Rilonacept - Uses, Dosage, Precautions, Side Effects, and Pharmacological Aspects

Overview

Rilonacept is a medication in the class of interleukin-1 (IL-1) blockers. It is designed to treat inflammatory conditions by inhibiting the activity of interleukin-1, a protein crucial in regulating the body's inflammatory response. Rilonacept is specifically indicated for the treatment of cryopyrin-associated periodic syndromes (CAPS), a group of rare, inherited autoinflammatory disorders, which include familial cold autoinflammatory syndrome (FCAS) that causes fever, rash, and joint pain triggered by cold exposure and Muckle-Wells syndrome (MWS) characterized by recurring fever, rash, joint pain, and potential hearing loss. These are rare, inherited autoinflammatory disorders (conditions characterized by episodes of inflammation) characterized by recurrent fever, rash, and joint pain. The USFDA (United States Food and Drug Administration) first approved Rilonacept on February 27, 2008, for adults and children aged 12 and older.

Drug Group

Rilonacept belongs to the drug group known as interleukin-1 (IL-1) blockers. These drugs work by inhibiting the activity of interleukin-1, a protein that plays a key role in the body's inflammatory response. This inhibition helps reduce the inflammation and symptoms associated with various autoinflammatory conditions.

Indications

Rilonacept is an interleukin-1 blocker approved for treating cryopyrin-associated periodic syndromes (CAPS), a group of rare, inherited autoinflammatory disorders, including familial cold autoinflammatory syndrome (FCAS) and Muckle-Wells syndrome (MWS), in adults and children aged 12 and older.

Dosage Forms and Available Strengths

Adults (18 Years and Older):

• Initial Dose: 320 mg (milligrams) administered as two 2 mL (milliliter) subcutaneous injections of 160 mg each on the same day at two different sites.

• Maintenance Dose: 160 mg administered once weekly as a single 2 mL subcutaneous injection.

• Frequency: Should not be administered more than once a week.

Pediatric Patients (12 to 17 Years):

• Initial Dose: 4.4 mg/kg (milligrams per kilogram), up to a maximum of 320 mg, administered as one or two subcutaneous injections, with a maximum single injection volume of 2 mL.

• Maintenance Dose: Administered once weekly as a single subcutaneous injection at a dose of 2.2 mg/kg, up to a maximum of 160 mg, with an injection volume of up to 2 mL.

• Frequency: Should not be administered more than once a week.

Available Strength:

• Rilonacept is a lyophilized powder for reconstitution, providing a final concentration of 80 mg/mL (milligrams per milliliter) after reconstitution.

• After reconstitution with 2.3 mL of preservative-free sterile water for injection, each vial provides 160 mg in 2 mL.

For Patients

What Is Cryopyrin-Associated Periodic Syndromes?

Cryopyrin-associated periodic syndromes, or CAPS, are a group of rare autoinflammatory diseases caused by genetic mutations in the NLRP3 (nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3) gene, which encodes the cryopyrin protein.

The syndromes include:

• Familial Cold Autoinflammatory Syndrome (FCAS): FCAS is a genetic disorder in which exposure to cold triggers inflammation. Symptoms include fever, rash, and joint pain, which can be managed by avoiding colds and treating symptoms as they arise.

• Muckle-Wells Syndrome (MWS): Similar to FCAS, MWS is another genetic condition like FCAS. It brings back fever, rash, joint pain, and swelling. Plus, it might cause hearing loss and kidney issues. Symptoms can pop up suddenly or when someone is stressed or active.

• Neonatal-Onset Multisystem Inflammatory Disease (NOMID) or Chronic Infantile Neurological Cutaneous and Articular (CINCA) Syndrome: This is the most severe type of CAPS, usually showing up in babies. It causes long-term swelling in many body parts, like the nerves, skin, and joints. Symptoms may include fever, rash, swollen joints, problems with the nervous system, and slower growth.

Treatment typically involves anti-inflammatory medications, such as interleukin-1 inhibitors, which can help reduce inflammation and improve symptoms for many patients with CAPS.

How Does the Rilonacept Work?

Rilonacept works through IL-1, a protein involved in inflammatory responses in the body. By inhibiting IL-1, Rilonacept helps reduce inflammation and alleviate symptoms associated with autoinflammatory diseases, such as CAPS. This helps to control fever, pain, and other inflammatory symptoms.

