Every year, asthma kills nearly a thousand people in France. The cause: uncontrolled symptoms that can, due to their frequency or severity, endanger the lives of patients. A feeling of suffocation, weight on the chest, air circulating with difficulty in the lungs: this is an asthma attack, or exacerbation. A manifestation similar to the flare-ups of chronic obstructive pulmonary disease (COPD).
Indeed, in both pathologies, the airways are obstructed following local inflammation and thickening of the bronchial walls. Although these are two distinct conditions with different causes, their symptoms and treatments can be similar in several respects. For decades, their management has most often involved inhalers that dilate the bronchi and oral corticosteroids that reduce inflammation in cases of severe asthma (5% of asthmatics) such as, for example, prednisolone.
But the 21st century marks a turning point in the treatment of these respiratory diseases thanks to monoclonal antibodies. These are immune molecules that bind to the cells causing inflammation, and cause their death. It was known that their use in basic treatment made it possible to reduce the frequency of severe exacerbations. Today, researchers from King's College (London) are going even further by showing that these molecules can be injected at the time of the crisis, and are more effective than conventional treatment. Their study, supported by the AstraZeneca UK Limited laboratory, was published in the journal The Lancet Respiratory Medicine
Source: BRUNO BOURGEOIS. Source: A new lease of life for treating severe asthma
What is a monoclonal antibody?
Monoclonal antibody biotherapy has already proven its worth in the treatment of chronic inflammatory diseases, and its use continues to expand. In 2023, a new molecule appeared in the prevention of Brochiolitis in infants, another was developed to treat severe asthma. This tool is gaining momentum but how does it work?
Antibodies are produced by the body when it is infected by a microorganism. They attach to the bacteria or virus and usually signal its presence to immune cells, which are responsible for eliminating it. The same process occurs when the antibody recognizes a foreign cell, or mistakenly attacks the body's cells.
The ability of antibodies to recognize a specific target has piqued the curiosity of scientists for years. Today, they are able to produce antibodies specific to a protein: these are called "monoclonal antibodies". To do this, researchers culture immune cells and expose them to the target protein.
No fewer than 5 molecules have emerged from this technique against severe asthma since the 2000s. But why so many different monoclonal antibodies?
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Adapt the molecule to your asthma
Asthma is actually plural. Its causes can be linked to different cells depending on the patient and are therefore variable. Today, it is possible to individually identify the metabolic pathway that leads to inflammation, and therefore to prescribe the appropriate monoclonal antibodies. A solution that allows patients with severe asthma to reduce their intake of corticosteroids, which are not harmless. In their new study, the researchers at King's College used a molecule already prescribed in cases of severe asthma: benralizumab. It is a monoclonal antibody that targets specific white blood cells, called eosinophils, to reduce lung inflammation, " explain the scientists.
THE Eosinophils are immune cells, white blood cells, involved in various pathologies. They are the cause of hyper-reactivity of the bronchi and their inflammation. The smooth muscle that lines the walls of the respiratory tract contracts, which results in their narrowing (remodeling). Eosinophils also cause hypersecretion of mucus.
The researchers divided the cohort into three groups, based on the treatment given during an exacerbation: one receiving an injection of benralizumab and placebo tablets, another receiving the standard treatment of prednisolone plus a placebo injection, and the third group receiving both the benralizumab injection and the prednisolone tablets.
Results? The 28-day post-attack milestone shows significant improvement in symptoms for patients who received immediate benralizumab injection. After 90 days, the number of people who failed treatment was four times lower in the benralizumab group compared with the standard prednisolone treatment," adds the King's College team. Following this injection, the quality of life of the patients improved, and the seizures significantly decreased, reports the study. Benralizumab is already used to treat severe asthma. We used it in a different way – at the time of an exacerbation – to show that it is more effective than steroid tablets, which are the only treatment currently available," concludes Mona Bafadhel, principal investigator of the study. For scientists, it is a question of targeting patients suffering from severe asthma to offer them this treatment, adapted to their level of inflammation.
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