Six Injections of Modified Adjuvanted PQ Grass Is Effective and Well-Tolerated in a Pivotal Phase III Trial

Background: PQ Grass 27600 SU (PQ Grass) cumulative dose is a pre-seasonal, six-injection, aluminium-free, modified subcutaneous immunotherapy product under development for the treatment of allergic rhinitis (AR). A pivotal Phase III randomised double-blind, placebo-controlled clinical trial was performed to evaluate the efficacy and safety of PQ Grass in subjects with seasonal AR. Methods: An adaptive group sequential trial PQGrass306 (G306) with one pre-defined interim analysis was designed, using 2 parallel groups applying a 1:1 active versus placebo randomisation of patients aged 18–65. The primary efficacy endpoint was the EAACI (European Academy of Allergy and Clinical Immunology) Combined Symptom and Medication Score (EAACI-CSMS_0–6) averaged over the peak grass pollen season (GPS). Results: 858 subjects were screened and 555 subjects were randomised. Based on the results of the pre-defined interim analysis, the trial was stopped for success showing superiority in favour of PQ Grass. The primary endpoint EAACI-CSMS_0–6 (peak GPS) demonstrated a highly significant and clinically meaningful point difference of PQ Grass over placebo of −0.27 points (95% CI: −0.42 to −0.12), corresponding to a relative difference of −20.3% (p = 0.0005). Highly consistent and beneficial results were obtained for PQ Grass for all key secondary endpoints. Significant induction of blocking IgG4 and IgA antibody subclasses occurred. PQ Grass was well tolerated, and no unexpected safety signals occurred. Conclusions: This pivotal Phase III trial demonstrated a significant and clinically meaningful effect on the primary endpoint as well as highly consistent secondary endpoint results and a supportive safety profile.