What Are the Benefits of the Rilonacept?

Rilonacept offers several benefits, particularly for individuals with autoinflammatory conditions.

The key benefits include:

• Reduced Inflammation: By blocking interleukin-1, Rilonacept helps lower inflammation levels in the body.

• Symptom Relief: It alleviates symptoms such as fever, rash, joint pain, and fatigue, improving the quality of life.

• Prevention of Flare-ups: Rilonacept helps prevent the recurrence of symptoms, providing more consistent symptom control.

• Improved Functioning: By reducing symptoms, individuals can perform daily activities more easily and with fewer interruptions.

• Long-term Management: It offers a long-term solution for managing chronic autoinflammatory conditions, leading to sustained symptom relief.

What Is the Dosage of the Rilonacept?

The dosage of Rilonacept generally is:

• Adults: 320 mg initially (two 160 mg injections), then 160 mg weekly.

• Children (12+ Years): 4.4 mg/kg initially (up to 320 mg), then 2.2 mg/kg weekly (up to 160 mg).

How Are Rilonacept Administered?

• Rilonacept is available as a powder in a vial that must be mixed with a liquid for subcutaneous (under the skin) injection. It is usually administered as two initial injections, followed by one weekly injection. The initial dose for children is one or two injections, followed by one weekly injection. One or two injections are given weekly to treat DIRA or deficiency of the interleukin-1 receptor antagonist (a rare genetic disorder). Follow the prescription label instructions carefully and consult the doctor or pharmacist if the patient has any questions. Use Rilonacept precisely as prescribed.

• A doctor or nurse will instruct the patient or a caregiver on mixing and injecting Rilonacept at home. Before the first use, read the manufacturer's patient information, which provides detailed instructions on mixing and injecting the medication. Ensure that a person understands these directions and ask the healthcare provider any questions about the medication usage, injection sites, injection procedure, and the appropriate syringe and needle.

• Mix the medication just before injecting it. Alternatively, one can mix it in advance, store it at room temperature, and use it within three hours. Always inspect the Rilonacept solution before injection. Ensure that the expiry date has not elapsed, and confirm that the liquid is clear to slightly yellow without any visible particles. Do not use it if it is expired, cloudy, discolored, or contains particles.

• Inject Rilonacept into the front middle of the thighs or lower stomach, avoiding the two-inch area around the navel. If someone else administers the injection, it can also be given in the outer upper arms. Alternate injection sites and avoid areas that appear red, bruised, tender, hard, or close to visible veins.

• Please do not reuse or share syringes or needles. Ensure that the used vials, syringes, and needles are disposed of in a puncture-resistant container that is kept out of children's reach. Consult the doctor or pharmacist on proper container disposal.

• Request a copy of the manufacturer's patient information from the pharmacist or doctor.

What Are the Side Effects of Rilonacept?

Rilonacept may cause side effects. Inform the doctor if any of these symptoms are severe or persistent:

• Symptoms such as pain, bruising, bleeding, swelling, redness, warmth, or itching may occur at the injection site.

• Nausea.

• Diarrhea (loose, watery stools).

• Upset stomach.

• Stuffy or blocked nose.

• Numbness.

• Pain in muscle and joints (in patients with pericarditis or inflammation of the pericardium).

Some side effects can be severe.

• Hives, rash, itching.

• Trouble breathing or swallowing.

• Swelling in the eyes, face, mouth, lips, tongue, or throat.

• Hoarseness of voice.

• Lightheadedness, fainting, or chest pain.

Rilonacept may elevate the risk of developing specific types of cancer. Discuss the risks with the doctor. It is necessary to call the doctor if one experiences any unusual problems while taking this medication.

What Are the Things to Inform the Doctor Before Taking Rilonacept?

Before using Rilonacept injection, individuals need to know the following:

• Allergies and Medications: Inform the doctor and pharmacist if allergic to Rilonacept, any other medicines, or any ingredients in the injection. Also, discuss all prescription and non-prescription medications, vitamins, supplements, and herbal products being taken, including drugs like Adalimumab, Anakinra, corticosteroids, and Warfarin.

