ]

Lipid Profile

Changes [see Warnings and Precautions (5.4) ] The most common adverse reactions reported by patients with CAPS and RP treated with ARCALYST are injection-site reactions and upper respiratory tract infections. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Kiniksa at 1-833-KINIKSA (1-833-546-4572) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1 Clinical Trial Experience Clinical trials are conducted under widely varying conditions and, as such, adverse reaction rates observed cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The data described herein reflect exposure to ARCALYST in over 2,000 patients who received at least one dose, including approximately 1700 exposed to 160 mg or more, of whom 151 patients were exposed for at least 6 months and 111 patients for at least one year. These included patients with CAPS and RP, patients with other diseases, and healthy volunteers.

Caps

Approximately 60 patients with CAPS were treated weekly with 160 mg of ARCALYST. The pivotal trial population included 47 patients with CAPS. These patients were between the ages of 22 and 78 years (average 51 years). Thirty-one patients were female and 16 were male. All of the patients were White/Caucasian. Six pediatric patients (12 to17 years) were enrolled directly into the open-label extension phase of the trial. Part A of the clinical trial was conducted in patients with CAPS who were naïve to treatment with ARCALYST. Part A of the study was a randomized, double-blind, placebo-controlled, six-week study comparing ARCALYST to placebo [see Clinical Studies (14) ] .

Table

1 reflects the frequency of adverse events reported by at least two patients during Part A.

Table

1: Most Frequent Adverse Reactions in Patients with CAPS (Part A, Reported by at Least Two Patients)

Adverse

Event ARCALYST 160 mg (n = 23) Placebo (n= 24) Any AE 17 (74%) 13 (54%) Injection-site reactions 11 (48%) 3 (13%) Upper respiratory tract infection 6 (26%) 1 (4%)

Nausea

1 (4%) 3 (13%)

Diarrhea

1 (4%) 3 (13%)

Sinusitis

2 (9%) 1 (4%) Abdominal pain upper 0 2 (8%)

Cough

2 (9%) 0 Hypoesthesia 2 (9%) 0 Stomach discomfort 1 (4%) 1 (4%) Urinary tract infection 1 (4%) 1 (4%)

Dira

In a 2-year, open-label study, 6 pediatric patients with DIRA, 3 years to 6 years of age, received a 2.2 to 4.4 mg/kg dose of ARCALYST once weekly [see Clinical Studies (14.2) ] . The safety profile was generally consistent with that seen in patients with CAPS. The most common adverse reactions were upper respiratory infection (6 of 6), rash (5 of 6), otitis media (3 of 6), pharyngitis (3 of 6) and rhinorrhea (3 of 6). RP In the RP phase 3 study, a total of 86 patients received at least one dose of ARCALYST with a median treatment duration of 9 months [see Clinical Studies (14.3) ]. Of the patients, 49 (57%) were female and 37 (43%) were male; 93% were White/Caucasian. The mean age was 44.7 years. Seven patients (8%) were aged 12-17 years old. No new adverse reactions were identified in this study.

Adverse

Reactions of Special Interest Injection-Site Reactions In patients with CAPS or RP, the most common and consistently reported adverse event associated with ARCALYST was injection-site reaction (ISR). The ISRs included erythema, swelling, pruritus, mass, bruising, inflammation, pain, edema, dermatitis, discomfort, urticaria, vesicles, warmth and hemorrhage. Most injection-site reactions lasted for one to two days.

Infections During

Part A in the CAPS study, the incidence of patients reporting infections was greater with ARCALYST (48%) than with placebo (17%).

In

Part B, randomized withdrawal, the incidence of infections was similar in the ARCALYST (18%) and the placebo patients (22%). Part A of the trial was initiated in the winter months, while Part B was predominantly performed in the summer months. In placebo-controlled studies across a variety of patient populations encompassing 360 patients treated with rilonacept and 179 treated with placebo, the incidence of infections was 34% and 27% (2.15 per patient-exposure year and 1.81 per patient-exposure year), respectively, for rilonacept and placebo.

Serious Infections

Six serious infections were reported by four patients during the CAPS clinical program: Mycobacterium intracellulare infection; gastrointestinal bleeding and colitis; sinusitis and bronchitis; and Streptococcus pneumoniae meningitis [see Adverse Reactions (6) ] . One patient receiving ARCALYST for an unapproved indication in another study developed an infection in his olecranon bursa with Mycobacterium intracellulare . The patient was on chronic glucocorticoid treatment. The infection occurred after an intraarticular glucocorticoid injection into the bursa with subsequent local exposure to a suspected source of mycobacteria. The patient recovered after the administration of the appropriate antimicrobial therapy. One patient treated for another unapproved indication developed bronchitis/sinusitis, which resulted in hospitalization. One patient died in an open-label study of CAPS from Streptococcus pneumoniae meningitis. Changes in Hematologic Parameters Laboratory Changes One patient in a study in an unapproved indication developed transient neutropenia (ANC < 1 × 10 9 /L) after receiving a large dose (2000 mg intravenously) of ARCALYST. The patient did not experience any infection associated with the neutropenia.

Lipid Profile Changes

Patients with CAPS treated with ARCALYST experienced increases in their mean total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The mean increases from baseline for total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were 19 mg/dL, 2 mg/dL, 10 mg/dL, and 57 mg/dL, respectively, after 6 weeks of open-label therapy.

