FLT3 Ligand, CD40 Agonist Antibody, and Stereotactic Radiotherapy

Fms-like tyrosine kinase 3 (FLT3) ligand is a potent hematopoietic growth factor that mobilizes stem cells and greatly increases the number of circulating dendritic cells (DCs) in blood and organs.

CD40 is a key molecule in the regulation of immune responses whose activity can be modulated using antibodies. CD40 is a tumor necrosis factor receptor superfamily member expressed on antigen presenting cells, including dendritic cells, as well as a host of other cell types, including a wide range of tumor cells

For subjects on Arm 1, SBRT will be delivered concurrently with FLT3 ligand during Week 1 of study therapy. If only one lesion is being treated, SBRT should be completed during week 1 (e.g., with daily treatments for a 5-fraction course of treatments every other day for a 3-fraction course). In cases where multiple lesions are being treated with SBRT (Arm 1 or Arm 2) or if treatment is interrupted due to technical issues or intercurrent illness, SBRT may extend beyond Week 1.