Progress & Results


Proof-of-Concept Progress

Sonnet BioTherapeutics has established proof of preclinical concept with our albumin binding ScFv whereby we demonstrate up to 10x increases in serum half-life and improved tumor penetration. We have also demonstrated that immune modulating cytokines delivered via Sonnet’s albumin-binding scaffold achieve improved antitumor activity.


  • Demonstrated up to a 10 fold increase in serum half-life using three different targets of interest (either recombinant cytokines or immune modulating ScFvs) when linked to our Albumin binding antibody fragment
  • Demonstrated that recombinant human cytokines linked to Sonnet’s albumin binding single chain antibody fragment:
    • Retain biologic activity in mice
    • Preferentially modulate immune response within tumors
    • Significantly enhance antitumor activity (tumor size and median survival in the anti-PD1 refractory B16F10 mouse model)
  • Demonstrated dose dependent efficacy with a single dose of Sonnet’s cytokine-ABD in preclinical mouse tumor models
  • Demonstrated greatly superior efficacy with a single dose of Sonnet’s cytokine-ABD compared to the parent recombinant human cytokine
  • Demonstrated superior activity compared to a PD1 antibody in a PD1 refractory mouse tumor model
  • Demonstrated that we can link two different cytokines to the same albumin binding antibody fragment (ABD) and retain full biologic activity for each cytokine in in vitro assays
  • Demonstrated that Sonnet’s dual cytokine-ABD retained biologic activity in a mouse tumor model