Phase I/Ib clinical and immunologic assessment of immunotherapeutic vaccine, DPX-Survivac in women with ovarian, Fallopian tube, or peritoneal cancer (OC).

5555 Background: Survivin plays a key role in apoptosis, proliferation and angiogenesis. It is overexpressed in 90% of epithelial OC making it an attractive target. Increases in expression have been correlated with progression and drug resistance. DPX-Survivac is a vaccine containing a mix of survivin HLA class I peptides designed to evoke a cytotoxic T cell response against survivin. This Phase I/Ib de-escalation study reports the safety and immune potency of DPX-Survivac in combination with metronomic low dose oral cyclophosphamide (CPA) in OC. Methods: 30 Stage IIc-IV advanced or recurrent OC patients (pts) with no evidence of disease progression post chemotherapy were enrolled. Dose limiting toxicities (DLT) were defined as ≥gd3 AEs, ≥gd2 allergic or autoimmune reactions by CTCAE v4.03. Immune correlates (MDSCs; T regs; B cells) and vaccine induced T cell immunity (ELISpot; tetramer analysis; multi-parametric intracellular cytokine staining) were assessed in purified PBMC and blood. Clinical response ...