RHAPSODY Phase 3 Study to Assess the Efficacy and Safety of Rilonacept Treatment in Subjects With Recurrent Pericarditis

This is a Phase 3, global, multi-center, double-blind, placebo-controlled, randomized
withdrawal study with open-label extension, to assess the efficacy and safety of rilonacept
treatment in subjects with recurrent pericarditis.

Key Inclusion Criteria:

1. Male or female aged 12 or older

2. Has a diagnosis of recurrent pericarditis

3. Must provide Informed Consent

4. Presents with at least the third episode of pericarditis during screening.

5. Has received Nonsteroidal Anti-inflammatory Drugs (NSAIDs) and/or colchicine and/or
corticosteroids (in any combination), if used, at stable dose levels (or at least not
increased) for at least 3 days prior to first study drug administration

6. Female subjects must be postmenopausal, or incapable of pregnancy or permanently
sterile, or if of childbearing potential must agree to use highly-effective method of
contraception.

7. Must be up-to-date with all immunizations, in agreement with current local
immunization guidelines for immunosuppressed subjects, before first study drug
administration.

8. Is able to adequately maintain a daily subject diary according to protocol.

9. Agrees to refrain from making any new, major lifestyle changes that may affect
pericarditis symptoms (e.g., changing exercise pattern) from the time that the
informed consent form (ICF) is signed through the end of the double-blind randomized
withdrawal period.

Key Exclusion Criteria:

1. Has a diagnosis of pericarditis that is secondary to specific prohibited etiologies.

2. Has a history of immunosuppression, including positive human immunodeficiency virus
(HIV) test results.

3. Has a history of myeloproliferative disorder.

4. Has a history of demyelinating disease or symptoms suggestive of multiple sclerosis.

5. Has a history of active or latent Tuberculosis (TB) prior to screening

6. Has chest x-ray at screening or within 12 weeks before receiving first administration
of study drug, with evidence of malignancy or abnormality consistent with prior or
active TB infection.

7. Has a history of positive or intermediate results for hepatitis B surface antigen,
hepatitis B core antibody, or hepatitis C virus antibody at screening.

8. Has a history of malignancy of any organ system within the past 5 years before
screening (other than a successfully treated non metastatic cutaneous squamous cell
carcinoma or basal cell carcinoma and/or localized carcinoma in situ of the cervix).

9. Has a known or suspected current active infection or a history of chronic or recurrent
infectious disease, including, but not limited to, chronic renal infection, chronic
chest infection, sinusitis, recurrent urinary tract infection, or an open, draining
infected skin wound.

10. Has had an organ transplant.

11. In the investigator's opinion, has a history of alcoholism or drug/chemical abuse
within 2 years before screening.

12. Has a known hypersensitivity to rilonacept or to any of its excipients.

13. Has received an investigational drug during the 30 days before screening or is
planning to receive an investigational drug (other than that administered during this
study) or use an investigational device at any time during the study.

14. In the investigator's opinion, has any other medical condition that could adversely
affect the subject's participation or interfere with study evaluations.