Low systemic exposure in infants with atopic dermatitis in a 1-year pharmacokinetic study with pimecrolimus cream

Systemic drug exposure following the application of topical agents is a very important safety consideration, particularly in infants, who have a significantly higher ratio of body surface area to body mass than older children and adults. Here, we report on drug exposure in five infants aged 5.7-11.9 months at baseline, with extensive, moderate-to-severe atopic dermatitis (AD). Patients were treated bid for 1 year, as needed, with pimecrolimus cream 1% in an open-label, non-controlled study. No indication of drug accumulation was found; pimecrolimus blood concentrations were consistently low, ranging from below the limit of quantitation (0.1 ng/ml) to 1.94 ng/ml. Treatment over this prolonged period was well tolerated, with no evidence of any treatment-related adverse events. The results of this 1-year study indicate that long-term management of AD with pimecrolimus cream 1% is associated with consistently very low systemic absorption, even in the youngest patients with extensive disease.