• Medical Conditions: Notify the doctor if asthma (breathing difficulty due to inflamed and narrowed airways), diabetes (high blood sugar), high cholesterol, or conditions affecting the immune system are present.

• Pregnancy and Breastfeeding: Notify the doctor if one is pregnant, planning to become pregnant, or breastfeeding.

• Infections: Rilonacept may lower the ability to fight infections and increase the risk of serious infections. Inform the doctor if one often gets infections or has conditions like HIV (human immunodeficiency syndrome), hepatitis B (liver infection), or hepatitis C (viral infection that affects the liver). Seek medical help if symptoms like fever, sore throat, cough, or painful skin sores are noticed during treatment.

• Tuberculosis (TB) Risk: Using Rilonacept may increase the risk of tuberculosis. Inform the doctor if one had TB, lived in a place where TB is typical or has been in contact with someone with TB. Report symptoms like coughing, weakness, weight loss, or fever immediately.

• Vaccinations: Avoid getting vaccinated without consulting the doctor.

Dietary Considerations

Unless advised otherwise by the doctor, maintain a regular diet.

Missed Dose

Contact the doctor if one misses a dose of this medication. Follow the doctor's instructions on when to administer the missed dose and administer the following scheduled dose. Avoid injecting a double dose to compensate for the missed one.

Overdose

There have been no reports of a Rilonacept overdose. Subcutaneous doses of up to 320 mg weekly for about 18 months in a few CAPS patients and up to six months in patients with other conditions in clinical trials have not shown dose-limiting toxicities. Additionally, intravenous doses of up to 2000 mg monthly in another patient group for up to six months were tolerated without issues. However, the maximum safe dose of Rilonacept has not been established. If an overdose occurs, monitor for signs of adverse reactions and provide immediate symptomatic treatment as needed.

Storage and Handling

Store Rilonacept in its original carton at 2 to 8 degrees Celsius (36 to 46 degrees Fahrenheit) in a refrigerator and protect it from light. Please refrain from using the medication once the expiration date indicated on the label has passed. Once reconstituted, Rilonacept can be stored at room temperature but must be used within three hours and kept away from light. Since Rilonacept does not contain preservatives, any unused portion should be discarded, and the vial should be discarded after a single withdrawal of the drug.

Disposal:

To safely dispose of Rilonacept or any medication, keep it out of the reach of children and pets. Do not flush it down the toilet. Instead, consult the pharmacist or local garbage or recycling department about medicine take-back programs available in the community. If such programs are not accessible, visit the FDA's Safe Disposal of Medicines website for guidelines on proper disposal methods.

For Doctors

Chemical Taxonomy

Rilonacept:

• Composition: Dimeric fusion protein of IL-1RI and IL-1RAcP linked to human IgG1 Fc portion.

• Molecular Weight: Approximately 251 kDa (kilo-daltons).

• Expression: Recombinant Chinese hamster ovary (CHO) cells.

Rilonacept Vials:

• Contents: Sterile, lyophilized powder.

• Reconstitution: 2.3 mL sterile water for injection per 20-mL vial.

• Resulting Solution: Viscous, transparent to pale yellow, particle-free.

• Dosage: 220 mg Rilonacept per vial (80 mg/mL after reconstitution).

• pH: 6.5 ± 0.3.

• Ingredients: Histidine, arginine, polyethylene glycol 3350, sucrose, glycine.

Warnings and Precautions

• Infections: Using Rilonacept, which blocks interleukin-1 (IL-1), might make infections more likely. Serious infections have happened in Rilonacept users more than in those not using it. If someone gets a severe infection while using Rilonacept, they should stop using it. Also, Rilonacept should not be used if someone already has an infection. It is not recommended to use Rilonacept with drugs that block tumor necrosis factor (TNF) because it increases the chance of serious infections. Before starting Rilonacept, doctors should check for and treat any hidden tuberculosis infections.

• Immunosuppression: Rilonacept might increase cancer risk.

• Immunizations: Rilonacept might make vaccines less effective, so live vaccines should not be given while using them. Patients should get all recommended vaccines before starting Rilonacept.

• Lipid Profile Changes: Rilonacept could change the fats in the blood, so doctors should check the blood fats and give treatment if needed.

• Hypersensitivity: If a hypersensitivity reaction occurs, Rilonacept administration should be stopped, and appropriate treatment should be started.

