LBA33 Maintenance olaparib plus bevacizumab (bev) in patients (pts) with newly diagnosed advanced high‐grade ovarian carcinoma (HGOC): Final analysis of second progression-free survival (PFS2) in the phase III PAOLA-1/ENGOT-ov25 trial

Improving PARP inhibitor efficacy in high-grade serous ovarian carcinoma: A focus on the immune system

High-grade serous ovarian carcinoma (HGSOC) is a genomically unstable malignancy responsible for over 70% of all deaths due to ovarian cancer. With roughly 50% of all HGSOC harboring defects in the homologous recombination (HR) DNA repair pathway (e.g., BRCA1/2 mutations), the introduction of poly ADP-ribose polymerase inhibitors (PARPi) has dramatically improved outcomes for women with HR defective HGSOC. By blocking the repair of single-stranded DNA damage in cancer cells already lacking high-fidelity HR pathways, PARPi causes the accumulation of double-stranded DNA breaks, leading to cell death. Thus, this synthetic lethality results in PARPi selectively targeting cancer cells, resulting in impressive efficacy. Despite this, resistance to PARPi commonly develops through diverse mechanisms, such as the acquisition of secondary BRCA1/2 mutations. Perhaps less well documented is that PARPi can impact both the tumour microenvironment and the immune response, through upregulation of the stimulator of interferon genes (STING) pathway, upregulation of immune checkpoints such as PD-L1, and by stimulating the production of pro-inflammatory cytokines. Whilst targeted immunotherapies have not yet found their place in the clinic for HGSOC, the evidence above, as well as ongoing studies exploring the synergistic effects of PARPi with immune agents, including immune checkpoint inhibitors, suggests potential for targeting the immune response in HGSOC. Additionally, combining PARPi with epigenetic-modulating drugs may improve PARPi efficacy, by inducing a BRCA-defective phenotype to sensitise resistant cancer cells to PARPi. Finally, invigorating an immune response during PARPi therapy may engage anti-cancer immune responses that potentiate efficacy and mitigate the development of PARPi resistance. Here, we will review the emerging PARPi literature with a focus on PARPi effects on the immune response in HGSOC, as well as the potential of epigenetic combination therapies. We highlight the potential of transforming HGSOC from a lethal to a chronic disease and increasing the likelihood of cure.

Individualization in the first-line treatment of advanced ovarian cancer based on the mechanism of action of molecularly targeted drugs

With the development of poly(ADP-ribose) polymerase inhibitors, the treatment of advanced ovarian cancer is changing dramatically. The purpose of this narrative review is to provide a direction for the individualization of advanced ovarian cancer treatment based on the mechanism of action of molecularly targeted drugs currently used in Japan. The PAOLA-1 study showed very good progression-free survival in patients with homologous recombination deficiency tumors who underwent complete surgery with primary debulking surgery and who received olaparib plus bevacizumab. Niraparib has high intratumor penetration, and in a subgroup analysis of the PRIMA study, it was most effective in patients with residual tumors after interval debulking surgery. These data suggest the importance of achieving complete surgery and aiming for cure in the treatment of ovarian cancer and how the use of bevacizumab, olaparib, and niraparib should be individualized.

Traitement médical de première ligne du cancer épithélial de l'ovaire de haut grade: First-line medical treatment of high-grade epithelial ovarian cancer

In early stages, standard treatment is adjuvant chemotherapy, consisting of platinum-based combination for 6 cycles, especially in serous and endometrioid high grade carcinomas. In advanced stages, indication of neoadjuvant chemotherapy must be discussed on a case-by-case basis in multidisciplinary meetings (MDM). Bevacizumab can also be considered in the neoadjuvant setting in some circumstances, always after discussion in MDM. Carboplatin plus paclitaxel every 21 days, with or without bevacizumab remains the standard of care for first-line chemotherapy. Inhibitors of poly-(ADP-riboses) polymerases (PARPi) have been approved and are reimbursed as maintenance monotherapy in tumors carrying BRCA1 or BRCA2 mutation after complete or partial response to chemotherapy. Two recent studies demonstrated the efficacy of PARPi on progression free survival, one for niraparib single-agent in patients with high-grade ovarian carcinoma regardless of BRCA status, the other one for the combination of bevacizumab and olaparib in patients with high grade carcinoma, with positive test for homologous recombination DNA repair deficiency (regardless of BRCA status). These two new modalities of maintenance therapy are now available in compassionate use programs or post compassionate use programs. Depending on pending decisions upon reimbursement, these indications might be somewhat modified.

