Although asthma is a common chronic disease, there is currently no cure for it. Currently, physicians use a variety of means to reduce inflammation and keep it at bay. The extent of their success depends upon environmental factors, patient compliance and the “fit” of the treatment.
For those with chronic, moderate-to-severe asthma, corticosteroids are used to reduce inflammation. These conventional drugs are anti-inflammatory medications that may be used in inhalers on a daily basis or taken orally on a tapering dose when an exacerbation occurs. One of the drawbacks of corticosteroids is side effects that can come along with them, including a cough, minor nosebleeds, oral thrush and difficulty speaking.
The side effects from long-term or high-dose oral steroid are a cause for concern as well. Some of those side effects include osteoporosis, glaucoma, diabetes, high blood pressure, heart disease, Cushing Syndrome and many others. A therapy that leads to fewer asthma attacks while reducing the need for corticosteroids is ideal, especially for those who continue to have severe symptoms while using traditional therapies. That’s where biologics come in.
Biologics for Asthma
Biologics are drugs made from biological sources. To manufacture these drugs, a piece of DNA is inserted into a living cell. The cell follows the instructions in the DNA to produce a large amount of a protein molecule. The protein molecule is separated from the rest of the material and becomes the active ingredient in the biologic drug. Systemic reactions are possible with biologics because the proteins are large and can trigger an immune response in the patient. Also, since the chemical bonds holding the molecules together are weak, sudden changes of temperature can damage or degrade the molecules. Because of this, it is imperative that the entire manufacturing process of a biologic drug occur under precise, optimal, monitored conditions.
The exact mechanism for a biologic is unknown: The manufacturers of these drugs cannot tell you precisely how or why they work. However, they can provide you with the theory and rationale for the combination of DNA and cells they used. Clinical trials are then done to ensure that the finished biologic produces the anticipated results. Once this has been demonstrated, FDA approval is sought. FDA approval has been received for several injectable asthma medications.
Which Biologic
There are currently two identified mechanisms that cause the inflammation in asthma and are targets for treatment. One has to do with the IgE levels in a patient’s blood. The other has to do with the number of eosinophils. Eosinophils are present in everybody’s blood. It is when they exist in numbers that contribute to inflammation in the airways that they become a treatment target.
Because there is not one perfect biologic treatment for every patient with asthma, it isn’t unusual for one allergist’s practice to use several different biologics for their patients. Dr. Rachel Schreiber has been using biologics for more than 15 years.
“We use Omalizumab (Xolair), Mepolizumab (Nucala), Benralizumab (Fasenra), and Dupilumab (Dupixent). Each is indicated for moderate to severe persistent asthma. Xolair is also approved for use in chronic urticaria, Schreiber said. “Dupilumab is also approved for atopic dermatitis and nasal polyposis.”
Xolair® (omalizumab) is used in combination with other treatments to treat allergic (IgE) asthma and chronic urticaria (hives). Developed by Genentech and licensed by Novartis, Xolair received FDA approval in 2003. By targeting the IgEs in a reaction, Xolair reduces or prevents inflammation in patients with asthma that is not controlled by inhaled corticosteroids.
Essentially, Xolair does its work once an allergen is inhaled. Researchers know that the body creates IgE (immunoglobulin E) to attach to the allergen and the cell when the allergen is introduced. This causes inflammation of the airway, which can lead to an asthma attack. Researchers speculate that Xolair may work by binding to the IgE and preventing it from binding to the inflammatory cell.
Nucala® (mepolizumab) is used in combination with other treatments to treat severe eosinophilic asthma. Produced by GSK, it was approved in 2015 for the treatment of severe asthma. The type of asthma Nucala targets is caused by eosinophils that cause inflammation in the lungs. By reducing the number of eosinophilic cells, Nucala reduces the inflammation in the lungs.
Fasenra® (benralizumab) was approved to treat severe eosinophilic asthma in 2017. This biologic is manufactured by AstraZeneca. It is an add-on treatment that also reduces the number of eosinophils in the patient’s blood.
Dupixent® (dupilumab) is also used as an add-on maintenance treatment for eosinophilic asthma. Approved by the FDA in 2018 for the treatment of moderate-to-severe asthma. A product of Sanofi and Regeneron, Dupixent works by blocking two key sources of inflammation – IgE and eosinophils. It also blocks FeNo, which is linked to inflammation in asthmatic patients.
Selecting the appropriate treatment depends on a variety of factors. Schreiber says, “There are risks and benefits to each [treatment] and given the patient’s overall profile we make decisions about what we think may be most effective for the individual patient.”
Why Use a Biologic
Even with the oversight of a physician trained in the intricacies of asthma management, it might seem that the use of a large-protein therapy that can induce a reaction in the patient receiving an injection for the treatment of asthma is not worth the risk. It might also seem that a judicious use of both inhaled and oral corticosteroids could be used to adequately control inflammation in the lungs. Unfortunately for patients with severe asthma, the use of the latter has not been the case, while the risks of the former must be weighed against the effects of severe asthma and the traditional medications used for its control.
Because there is no on/off switch for the immune system response that triggers the inflammation in severe asthma, there are new biologics in the pipeline that are designed to better meet existing patients or the needs of entirely new populations of patient.
“These drugs help us decrease inhaled and oral corticosteroid use, asthma exacerbation rates, and hospitalizations and ER visits due to asthma,” Schreiber said. ’They make our patients feel better and have fewer symptomatic days. Biologic medications are state of the art and I believe they are the future as well.”
Published on BioSpace