Orphan drugs get 7 years of exclusivity and typical new drugs get only 5 years. Exclusivity does not prevent marketing of a new chemical entity for the orphan disease but rather a generic with the same active moiety. So the FDA's action on trofinetide has no bearing on the regulatory approval of blarcamesine. Though regulatory exclusivity is 7 years for Rett (and other orphan diseases), for AD or PDD, it would only be 5 years. However, patents listed in the Orange book associated with the approval of a drug can extend the commercial exclusivity (commercial exclusivity is the longer of regulatory and legal exclusivity). Patents not listed in the Orange book can usually be litigated away so seldom prolong the exclusivity.