Androgen receptor, PARP signaling, and tumor microenvironment: the 'perfect triad' in prostate cancer?

Aberrations in the homologous recombination repair (HRR) pathway in prostate cancer (PCa) provide a unique opportunity to develop therapeutic strategies that take advantage of the reduced tumor ability to repair DNA damage. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have been shown to prolong the survival of PCa patients with HRR defects, particularly in those with Breast Cancer type 1 susceptibility protein/Breast Cancer type 2 susceptibility protein alterations. To expand the benefit of PARPi to patients without detectable HRR alterations, multiple preclinical and clinical studies are addressing potential synergies between PARPi and androgen receptor signaling inhibitors, and these strategies are also being evaluated in combination with other drugs such as immune checkpoint inhibitors. However, the effectiveness of these combining therapies could be hindered by multiple mechanisms of resistance, including also the role played by the immunosuppressive tumor microenvironment. In this review, we summarize the use of PARPi in PCa and the potential synergies with different molecular pathways. However, numerous unanswered questions remain, including the identification of the patient population that could benefit most from PARPi, determining whether to use PARPi as monotherapy or in combination, and finding the optimal timing of PARPi, expanding the use of genomic tests, and optimizing combination therapies.

Prognostic role of circulating cytokines and inflammation indexes for avelumab maintenance in metastatic urothelial carcinoma.

Background: Avelumab maintenance after first-line platinum-based chemotherapy represents a cornerstone for the treatment of metastatic urothelial carcinoma (mUC). However, identifying prognostic biomarkers is paramount for optimizing patients' benefits while minimizing toxicity. Cytokines represent circulating mediators of the complex interaction between cancer, the immune system, and inflammation. Inflammation, a hallmark of cancer, can be expressed by circulating factors. In different tumor subtypes, peripheral blood biomarkers, such as circulating cytokines, and systemic inflammatory indexes, have been addressed as potential prognostic factors for immune checkpoint inhibitors. However, their role in mUC still needs to be determined. Methods: Between February 2021 and April 2023, we prospectively collected plasma cytokines and inflammation indexes in 28 patients with mUC before starting avelumab as first-line maintenance. The primary endpoint was the relationship between baseline cytokines and inflammatory indexes with the clinical benefit (CB), defined as the number of Responders. Secondary endpoints included the correlation of baseline cytokines and inflammatory indexes with progression-free survival (PFS), overall survival (OS), and the number and grade of immune-related adverse events. Results: High pre-treatment levels of interferon (IFN)-γ and interleukin (IL)-2, and low levels of IL-6, IL-8, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and systemic-inflammation index (SII) were associated with clinical benefit and longer survival. In the multivariate analysis, low IL-8, NLR, and SII levels maintained a positive prognostic value for OS. Conclusion: Our data suggest that, in mUC patients receiving avelumab, pre-treatment levels of plasma cytokines and inflammatory indexes may serve as potential prognostic biomarkers for response and efficacy. In particular, patients with signs of pre-therapeutic inflammation showed a significantly lower response and survival to avelumab. On the contrary, low systemic inflammation and high levels of cytokines characterized responders and longer survivors.

Neutrophil-to-Eosinophil Ratio Predicts the Efficacy of Avelumab in Patients With Advanced Urothelial Carcinoma Enrolled in the MALVA Study (Meet-URO 25).

BACKGROUND: Neutrophil-to-eosinophil ratio (NER) has been described to be associated with outcomes to immune checkpoint inhibitors (ICI) in several tumor types, but less is known about its role of in the response to avelumab in advanced urothelial cancer (aUC). Thus, we reported outcomes by NER of aUC patients treated with avelumab as maintenance after initial response to platinum-based chemotherapy and enrolled in the Maintenance with AVeLumAb ([MALVA] in advanced urothelial neoplasms in response to first-line chemotherapy: an observational retrospective study) study (Meet-URO 25). PATIENTS AND METHODS: Median NER at baseline and after 3 cycles of avelumab were calculated. Progression-free survival (PFS) and overall survival (OS) by NER were reported. RESULTS: At the cutoff date (April 15, 2023), a total of 109 patients were included. The median NER was 28.05 at baseline and 24.46 after 3 cycles of avelumab, respectively. Median PFS was not reached for patients with baseline NER less than the median (

Clinical Outcomes and Prognostic Factors in Patients With Penile Carcinoma: A Sub-Analysis From Meet-URO 23 (I-RARE) Registry Study.