What Are the Pharmacological Actions of Rilonacept?

• Pharmacodynamics: C-reactive protein (CRP) and serum amyloid A (SAA) are elevated inflammation markers in CAPS patients. High SAA levels are linked to systemic amyloidosis development in CAPS patients. Rilonacept treatment significantly lowered mean CRP and SAA levels compared to placebo, returning them to normal ranges during the trial and normalizing elevated SAA levels.

• Mechanism of Action: CAPS are rare genetic syndromes caused by mutations in the NLRP-3 gene, also known as CIAS1. These conditions are passed down in an autosomal dominant pattern, affecting both males and females equally. Mutations in the NLRP-3 gene lead to overactivity of the inflammasome, resulting in excessive release of IL-1beta, a key driver of inflammation in CAPS. Rilonacept binds IL-1beta as a soluble decoy receptor, preventing its interaction with cell surface receptors. Rilonacept interacts with IL-1alpha and IL-1 receptor antagonists (IL-1ra), albeit with lower affinity.

• Pharmacokinetics: The average steady-state trough levels of Rilonacept were around 24 mcg/mL in patients with CAPS who received weekly subcutaneous doses of 160 mg for up to 48 weeks. Steady-state concentrations were typically achieved by six weeks. There is no available pharmacokinetic data for patients with liver or kidney impairment. Studies did not thoroughly assess how age, gender, or body weight affect Rilonacept exposure. Still, steady-state concentrations were similar across different ages and body weights in the limited data available.

Non-Clinical Toxicity

Long-term studies on animals to check if Rilonacept causes cancer have not been conducted. Its potential to cause genetic mutations has yet to be assessed. In a study using a mouse model similar to Rilonacept, male mice treated before mating and female mice treated during pregnancy did not show changes in fertility even at doses up to 200 mg/kg, which is about six times higher than the human maintenance dose of 160 mg.

What Are the Contraindications of Rilonacept?

None.

What Are the Drug Interactions of Rilonacept?

• TNF-Blocking Agents: Combining Rilonacept with TNF-blocking agents increases the risk of severe infections and neutropenia. This combination is not recommended.

• Other IL-1 Blocking Agents: Using Rilonacept with other IL-1 blockers can lead to similar toxicities and is not recommended.

• Cytochrome P450 Substrates: Rilonacept can normalize CYP450 enzyme levels, suppressed during chronic inflammation. This is particularly relevant for medications with a narrow therapeutic index, such as Warfarin. Monitoring and potential dose adjustments are recommended when starting Rilonacept with these medications.

Clinical Studies

Rilonacept's efficacy in treating CAPS was demonstrated through a clinical study of two parts (A and B). Part A involved a six-week, double-blind comparison where patients received either Rilonacept at 160 mg weekly (after an initial higher dose) or placebo. Part B was followed immediately by a nine-week period in which all patients received Rilonacept, followed by a nine-week double-blind withdrawal phase.

Patients could then enroll in a 24-week open-label extension phase. Symptoms such as joint pain, rashes, fever or chills, eye redness or pain, and fatigue were assessed using daily diaries. Rilonacept-treated patients showed significant improvement compared to placebo patients, with sustained reductions in symptoms and inflammation markers over the study period.

Use in Specific Populations

• Pregnancy: Rilonacept is classified as pregnancy category C, indicating no well-controlled studies in pregnant women and potential risks based on animal data, including fetal abnormalities in monkeys and increased stillbirths in mice at high doses. It should be used during pregnancy if the benefits to the mother justify the potential risks to the fetus. The excretion of Rilonacept in human milk is unknown, so caution is advised for nursing mothers.

• Pediatric Use: Improvements were seen in symptom scores and inflammation markers for patients aged 12 to 16, but its safety and effectiveness are not established for children under 12. Pediatric patients should be monitored for growth and development due to potential bone development issues.

• Geriatric Use: In geriatric use, the efficacy and safety are generally similar to those of younger adults. However, caution is noted as one elderly patient developed bacterial meningitis and died in an extension study.

• Patients with Renal or Hepatic Impairment: No formal pharmacokinetic studies have been conducted for patients with renal or hepatic impairment, and no specific details are available on overdose management.