TP53 mutations and survival in ovarian carcinoma patients receiving first‐line chemotherapy plus bevacizumab: Results of the MITO16A/MaNGO OV‐2 study

To date, there are no biomarkers that define a patient subpopulation responsive to bevacizumab (BEV), an effective treatment option for advanced ovarian carcinoma (OC). In the context of the MITO16A/MaNGO OV-2 trial, a Phase IV study of chemotherapy combined with BEV in first-line treatment of advanced OC, we evaluated TP53 mutations by next-generation sequencing and p53 expression by immunohistochemistry (IHC) on 202 and 311 cases, respectively. We further correlated TP53 mutations in terms of type, function, and site, and IHC data with patients' clinicopathological characteristics and survival. TP53 missense mutations of unknown function (named unclassified) represented the majority of variants in our population (44.4%) and were associated with a significantly improved overall survival (OS) both in univariable (hazard ratio [HR] = 0.43, 95% confidence interval [CI] = 0.20-0.92, p = .03) and multivariable analysis (HR = 0.39, 95% CI = 0.18-0.86, p = .02). Concordance between TP53 mutational analysis and IHC was 91%. We observed an HR of 0.70 for OS in patients with p53 IHC overexpression compared to p53 wild-type, which however did not reach statistical significance (p = .31, 95% CI = 0.36-1.38). Our results indicate that the presence of unclassified TP53 mutations has favorable prognostic significance in patients with OC receiving upfront BEV plus chemotherapy. In particular, unclassified missense TP53 mutations characterize a subpopulation of patients with a significant survival advantage, independently of clinicopathological characteristics. Our findings warrant future investigations to confirm the prognostic impact of TP53 mutations in BEV-treated OC patients and deserve to be assessed for their potential predictive role in future randomized clinical studies.