INTRODUCTION: Penile squamous cell carcinoma (PSCC) is a rare tumor with an aggressive behavior. The Meet-URO 23/I-RARE registry includes rare genitourinary malignancies. We extracted patients with PSCC to conduct a retrospective study aimed at assessing clinical outcomes and prognostic factors. PATIENTS AND METHODS: Primary endpoints were overall survival and progression-free survival. Prognostic factors for OS and PFS were analyzed using univariate and multivariate analysis. From the Meet-URO 23/I-RARE database, we extracted 128 patients with diagnosis of PSCC. About 48% of patients underwent first-line of therapy. RESULTS: In the overall population, median OS from diagnosis was 34.6 months. Significant differences in median OS were observed according to ECOG PS at diagnosis (57.3 months vs. 8.3 months; P < .001), and median age (≤77y 88.8 months vs. >77y 26 months; P = .013). At multivariate analysis, ECOG PS 2-4 at diagnosis (HR 3.04) and lymph node metastases (HR 2.49) were independently associated with a higher risk of death. Among patients undergoing first-line therapy (n = 61), median OS was 12.3 months, and a statistically significant difference was found according to type of response to first-line (DCR 24.4 months vs. PD 7.1 months; P < .001). Multivariate analysis showed that only age >77 years was associated with a worse OS (HR 2.16). A statistically significant difference in PFS was found according to platinum plus 5-fluorouracil versus platinum plus taxane (4.9 vs. 3.4 months; P = .036) and regimens with 2 versus 3 drugs (3.4 vs. 8.6 months; P = .019). At the multivariate analysis only regimens with platinum plus taxane were associated with worse PFS (HR 2.83). CONCLUSION: In our registry study, PSCC is confirmed to be an aggressive disease. Poor ECOG PS, presence of lymph node metastases, and higher age at diagnosis appear to be associated with worse survival outcomes.

Real World Analysis of Peritoneal Metastasis From Renal Cell Carcinoma. Meet-Uro27.

BACKGROUND: Peritoneal metastases (PM) have been reported in approximately 1% of patients with metastatic Renal Cell Carcinoma (mRCC). Outcome data are limited due to the rarity of this metastatic site. Therefore, the aim of our study is to describe renal cell carcinoma (RCC) patients with PM treated as per clinical practice. MATERIALS AND METHODS: Baseline characteristics and outcome data of patients with PM from RCC were retrospectively collected from 18 Italian oncological referral centers adhering to the Meet-Uro group, from January 2016 to January 2023. RESULTS: We collect 81 RCC patients with PM. 78/81 received systemic treatment, 3/81 only best supportive care. First line treatment included tyrosine-kinase inhibitors (TKI) (46/78), ImmuneOncology (IO)-TKI (26/78) and IO-IO (6/78), with different Objective Response Rate (ORR) (43.4% in TKI monotherapy group vs 50% in IO-TKI group, respectively) and Disease Control Rate (DCR) (60.8% in TKI treated patients vs. 76.9% in IO-TKI treated patients). Median PFS was 6.4 months (95%CI 4.18-14.8) in patients treated with TKI monotherapy vs 23.7 months (95%CI 11.1-NR) in patients treated with IO-TKI (p < 0.015). The median OS (mOS) was 22.7 months (95%CI 13.32 - 64.7) in the TKI monotherapy group vs 34.5 mo (95%CI NR-NR) in the IO-TKI group with 53.8% of patients alive at 1 years in the latter group, (p < 0.16). Primary refractory patients were 36.9% for TKI and 15.3% for IO-TKI. According to International Metastatic renal cell carcinoma Database Consortium (IMDC) score, mPFS and mOS were consistent among risk categories. Median PFS was 36.6 months (95%CI 10.9-NR) for good risk patients compared to 10 months (95%CI 7.5-29.8) for intermediate risk and 2.96 months (95%CI 2.43-11.28) for poor risk population (p < 0.0005) whereas mOS was NR (95%CI 28.65-NR) for good risk patients compared to 35.3 months (95%CI 24.6-NA) and 12.4 months (95%CI 3.52-NR) for intermediate and poor risk population, respectively, (p < 0.0002). Only 34/78 (43.5%) received a second line treatment that was TKI (ORR 8.3% and DCR 41.6%) or IO (ORR 18.1% and DCR 40.9%). CONCLUSION: We report one of the largest case series regarding PM from RCC. Characteristics of patients suggest a more aggressive behavior of PM from mRCC. Outcome data suggest that TKI-IO as first line treatment, and TKI as second line, confirm their activity for these patients with dismal prognosis.

