Gemogenovatucel-T Advantage in Clonal Tumor Mutation Burden-High Ovarian Cancer.

[PURPOSE] Frontline ovarian cancer treatment protocols involving bevacizumab, poly (ADP-ribose) polymerase inhibitors, and PD-1/PD-L1 inhibitors have failed to improve overall survival (OS) in patients with homologous recombination-proficient (HRP) tumors. To determine mechanistic mutation signatures associated with OS advantage, we constructed a whole-exome sequencing bioinformatic pipeline assay to analyze all 91 patients enrolled in the double-blind randomized placebo-controlled phase II VITAL trial.

[METHODS] We hypothesized that patients with stage IIIb-IV ovarian cancer who have HRP profile and high clonal tumor mutation burden (cTMB-H) will achieve greater response when undergoing maintenance therapy with gemogenovatucel-T. Our primary objective was assessment of OS using the Kaplan-Meier method among randomly assigned patients receiving either gemogenovatucel-T or placebo.

[RESULTS] The median OS in cTMB-H/HRP patients treated with gemogenovatucel-T was 68 months versus 19 months in those treated with placebo (hazard ratio [HR], 0.23; 95% CI, 0.06 to 0.83; 1-sided = .008). The cTMB-H patients in the non-HRP group did not demonstrate OS advantage (HR, 0.99; 95% CI, 0.39 to 2.47; 1-sided = .488). No grade 3 treatment-related toxicity was observed in the gemogenovatucel-T group with a follow-up of 8.4 years.

[CONCLUSION] These results demonstrate OS advantage for maintenance treatment of adult females with newly diagnosed, advanced stage IIIb-IV ovarian cancer with HRP status and cTMB-H profile who are in complete response after debulking surgery and frontline platinum-based doublet chemotherapy.