MONOCLONAL ANTIBODY-STANDARDIZED CAT EXTRACT IMMUNOTHERAPY - RISK-BENEFIT EFFECTS FROM A DOUBLE-BLIND PLACEBO STUDY

Twenty-eight patients (14 in an active treatment group and 14 in a pla cebo group) with rhinoconjunctivitis and asthma caused by cat hypersen sitivity took part in a placebo-controlled, randomized, double-blind s tudy to evaluate the risk-benefit quotient of the maintenance dose cor responding to 13.2 mug Fel d I antigen. The cat extract was biological ly standardized and quantified with monoclonal antibodies (100 biologi cal units. 33 mug of Fel d I antigen, 650 mug of albumin, and 99 mug o f Fel d Bd/K30 antigen). After 1 year of treatment, the systemic react ions to cat extract immunotherapy were mild and infrequent. Improvemen t was observed in the active treatment group in comparison with the pl acebo group in the medication-symptoms score (p < 0.001); in skin pric k test (p < 0.001), conjunctival provocation test (p < 0.001), and all ergen bronchoprovocation test (p < 0.05) results, and in nonspecific b ronchial hyperreactivity measured with methacholine, which was not sta tistically significant. This study demonstrates the favorable risk-ben efit quotient of the dose of 13.2 mug of Fel d I antigen, which may se rve as a future reference in defining the optimum dose and appropriate proportion of antigens that should be administered in cat extract imm unotherapy.