Asthma is a chronic lung disease characterized by inflammation in the airways, which makes them swell and narrow. This can quickly lead to a cascade of respiratory symptoms, including chest tightness, wheezing and a feeling of gasping for breath. In severe cases when symptoms worsen, it can lead to an asthma attack, which can be fatal. Asthma affects about one in 10 children and one in 15 adults globally.
Asthma symptoms flare up when the immune system overreacts in response to exposure to a trigger, says Liza O’Dowd, M.D., Vice President, Disease Area Stronghold Leader of Immunodermatology and Respiratory at Johnson & Johnson. A variety of factors can trigger the immune system, including allergies to dust, pet dander, pollen or other substances, as well as air pollution from smoke or fumes. Asthma symptoms can also stem from physical activity, stress or a respiratory infection, such as a cold or the flu.
Exactly why some people get asthma isn’t known, says Dr. O’Dowd. Individuals with a family history of asthma are more likely to have it themselves, as are those with allergies. Asthma can develop at any age, from infancy to adulthood. Though symptoms can often be managed and improved, there’s no cure, and in the long-term the disease can take a toll on a patient’s overall health.
Find out more about this common condition, why some people develop a more serious, treatment-resistant type and how Johnson & Johnson is investigating the connection between asthma and other immune-mediated diseases to develop potential options for treatment.
The two types of asthma
Asthma is classified into two main categories.
Eosinophilic asthma, also known as type 2 inflammation high (T2-high) asthma, is defined by high levels of T2 biomarkers and refers to a complex, systemic immune response to an allergen or other trigger that leads to the release of certain immune signals (known as cytokines). This increases inflammation and causes typical asthma symptoms.
Eosinophilic asthma can also be defined by elevated levels of eosinophils (a type of white blood cell that regulates inflammation) or fractional exhaled nitrous oxide (FeNO) in the airways, says Dr. O’Dowd. It’s estimated that greater than two-thirds of severe asthma cases are eosinophilic. Biologic medications targeting some of the mediators of T2 inflammation are effective and available, although many patients have an incomplete response or no response, and unmet need remains.
Noneosinophilic asthma, sometimes called non–T2 high asthma or nonallergic asthma, is a type of asthma triggered by a different inflammatory pathway. People with this kind of asthma may have increased levels of neutrophils, another type of immune cell. Noneosinophilic asthma typically causes more persistent symptoms and is often more difficult to treat, as it doesn’t respond as well as eosinophilic asthma to inhaled steroids, or to most available biologics, which are mainstay treatments.
The inflammatory pathways driving this form of asthma are poorly understood. There is a great need for therapies targeting non-T2 inflammation for asthma.
Symptoms of asthma
For some, it feels like a cough they can’t get rid of. Others describe wheezing when they exhale because the “airways are constructed so air can go in, but it just can’t go out,” says Dr. O’Dowd. A tight feeling as you inhale and exhale and other breathing difficulties are also symptoms. “Sometimes it’s pretty subtle, like ‘I can’t quite catch my breath’ or ‘I can’t take a full breath,’” she says.
Some people with asthma have mild disease and only have symptoms when they have a cold, are exercising or encounter a specific trigger, says Dr. O’Dowd. But individuals with severe disease in general may have persistent decreased lung function, which may lead to decreased exercise tolerance, fatigue and increased risk for cardiovascular disease over the longer term. Quality of life can be greatly affected; people with severe asthma may be unable to climb stairs or play with their kids, and it can even make it difficult to leave their house.
What is an asthma attack?
Asthma flares can occur and, when severe, they may result in a medical emergency. A flare may occur in response to exposure to a trigger (e.g., smoke), an allergen (e.g., animal dander or pollen) or the development of a respiratory tract infection, such as the common cold, flu or bacterial infection. As a result, a person’s airways become so constricted and swollen, they may feel like they’re breathing through a straw. In some cases, they may not feel like they can breathe at all. This can exhaust their respiratory muscles, says Dr. O’Dowd, putting the person at risk of death.