Significance of PD-L1 in Metastatic Urothelial Carcinoma Treated With Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis.

Importance: Immune checkpoint inhibitors (ICIs) have broadened the metastatic urothelial carcinoma (mUC) therapeutic scenario. The association of programmed death ligand 1 (PD-L1) with response and survival in patients treated with ICIs is still controversial. Objectives: To evaluate the association of PD-L1 with response rate and overall survival among patients with mUC treated with ICIs. Data Sources: PubMed, Embase, American Society of Clinical Oncology and European Society for Medical Oncology Meeting Libraries, and Web of Science were searched up to December 10, 2023. Study Selection: Two authors independently screened the studies. Included studies were randomized and nonrandomized clinical trials enrolling patients with mUC receiving ICIs with available overall survival (OS), progression-free survival (PFS), or overall response rate (ORR) data, separated between patients with PD-L1-positive and -negative tumors. Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed. Two reviewers independently extracted data. Fixed- or random-effects models were used depending on the heterogeneity among the studies. Main Outcomes and Measures: Primary outcomes were odds ratios (ORs) for ORR and hazard ratios (HRs) for OS, comparing patients with PD-L1-positive tumors and patients with PD-L1-negative tumors. Secondary outcomes were the PFS HR between patients with PD-L1-positive and -negative tumors and OS HR between ICI arms and non-ICI arms of only randomized clinical trials. Results: A total of 14 studies were selected, comprising 5271 patients treated with ICIs (2625 patients had PD-L1-positive tumors). The ORR was 13.8% to 78.6% in patients with PD-L1-positive tumors and 5.1% to 63.2% in patients with PD-L1-negative tumors, with an association between PD-L1 status and ORR favoring patients with PD-L1-positive tumors (OR, 1.94; 95% CI, 1.47-2.56; P < .001). Median OS ranged from 8.4 to 24.1 months in patients with PD-L1-positive tumors and from 6.0 to 19.1 months in patients with PD-L1-negative tumors. The pooled HR showed a significant reduction for patients with PD-L1-positive tumors compared with those with PD-L1-negative tumors in the risk of death (HR, 0.71; 95% CI, 0.57-0.89; P = .003) and risk of progression (HR, 0.55; 95% CI, 0.44-0.69; P < .001) when ICIs were administered. PD-L1 is not likely to be a predictive biomarker of ICI response. Conclusions and Relevance: This systematic review and meta-analysis suggests that PD-L1 expression is associated with improved ORR, OS, and PFS for patients with mUC who receive ICIs, but it is unlikely to be useful as a predictive biomarker. Developing predictive biomarkers is essential to select patients most likely to benefit from ICIs and avoid toxic effects and financial burden with these agents.

Immune checkpoint inhibitors plus chemotherapy in first-line endometrial cancer treatment: Still the era of microsatellites?

OBJECTIVE: The combination of immune checkpoint inhibitors (ICIs) plus chemotherapy is currently being tested as the first-line treatment of advanced endometrial. We aimed to evaluate the efficacy and safety of this combination. DESIGN: We performed a meta-analysis of randomized clinical trials. POPULATION AND SETTING: Patients with advanced endometrial carcinoma receiving ICIs plus chemotherapy in the experimental arm, compared with chemotherapy plus placebo in the control arm, were included. METHODS AND OUTCOMES: We evaluated the progression-free survival (PFS) as an efficacy outcome and the number and grades of adverse events (AEs) for safety. Hazard ratios (HR) for PFS and risk ratios (RR) for AEs, with 95% confidence intervals (CI), were calculated. RESULTS: 1303 patients were treated in the included studies. Adding ICIs to chemotherapy significantly improved PFS in mismatch repair deficient (dMMR-HR 0.29; 95% CI, 0.20-0.42; p < 0.00001) and in mismatch repair proficient (pMMR-HR 0.64; 95% CI, 0.46-0.90; p = 0.01) patients. No difference emerged for all-grades AEs (RR 1.00; p = 0.98), but the risk of ≥G3 AEs was increased in the ICIs + chemotherapy group (RR 1.22; 95% CI, 1.11-1.34; p < 0.0001). CONCLUSIONS: Adding ICIs to chemotherapy significantly improves PFS in first-line endometrial cancer, regardless of MMR status.