Olaparib: A Review as First-Line Maintenance Therapy in Advanced Ovarian Cancer

Olaparib (Lynparza^®) is a poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor approved for first-line maintenance treatment in adults with advanced ovarian cancer who are in complete or partial response to first-line, platinum-based chemotherapy. Originally approved as monotherapy, olaparib is also approved to be administered in combination with bevacizumab in patients whose cancer is associated with homologous recombination deficiency (HRD), defined by either a BRCA1/2 mutation and/or genomic instability. In phase III trials, olaparib monotherapy significantly improved progression-free survival (PFS) relative to placebo (SOLO-1), as did olaparib plus bevacizumab relative to placebo plus bevacizumab (PAOLA-1), in patients with advanced ovarian cancer who had responded to platinum-based chemotherapy. In PAOLA-1, improvements in PFS with olaparib plus bevacizumab were not seen in patients with HRD-negative tumours relative to placebo plus bevacizumab. Both olaparib monotherapy and olaparib in combination with bevacizumab had generally manageable tolerability profiles. Olaparib, alone or in combination with bevacizumab, is a useful option for the first-line maintenance treatment of adults with HRD-positive, advanced epithelial ovarian, fallopian tube or primary peritoneal cancer who are in complete or partial response to first-line, platinum-based chemotherapy.

PARP-inhibitors in epithelial ovarian cancer: Actual positioning and future expectations

Poly-(ADP)-ribose polymerase inhibitors (PARPi) are a class of oral anticancer drugs first developed as "synthetically lethal" in cancers harboring BRCA1/BRCA2 inactivating mutations. In high-grade serous or endometrioid ovarian cancers (HGOC), PARPi demonstrated benefit as maintenance therapy in relapsing BRCA-mutated and non-mutated tumors. Recently, they extended their indications to frontline maintenance therapy. This review summarizes the current place of PARPi (i) as maintenance or single agent in recurrent disease and (ii) frontline maintenance with different settings. We reviewed the course of biomarker identification, the challenge of overcoming resistance to PARPi and future combinations with targeted therapies, including anti-angiogenic, immune checkpoint inhibitors and DNA damage response inhibitors.

Report from the European Society of Gynaecological Oncology (ESGO) 2020 State-of-the-Art Virtual Meeting

This is a report from the European Society of Gynaecological Oncology State-of-the-Art Virtual Meeting held December 14-16, 2020. The unique 3-day conference offered comprehensive state-of-the-art summaries on the major advances in the treatment of different types of gynecological cancers. Sessions opened with a case presentation followed by a keynote lecture and interactive debates with opinion leaders in the field. The speakers also presented scientific reviews on the clinical trial landscape in collaboration with the European Network of Gynecological Oncological Trial (ENGOT) groups. In addition, the new ESGO-ESRTO-ESP endometrial cancer guidelines were officially presented in public. This paper describes the key information and latest studies that were presented for the first time at the conference.

Poly(ADP-ribose) polymerase inhibitors in combination with anti-angiogenic agents for the treatment of advanced ovarian cancer

Homologous recombination deficiency and VEGF expression are key pathways in high-grade ovarian cancer. Recently, three randomized practice changing trials were published: the PAOLA-1, PRIMA and VELIA trials. The use of PARP inhibitors (PARPi) following chemotherapy has become standard of care in first line. Combination of PARPi with anti-angiogenic agents has demonstrated synergistic activity in preclinical study. This review summarizes the body of evidence supporting the efficacy and safety of the combination of PARPi and anti-angiogenic drugs in first-line homologous recombination deficiency high-grade ovarian cancer leading to US FDA and EMA approvals. This double maintenance is supported by: a large benefit with bevacizumab + olaparib compared with olaparib alone, a rationale for additive effect, and a good safety and cost-effective profile.