FS222: Improving outcomes in PD-L1 low tumors

Patients with low levels of PD-L1 expression require additional pathways to be targeted in order to activate their immune system. FS222 simultaneously “releases the brake” on immune control of cancer by blocking the PD-1/PD-L1 pathway and “hits the gas” on immune activation by stimulating the CD137 pathway.

With FS222 there is an exciting opportunity to address patients where other therapies aren’t working, with superior potency seen in pre-clinical activity.


Our approach for improving outcomes in PD-L1 low tumors:
  • CD137/PD-L1 mAb² bispecific antibody
  • Conditional PD-L1 dependent activation of effector cells leading to profound anti-tumor activity in preclinical models
  • Conditionally active and FcγR null for improved safety
  • Potential clinical differentiation in patients with low tumor expressed PD-L1
  • Phase 1 trial ongoing