How long does Fasenra take to work?

• Fasenra significantly decreases eosinophils in the blood within 24 hours of a dose

• After 4 weeks, treatment with Fasenra started to reduce asthma exacerbations

• Improvement in lung function was also observed 4 weeks after Fasenra was administered

Fasenra (benralizumab) is a medication used on an ongoing basis alongside other treatments to control severe eosinophilic asthma, an inflammatory lung condition. Fasenra is a monoclonal antibody and interleukin-5 (IL-5) antagonist.

Fasenra works by targeting and removing cells that play a key role in asthma, including eosinophils. Eosinophils are white blood cells and part of the immune system, which are found in increased numbers in patients with eosinophilic asthma. It is not fully understood exactly how it helps to control asthma, but Fasenra depletes eosinophils once administered. A key mechanism of action of the drug involves the blocking of IL-5. IL-5 enhances the survival and state of activation of eosinophils.

When does Fasenra start working?

Fasenra starts working straight away. Significant reductions in peripheral blood eosinophil levels occur within 24 hours of Fasenra being administered. Eosinophil cationic protein (ECP) levels are also significantly reduced after treatment with Fasenra. ECP is a protein found in eosinophils and it is used as a measure of eosinophil activation. Activation of eosinophils can lead to the release of substances that promote inflammation.

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How quickly does Fasenra work?

Within 7 days of treatment with Fasenra, median peripheral blood eosinophil counts reached zero in patients with asthma enrolled in a phase II trial.

Phase III results also showed that treatment with Fasenra significantly improved exacerbation rates in patients with asthma, compared with those treated with placebo. The improvement in exacerbation rates started to appear 4 weeks after administration with Fasenra, suggesting that it begins to have a beneficial effect shortly after patients start taking it. Results from a phase III trial also showed that Fasenra works quickly, improving lung function in as little as 4 weeks.

A small study conducted in the clinical practice setting, has also reported that significant improvements in quality of life and asthma control scores were observed 4 weeks after treatment with Fasenra was initiated.

Fasenra is administered via subcutaneous injection using either a prefilled syringe designed for health care professionals, or an autoinjector pen designed for patients and caregivers. Patients receive a dose of Fasenra once every 4 weeks for the first 3 doses, after which it is injected every 8 weeks.