Leerink analyst Geoffrey Porges believes that comparisons between Alexion's (ALXN) Soliris in Myasthenia Gravis, following its pivotal trial primary endpoint miss, and Sarepta's (SRPT) eteplirsen and Biomarin's (BMRN) drisapersen in Duchenne muscular dystrophy, and their respective regulatory experiences, are "ill-founded" despite superficial similarities. The analyst views Soliris as a "thoroughly validated" medicine, with proven safety, a recognized target and multiple indications of significant effect in Myasthenia Gravis. Porges reiterates an Outperform rating and $200 price target on Alexion's shares.