Allergy Skin Testing and Eosinophils
Skin prick testing (SPT) was positive to at least one of the thirty
aeroallergens tested at baseline in about half the patients in both the
benralizumab and placebo groups. Benralizumab treated patients with six
or more positive skin tests had minimal improvement in endoscopic nasal
polyps score, whereas all five subjects with two or less positive SPT
improved. As seen in Figure 5A, there was an inverse correlation between
the number of skin tests positives and endoscopic NP score improvement
(P=0.023). Total serum serum IgE and polyp score reduction were not
correlated (P=0.071).
Benralizumab reduced blood eosinophil counts in all treated patients
(100%). The absolute eosinophil count for the benralizumab treated
group decreased from 698/µl (SD=412.7) to 20/µl (SD=49.7) at week twenty
(P<0.001). Mean eosinophil count for the placebo group
decreased slightly from 846/µl (SD=592.6) to 650/µl (SD=552.8) but was
not significant (P=0.106). Blood eosinophils were undetectable in ten of
the twelve patients treated with benralizumab but remained elevated in
all subjects in the placebo group. In contrast to what was seen for
allergen SPT, higher blood eosinophil counts correlated with better
reduction in polyp scores, although this trend did not reach statistical
significance (P=0.301). Nonetheless, as seen in Figure 5B, all
benralizumab treated patients with blood eosinophil counts greater than
700/µl improved.