Rilonacept vs Canakinumab for CAPS with Recurrent Pericarditis
For a patient with CAPS and recurrent pericarditis, both canakinumab (Ilaris) and rilonacept are equally effective first-line IL-1 blocking agents with equivalent Level 1B evidence, but canakinumab offers the practical advantage of less frequent dosing (every 8 weeks vs weekly) and has broader regulatory approval (FDA + EMA vs FDA only). 1
Treatment Framework for CAPS-Associated Pericarditis
When pericarditis occurs in the context of CAPS, IL-1 blockers are appropriate first-line therapy as part of CAPS management, bypassing the standard pericarditis algorithm that would otherwise start with NSAIDs/colchicine. 1 This is a critical distinction—CAPS-associated pericarditis is treated differently than idiopathic recurrent pericarditis.
Canakinumab (Ilaris) Characteristics
Dosing and Administration:
- 150 mg subcutaneously every 8 weeks for patients >40 kg 2
- 2 mg/kg every 8 weeks for patients 15-40 kg 2
- FDA and EMA approved for CAPS (FCAS and MWS phenotypes) 1
Efficacy Data:
- Achieves complete clinical response in 97% of CAPS patients by week 8, with 71% responding within 8 days 2, 3
- In randomized withdrawal trials, 0% of canakinumab patients relapsed vs 81% on placebo 2, 3
- Normalizes inflammatory markers (CRP and SAA) within 8 days in the majority of patients 2
- Long-term studies demonstrate sustained disease control over 2+ years 3, 4
Rilonacept (Arcalyst) Characteristics
Dosing and Administration:
- Weekly subcutaneous injections (specific dosing varies by weight and indication) 5
- FDA approved for CAPS but not EMA approved 1
- Also FDA approved for recurrent pericarditis as a separate indication 5
Efficacy Data:
- Equivalent Level 1B evidence from randomized controlled trials as canakinumab 1
- The American College of Rheumatology considers both agents equally effective for CAPS 1
Clinical Decision-Making Algorithm
Choose Canakinumab if:
- Patient preference for less frequent injections (every 8 weeks vs weekly) 1, 2
- Patient located in Europe or requires EMA-approved therapy 1
- Extensive long-term safety data is prioritized 3, 4
Choose Rilonacept if:
- Patient has concurrent recurrent pericarditis as a dominant feature (has specific FDA indication for this) 5
- Weekly dosing allows for more flexible dose adjustments 1
- Cost considerations favor rilonacept in specific insurance formularies
Monitoring and Treatment Goals
Both agents should be titrated using treat-to-target strategies guided by: 1
- Clinical symptom resolution (fever, rash, headache, musculoskeletal symptoms)
- CRP normalization to <5-10 mg/L 1
- Assessment of disease activity scores (physician global assessment, skin disease assessment) 2
Safety Considerations
Common to Both Agents:
- Avoid initiation during active infection or untreated tuberculosis 6
- Most common adverse events are mild-to-moderate infections responsive to standard treatment 3, 7
- Screen for TB exposure and chronic recurring infections before starting 6
Canakinumab-Specific:
- Predominantly mild-to-moderate infections without consistent pattern of serious side effects 3, 8
- Long-term safety demonstrated over 109 weeks median exposure in Japanese cohorts 4
Critical Pitfalls to Avoid
- Do not treat CAPS-associated pericarditis with the standard pericarditis algorithm first (NSAIDs/colchicine)—this delays appropriate IL-1 blockade 1
- Do not use corticosteroids as first-line for CAPS, as IL-1 blockers provide superior disease control 9, 1
- Do not assume rilonacept and canakinumab are interchangeable in regulatory contexts—rilonacept lacks EMA approval 1
- Ensure TB screening is complete before initiating either agent 6