PARP Inhibitors in Patients With Newly Diagnosed Advanced Ovarian Cancer: A Meta-Analysis of Randomized Clinical Trials

Clinical practice guidelines for molecular tumor marker, 2nd edition review part 2

In recent years, rapid advancement in gene/protein analysis technology has resulted in target molecule identification that may be useful in cancer treatment. Therefore, "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" was published in Japan in September 2021. These guidelines were established to align the clinical usefulness of external diagnostic products with the evaluation criteria of the Pharmaceuticals and Medical Devices Agency. The guidelines were scoped for each tumor, and a clinical questionnaire was developed based on a serious clinical problem. This guideline was based on a careful review of the evidence obtained through a literature search, and recommendations were identified following the recommended grades of the Medical Information Network Distribution Services (Minds). Therefore, this guideline can be a tool for cancer treatment in clinical practice. We have already reported the review portion of "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" as Part 1. Here, we present the English version of each part of the Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition.

The impact of varying levels of residual disease following cytoreductive surgery on survival outcomes in patients with ovarian cancer: a meta-analysis

BACKGROUND

Residual disease following cytoreductive surgery in patients with ovarian cancer has been associated with poorer survival outcomes compared with no residual disease. We performed a meta-analysis to assess the impact of varying levels of residual disease status on survival outcomes in patients with ovarian cancer who have undergone primary cytoreductive surgery or interval cytoreductive surgery in the setting of new therapies for this disease.

METHODS

Medline, Embase, and Cochrane databases (January 2011 - July 2020) and grey literature, bibliographic and key conference proceedings, were searched for eligible studies. Fixed and random-effects meta-analyses compared progression and survival by residual disease level across studies. Heterogeneity between comparisons was explored via type of surgery, disease stage, and type of adjuvant chemotherapy.

RESULTS

Of 2832 database and 16 supplementary search articles screened, 50 studies were selected; most were observational studies. The meta-analysis showed that median progression-free survival and overall survival decreased progressively with increasing residual disease (residual disease categories of 0 cm, > 0-1 cm and > 1 cm). Compared with no residual disease, hazard ratios (HR) for disease progression increased with increasing residual disease category (1.75 [95% confidence interval: 1.42, 2.16] for residual disease > 0-1 cm and 2.14 [1.34, 3.39] for residual disease > 1 cm), and also for reduced survival (HR versus no residual disease, 1.75 [ 1.62, 1.90] for residual disease > 0-1 cm and 2.32 [1.97, 2.72] for residual disease > 1 cm). All comparisons were significant (p < 0.05). Subgroup analyses showed an association between residual disease and disease progression/reduced survival irrespective of type of surgery, disease stage, or type of adjuvant chemotherapy.

CONCLUSIONS

This meta-analysis provided an update on the impact of residual disease following primary or interval cytoreductive surgery, and demonstrated that residual disease was still highly predictive of progression-free survival and overall survival in adults with ovarian cancer despite changes in ovarian cancer therapy over the last decade. Higher numerical categories of residual disease were associated with reduced survival than lower categories.

Comparison of poly (ADP-ribose) polymerase inhibitors (PARPis) as maintenance therapy for newly-diagnosed and platinum-sensitive recurrent ovarian cancer with BRCA mutational status: a systematic review and network meta-analysis

BACKGROUND

Poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitors (PARPi) treatment for ovarian cancer (OC) are ever-changing. This study aimed to compare the efficacy and overall safety of available PARPi as maintenance therapy for BRCA mutation status in patients with newly diagnosed and platinum-sensitive recurrent (PSR) OC patients.

RESEARCH DESIGN AND METHODS

Relevant RCTs were systematically retrieved from PubMed and Embase until 31 May 2022. Progression-free survival (PFS) and overall survival (OS) based on BRCA mutation status and adverse events (AEs) regardless of mutation were efficacy and safety endpoints.

RESULTS

In newly diagnosed BRCAm-OC patients, olaparib (HR: 0.33; 95% confidence interval [CI]: 0.25, 0.43) and other PARPis [niraparib (HR: 0.40; 95% CI: 0.29, 0.55), rucaparib (HR: 0.40; 95% CI: 0.21, 0.76) and veliparib (HR: 0.44; 95% CI: 0.28, 0.69)] had a statistically significant effect on PFS versus placebo. In BRCAm-PSROC patients, Olaparib exhibited significant benefit (HR: 0.69; 95% CI: 0.54, 0.88) for OS compared to other PARPis. In BRCAwt-PSR OC patients, Olaparib showed a favorable OS benefit than other PARPis (HR: 0.84; 95% CI: 0.57,1.22). Overall, safety profile of all PARPis was acceptable.

CONCLUSION

All PARPis showed significant benefit, with olaparib showing greater benefit in newly diagnosed and PSR OC women.

REGISTRATION

CRD42021288932.

Maintenance therapy with a poly(ADP-ribose) polymerase inhibitor in patients with newly diagnosed advanced epithelial ovarian cancer: individual patient data and trial-level meta-analysis

Background

We synthesize the efficacy and toxicity of poly(ADP-ribose) polymerase inhibitors (PARPis) in patients with newly diagnosed advanced ovarian cancer.

