Methods: Nine ragweed allergic participants were enrolled out of season. The nasal cavity was washed with saline and diluent control delivered intra-nasally; participants were excluded if their Total Nasal Symptom Scores(TNSS), recorded 15 minutes following each step, were >2. The lowest allergen concentration was delivered and TNSS and Peak Nasal Inspiratory Flow(PNIF) recorded 15 minutes later. Participants qualified if a TNSS≥8 and PNIF reduction≥50% were achieved, otherwise the next higher allergen concentration, (4-fold increase), was administered until criteria were met. Participants returned 21-28 days later for a NAC visit(NAC1), and received an allergen challenge concentration equal to all doses delivered at screening, including the qualifying concentration. TNSS/PNIF were recorded at 15 minutes, 30 minutes, 1 hour, hourly up to 12 hours, and at 24 hours following NAC. A second NAC visit(NAC2) was conducted 21-28 days after NAC1.
Results: Participants experienced an initial peak in TNSS at 15 minutes (mean=8.0 NAC1; 7.33 NAC2) followed by gradual decline. PNIF changes mirrored TNSS findings, decreasing to a nadir at 30 minutes following NAC, followed by a gradual return to near-baseline. Both NAC visits had similar results, with no statistical difference (two-way ANOVA with Bonferroni corrections and paired t-tests).
Conclusions: The AR-CIC’s NAC protocol reliably reproduces clinical results, ensuring that any change would be purely due to medication under investigation in a clinical trial setting.