Short‐course subcutaneous treatment with PQ Grass strongly improves symptom and medication scores in grass allergy.

Background: A modified grass allergen subcutaneous immunotherapy (SCIT) product with MicroCrystalline Tyrosine and monophosphoryl lipid‐A as an adjuvant system (Grass MATA MPL [PQ Grass]) is being developed as short‐course treatment of grass‐pollen allergic rhinitis (SAR) and/or rhinoconjunctivitis. We sought to evaluate the combined symptom and medication score (CSMS) of the optimized cumulative dose of 27,600 standardized units (SU) PQ Grass in a field setting prior to embarking on a pivotal Phase III trial. Methods: In this exploratory, randomized, double‐blind, placebo‐controlled trial subjects were enrolled across 14 sites (Germany and the United States of America). Six pre‐seasonal subcutaneous injections of PQ Grass (using conventional or extended regimens) or placebo were administered to 119 subjects (aged 18–65 years) with moderate‐to‐severe SAR with or without asthma that was well‐controlled. The primary efficacy endpoint was CSMS during peak grass pollen season (GPS). Secondary endpoints included Rhinoconjunctivitis Quality of Life Questionnaire standardized (RQLQ‐S) and allergen‐specific IgG4 response. Results: The mean CSMS compared to placebo was 33.1% (p =.0325) and 39.5% (p =.0112) for the conventional and extended regimens, respectively. An increase in IgG4 was shown for both regimens (p <.01) as well as an improvement in total RQLQ‐S for the extended regimen (mean change −0.72, p =.02). Both regimens were well‐tolerated. Conclusions: This trial demonstrated a clinically relevant and statistically significant efficacy response to PQ Grass. Unprecedented effect sizes were reached for grass allergy of up to ≈40% compared to placebo for CSMS after only six PQ Grass injections. Both PQ Grass regimens were considered equally safe and well‐tolerated. Based on enhanced efficacy profile extended regime will be progressed to the pivotal Phase III trial. [ABSTRACT FROM AUTHOR]