Aviptadil

Pharmaceutical

Aviptadil is a synthetic version of vasoactive intestinal peptide (VIP), a naturally occurring 28-amino-acid neuropeptide widely distributed throughout the body, including the lungs, gastrointestinal tract, and nervous system. VIP is a potent vasodilator and smooth-muscle relaxant and has anti-inflammatory and cytoprotective properties. In the lung it is highly concentrated in alveolar type II cells — the cells that produce surfactant and are central to gas exchange — which is the biological rationale behind exploring aviptadil for severe lung injury. As a synthetic peptide identical in sequence to human VIP, aviptadil reproduces these actions when administered pharmacologically. Aviptadil's most prominent investigational use has been in acute respiratory distress syndrome (ARDS), including ARDS caused by COVID-19. Under the development names Zyesami and RLF-100, it was studied intravenously (and by inhalation) on the hypothesis that protecting alveolar type II cells and reducing pulmonary inflammation could improve outcomes in critically ill patients with respiratory failure. The clinical trial results in this setting were mixed and did not establish clear, consistent benefit, and aviptadil has not received approval for ARDS. It remains investigational for respiratory indications, and any use for that purpose is confined to research and clinical trials. In a separate and much older application, aviptadil is combined with phentolamine (an alpha-adrenergic blocker) in a product marketed as Invicorp for the treatment of erectile dysfunction. Given by intracavernosal injection (directly into the penis), the VIP component promotes smooth-muscle relaxation and increased blood flow while phentolamine complements this vasodilatory effect. Invicorp is an approved prescription medicine in several European countries, including the United Kingdom and Denmark, used as a second-line option for erectile dysfunction, particularly when oral therapies are unsuitable or ineffective. This is a clinician-prescribed treatment administered under medical guidance. Aviptadil illustrates how a single endogenous signaling peptide (VIP) can be developed toward very different indications depending on the delivery route and target tissue. It is best understood in the context of the VIP/secretin peptide family — VIP is structurally related to secretin and to glucagon, which share a common ancestral peptide superfamily and act on related receptor systems. For readers exploring gut–brain and vasoactive peptides, aviptadil is a useful example of a natural neuropeptide translated, with varying success, into pharmaceutical products.