Hematological Toxicity of PARP Inhibitors in Metastatic Prostate Cancer Patients with Mutations of BRCA or HRR Genes: A Systematic Review and Safety Meta-analysis.

BACKGROUND: PARP inhibitors (PARPis) are effective treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC) as single agents or in combination with androgen receptor-targeted agents (ARTA). However, a clinically relevant adverse effect of these agents is hematological toxicity, a typical class adverse event (AE), which can lead to treatment modifications and discontinuations. OBJECTIVE: We aimed to analyze the risk of hematological AEs, including anemia, neutropenia, and thrombocytopenia secondary to PARPi treatments in mCRPC. PATIENTS AND METHODS: This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. We systematically searched the PubMed, EMBASE, and Cochrane databases, the American Society of Clinical Oncology (ASCO), and the European Society of Medical Oncology (ESMO) meeting abstracts for clinical trials concerning the use of PARPis, both as single agents and in combination, in patients with mCRPC. The search deadline was 30 June, 2023. We analyzed the pooled incidence of all grades of and ≥ G3 anemia, neutropenia, and thrombocytopenia. We subsequently calculated risk ratios (RRs) for all grades of and ≥ G3 AEs of PARPis versus non-PARPis from randomized clinical trials (RCTs). RESULTS: Eleven phase 2/3 trials with olaparib, niraparib, rucaparib, and talazoparib administered as single agents or combined with ARTA were selected. Anemia was the most common all grades (38.6%) and ≥ G3 AE (24.9%). In the analysis of relative risk, six RCTs were included. The administration of PARPis significantly increased the risk of developing all grades of anemia (RR = 2.44), neutropenia (RR = 3.15), and thrombocytopenia (RR = 4.66) compared with non-PARPis. Similarly, a significant increase in the risk of ≥ G3 anemia (RR = 5.73) and thrombocytopenia (RR = 5.44), and a not significant increased risk of neutropenia (RR = 3.41), were detected. CONCLUSIONS: In mCRPC, PARPis increase the risk of hematological toxicity compared with other treatments, both as single agents or combined with ARTA (high-quality evidence). Clinicians should be aware of this risk and the correct management, especially with the expected increased PARPis use in mCRPC.

Personalized medicine for metastatic prostate cancer: The paradigm of PARP inhibitors.

Despite remarkable progress in the last decade, metastatic prostate cancer (mPCa) remains incurable. The approval of PARP inhibitors (PARPis) represents a milestone in this field, which definitively enters the era of precision medicine, as mPCa is often enriched for defects of homologous recombination repair genes. PARPis are now used as single agents for patients with metastatic castration-resistant PCa. Moreover, combinations of PARPis plus androgen-receptor targeted agents and immune checkpoint inhibitors, and earlier applications of PARPis in the metastatic hormone-sensitive PCa are under evaluation, representing the possible upcoming applications of these agents. Mechanisms of sensitization and resistance have been only partially elucidated. In our review, we summarize the current clinical evidence regarding PARPis in mPCa and the future directions of these targeted agents.

Enfortumab vedotin in metastatic urothelial carcinoma: the solution EVentually?

Metastatic urothelial carcinoma (mUC) is an aggressive malignancy with a dismal prognosis. Enfortumab vedotin (EV) is an antibody-drug conjugate consisting of an antibody targeting Nectin-4. This protein is highly expressed in UC cells. After binding, monomethyl auristatin E is released into cells, causing UC cell death. EV has been approved as a single agent for pre-treated mUC, with interesting improvements in response rate and survival in a setting with limited treatment options. More recently, EV approval occurred in cisplatin-ineligible naïve mUC patients in combination with pembrolizumab. Our review aims to summarize the pharmacological properties, clinical studies, and future developments of EV in mUC.

Niraparib and Advanced Ovarian Cancer: A Beacon in the Non-BRCA Mutated Setting.

Ovarian cancer (OC) is the eighth most common cancer among the female population and the most lethal of all the female reproductive system malignancies. Poly (ADP-ribose) polymerase inhibitors (PARPis) have reshaped the treatment scenario of metastatic OC in the maintenance setting post platinum-based chemotherapy. Niraparib is the first Food and Drug Administration (FDA)- and European Medical Agency (EMA)-approved PARPi as maintenance therapy for platinum-sensitive OC, regardless of BReast CAncer gene (BRCA) status, in first-line patients, with a recent restriction to germline BRCA mutations in second-line patients. In this review, we comprehensively summarized the pharmacological properties of niraparib, alongside the efficacy and safety data of the main trials leading to the current approvals, and discussed the future development of this agent.

