Strong dose response after immunotherapy with PQ grass using conjunctival provocation testing.

Area of Science:

• Allergy and Immunology
• Clinical Pharmacology
• Immunotherapy

Background:

• Pollinex Quattro Grass (PQ Grass) is a subcutaneous immunotherapy for seasonal allergic rhinoconjunctivitis (SAR) caused by grass pollen.
• This Phase II study aimed to identify the optimal cumulative dose of PQ Grass.

Purpose of the Study:

• To evaluate the dose-response relationship of different cumulative doses of PQ Grass.
• To assess the safety and efficacy of PQ Grass in treating grass pollen-induced SAR.

Main Methods:

• 447 patients with grass pollen-induced SAR were randomized to receive PQ Grass (4 cumulative doses) or placebo via 6 weekly subcutaneous injections.
• Conjunctival provocation tests (CPT) were used to measure the total symptom score (TSS) before and after treatment.
• Pre-defined models (Emax, logistic, linear in log-dose) were used to analyze dose-response.

Main Results:

• A statistically significant, monotonic dose response was observed across all models (p < 0.0001).
• All PQ Grass doses significantly reduced TSS compared to placebo, with the 27600 SU dose showing the largest decrease.
• 95.5% of patients completed the 6-injection course; adverse events were mild and transient.

Conclusions:

• PQ Grass demonstrated a significant curvilinear dose response in TSS after CPT.
• The optimal cumulative dose of PQ Grass did not compromise its safety profile.