ALT-803   Click here for help

GtoPdb Ligand ID: 9615

Synonyms: IL-15 N72D:IL-15RαSu/Fc | IL-15SA | N-803
Immunopharmacology Ligand
Compound class: Antibody
Comment: ALT-803 (N-803) is an IL-15 superagonist developed to promote immune activation [1]. It is being investigated as an immuno-oncology agent [2,6,8-9], as immunotherapy post-allogeneic transplantation for hematological malignancies [7], and as an HIV therapy.
ALT-803 is produced from a high-yield recombinant mammalian cell line which co-expresses an IL-15 activation mutant, IL-15N72D (nogapendekin alfa) and IL-15Rαsushi domain/Fc fusion protein (inbakicept) as a stable soluble complex. The sushi domain increases transpresentation of the ALT-803 complex to the IL-2β/γ dimer which is the signal transducing component of the IL-15 receptor. The IgG Fc domain increases in vivo half-life [1].
Image re-produced from Altor BioScience Corporation's ALT-803 fact sheet (download the pdf here).

COVID-19: ALT-803 is being evaluated for safety and efficacy as an immunostimulatory agent in patients with COVID-19. This study is predicated upon the hypothesis that activating NK and T cells, via the IL-15 pathway, in patients with mild-to-moderate stage COVID-19, might reduce viral load and protect against disease progression.
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Ligand Activity Visualisation Charts

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2D Structure
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2D Structure

An image of the ligand's 2D structure. For small molecules with SMILES these are drawn using the NCI/CADD Chemical Identifier Resolver. Click on the image to access the chemical structure search tool with the ligand pre-loaded in the structure editor. For other types of ligands, e.g. longer nucleotides and peptides, a manually drawn representation of the molecule may be provided.

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Immunopharmacology Comments
ALT-803 was designed to promote stimulatory signalling to NK and memory CD8+ T cells [3]. It enhances NK cell cytotoxicity against cancer cells and this mechanism is being evaluated as a novel intervention in oncology indications.