Multicenter Real-World Data of Subsequent Chemotherapy after Progression to PARP Inhibitors in a Maintenance Relapse Setting

Poly (ADP-ribose) polymerase inhibitor therapy and mechanisms of resistance in epithelial ovarian cancer

Advanced epithelial ovarian cancer is the commonest cause of gynaecological cancer deaths. First-line treatment for advanced disease includes a combination of platinum-taxane chemotherapy (post-operatively or peri-operatively) and maximal debulking surgery whenever feasible. Initial response rate to chemotherapy is high (up to 80%) but most patients will develop recurrence (approximately 70-90%) and succumb to the disease. Recently, poly-ADP-ribose polymerase (PARP) inhibition (by drugs such as Olaparib, Niraparib or Rucaparib) directed synthetic lethality approach in BRCA germline mutant or platinum sensitive disease has generated real hope for patients. PARP inhibitor (PARPi) maintenance therapy can prolong survival but therapeutic response is not sustained due to intrinsic or acquired secondary resistance to PARPi therapy. Reversion of BRCA1/2 mutation can lead to clinical PARPi resistance in BRCA-germline mutated ovarian cancer. However, in the more common platinum sensitive sporadic HGSOC, the clinical mechanisms of development of PARPi resistance remains to be defined. Here we provide a comprehensive review of the current status of PARPi and the mechanisms of resistance to therapy.

Global publication productivity and research trends on recurrent ovarian cancer: a bibliometric study

Introduction

Recurrent ovarian cancer (ROC) presents a dismal prognosis, persistently devoid of efficacious therapeutic strategies. Over the past decade, significant shifts have transpired in ROC management, marked by the identification of novel therapeutic targets and advancements in biomarker research and innovation. Since bibliometrics is an effective method for revealing scientific literature, we conducted a bibliometric analysis of literature pertaining to ROC. Our exploration encompassed identifying emerging research trends and common patterns, analyzing collaborative networks, and anticipating future directions within this clinical context.

Methods

We conducted a search in the Web of Science Core Collection (WoSCC) to acquire relevant articles as our dataset, which were then exported using R-Studio-2023.12.0-369 software. The Bibliometrix R package was utilized to perform visual analyses on countries, institutions, journals, authors, landmark articles, and keywords within this research field.

Results

A total of 1538 articles and 173 reviews published between 2014 and 2023 were eventually retrieved. The annual growth rate of scientific production was 4.27%. The USA led the way in the number of published works, total citations, and collaboration. Gynecologic Oncology was the most favoured journal in this research field. Vergote I from the University Hospital Leuven, was the most influential author. At last, the most prominent keywords were "chemotherapy" (n = 124), "bevacizumab" (n = 87), and "survival" (n = 65). Clinical outcomes (prognosis, survival), chemotherapy, bevacizumab, and PARP inhibitors (olaparib, niraparib) represented the basic and transversal themes, while antibody-drug conjugate (ADC) and drug resistance were emerging themes. Cytoreduction surgical procedures and tamoxifen were niche themes, while immunotherapy and biomarkers were motor themes and had high centrality.

Conclusion

The trends in the ROC research field over the past decade were revealed through bibliometric analysis. Platinum resistance, ADC, and immunotherapy have emerged as the current prominent research topics.

Real world data of niraparib in platinum sensitive relapsed ovarian cancer: A multicenter experience of the MITO group

OBJECTIVE

PARP (poly adenosine diphosphate [ADP]-ribose polymerase) inhibitors are approved as maintenance therapy in platinum sensitive ovarian cancer (OC), in first line and in the recurrent setting, regardless of BRCA mutational status. Real-world data after the introduction of these agents are needed to evaluate whether the benefit observed in phase III randomized clinical trials can be translated into clinical practice. The aim of our study was to provide real-life data on efficacy and safety of niraparib administered as maintenance in platinum sensitive relapsed OC patients (PSROC).

