Mezzion Pharma Co. Ltd. announced that it has received notice from the FDA that its NDA submitted on March 26, 2021 for the use of udenafil to treat SVHD patients who have undergone Fontan palliation is sufficiently complete to permit a substantive review (the "FDA Notice"). In the FDA Notice, the FDA advised that there were no filing review issues identified. Thus, the FDA review cycle has started with an expected NDA approval date of March 26, 2022. The FDA also advised in the FDA Notice that the FDA is not currently planning to hold an advisory committee meeting to discuss Mezzion's NDA. The FDA had previously granted Mezzion's request to designate udenafil for treatment of single ventricle congenital heart disease as a drug for a Rare Pediatric Disease. To encourage the development of drugs to treat rare pediatric diseases, the US established a priority review voucher (PRV) program under which the FDA awards a PRV to a drug sponsor (manufacturer) upon approval of that sponsor's drug for the treatment of a rare pediatric disease. Mezzion fully expects that, upon FDA approval of its NDA for the treatment of SVHD patients, a rare pediatric disease, it will be awarded a PRV, at which time the PRV will be fully redeemable and/or transferrable.