A Phase I Study Of Concomitant Galinpepimut-S (Gps) In Combination With Nivolumab (Nivo) In Patients (Pts) With Wt1+Ovarian Cancer (Oc) In Second Or Third Remission.

5553Background: WT1 is highly expressed in serous ovarian cancer. GPS is WT1-targeting heteroclitic peptide tetravalent non-HLA-restricted vaccine, and has shown promising phase 2 activity in AML, mesothelioma and myeloma. Efficacy of GPS may be enhanced through checkpoint blockade, providing a rationale for combining it with anti-PD1 antibody, nivo. We conducted a phase I study to evaluate the safety and immunogenicity of the combination in WT1+ OC in remission. Methods: Pts with WT1+ OC in ≥2nd remission were enrolled from 06/16-07/2017, and received GPS (800 mcg) x 6 total doses mixed with adjuvant (0.5 ml) and 70 mcg GM-CSF (all s.c. in extremities) and nivo 3 mg/kg IV q2wks over 12 weeks. DLTs were assessed using CTCAE criteria, with detection of u003e 2/10 DLTs deeming the combination unsafe. Treatment was continued until disease progression or toxicity. Immune responses (IgG u0026 IgM WT1 antibody, T cell assays) induced by the combination were evaluated. The 1-year progression-free survival (PFS) rate, de...