METHODS

This retrospective/prospective observational study included relapsed OC patients that received niraparib as maintenance, at the time of platinum sensitive recurrence within the Italian expanded-access program. Clinical data at the time of diagnosis and at the time of recurrence were collected and analyzed. Median progression free survival (PFS) and overall survival (OS) were calculated as the time from start of niraparib treatment to subsequent radiologically confirmed relapse and death or last contact, respectively.

RESULTS

Among 304 eligible patients, 260 (85%) had BRCA wild-type tumor and 36. (11.9%) were BRCA mutated. Median PFS was 9.1 months (95% CI: 6.9-11.2) and 10.3 months (95% CI: 7.0-13.5) in the BRCAwt and BRCAmut cohorts, respectively. Furthermore, median OS was 41.7 months (95% CI: 31.6-41.9) and 34.6 months (95% CI: N.E.) in the BRCAwt and BRCAmut cohorts, respectively.

CONCLUSION

Data from this large real-life dataset suggested that maintenance with niraparib in the real-life setting of platinum sensitive OC recurrence is effective and well tolerated.

A real-world study of treatment patterns following disease progression in epithelial ovarian cancer patients undergoing poly-ADP-ribose polymerase inhibitor maintenance therapy

BACKGROUND

The efficacy of subsequent therapy after poly-ADP-ribose polymerase (PARP) inhibitor maintenance treatment has raised concerns. Retrospective studies show worse outcomes for platinum-based chemotherapy after progression of PARP inhibitor-maintenance therapy, especially in BRCA-mutant patients. We aimed to describe subsequent therapy in ovarian cancer patients after PARP inhibitor-maintenance therapy and evaluate their response to treatment. We focused on chemotherapy for patients with a progression-free interval (PFI) of ≥ 6 months after prior platinum treatment, based on BRCA status.

METHODS

We analyzed real-world data from Peking University Cancer Hospital, subsequent therapy after progression to PARP inhibitor-maintenance therapy for epithelial ovarian cancer between January 2016 and December 2022. Clinicopathological characteristics and treatment outcomes were extracted from medical records. The last follow-up was in May 2023.

RESULTS

A total of 102 patients were included, of which 29 (28.4%) had a germline BRCA1/2 mutation and 73 (71.6%) exhibited BRCA1/2 wild-type mutations. The PARP inhibitors used were Olaparib (n = 62, 60.8%), Niraparib (n = 35, 34.3%), and others (n = 5, 4.9%). The overall response rate (ORR) was 41.2%, and the median time to second progression (mTTSP) was 8.1 months (95%CI 5.8-10.2). Of 91 platinum-sensitive patients (PFI ≥ 6 months) after progression to PARP inhibitor-maintenance therapy, 65 patients subsequently received platinum regimens. Among them, 30 had received one line of chemotherapy before PARP inhibitor-maintenance therapy. Analysis of these 30 patients by BRCA status showed an ORR of 16.7% versus 33.3% and mTTSP of 7.1 (95% CI 4.9-9.1) versus 6.2 months (95% CI 3.7-8.3, P = 0.550), for BRCA-mutant and wild-type patients, respectively. For the remaining 35 patients who had received two or more lines of chemotherapy before PARP inhibitor-maintenance therapy, ORR was 57.1% versus 42.9%, and mTTSP was 18.0 (95% CI 5.0-31.0) versus 8.0 months (95% CI 4.9-11.1, P = 0.199), for BRCA-mutant and wild-type patients, respectively.

CONCLUSION

No differences in survival outcomes were observed among patients with different BRCA statuses. Furthermore, for patients who had undergone two or more lines of chemotherapy before PARP inhibitor maintenance therapy, no negative effects of PARP inhibitors on subsequent treatment were found, regardless of BRCA status.

