Asthma is a chronic disease that can be difficult to treat.
But now a biologic drug in development to treat severe asthma reduces the rate of serious attacks by about two-thirds compared to a placebo drug, according to preliminary research findings.
Effective drugs available soon
If approved, the drug, tezepelumab, could join a group of costly medications that appear to offer relief when nothing else curbs respiratory distress.
"A new era has begun in which many new drugs are being developed for patients with severe asthma," said Dr Elisabeth Bel, a professor of respiratory medicine at the University of Amsterdam in the Netherlands.
"Similar to what has happened for rheumatoid arthritis, I expect that in a few years effective treatments will be available for almost all patients with severe asthma," said Dr Bel, author of a commentary accompanying the new study.
The study was published in The New England Journal of Medicine.
The new research was funded by the drug's developers, Amgen and MedImmune, a subsidiary of AstraZeneca.
Inhalers not always effective
Asthma is a chronic lung disease. Dr Bel said an estimated 15% of asthma patients can't control the disease with current inhaled medications.
"They have severe disease with persistent airway inflammation, which causes continuous symptoms of breathlessness and exercise intolerance," Dr Bel said. This also puts them at risk of severe attacks for which they have to be hospitalised, she added.
In South Africa alone, 1.5% out of the estimated 3.9 million asthma sufferers die from this condition annually, according to statistics recently published on Health24.
Tezepelumab, an injectable drug, is a monoclonal antibody – a term that refers to how it's made.
Drugs may not help all patients
Drugs in this category help many patients with severe asthma, but not all of them, Dr Bel said. That's because the disease comes in different types, she explained.
The new study represents the second of three phases of research required before a drug can be approved in the United States. Researchers wanted to understand tezepelumab's effects on asthma patients who'd suffered at least one asthma attack that required hospitalisation within the past year, or two attacks that forced physicians to increase their medication level.
The 584 study patients with severe asthma were non-smokers, aged 18 to 75, who used asthma inhalers. They were randomly divided into low-dose, medium-dose or high-dose groups, or assigned to take a sham ("placebo") drug.
Improvement in lung function and asthma attacks
The researchers found that those on the drug had 61% to 71% fewer asthma attacks that required a hospital visit or change in medication dose than those who took a placebo.
Study co-author Dr Rene van der Merwe said, "Tezepelumab also demonstrated improvements in lung function at all doses, in asthma control at the two higher doses, and in quality of life across all treatment groups relative to placebo." She's a researcher with MedImmune.
The study "did not reveal any unexpected safety concerns," said Dr Van der Merwe. Between 62% and 66% of the patients in the various groups reported side effects, and between 9% and 12% reported serious side effects.
The drug blocks a molecule that's key to the development of swelling in the airway, Dr Bel said, "and is therefore effective in different subtypes of asthma."
As a result, "the chances that the drug will work in severe asthma patients are higher than with the existing monoclonals that are more selective for a specific subtype of patients," she said.
Dr Van der Merwe said it's too early to estimate how much the drug may cost. A spokesperson for AstraZeneca also refused to discuss the cost.
Until this drug becomes available, the key to a good quality of life lies in controlling asthma symptoms. A treatment plan for asthma sufferers should include the following:
- Effective treatment of factors such as hay fever, sinusitis and bronchitis.
- Reduced exposure to triggers such as viral infections, flu, allergens, active and passive smoking.
- Proper education about the condition.
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