Intensive Locoregional Chemoimmunotherapy, Intradermal Autologous Alpha-DC1 Vaccines, and Systemic Pembrolizumab for Advanced-Stage Ovarian Cancer

In addition to its typically late detection, the difficulty in treating OvCa results from its particular adeptness at avoiding immune elimination. Several vaccine trials targeting ovarian cancer have recently reported a lack of efficacy with vaccine only approaches. OvCa cells have been reported to display numerous defects in their MHC class I antigen-presenting capacity, involving loss of HLA alleles and loss of the molecules involved in the generation of antigenic peptides. In addition to these passive mechanisms of immune subversion, OvCa employs a series of active suppressive mechanisms, involving the suppression of endogenous immune cells and innate immune response pathways, and a particularly high ability to attract regulatory T cells (Tregs), mediated by elevated expression of CXCL12 and CCL22 2. It is suspected that massive chemotherapy-induced apoptosis may further promote this modulation by enhancing local immunity. These considerations suggest that effective immunotherapies of OvCa may need to involve countermeasures to both these modes (passive and active) of immune subversion. Since αDC1-induced CD8+ T cells express particularly high levels of the typical CTL-associated chemokine receptors (CXCR3 and CCR5), the therapeutic benefit of αDC1 vaccination is likely to be enhanced by the CKM therapies, able of selectively enhancing CXCL10 (and other CXCR3 ligands) as well as CCR5 ligands, such as CCL5/RANTES, in order to promote the entry of the vaccination-induced effector cells to tumor tissue.