Genomic heterogeneity and efficacy of PI3K pathway inhibitors in patients with gynaecological cancer

The Potential of PI3K/AKT/mTOR Signaling as a Druggable Target for Endometrial and Ovarian Carcinomas

AIMS

In this narrative review, we summarize the role and significance of PI3K-AKTmTOR (PAM) pathway in ovarian and endometrial cancers, providing the most recent and relevant literature on the topic and addressing options for targeting PAM along with future perspectives of drug development.

BACKGROUND

Alterations of the PAM-pathway are common in both endometrial and ovarian cancers, and are described in specific histology-defined subtypes. PAM seems to be involved in critical steps of endometrial and ovarian carcinogenesis, often mechanistically involved in the acquisition of a phenotype of treatment resistance, which could be targetable. However, early clinical trials with PAMinhibitors (PAMi) have provided disappointing results, particularly when non isoform-specific inhibitors were tested in unselected populations, accompanied by an adverse safety profile. Since then, more encouraging observations have been collected when targeting specific isoforms of PAM proteins with more selective drugs, resulting in encouraging activity and more manageable toxicity.

CONCLUSION

Although the rationale of inhibiting the PAM-pathway has been demonstrated in several promising preclinical studies, no Phase III clinical trial is available to demonstrate a significant benefit of PAM-inhibitors. A way to manage targeted agents is to tailor their use to particular subpopulations most likely to obtain a considerable benefit, namely pursuing an individualized, precision-medicine approach.

Exploring the Clinical Impact of Predictive Biomarkers in Serous Ovarian Carcinomas

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. Although initial response rates to standard platinum-based treatment are at 70-80%, long-term response in advanced EOC disease is rarely achieved with the development of chemoresistance and recurrence, contributing to overall survival rates below 45%. Additional challenges stem from EOC heterogeneity, reflecting at least five histological subtypes, each with different underlying molecular characteristics and clinicopathology that have significant implications in treatment effectiveness and management. Since the last decade, technologies in genomics, proteomics and pathology have been deployed to find reliable clinical markers that can identify patients sensitive to standard chemotherapy treatments and stratify patients for more suitable targeted therapies. These efforts have identified several molecular markers of prognostic value that have been validated as biomarkers, such as BRCA and KRAS mutations, or are currently under investigation in clinical trials, such as CD8 T cells, immune checkpoint inhibitors and progesterone receptor. Recent advancements in biomarker research have also revealed new targets that have expanded treatment options, introducing poly (ADP-ribose) polymerase (PARP) inhibitors, anti-angiogenic agents, inhibitors targeting signaling pathways, and immunotherapy to improve maintenance therapies or enhance first-line therapy. This review presents a summary of current biomarkers, in clinical use or under evaluation, demonstrating a potential to inform on patient selection for treatment efficacy and predict response to EOC therapies, with particular focus on the serous subtypes, including high-grade and low-grade serous carcinomas.