5 Posttreatment, Long-Term Clinical Efficacy of a 300 IR Sublingual Tablet of 5-Grass Pollen Allergen Extract in Adults With Grass Pollen Induced Allergic Rhinoconjunctivitis

BACKGROUND: A 5-year study of adults with grass-pollen related rhinoconjunctivitis has demonstrated the sustained efficacy of discontinuous treatment with a 300 IR sublingual tablet of 5-grass pollen allergen extract, initiated 4 or 2 months before each pollen season and continued for its duration for 3 consecutive years. Here we report on the persistence of efficacy during the first of 2 post-treatment pollen seasons. METHODS: 633 adults were randomized to either placebo or one of 2 active groups receiving pre- and co-seasonal treatment for 3 pollen seasons starting each year either 4 months [4M] or 2 months [2M] prior to the pollen season. Patients were followed during the subsequent, treatment-free, grass pollen season. The primary endpoint for the Year 4 assessment of the post-treatment long-term efficacy was the Average Adjusted Symptom Score (AAdSS, adjusting the Rhinoconjunctivitis Total Symptom Score for rescue medication usage) during the fourth pollen period. Secondary efficacy criteria included the Average Rescue Medication Score (ARMS) and the overall Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score. RESULTS: Statistically significant differences compared to Placebo in the mean AAdSS during the Year 4 pollen period were observed for both 300 IR (4M) and 300 IR (2M). The treatment effect for 300 IR (4M) was estimated as the difference in LS Means of −1.14 (95% CI, [−2.03 to −0.26], P = 0.0114), corresponding to a relative LS Mean difference from Placebo of −22.9%, whilst the treatment effect for 300 IR (2M) is estimated as the difference in LS Means of −1.43 (95% CI, [−2.32 to −0.53]), P = 0.0019), corresponding to a relative LS Mean difference from Placebo of −28.5%. The primary results were confirmed over the worst pollen period. Compared to placebo, the active treatment groups (4M and 2M) also showed a statistically significant LS Mean difference in ARMS (−24.6%; P = 0.00184 and −27.9%; P = 0.0082) and in overall RQLQ score (−32.8%; P = 0.0001 and −37.6%; P < 0.0001). No unexpected risk was identified in this study. CONCLUSIONS: The post-treatment, long-term efficacy of 300 IR sublingual tablets of grass pollen allergen extract was demonstrated during the first of 2 post-treatment pollen seasons. This persistent improvement was clinically meaningful to patients.