Encoded Therapeutics presented trial findings tied to steroid and sirolimus use designed to manage immune responses in an AAV9-based gene therapy program for Dravet syndrome. In a subset of patients, adding sirolimus alongside steroids was associated with reduced therapy effectiveness, according to a study reported on STAT+. The trial assigns immune suppression to most children receiving steroids, with many on the highest dose level also receiving sirolimus (rapamycin). The reported concern centers on whether sirolimus—used historically in transplant settings—can dampen anti-viral immunity but also blunt gene expression outcomes important for seizure and developmental benefit.