Olaparib and advanced ovarian cancer: Summary of the past and looking into the future.

Ovarian cancer (OC) is women's eighth most common cancer, bearing the highest mortality rates of all female reproductive system malignancies. Poly (ADP-ribose) polymerase inhibitors (PARPis) have reshaped the treatment scenario of metastatic OC as a maintenance post platinum-based chemotherapy. Olaparib is the first PARPi developed for this disease. Results from Study 42, Study 19, SOLO2, OPINION, SOLO1, and PAOLA-1 clinical trials, led to the FDA and EMA approval of olaparib for the maintenance treatment of women with high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer without platinum progression: in the platinum-sensitive recurrent OC; in the newly diagnosed setting in case Breast Cancer (BRCA) mutations and, in combination with bevacizumab, in case of BRCA mutation or deficiency of homologous recombination genes. In this review, we synthetized olaparib's pharmacokinetic and pharmacodynamic properties and its use in special populations. We summarized the efficacy and safety of the studies leading to the current approvals and discussed the future developments of this agent.

Comparison of Anti-Programmed Cell Death Ligand 1 Therapy Combinations vs Sunitinib for Metastatic Renal Cell Carcinoma: A Meta-analysis.

This meta-analysis of 3 randomized clinical trials evaluates the association of combined anti­PD-L1 agents with survival and response rate among patients with metastatic renal cell carcinoma.

Dabrafenib-Trametinib and Radiotherapy for Oligoprogressive BRAF Mutant Advanced Melanoma.

The clinical management of metastatic melanoma has been changed by BRAF (BRAFi) and MEK inhibitors (MEKi), which represent a standard treatment for BRAF-mutant melanoma. In oligoprogressive melanoma patients with BRAF mutations, target therapy can be combined with loco-regional radiotherapy (RT). However, the association of BRAF/MEK inhibitors and RT needs to be carefully monitored for potential increased toxicity. Despite the availability of some reports regarding the tolerability of RT + target therapy, data on simultaneous RT and BRAFi/MEKi are limited and mostly focused on the BRAFi vemurafenib. Here, we report a series of metastatic melanoma patients who received fractioned RT regimens for oligoprogressive disease in combination with the BRAFi dabrafenib and the MEKi trametinib, which have continued beyond progression. None of the cases developed relevant adverse events while receiving RT or interrupted dabrafenib and trametinib administration. These cases suggest that a long period of dabrafenib/trametinib interruption during radiotherapy for oligoprogressive disease can be avoided. Prospective trials are warranted to assess the efficacy and safety of the contemporary administration of BRAF/MEK inhibitors and radiotherapy for oligoprogressive disease.

Pembrolizumab Plus Axitinib for Metastatic Papillary and Chromophobe Renal Cell Carcinoma: NEMESIA (Non Clear MEtaStatic Renal Cell Carcinoma Pembrolizumab Axitinib) Study, a Subgroup Analysis of I-RARE Observational Study (Meet-URO 23a).

Non-clear cell renal cell carcinoma (nccRCC) represents a heterogeneous histological group which is 20-25% of those with renal cell carcinoma (RCC). Patients with nccRCC have limited therapeutic options due to their exclusion from phase III randomized trials. The aim of the present study was to investigate the effectiveness and tolerability of pembrolizumabaxitinib combination in chromophobe and papillary metastatic RCC (mRCC) patients enrolled in the I-RARE (Italian Registry on rAre genitor-uRinary nEoplasms) observational ongoing study (Meet-URO 23). Baseline characteristics, objective response rate (ORR), disease control rate (DCR) and progression-free survival (PFS) and toxicities were retrospectively and prospectively collected from nccRCC patients treated in 14 Italian referral centers adhering to the Meet-Uro group, from December 2020 to April 2022. Only patients with chromophobe and papillary histology were considered eligible for the present pre-specified analysis. There were 32 eligible patients who received pembrolizumab-axitinib as first-line treatment, of whom 13 (40%) had chromophobe histology and 19 (60%) were classified as papillary RCC. The DCR was 78.1% whereas ORR was 43.7% (11 patients achieved stable disease and 14 patients obtained partial response: 9/19 papillary, 5/13 chromophobe). Six patients (18.7%) were primary refractory. Median PFS was 10.8 months (95%CI 1.7-11.5). Eleven patients (34.3%) interrupted the full treatment due to immune-related adverse events (irAEs): G3 hepatitis (n = 5), G3 hypophisitis (n = 1), G3 diarrhea (n = 1), G3 pancreatitis (n = 1), G3 asthenia (n = 1). Twelve patients (37.5%) temporarily interrupted axitinib only due to persistent G2 hand-foot syndrome or G2 hypertension. Pembrolizumab-axitinib combination could be an active and feasible first-line treatment option for patients with papillary or chromophobe mRCC.

