Dornase alfa is a medication that helps individuals with chronic respiratory conditions clear thick, sticky mucus from their airways. This inhaled treatment reduces mucus viscosity, making it easier to breathe and manage lung health.
The Problem of Thick Mucus
Many chronic respiratory conditions, particularly cystic fibrosis (CF), produce abnormally thick, sticky mucus in the airways. This mucus creates a significant physiological problem. In CF, dysfunctional proteins alter chloride and bicarbonate transport, causing dehydrated, viscous secretions to accumulate in various organs, especially the lungs. This thick mucus obstructs airways, making breathing difficult and impairing natural lung clearance.
Stagnant, viscous mucus also becomes a breeding ground for bacteria, leading to persistent lung infections and chronic inflammation. Repeated infections and the body’s inflammatory response can cause progressive, irreversible lung damage, including bronchiectasis. This cycle of obstruction, infection, and inflammation significantly reduces lung function and is the primary cause of illness and death in individuals with CF.
How Dornase Alfa Breaks Down Mucus
Dornase alfa is a recombinant human deoxyribonuclease I (rhDNase), an enzyme that specifically targets and breaks down extracellular DNA. This DNA is a major component contributing to the excessive stickiness and thickness of mucus in conditions like cystic fibrosis. The DNA originates primarily from dead white blood cells, called neutrophils, which accumulate in the airways in response to chronic infection and inflammation.
When these inflammatory cells break down, they release long DNA strands into the mucus, increasing its viscosity and elasticity. Dornase alfa cleaves these long DNA strands into smaller fragments. This enzymatic action reduces the DNA’s size within the mucus, decreasing its stickiness and making it less elastic. The reduction in viscosity allows the thinned mucus to be more easily moved out of the lungs through coughing or the natural actions of cilia, improving airway clearance. The enzyme specifically acts on extracellular DNA and does not affect the DNA within healthy cells.
Administering Dornase Alfa
Dornase alfa is administered through inhalation using a nebulizer. A nebulizer transforms the liquid medication into a fine mist, allowing it to be inhaled directly into the lungs where it acts on the mucus. This method ensures targeted delivery to the respiratory tract.
Patients use a jet nebulizer connected to an air compressor or a vibrating mesh nebulizer. The recommended dose is 2.5 mg of Dornase alfa once daily. Some individuals may benefit from twice-daily administration, which can help further reduce lung infection risk. Consistent and proper nebulizer use is important to achieve the medication’s full effects, and the nebulizer should be cleaned regularly.
Benefits for Patients
The primary benefit of Dornase alfa is its ability to thin thick, sticky mucus, leading to easier breathing. By reducing mucus viscosity, the medication improves lung function. Studies show Dornase alfa can improve lung function within one month, with sustained improvements observed in longer trials.
Improved mucus clearance also reduces the frequency of lung infections. Fewer infections mean fewer pulmonary exacerbations, which are periods of worsening lung symptoms. These clinical outcomes enhance the quality of life for individuals managing chronic lung conditions characterized by thick mucus. Early and consistent use of Dornase alfa can also help slow the rate of lung function decline over several years, potentially extending survival.