Achieving complete type 2 (T2) biomarker suppression in patients treated with biologics offers no additional clinical benefit in severe asthma, challenging the relevance of biological remission as a treatment goal, according to an analysis of UK Severe Asthma Registry data.
The research, led by a team at Queen’s University Belfast, investigated whether achieving biological remission – defined as blood eosinophils <0.15 x109/L and fractional exhaled nitric oxide (FeNO) <20 ppb – translates into better outcomes for patients with severe asthma who receive biologic therapy.
Using data from the UK Severe Asthma Registry, the study included 778 adults who met national criteria for biologic treatment and had complete biomarker data at baseline and one-year follow-up.
Among these, 148 patients (19%) achieved biological remission, while 630 (81%) did not. Patients achieving biological remission tended to have a longer disease duration, were more often ex-smokers, and had lower baseline T2 biomarker levels before starting biologics.
Biological remission not superior
Despite biomarker suppression, biological remission was not associated with superior clinical outcomes, including exacerbation rates, lung function, symptom control or quality of life, compared with those who did not achieve biological remission.
The authors noted that biological remission was more common in individuals with lower baseline T2 inflammation, suggesting it may reflect a less T2-driven phenotype rather than a direct treatment effect.
However, independent reductions in FeNO and blood eosinophils were associated with modest improvements in lung function, supporting the ongoing use of biomarker monitoring during therapy. Only 4.8% of patients achieved both clinical and biological remission – or complete remission.
The researchers acknowledged that the study was limited by its observational, single-arm design without a control group, as well as a lack of representation of newer biologics, such as anti-TSLP agents. There was also a reduced sample size due to reduced biomarker data during the Covid-19 pandemic, which may have impacted the results.
Next steps and treatment targets
Prospective trials to evaluate whether intensified T2 suppression or dual-pathway strategies targeting IL-5 and IL-4/13 may benefit patients with persistently high T2 biomarker levels, would be a valuable next step, they said.
This research challenges the assumption that achieving biological remission should be a primary treatment goal in severe asthma. While T2 biomarker suppression correlates with incremental improvements in lung function, biological remission did not lead to better overall outcomes.
Focusing on clinical remission, particularly when including lung function criteria, could offer a more patient-relevant and achievable treatment target, the researchers concluded.
Reference
Jane MP et al. Observational analysis of biological remission as a treatment target for severe asthma: UK severe asthma registry. J Allergy Clin Immunol Pract 2025;Sep 5:doi.org/10.1016/j.jaip.2025.08.027.
