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
], 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
) 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
].Image re-produced from Altor BioScience Corporation's ALT-803 fact sheet (download the pdf here)
: 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.