There is limited evidence that therapies against TNF-α are effective in subjects with severe asthma. However, in addition to promoting airway inflammation and AHR, TNF-α might play a central role in airway remodeling and induce glucocorticoid resistance, myocyte proliferation, vascular remodeling, and stimulation of fibroblast growth and maturation into myofibroblasts by promoting TGF-β expression.84 and 85 Patients with treatment-refractory asthma have an upregulation of their TNF-α axis.86 Initial enthusiasm for TNF-α blockade occurred after a clinical study using 10 weeks of etanercept by Berry et al86 found a decrease in AHR, as well as improved quality of life and lung function.
Unfortunately, a larger, randomized, double-blind, placebo-controlled study87 of golimumab (mAb against TNF-α) tempered these expectations. This phase 2 study randomized 309 subjects with severe and uncontrolled asthma to either placebo or golimumab for 1 year in addition to the usual treatment. No significant differences were observed in lung function or exacerbation rates through 24 weeks of treatment, but the study was prematurely terminated at that time because of an unacceptable risk/benefit profile (increased serious adverse events, including increased serious infections, malignancies, and 1 death).87 Interestingly, Wenzel et al87 found patients with reversible airflow obstruction at enrolment had a significantly improved response to golimumab therapy, as reflected by a decrease in exacerbations, thus suggesting that patients with fixed airway disease represent a phenotype that is less responsive to anti-TNF agents. In the absence of human studies specifically examining airway tissue, there is little evidence that anti-TNF agents affect remodeling in asthmatic subjects.