Relief Therapeutics Holding SA's (OTC:RLFTF) collaborating partner NRx Pharmaceuticals Inc (NASDAQ:NRXP) has announced that the FDA has denied Breakthrough Therapy Designation for aviptadil. 

• NRx noted that though the designation is not required for drug approval or emergency use authorization, but can afford faster review times, the ability to submit a rolling application, and dedicated FDA review personnel.
• Related content: Benzinga's Full FDA Calendar.
• Additionally, according to the CEO Update, the FDA has already granted priority and rolling review as part of the Fast Track Designation awarded in July 2020. 
• Therefore, the denial does not impede NRx's ability to seek drug approval.
• Relief's lead drug candidate, RLF-100 (aviptadil), is a synthetic form of Vasoactive Intestinal Peptide (VIP).
• It is in late-stage clinical testing in the U.S. for respiratory deficiency due to COVID-19. 
• Related Link: NRx Pharma's COVID-19 Candidate Receives FDA Review For Manufacturing Information.
• Price Action: NRXP shares closed 5.56% lower at $4.25 during after-hours trading on Tuesday.