Researchers say they have found the first new treatment for asthma attacks in 50 years.
The injection dampens a part of the immune system that can go into overdrive in both asthma flare-ups and a lung condition called chronic obstructive pulmonary disease (COPD).
Benralizumab is already used in the most severe cases, but recent research suggests it could be used routinely.
The research team at King's College London said the drug was a "game changer" that could "revolutionize" asthma care.
According to the study, not all asthma or COPD attacks are the same. Instead, different parts of the immune system reacted en masse in different patients.
"Now we can see that there are different models of inflammation, and provide the right treatment, for the right patient, at the right time", said Prof. Mona Bafadhel.
Benralizumab targets a type of white blood cell - called eosinophils - that can cause inflammation and damage to the lungs.
Eosinophils are involved in about half of asthma attacks and a third of COPD flares.
If such an attack involving difficulty breathing, coughing and tightness in the chest cannot be controlled with regular inhalers then doctors will recommend steroid medication.
The study, with the participation of 158 people, monitored the patients for three months.
People treated with the new therapy were less likely to be hospitalized, need another round of treatment, or die.
Volunteers also reported improved symptoms and a better quality of life with the new drug.
It will still take a larger trial, which will start in 2025 and last two years, to be sure for use. Anyone already given these drugs should continue to follow their prescription.