Successful Management of Ovarian Cancer Progressing on Olaparib by Niraparib Following Cytoreduction: A Case Report

BACKGROUND

Polyadenosine 5'-diphosphoribose polymerase inhibitors (PARP-Is) are novel, effective agents for treating newly diagnosed epithelial ovarian cancer (EOC). However, the effect of PARP-I on the progression of recurrent EOC has not yet been determined. In particular, there is limited evidence regarding retreatment with PARP-I for recurrent EOC that has progressed on PARP-I in the short term.

CASE REPORT

A 69-year-old woman with a BRCA1 mutated EOC relapsed five months after starting olaparib maintenance following neoadjuvant chemotherapy and interval debulking surgery. Although the platinum-free interval was within six months, secondary cytoreductive surgery was performed because the tumor was locoregional. Following two cycles of weekly nedaplatin, niraparib induced a complete response, and the patient maintained a progression-free status for 15 months.

CONCLUSION

Even with short-term progression on PARP-I, local control combined with different platinum agents and PARP-I can be used to achieve good responses.

Secondary cytoreduction surgery for recurrent epithelial ovarian cancer patients after PARPi maintenance: A multicenter, randomized, controlled clinical trial

BACKGROUND

Poly ADP-ribose polymerase inhibitors (PARPi) treatment has radically changed the treatment strategy for epithelial ovarian cancer. Cancer progression with PARPi maintenance is a new problem that has arisen in clinical practice, and the value of secondary cytoreduction surgery remains unknown.

PRIMARY OBJECTIVE

To evaluate the benefits of secondary cytoreductive surgery and to clarify the sensitivity to platinum in patients with firstline or secondline recurrent epithelial ovarian cancer who have completed ≥6 months of PARPi maintenance.

STUDY HYPOTHESIS

Carefully selected patients who progress on PARPi maintenance will benefit from secondary cytoreductive surgery.

TRIAL DESIGN

This is a multicenter phase III trial. Eligible patients will be randomly assigned at a ratio of 1:1 to either the experimental or standard arm. Patients in the experimental arm will receive secondary cytoreductive surgery followed by platinum based chemotherapy, while patients in the standard arm will be provided with chemotherapy alone.

MAJOR INCLUSION/EXCLUSION CRITERIA

Patients diagnosed with firstline or secondline recurrent epithelial ovarian cancer who had previously received ≥4 cycles of platinum based chemotherapy in initial treatment followed by PARPi maintenance therapy for ≥6 months prior to recurrence.

PRIMARY ENDPOINT

Progression free survival.

SAMPLE SIZE

400 patients.

ESTIMATED DATES FOR COMPETING ACCRUAL AND PRESENTING RESULTS

Accrual completion is expected in December 2024 with results mature after 2 years of follow-up in 2026.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05607329.

Carboplatin in metastatic castration-resistant prostate cancer patients with molecular alterations of the DNA damage repair pathway: the PRO-CARBO phase II trial

Introduction

DNA damage repair genes are altered in 20-35% of metastatic castration-resistant prostate cancer (mCRPC). Poly-ADP (Adénosine Diphosphate)-ribose polymerase inhibitors (PARPi) showed significant activity for these selected tumors, especially with homologous recombination repair (HRR) deficiency. These alterations could also predict platinum sensitivity. Although carboplatin was inconclusive in unselected mCRPC, the literature suggests an anti-tumoral activity in mCRPC with HHR gene alterations. We aimed to assess the efficacy of carboplatin monotherapy in mCRPC patients with HRR deficiency.

Methods

This prospective multicenter single-arm two-stage phase II addressed mCRPC men with HRR somatic and/or germline alterations, pretreated with ⩾2 taxane chemotherapy regimens and one androgen receptor pathway inhibitor. Prior PARPi treatment was allowed. Enrolled patients received intravenous carboplatin (AUC5) every 21 days for 6-9 cycles. The primary endpoint was the best response rate according to adapted PCWG3 guidelines: radiological response (RECIST 1.1 criteria) and/or biological response [⩾50% prostate-specific antigen (PSA) decline].

