Translational immune correlates of indirect antibody immunization in a randomized phase II study using scheduled combination therapy with carboplatin/paclitaxel plus oregovomab in ovarian cancer patients

The standard-of-care (SOC) first-line therapy for ovarian cancer (OC) patients is plagued with high relapse rates. Several studies indicated the immune system’s prominent role changing the disease course in OC patients. Chemo-immunotherapy regimens, currently being explored, include oregovomab, which is a monoclonal antibody specific for the OC associated antigen carbohydrate/cancer antigen 125 (CA125) that yielded promising results when administered together with SOC in a previous study. The QPT-ORE-002 multi-site phase II randomized study demonstrated that in patients with advanced OC, oregovomab combined with first-line SOC improved overall and progression-free survival, compared to SOC alone. The study included an Italian cohort in which we demonstrated that adding oregovomab to SOC resulted in increased patient numbers with amplified CA125-specific CD8+T lymphocytes/ml peripheral blood counts, which might explain the improved therapeutic effect of SOC + oregovomab over SOC alone. Predictive for oregovomab efficacy was a less suppressive immune environment at baseline as indicated by low numbers of circulating myeloid-derived suppressor cells, subset type 4, and a low neutrophil-and-monocyte to lymphocyte ratio

Front-line chemo-immunotherapy with carboplatin-paclitaxel using oregovomab indirect immunization in advanced ovarian cancer: A randomized phase II study

Background: This randomized phase II study tested the hypothesis that schedule dependent chemo-immunotherapy with oregovomab improves progression free survival (PFS) and overall survival (OS) in optimally resected, Stage III/IV ovarian cancer. Methods: Patients from both academic centers and private practice in the US and Italy with Stage III/IV optimally cytoreduced ovarian cancer were randomized to standard six cycle IV carboplatin-paclitaxel chemotherapy (CP) versus CP plus four immunizations with oregovomab (CPO). A translational assessment of a cellular immune response was the primary endpoint; PFS and OS were measured as secondary endpoints. Findings: 97 patients at thirteen centers were accrued to the protocol, 47 to CPO and 50 to CP. Technical issues led to inconsistent performance of the primary CA125 ELISPOT leading to unevaluable results. At a median follow up of 42 months, PFS and OS outcomes revealed an unexpectedly large treatment effect for CPO relative to CP alone, with median PFS of 41.8 months (95% C.I.: 21.8 - N.E.) for CPO and 12.2 months (10.4\u201318.6) for CP (p = 0.0027, HR 0.46, CI 0.28\u20130.7). For OS, the median for CPO has not yet been reached (NE) (45.2-NE) and for CP was 43.2 months (31.8-NE) (p = 0.043, HR 0.35, CI 0.16\u20130.74). The oregovomab treatment resulted in no change in toxicity profile from CP. Interpretation: The previously identified potential clinical benefit of IV CP when administered with oregovomab was further refined in this randomized phase II study. Increases of PFS and OS of statistically and clinically significant magnitude were evident in this study of a front line chemo-immunotherapy treatment of ovarian cancer