The Eagle-like effect of echinocandins: what's in a name?

Despite several years of research, a lot of questions remain about the paradoxical attenuation of echinocandin activity against Candida and Aspergillus species at certain drug concentrations above the MIC values, the so-called paradoxical growth effect or Eagle-like effect. Although this phenomenon has been observed in several in vitro studies, confirming in vivo data are scarce. The clinical relevance remains unknown, although more and more data suggest that the clinical impact of this phenomenon might be heavily overrated. Detailed knowledge about the mechanisms responsible for this phenomenon and further research about the presence of the effect in the human body is necessary to decide whether the paradoxical growth effect of echinocandins can really interfere with an adequate treatment of invasive fungal diseases in clinical practice.