An asthma attack can last minutes or even hours. “It’s really terrifying,” adds Dr. O’Dowd. Nearly 40% of asthma patients report having an asthma attack about once a year, and these attacks have the potential to be fatal. Asthma attacks are treated with bronchodilators (medicines that relax the muscles in the airways) and systemic steroids, leading to serious steroid side effects after multiple asthma attacks over time.
How asthma is diagnosed
To diagnose asthma, a primary-care doctor, allergist or pulmonologist will ask patients about their symptoms, allergies, family history of the disease, lifestyle factors and if they have any other medical conditions. The physician will also do a physical exam and listen to the chest and lungs.
Lung function tests confirm asthma. One test, spirometry, involves patients performing a controlled inhalation-exhalation maneuver to measure airflow, says Dr. O’Dowd. “By that pattern of airflow and the absolute amount of air someone can exhale in a certain number of seconds, you can determine whether or not they have impaired airflow obstruction.” In patients with asthma, this obstruction should improve after they are given a dose of inhaled bronchodilators. Lack of improvement suggests the patient may have another condition, such as chronic obstructive lung disease.
A FeNO test can measure airway swelling and inflammation. High levels help support the diagnosis of asthma for the subset of asthmatics with eosinophilic/allergic asthma, says Dr. O’Dowd.
Treatment for asthma
Asthma treatment has evolved over the years. Decades ago, the standard treatment meant using a bronchodilator, which relaxes the smooth muscles lining the airway to improve breathing. Bronchodilators are currently delivered to patients in inhaled or nebulized form. Either way, they don’t address the root cause, which is lung inflammation.
Inhaled steroids provide an advancement over bronchodilators. These medications deliver drugs directly to the lungs to calm inflammation, says Dr. O’Dowd. The next evolution involves using an inhaler that contains a long-acting bronchodilator and an inhaled steroid, delivering both a bronchodilator and an anti-inflammatory in the same dose. This has been the mainstay treatment for about 20 years, she says.
My dream is that we can put patients in clinical remission. You’re not symptomatic any longer. You don’t have to feel like you’re attached to your inhaler.
More recently, doctors are prescribing biologic medications for patients with persistent asthma that isn’t well-controlled. These injectable medications target specific underlying inflammatory pathways to reduce airway swelling and prevent acute asthma attacks (exacerbations). Biologics can help some patients, but there are more limited options for those with noneosinophilic asthma.
“We’re still, as a field, looking to figure out how we can better help those patients,” says Dr. O’Dowd. The hope is that newer biological medications can help more patients achieve clinical remission (meaning the patient feels well, without symptoms or exacerbations and not requiring oral steroids).
A severe asthma attack requires care in an ER or hospital setting. Treatment starts with nebulized bronchodilators and systemic (delivered by IV or by mouth) steroids. In the most severe cases, patients may need to be put on a ventilator or, if that doesn’t work, a bypass machine to keep oxygen in the body.
The future of treating asthma and related conditions
Many people with asthma have other medical conditions, including atopic dermatitis, a chronic inflammatory skin condition causing itchiness, redness and oozing, says Dr. O’Dowd.
Johnson & Johnson has announced plans to develop a portfolio of assets for the treatment of T2-driven and non–T2 driven disease, including atopic dermatitis, which may also be beneficial in the treatment of other T2-mediated conditions such as asthma. The company is also developing bispecific antibodies, among other therapeutic modalities including orals, to potentially benefit patients with moderate to severe atopic dermatitis and asthma.
Dr. O’Dowd says this is a continuation of the company’s work developing innovations to treat inflammatory diseases now being directed to “tackle the problem of asthma.” This is crucial, because up to half of asthma patients don’t have their disease under control, with even less achieving clinical remission.
“My dream is that we can put patients in clinical remission,” says Dr. O’Dowd. In other words, “you’re not symptomatic any longer. You don’t have to feel like you’re attached to your inhaler. Your lung function is normal. You live a normal life with normal activity. That is an attainable goal.”