6.2 Immunogenicity As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. The data reflect the percentage of patients whose test results were positive for antibodies to the rilonacept receptor domains in specific assays. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay is highly dependent on several factors including assay sensitivity and specificity, assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to rilonacept with the incidence of antibodies in other studies or to other products may be misleading. Antibodies directed against the receptor domains of rilonacept were detected by an ELISA assay in patients with CAPS after treatment with ARCALYST. Nineteen of 55 patients (35%) who had received ARCALYST for at least 6 weeks tested positive for treatment-emergent binding antibodies on at least one occasion. Of the 19, seven tested positive at the last assessment (Week 18 or 24 of the open-label extension period), and five patients tested positive for neutralizing antibodies on at least one occasion. There was no correlation of antibody activity and either clinical effectiveness or safety. In the Phase 3 study of patients with RP, there were no patients who tested positive for antibodies at baseline. At any point in time, 26 out of 86 (30%) subjects tested positive at any assessment and of these, 6 tested positive for neutralizing antibodies (NAb). At the last assessment, 10 subjects remained positive for anti-drug antibodies (ADA) and 1 subject remained positive for NAb. There was no correlation of antibody activity and either clinical effectiveness or safety.

Warnings

AND PRECAUTIONS Serious Infections : Serious, life-threatening infections have been reported in patients taking ARCALYST. Do not initiate treatment with ARCALYST in patients with active or chronic infections. Discontinue treatment if a patient develops a serious infection. ( 5.1 )

Hypersensitivity

Reactions : If a hypersensitivity reaction occurs, discontinue administration of ARCALYST and initiate appropriate therapy. ( 5.3 ) Immunizations : Avoid live vaccines. Update recommended vaccinations prior to initiation of therapy per current guidelines. ( 5.5 )

5.1 Serious Infections Interleukin-1 (IL-1) blockade may interfere with the immune response to infections. Treatment with another medication that works through inhibition of IL-1 has been associated with an increased risk of serious infections, and serious infections have been reported in patients taking ARCALYST <span class="opacity-50 text-xs">[see Clinical Studies (14) ]</span> . There was a greater incidence of infections in CAPS and RP patients on ARCALYST compared with placebo. In the controlled portion of the CAPS study <span class="opacity-50 text-xs">[see Clinical Studies (14.1) ]</span> , severe infection (bronchitis) was reported in one patient receiving ARCALYST. In an open-label extension study in CAPS, one patient developed bacterial meningitis and died <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . In clinical studies, ARCALYST has not been administered concomitantly with tumor necrosis factor (TNF) inhibitors. An increased incidence of serious infections has been associated with administration of an IL-1 blocker in combination with TNF inhibitors. ARCALYST is not recommended for use with TNF inhibitors because this may increase the risk of serious infections. Drugs that affect the immune system by blocking TNF have been associated with an increased risk of reactivation of latent tuberculosis (TB). It is possible that taking drugs such as ARCALYST that block IL-1 increases the risk of TB or other atypical or opportunistic infections. Refer to current practice guidelines for evaluation and treatment of possible latent tuberculosis infections before initiating therapy with ARCALYST. Treatment with ARCALYST should not be initiated in patients with an active or chronic infection. Discontinue ARCALYST if a patient develops a serious infection.

5.2 Risk of Malignancy The impact of treatment with ARCALYST on the development of malignancies is not known. Treatment with immunosuppressants, including ARCALYST, may result in an increase in the risk of malignancies.

5.3 Hypersensitivity Reactions Hypersensitivity reactions associated with ARCALYST occurred in clinical trials. If a hypersensitivity reaction occurs, discontinue ARCALYST and initiate appropriate therapy.

5.4 Lipid Profile Changes Cholesterol and lipid levels may be reduced in patients with chronic inflammation. Increases in non-fasting lipid profile parameters occurred in patients treated with ARCALYST in clinical trials. Monitor patients&apos; lipid profiles and consider lipid-lowering therapies if needed, based on cardiovascular risk factors and current guidelines <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> .

5.5 Immunizations Since no data are available on the risks of secondary transmission of infection by live vaccines in patients receiving ARCALYST, avoid administration of live vaccines during treatment with ARCALYST. No data are available on the effectiveness of vaccines in patients receiving ARCALYST. Since ARCALYST may interfere with normal immune response to new antigens, vaccines may not be effective in patients receiving ARCALYST. Because IL-1 blockade may interfere with immune response to infections, it is recommended that prior to initiation of therapy with ARCALYST, adult and pediatric patients receive all recommended vaccinations, as per current immunization guidelines, including pneumococcal vaccine and inactivated influenza vaccine.

Drug Interactions

INTERACTIONS

7.1 TNF-Blocking Agent and IL-1 Blocking Agent Specific drug interaction studies have not been conducted with ARCALYST. Concomitant administration of another drug that blocks IL-1 with a TNF-blocking agent in another patient population has been associated with an increased risk of serious infections and an increased risk of neutropenia. The concomitant administration of ARCALYST with TNF-blocking agents may also result in similar toxicities and is not recommended <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> . The concomitant administration of ARCALYST with other drugs that block IL-1 has not been studied. Based upon the potential for pharmacologic interactions between rilonacept and a recombinant IL-1ra, concomitant administration of ARCALYST and other agents that block IL-1 or its receptors is not recommended.

7.2 Cytochrome P450 Substrates The formation of CYP450 enzymes is suppressed by increased levels of cytokines (e.g., IL-1) during chronic inflammation. Thus it is expected that for a molecule that binds to IL-1, such as rilonacept, the formation of CYP450 enzymes could be normalized. This is clinically relevant for CYP450 substrates with a narrow therapeutic index, where the dose is individually adjusted (e.g., warfarin). Upon initiation of ARCALYST in patients being treated with these types of medicinal products, therapeutic monitoring of the effect or drug concentration should be performed, and the individual dose of the medicinal product may need to be adjusted.