"You read the literature and it’s a 6%-7% improvement in FEV1 [with omalizumab], but we had a 43% improvement in FEV1 by selecting the correct patients," he remarked.
Omalizumab is approved in the United States for the treatment of moderate to severe persistent allergic asthma despite inhaled corticosteroids, but it is approved only as an add-on therapy in the European Union, due in part to the difficulty of predicting which patients will respond. A previous analysis of seven randomized omalizumab trials including the INNOVATE trial reported that baseline characteristics do not reliably predict benefit with omalizumab (Respir. Med. 2007;101:1483-92).
Further investigation is needed to determine the exact tissue eosinophil number that is important for treatment, Dr. Martin said. For the purpose of this preliminary work, which was described as a real-world study that took all comers, the phenotype was defined as more than 10 eosinophils per high-power field.
A study is now underway to validate the SGI, including intra- and interoperator variability. Further research is also needed to identify a noninvasive means of evaluation, to better understand the subacute bacterial infection phenotype and microbiome, and to determine how to treat the more problematic nonspecific phenotype. Dr. Martin stressed that for patients with the combination phenotype, each of the phenotypes must be treated to obtain maximum benefit.
During a discussion of the study, he said that lavage, biopsy, and brush evaluations are all needed to identify atypical bacteria, and that careful attention must be paid to the cleanliness of the endoscope to avoid cross-contamination of the airways during evaluation. Endobronchial biopsies were typically taken from the right lower lobe as well as from areas of abnormality.
Dr. Martin also noted that no association was identified between a specific phenotype and sinusitis, which was present in 71% of the patients, or with obesity. The mean body mass index of the cohort was 31 kg/m2.
Additional details of the study can be found online (Chest 2011 Aug. 11 [doi:10.1378/chest.11-0741]).
Dr. Martin reported no relevant conflicts of interest.