Pericarditis is an inflammatory condition affecting the pericardium, the thin, fluid-filled sac surrounding the heart. This inflammation can cause discomfort and impact heart function. Rilonacept is a medication used to address this condition, particularly when inflammation recurs. This article explores how rilonacept works to manage pericarditis symptoms and recurrence.
Understanding Pericarditis
The pericardium is a two-layered sac that encases the heart, providing protection and keeping it in place. A small amount of fluid between these layers allows the heart to move smoothly. When inflamed, known as pericarditis, the layers can rub, leading to discomfort and potentially affecting the heart’s ability to pump blood effectively.
Common symptoms include sharp, stabbing chest pain, often felt in the center or left side, worsening with deep breaths, coughing, or lying down, and improving by leaning forward. Other symptoms may include shortness of breath, fever, fatigue, and a dry cough. Pericarditis can arise from various causes, such as viral, bacterial, or fungal infections, autoimmune diseases like lupus or rheumatoid arthritis, or complications following a heart attack or surgery. Sometimes, the exact cause remains unknown, referred to as idiopathic pericarditis.
Pericarditis is categorized by its duration and pattern. Acute pericarditis presents suddenly and typically resolves within a few weeks. Incessant pericarditis involves continuous symptoms lasting between four to six weeks. Recurrent pericarditis occurs when symptoms return after an initial episode, following a period of improvement without symptoms. Chronic pericarditis refers to inflammation that persists for more than three months. Rilonacept is primarily indicated for recurrent forms of the condition.
How Rilonacept Works for Pericarditis
Rilonacept, marketed as Arcalyst, is a recombinant fusion protein. It functions as an interleukin-1 (IL-1) blocker, specifically targeting IL-1 alpha (IL-1α) and IL-1 beta (IL-1β). These interleukins are pro-inflammatory cytokines, signaling proteins that play a significant role in triggering and sustaining the inflammation observed in recurrent pericarditis.
Rilonacept acts as a “decoy receptor” or “trap” for these inflammatory cytokines. It binds to circulating IL-1α and IL-1β, preventing them from attaching to their natural receptors on cell surfaces. By blocking this interaction, rilonacept effectively interrupts the inflammatory cascade that drives pericarditis, reducing swelling and pain. This targeted approach helps control the body’s inflammatory response.
Rilonacept is used in patients with recurrent pericarditis, particularly those who have not responded adequately to conventional treatments such as nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, or corticosteroids. It is administered through subcutaneous injection. Adults typically receive an initial loading dose of 320 mg, followed by weekly injections of 160 mg. For adolescents, the dosage is determined by their weight.
Effectiveness and Patient Experience
Clinical studies demonstrate rilonacept’s effectiveness in managing recurrent pericarditis. The RHAPSODY trial, a phase 3 study, showed rilonacept significantly reduced the risk of pericarditis recurrence. In this trial, recurrence occurred in only about 7% of patients receiving rilonacept, compared to approximately 74% in the placebo group. This translated to a 96% reduction in recurrent events.
Patients treated with rilonacept experienced rapid symptom resolution, including a significant reduction in chest pain. The median time to pain resolution was about 5 days, and to normalization of C-reactive protein (CRP) levels, a marker of inflammation, was approximately 7 days. Many patients also saw improvements in their quality of life, sleep patterns, and ability to reduce or discontinue corticosteroids.
Rilonacept can lead to sustained remission, allowing patients to taper off other anti-inflammatory medications. In the RHAPSODY trial, a majority of patients on corticosteroids at the study’s start successfully discontinued them. The treatment course is often long-term, aiming to prevent future flares and maintain a stable, symptom-free state.
Potential Side Effects and Important Considerations
Rilonacept can cause side effects. Common adverse effects include reactions at the injection site, such as pain, redness, swelling, bruising, or itching. Upper respiratory tract infections, such as cold symptoms, are also frequently reported. Other possible side effects include nausea, diarrhea, stomach upset, and muscle or joint pain.
More serious risks include increased susceptibility to serious infections due to its immune-suppressing effects. Patients should be screened for infections like tuberculosis before starting treatment. Allergic reactions, though rare, can also occur, presenting as hives, rash, swelling of the face or throat, or difficulty breathing. Changes in laboratory parameters, such as elevated cholesterol and triglyceride levels, have also been observed.
Rilonacept should not be initiated if a patient has an active infection. Inform a healthcare provider about all other medications, as certain drugs, particularly other interleukin-1 or tumor necrosis factor blockers, may increase the risk of serious infections when combined with rilonacept. Patients receiving rilonacept should avoid live vaccines. Regular monitoring by a healthcare professional, including blood tests, is recommended to track potential side effects and overall response to treatment.