Beyond Platinum, ICIs in Metastatic Cervical Cancer: A Systematic Review.

BACKGROUND: Cervical cancer (CC) constitutes the fourth most common tumor among the female population. Therapeutic approaches to advanced CC are limited, with dismal results in terms of survival, mainly after progression to platinum-based regimens. Immune checkpoint inhibitors (ICIs) are remodeling the therapeutic scenario of many solid tumors. The role of ICIs in CC should be addressed. Therefore, we systematically reviewed the latest clinical trials employing ICIs in advanced CC to assess which ICIs have been employed and how ICIs might meet the need for new therapeutic options in terms of efficacy and safety. METHODS: The review was conducted following the PRISMA guidelines. The following efficacy outcomes were specifically collected: overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS); for safety: type, number, and grade of adverse events (AEs). RESULTS: A total of 17 studies were analyzed. Anti-PD1 (pembrolizumab, nivolumab, cemiplimab, balstilimab, and tislelizumab), anti-PD-L1 (atezolizumab), and anti-CTLA-4 (ipilimumab, zalifrelimab) agents were employed both as single agents or combinations. Overall ORR ranged from 0% to 65.9%. ORR ranged from 5.9% to 69.6% in PD-L1-positive patients and from 0% to 50% in PD-L1-negative patients. DCR was 30.6-94.1%. mPFS ranged from 2 to 10.4 months. mOS ranged from 8 months to not reached. PD-L1 status did not impact survival. A total of 33.9% to 100% of patients experienced AEs. CONCLUSION: Immunotherapy represents an appealing strategy for patients with advanced CC, as 2 out of 3 patients seem to respond to ICIs. PD-L1 status might be an indicator of response without impacting survival.

Efficacy and safety of PARP inhibitors in elderly patients with advanced ovarian cancer: a systematic review and meta-analysis.

BACKGROUND: Poly-(ADP-ribose)-polymerase (PARP) inhibitors have shown to be effective as maintenance treatment in patients with advanced ovarian cancer. Although most ovarian cancers develop after age 65, older patients are often under-represented in clinical trials. OBJECTIVE: To assess the efficacy and safety of PARP inhibitors versus placebo as maintenance therapy in older patients with ovarian cancer. METHODS: This systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items of Systematic reviews and Meta-Analysis (PRISMA) guidelines. We searched PubMed, Embase, Cochrane databases, and the American Society of Clinical Oncology (ASCO), European Society of Medical Oncology (ESMO), Society of Gynecologic Oncology (SGO) meeting abstracts, for randomized clinical trials using maintenance with PARP inhibitors in patients with advanced ovarian cancer, up to June 30, 2021. The measured outcomes were progression-free survival and safety (number and grade of adverse events), stratified by age (cut-off point: 65 years). RESULTS: A total of eight phase III trials were selected. Among the 4364 patients, 1435 (32.9%) were aged ≥65 (919 receiving PARP inhibitors, 516 receiving placebo). Compared with placebo, maintenance with PARP inhibitors improved progression-free survival in older patients (HR=0.54; 95% CI 0.45 to 0.65; p<0.00001). No differences were found in progression-free survival in comparison with a younger population (HR=0.47; p=0.13). Only hematologic adverse events were available for the age subgroups, and no differences emerged for all-grade hematologic adverse events (risk ratio (RR)=1.22, p=0.33 for anemia; RR=0.97, p=0.74 for neutropenia) and severe neutropenia (RR=0.97, p=0.86); old women were at lower risk of severe anemia (RR=0.79, p=0.04) but had a higher risk of severe thrombocytopenia (RR=1.27, p=0.01). CONCLUSIONS: Maintenance with PARP inhibitors prolongs progression-free survival compared with placebo, both as monotherapy and combined with chemotherapy or bevacizumab, in older patients with advanced ovarian cancer (high-quality evidence). Hematologic safety is similar to that seen in younger patients. No overall survival data are available at this time. PROSPERO REGISTRATION NUMBER: CRD42021261039.