Main idea: Treatment with grass allergen peptides led to an improvement in allergic rhinoconjunctivitis symptoms after 3 intervening GPSs, corresponding to up to 2 years off treatment.
Grass allergen peptides are in development for the treatment of grass pollen-induced allergic rhinoconjunctivitis. A previous randomized, placebo-controlled study demonstrated that grass allergen peptides significantly improved total rhinoconjunctivitis symptom scores (TRSSs) after posttreatment challenge (PTC) to ryegrass in an environmental exposure unit after 1 intervening grass pollen season (GPS1).
The objective of the study was to evaluate the efficacy and safety of 4 dosing regimens of grass allergen peptides after the second (GPS2) and the third (GPS3) intervening grass pollen seasons in the environmental exposure unit.
Eligible subjects who were randomized in the parent study (GPS1) during the first year of recruitment were invited to participate in GPS2 and GPS3, which took place 1 and 2 years after treatment cessation, respectively. Participants were not treated further, and both participants and study personnel remained blinded. The primary efficacy endpoint was the change in mean TRSS (reported every 30 minutes) from GPS1 baseline to the follow-up PTC calculated across all-time points over days 2 to 4 for GPS2 and across hours 1 to 3 over days 2 to 4 for GPS3.
Results: 122 and 85 participants were enrolled in GPS2 and GPS3, respectively. A numerically greater, but not statistically significant improvement from baseline in mean total rhinoconjunctivitis symptom scores at posttreatment challenge was observed in the group receiving one 6-nmol intradermal injection every 2 weeks for 14 weeks compared with the placebo group at GPS2 and GPS3. Similar findings were observed for the group receiving one 6-nmol intradermal injection every 2 weeks for 14 weeks at GPS3. No adverse safety signals were detected.