Results

A total of 15 out of 16 enrolled patients started carboplatin treatment. Genomic alterations were identified for BRCA2 (n = 5), CDK12 (n = 3), ATM (n = 3) CHEK2 (n = 2), CHEK1 (n = 1), and BRCA1 (n = 1) genes. Objective response (partial biological response + stable radiological response) was achieved in one patient (6.7%), carrying a BRCA2 mutation and not pre-treated with PARPi; stable disease was observed for five patients (33.5%). Among seven patients (46.7%) with previous PARPi treatment, four patients (57.1%) had a stable disease. The median progression-free and overall survivals were 1.9 [95% confidence interval (95% CI), 1.8-9.5] and 8.6 months (95% CI, 4.3-19.5), respectively. The most common severe (grade 3-4) treatment-related toxicities were thrombocytopenia (66.7%), anemia (66.7%), and nausea (60%). Overall, 8 (53.3%) patients experienced a severe hematological event.

Conclusion

The study was prematurely stopped as pre-planned considering the limited activity of carboplatin monotherapy in heavily pre-treated, HHR-deficient mCRPC patients. Larger experience is needed in mCRPC with BRCA alterations.

Trial registration

NCT03652493, EudraCT ID number 2017-004764-35.

Systemic therapy de-escalation in advanced ovarian cancer: a new era on the horizon?

Poly(ADP-ribose) polymerase inhibitors (PARPi) have sculpted the current landscape of advanced ovarian cancer treatment. With the advent of targeted maintenance therapies, improved survival rates have led to a timely interest in exploring de-intensified strategies with the goal of improving quality of life without compromising oncologic outcomes. The emerging concept of systemic treatment de-escalation would represent a new frontier in personalizing therapy in ovarian cancer. PARPi are so effective that properly selected patients treated with these agents might require less chemotherapy to achieve the same oncologic outcomes. The fundamental key is to limit de-escalation to a narrow subpopulation with favorable prognostic factors, such as patients with BRCA-mutated and/or homologous recombination-deficient tumors without macroscopic residual disease after surgery or other high-risk clinical factors. Potential de-escalation strategies include shifting PARPi in the neoadjuvant setting, de-escalating adjuvant chemotherapy after primary debulking surgery, reducing PARPi maintenance therapy duration, starting PARPi directly after interval debulking surgery, omitting maintenance therapy, and continuing PARPi beyond oligoprogression (if combined with locoregional treatment). Several ongoing trials are currently investigating the feasibility and safety of de-escalating approaches in ovarian cancer and the results are eagerly awaited. This review aims to discuss the current trends, drawbacks, and future perspectives regarding systemic treatment de-escalation in advanced ovarian cancer.

Poly (ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer: lessons learned and future directions

Poly (ADP-ribose) polymerase inhibitors (PARPi) represent a new standard of care in the upfront treatment of advanced epithelial ovarian cancer to the point that the vast majority of patients now receive a PARPi, alone or in combination with the anti-angiogenic bevacizumab, as part of their first-line maintenance therapy. The clinical benefit of PARPi is well established; however, much has changed since their introduction and several relevant questions have been raised and remain unresolved in the post-PARPi era. The decision-making process regarding the most appropriate first-line maintenance therapy could be challenging in clinical practice, especially in the homologous recombination-proficient setting, and several other factors need to be considered apart from the mutational status. Concerns regarding post-PARPi progression treatment have emerged, highlighting an unmet need to define a valid algorithm strategy. PARPi may not only compromise the response to further platinum due to cross-resistance mechanisms but the impact on subsequent non-platinum chemotherapy and surgery also remains unclear. Definitive results on the role of PARPi rechallenge are awaited, especially in the case of oligoprogression managed with locoregional treatment. Moreover, the updated overall survival data from the recurrent setting warrant caution in using PARPi as single agents for unselected patients. Several PARPi combination regimens are emerging for overcoming PARPi resistance and may become our new therapeutic armamentarium. This review discusses a set of clinically relevant issues in the PARPi era and provides a glimpse of future challenges and opportunities in ovarian cancer treatment.