Maintenance olaparib rechallenge in patients with platinum-sensitive relapsed ovarian cancer previously treated with a PARP inhibitor (OReO/ENGOT-ov38): a phase IIIb trial

Top advances of the year: Ovarian cancer

Although cure rates remain low and effective screening strategies are elusive, the recent advances in systemic therapies over the past year highlighted in this review have prolonged survival for women with ovarian cancer. In 2022, the first antibody-drug conjugate for platinum-resistant ovarian cancer received accelerated US Food and Drug Administration (FDA) approval. Confirmatory studies examining the efficacy of mirvetuximab and other antibody-drug conjugates are underway. In the upfront setting, the first data establishing an overall survival benefit from poly(ADP-ribose) polymerase inhibitor maintenance was demonstrated after a 7-year follow-up period. In contrast, long-term updates from poly(ADP-ribose) polymerase inhibitor trials in the noncurative setting reported survival detriments, and the FDA withdrew the respective indications. Several trials attempted to improve upon the standard of care for platinum-sensitive ovarian carcinoma and those with rare ovarian cancer histologies (carcinosarcoma, clear cell carcinoma) but failed to demonstrate a clinically or statistically meaningful benefit. This leaves the open question of how to further optimize systemic therapy for advanced ovarian carcinoma to improve long-term survival and cure rates.

PARP Inhibitors: Strategic Use and Optimal Management in Ovarian Cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors have become an established part of the anticancer armamentarium. Discovered in the 1980s, PARP inhibitors (PARPis) were initially developed to exploit the presence of BRCA mutations, which disrupt the homologous recombination repair of deoxyribonucleic acid (DNA) via synthetic lethality, an intrinsic vulnerability caused by the cell's dependence on other DNA repair mechanisms for which PARP is an essential contributor. PARPi use expanded with the demonstration of clinical benefit when other mechanisms of high-fidelity DNA damage response were present in cancer cells called homologous repair deficiency (HRD). Recently, new data have resulted in the voluntary withdrawal of later-line treatment indications for all the available PARPis used in ovarian cancer because of a negative impact on overall survival (OS). PARPi switch maintenance to consolidate a response to platinum-based therapy is recommended for earlier treatment lines to have the greatest impact on the chance of cure and length of survival. This article reviews the clinical utility of PARPis and how to integrate them into best practices.

Maintenance therapy for newly and recurrent epithelial ovarian cancer: current therapies and future perspectives

PURPOSE OF REVIEW

Epithelial ovarian cancer (EOC) is the fifth cause of cancer death among women, and 70-80% of patients relapse within 2 years from the last cycle of first-line chemotherapy despite a complete response to chemotherapy and optimal debulking surgery. In this context, the goal of the maintenance treatment strategy is to prolong the time to recurrence. The recent development of targeted molecular therapies resulted in a broader spectrum of maintenance therapeutic options with consequent higher clinical benefit but less toxicity. This review summarizes the currently available maintenance strategies for newly and recurrent EOC, focusing on the decision-making process to personalize treatment and future perspectives.

RECENT FINDINGS

Over the past 10 years, several studies have demonstrated the clear benefit in terms of survival with the addition of a maintenance treatment strategy over the 'watchful waiting' approach both in the first line and recurrent setting. Since December 2016, the United States Food and Drug Administration and European Medicines Agency have approved four drugs for ovarian cancer maintenance based on the results of several clinical trials demonstrating efficacy and tolerability. These include the antiangiogenic drug Bevacizumab and three polyadenosine diphosphate-ribose polymerase (PARP) inhibitors: olaparib, niraparib, and rucaparib.

SUMMARY

These data led American and European Treatment guidelines to include bevacizumab, olaparib, niraparib, rucaparib, and combination bevacizumab-olaparib as maintenance treatment options in first-line and recurrent ovarian cancer therapy. However, with the availability of different maintenance options, identifying the best treatment choice for each patient can be challenging, and several clinical and molecular aspects have to be taken into account in the decision-making process.