EVALUATION OF A COMPOSITE SCORING SYSTEM IN CONJUNCTIVAL CHALLENGE WITH ALLERGEN - REPRODUCIBILITY AND EVOLUTION DURING LORATADINE TREATMENT

The reproducibility of any challenge and its sensitivity to change dur ing therapeutic interventions should always be examined before any dru g trial is conducted. Conjunctival challenge has been widely used to a ssess objectively the efficacy of antiallergic treatments. A double-bl ind, placebo-controlled, crossover study was carried out in 26 patient s allergic to grass pollen to test the reproducibility of a composite symptom score during placebo and control days, and to check the abilit y of loratadine to increase the provocative dose inducing a positive c hallenge. Conjunctival challenge was carried out with increasing conce ntrations of a standardized orchard grass pollen extract until a compo site symptom score of 5 was reached. The provocative dose inducing a p ositive challenge was similar for the baseline (6.94 +/- 8.7 index of reactivity (IR)) and placebo days (20.0 +/- 32.5 IR) and was significa ntly increased (P<0.01 and P<0.001) when patients received loratadine (117.3 +/- 136.8 IR). This study shows that the composite score used w as reproducible and sensitive to change, making it possible to use in drug trials.