Table 2.

Summary of combination therapies targeting MDSC and key study findings.

Agents	Study finding	Reference
ATRA + antigen specific peptide vaccine	In two different murine tumor models, significantly prolonged the anti-tumor treatment effect	Gabrilovich et al. (2001)
Gemcitabine + IFN-b	Significantly increased anti-tumor activity in a murine tumor model	Suzuki et al. (2005)
Gemcitabine + HER-2/neu vaccine + anti-GITR mAb	Potent therapeutic anti-tumor immunity in a murine tumor model	Ko et al. (2007)
Sunitinib + low-dose radiotherapy	Modestly improved survival in a mouse glioma model Sunitinib with high dose radiation resulted in fatal toxicities	D’Amico et al. (2012)
Sunitinib + DC based vaccine	Combination Rx had superior anti-tumor effect than either Rx alone in a murine melanoma model and enhanced anti-tumor T cell response and reduced MDSC/Treg	Bose et al. (2010)
Sunitinib + adoptive T cell therapy	In murine melanoma and RCC models Inhibited Stat3 in DC and T cells Reduced conversion of T cells to Tregs Increased CD8+ T cell infiltration and activation at the tumor site Inhibited primary tumor growth	Kujawski et al. (2010)
Sunitinib + IL-12 + 4-1BB activation	Significantly improved long-term survival rate of large tumor bearing mice in liver and lung tumor models, promoted T cell response and reduced MDSC levels	Ozao-Choy et al. (2009)
Sunitinib + CEA vaccine	In a murine colon cancer model: continuous sunitinib followed by vaccine increased tumor infiltration of Ag-specific T lymphocytes Reduced tumor volumes Increased survival Decreased Treg Decreased MDSC	Farsaci et al. (2012)
Bevacizumab ± IL-2	Did not reduce MDSC levels in the peripheral blood	Rodriguez et al. (2009)
Phase III trial, TroVAax (MVA-5T4) vaccine + sunitinib, IL-2, or IFN-a	In RCC pts did not enhance survival relative to sunitinib, IL-2, or IFN-a alone	Amato et al. (2010)