SYK and asthma: While the effect of Syk RNA interference was only demonstrated in an asthma model using ASO, but not siRNA, an inhaled siRNA drug candidate named ExcellairTM, which was designed to silence Syk (ZaBeCor Pharmaceuticals, Bala Cynwyd, PA, USA), entered a Phase II clinical trial in asthma patients in 2009 following positive Phase I trial results, but the Phase II trial was discontinued in 2015.