Reslizumab Injection

Reslizumab injection (Cinqair) is approved for one specific use in adults:

• Cinqair is indicated as add-on maintenance treatment for adults aged 18 years and older with severe asthma that has an eosinophilic phenotype — meaning asthma driven by elevated eosinophil (a type of white blood cell) counts.
• Cinqair is used alongside other asthma treatments, not as a standalone or replacement therapy.
• Cinqair is not approved for the relief of sudden asthma symptoms, acute bronchospasm, or status asthmaticus (a prolonged, dangerous asthma attack).
• Cinqair is not approved to treat other conditions involving high eosinophil counts.
• Cinqair is not approved for use in patients under 18 years of age.

Reslizumab is a monoclonal antibody — a lab-made protein — that specifically targets and blocks interleukin-5 (IL-5), a chemical messenger that plays the central role in producing, maturing, activating, and keeping eosinophils alive. Eosinophils are white blood cells that contribute to the airway inflammation seen in severe eosinophilic asthma. By blocking IL-5 from attaching to its receptor on eosinophils, reslizumab sharply reduces eosinophil levels in the blood, which in turn lowers inflammation in the airways. The exact way this translates to better asthma control has not been fully established, but the reduction in eosinophils is the key measurable effect.

Cinqair is given exclusively as an intravenous (IV) infusion — a slow drip into a vein — in a healthcare setting, once every 4 weeks. Each infusion takes 20 to 50 minutes, with the exact time depending on your body weight (since the dose is weight-based). There are no food or drink restrictions.

• Cinqair must be given by a healthcare professional trained to manage serious allergic reactions.
• You will be monitored during and after each infusion.
• Never receive Cinqair as an IV push (rapid injection) or bolus.
• If you miss a scheduled infusion, contact your healthcare provider to reschedule as soon as possible.

The most commonly reported side effect with Cinqair in clinical trials was oropharyngeal pain (soreness in the mouth or throat). Other side effects include:

Serious reactions — including anaphylaxis (a life-threatening allergic reaction) and a slightly increased rate of malignancy (cancer) — were also observed in clinical studies. Seek emergency help immediately if you experience difficulty breathing, wheezing, hives, or feel faint during or after your infusion.

• Anaphylaxis: A severe, potentially fatal allergic reaction occurred in 0.3% of patients in trials — sometimes as early as the second dose. Signs include breathing difficulty, wheezing, low oxygen, vomiting, and hives. Cinqair must be given by a professional who can treat this reaction immediately. If it occurs, the infusion is stopped and Cinqair is permanently discontinued.
• Not for acute asthma: Cinqair is a maintenance medication only. Do not use it to relieve a sudden asthma attack. Seek medical care right away if your asthma suddenly worsens.
• Malignancy: Cancer was reported slightly more often in Cinqair-treated patients (0.6%) than placebo (0.3%) in clinical studies. The cancers were diverse, and no single type predominated. Discuss any concerning new symptoms with your doctor.
• Corticosteroid tapering: If you take systemic or inhaled corticosteroids, never stop them suddenly when starting Cinqair. Any reduction should be slow and supervised by your doctor, as stopping abruptly can cause withdrawal symptoms or unmask other conditions.
• Parasitic infections: Eosinophils help fight certain parasitic (worm) infections. Pre-existing parasitic infections should be treated before starting Cinqair. If you develop one while on Cinqair and it doesn't respond to treatment, Cinqair may need to be paused.

No formal drug interaction studies have been conducted with reslizumab, so information is limited. Based on available data:

• Leukotriene antagonists (e.g., montelukast) — do not appear to affect how reslizumab behaves in the body; can be used together.
• Corticosteroids — do not affect reslizumab's pharmacokinetics; however, corticosteroid doses should never be abruptly reduced when starting Cinqair.
• Other IV medications — Cinqair must not be infused through the same IV line as any other drug; no compatibility studies have been done.
• Reslizumab is unlikely to affect the activity of common drug-metabolizing liver enzymes (CYP1A2, 2B6, or 3A4), suggesting a low risk of enzyme-based drug interactions.

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

• Allergy to reslizumab: Cinqair is contraindicated if you have had a known hypersensitivity reaction to reslizumab or any of its ingredients.
• Parasitic infections: Tell your doctor if you have or recently had a parasitic (helminth/worm) infection — it should be fully treated before starting Cinqair.
• Pregnancy: The safety of Cinqair during pregnancy is not established. Monoclonal antibodies like reslizumab can cross the placenta, particularly in the second and third trimesters. Poorly controlled asthma in pregnancy carries its own risks. Discuss the benefits and risks carefully with your doctor.
• Breastfeeding: It is unknown whether reslizumab passes into human breast milk. The decision to breastfeed while using Cinqair should be made with your doctor, weighing benefits to the infant against your need for treatment.
• Children and adolescents: Cinqair is not approved for anyone under 18. In a study of adolescents aged 12–17, asthma flare-up rates were actually higher in those who received Cinqair than those who received placebo.
• Older adults (65+): No dosage adjustment is needed. Safety and effectiveness appeared similar to younger patients in clinical studies.
• Kidney or liver impairment: Based on population analysis, mild-to-moderate kidney impairment or mild liver function abnormalities do not significantly change how reslizumab behaves in the body.

In clinical trials, single doses much higher than the recommended dose were given intravenously without evidence of dose-related toxic effects. There is no specific antidote for a reslizumab overdose. If an overdose occurs, treatment would be supportive — meaning monitoring and care based on the symptoms present.

After the first Cinqair infusion, blood eosinophil counts begin to drop quickly — measurably within just 2 to 3 days. Over 52 weeks of treatment, Cinqair at the recommended dose produced about a 92% reduction in blood eosinophil counts compared to a 21% reduction with placebo. This effect was sustained throughout treatment with no sign of the body adapting or becoming tolerant. When Cinqair is stopped, eosinophil levels gradually return toward their pre-treatment levels, reaching near-baseline about 120 days after the last dose.

Reslizumab reaches its peak concentration in the blood at the end of each IV infusion, then declines in a two-phase pattern. It has a half-life of about 24 days, meaning it stays active in the body for a substantial period after each dose. The drug is broken down by natural protein-digesting enzymes into small peptides and amino acids — similar to how the body processes other proteins. Clearance is slow (approximately 7 mL/hour), and the drug does not appear to be significantly affected by age, sex, race, or mild kidney or liver impairment based on population analyses.

Refrigerate at 2 ºC to 8ºC (36°F to 46°F). Do not freeze. storing in the original package until time of use.