Using a combination of anti-CSF-1R and agonist anti-CD40 antibodies, Wiehagen et al. shifted the tumor microenvironment toward a more proinflammatory state, and improved tumor control and survival by reducing tumor-associated macrophages and Tregs, increasing the frequency of newly-differentiated proinflammatory macrophages, increasing the number of activated dendritic cells in the draining lymph nodes, and enhancing CD8+ T cell and CD4+ helper T cell effector function and infiltration within the tumor.

Efficacious antitumor immune responses must overcome multiple suppressive mechanisms in the tumor microenvironment (TME) to control cancer progression. In this study, we demonstrate that dual targeting of suppressive myeloid populations by inhibiting CSF-1/CSF-1R signaling and activation of antigen presenting cells (APCs) with agonist anti-CD40 treatment confers superior antitumor efficacy and increased survival compared to monotherapy treatment in preclinical tumor models. Concurrent CSF-1R blockade and CD40 agonism lead to profound changes in the composition of immune infiltrates, causing an overall decrease in immunosuppressive cells and a shift toward a more inflammatory milieu. Anti-CD40/anti-CSF-1R treated tumors contain decreased tumor-associated macrophages (TAMs) and Foxp3+ regulatory T cells. This combination approach increases maturation and differentiation of pro-inflammatory macrophages and dendritic cells and also drives potent priming of effector T cells in draining lymph nodes. As a result, tumor-infiltrating effector T cells exhibit improved responses to tumor antigen rechallenge. These studies show that combining therapeutic approaches may simultaneously remove inhibitory immune populations and sustain endogenous antitumor immune responses to successfully impair cancer progression.

Author Info: (1) Janssen Research & Development rverona@its.jnj.com. (2) Janssen Research & Development. (3) Constellation Pharmaceuticals. (4) Janssen Research & Development. (5) Janssen Resea

Author Info: (1) Janssen Research & Development rverona@its.jnj.com. (2) Janssen Research & Development. (3) Constellation Pharmaceuticals. (4) Janssen Research & Development. (5) Janssen Research & Development. (6) Janssen Research & Development. (7) Janssen Research & Development. (8) Bristol-Myers Squibb.