Rilonacept (IL-1 Trap — Recurrent Pericarditis)

NO UK SPC (eMC) WAS RETRIEVED IN THIS BUNDLE — the regimen above is taken from the US FDA prescribing information for ARCALYST (Kiniksa Pharmaceuticals (UK), Ltd.; label date 2025-12-16; https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=11e22c54-9b9a-4f9f-8680-cb7327511a23). VERBATIM (§2.2, adults, CAPS/FCAS/MWS and recurrent pericarditis): '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.' SEPARATE INDICATION — DIRA (deficiency of IL-1 receptor antagonist, §2.3): adults 320 mg once weekly given as two subcutaneous injections on the same day at two different sites (maximum single-injection volume 2 mL); paediatric patients weighing 10 kg or more 4.4 mg/kg (up to a maximum of 320 mg) once weekly as one or two subcutaneous injections. MISSED DOSE: '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.' SWITCHING: when switching from another IL-1 blocker, discontinue the IL-1 blocker and begin ARCALYST at the time of the next dose. RECONSTITUTION (§2.4–2.5): supplied as a 220 mg single-dose lyophilised powder vial; reconstitute with 2.3 mL preservative-free Sterile Water for Injection to give an 80 mg/mL solution allowing a withdrawal volume of up to 2 mL; shake for approximately one minute then allow to sit for one minute; use within three hours of reconstitution, protected from light; each vial is for a single dose only. NO RENAL DOSING SECTION WAS RETRIEVED IN THIS BUNDLE. Several sections of the fetched US label were truncated at the source-fetch limit — clinician to confirm against the full label and the UK SPC before publication.

US label §2.2, paediatric patients 12 years to 17 years with CAPS/FCAS/MWS or recurrent pericarditis. VERBATIM: '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.' The dosePerKg value above is the MAINTENANCE dose; the loading dose is 4.4 mg/kg (maximum 320 mg). §8.4: safety and effectiveness in paediatric patients with CAPS and recurrent pericarditis BELOW the age of 12 years have not been established. Separately, for DIRA (§2.3) the US label gives 4.4 mg/kg (up to a maximum of 320 mg) once weekly for paediatric patients weighing 10 kg or more. US labelling — verify against the UK SPC and a children's formulary before any under-18 use.