I was surprised to find out an important information on Mel...

I was surprised to find out an important information on Mel Lancaster's website Trail to a Texas trial, namely both Newron and Anavex received Rare Pediatric Disease Designation from FDA for Rett syndrome: Newron for Sarizotan and Anavex for Anavex2-73.
I checked websites for both companies and the information is there in News or Press Releases.
Considering this information, I see no issues for Acadia to receive the same designation when they apply fot it.

Newron Receives FDA Rare Pediatric Disease Designation for Sarizotan for the Treatment of Rett SyndromeMilan, Italy and Morristown, NJ, USA, November 19, 2019 - Newron Pharmaceuticals S.p.A. (“Newron”) (SIX: NWRN, XETRA: NP5), a biopharmaceutical company focused on the development of novel therapies for patients with diseases of the central and peripheral nervous system, announced today that the U.S. Food and Drug Administration (FDA) has granted the Rare Pediatric Disease designation for sarizotan, the company’s product candidate for the treatment of Rett syndrome, a rare neurodevelopmental disorder primarily affecting females, with no approved treatments currently available.“The decision of the FDA to designate sarizotan for the treatment of a rare pediatric population, following an earlier decision to grant it an Orphan Drug designation (ODD), highlights the critical need within the Rett community for treatments for this devastating disease,” stated Ravi Anand, Newron’s Chief Medical Officer. “This designation also represents progress towards qualifying sarizotan for a rare pediatric disease priority review voucher upon potential US marketing approval in the future. We are looking forward to the results of our Sarizotan Treatment of Apneas in Rett Syndrome (STARS) study, a study to evaluate the efficacy, safety and tolerability of sarizotan in patients with Rett syndrome, which we expect within the next few weeks.”The U.S. FDA defines a “rare pediatric disease” as a serious or life-threatening disease primarily affecting individuals age 18 years or younger that impacts fewer than 200,000 individuals in the United States.The Rare Pediatric Disease designation provides incentives to advance the development of rare disease drugs and biologics. Additionally, the FDA’s Rare Pediatric Disease Priority Review Voucher Program states that a sponsor with a Rare Pediatric Disease designation who receives marketing approval for a rare pediatric disease may be eligible for a voucher that can be redeemed to obtain priority review for any subsequent marketing application.

GLTA