Patients and methods

We manually extracted individual patient data (IPD) for progression-free survival (PFS) from published survival curves of randomized controlled trials (RCTs) that compared PARPi versus placebo as maintenance therapy in first-line treatment, for whole study populations and subgroups, based on BRCA1/BRCA2 mutation (germline and/or somatic) and homologous recombination deficiency (HRD) status, using WebPlotDigitizer software. The respective PFS curves for each study and combined population were reconstructed from extracted IPD. The primary outcome was PFS in combined whole population and subgroups.

Results

In IPD analysis of combined population from three RCTs, with 2296 patients and 1287 events, PFS was significantly longer in PARPi versus placebo [median 20.4 (95% confidence interval (CI) 18.6-21.9) versus 14.9 (95% CI 13.9-16.5) months, respectively; hazard ratio (HR) 0.67, 95% CI 0.60-0.75; P < 0.001]. In IPD subgroup analyses from four eligible RCTs (2687 patients and 1485 events), median PFS was significantly longer in PARPi versus placebo arm, in the BRCA-mutated (45.7 versus 17.7 months, respectively; HR 0.38, 95% CI 0.32-0.46; P < 0.001), HRD-positive including BRCA-mutated (34.7 versus 17.9 months, respectively; HR 0.45, 95% CI 0.38-0.54; P < 0.001), and HRD positive excluding BRCA-mutated (22.3 versus 13.1 months, respectively; HR 0.47, 95% CI 0.34-0.65; P < 0.001) subgroups, but not in the HRD-negative (15.0 versus 11.3 months, respectively; HR 0.90, 95% CI 0.76-1.05; P = 0.75) subgroup. Results of trial-level meta-analysis were concordant with IPD analysis in whole population and subgroups.

Conclusions

Among newly diagnosed ovarian cancer patients, PARPi maintenance therapy significantly improves PFS in those with germline and/or somatic BRCA mutation and/or HRD-positive tumor but not in those with HRD-negative tumor.

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Maintenance PARPi resulted in significant PFS improvement in total population, but benefit varied in subgroups.

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PARPi showed PFS gain in BRCA-mutated (45.7 versus 17.7 m) and HRD-positive subgroups.

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No significant PFS benefit was seen in the HRD-negative subgroup (15.0 versus 11.3 months; P = 0.75).

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PARPi should be a standard treatment in newly diagnosed ovarian cancer patients except those with HRD-negative tumors.

Combining PARP inhibition and immune checkpoint blockade in ovarian cancer patients: a new perspective on the horizon?

Immune checkpoint inhibitors (ICIs) have completely reshaped the treatment of many malignancies, with remarkable improvements in survival outcomes. In ovarian cancer (OC), however, this emerging class of drugs has not yet found a favorable use due to results from phase I and II studies, which have not suggested a substantial antitumoral activity of these agents when administered as monotherapy. Robust preclinical data seem to suggest that the combination ICIs with poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) may result in a synergistic activity; furthermore, data from phase II clinical studies, evaluating this combination, have shown encouraging outcomes especially for those OC patients not suitable for platinum retreatment. While waiting for ongoing phase III clinical trial results, which will clarify the role of ICIs in combination with PARPis in the newly diagnosed OC, this review aims to summarize the preclinical data and clinical evidence available to date.

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Preclinical data indicate that PARPis exhibit immune modulating properties.

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The combination of PARPi with ICIs displays significant synergistic activity in preclinical models.

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Phase I and II clinical trials showed encouraging results for this combination, especially in platinum-resistant OC.

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Four ongoing phase III trials exploring the combination in first-line setting will delineate the role of immunotherapy in OC.

Macrophage-derived CCL23 upregulates expression of T-cell exhaustion markers in ovarian cancer

BACKGROUND

Macrophages are an important component of the tumour immune microenvironment (TME) and can promote tumour growth and metastasis. Macrophage-secreted chemokine-ligand-23 (CCL23) induces ovarian cancer cell migration via chemokine-receptor 1 (CCR1). However, the effect of CCL23 on other immune cells in the TME is unknown.

METHODS

CCL23 levels were measured by ELISA. The expression of surface markers in exhaustion assays was quantified by flow cytometry. Signalling pathways were identified by phosphokinase array and validated by western blot.

RESULTS

Ascites from patients with high-grade serous ovarian cancer (HGSC) contain high levels of CCL23. Similarly, significantly higher CCL23 levels were found in plasma from HGSC patients compared to healthy individuals. RNA-seq analysis of ovarian cancer tissues from TCGA showed that expression of CCL23 correlated with the presence of macrophages. In tissues with high levels of CCL23 and macrophage content, the fraction of CD8 + T cells expressing exhaustion markers CTLA-4 and PD-1 were significantly higher compared to low-level CCL23 tissues. In vitro, CCL23 induced upregulation of immune checkpoint proteins on CD8 + T cells, including CTLA-4, TIGIT, TIM-3 and LAG-3 via phosphorylation of GSK3β in CD8 + T cells.

CONCLUSIONS

Our data suggest that CCL23 produced by macrophages contributes to the immune-suppressive TME in ovarian cancer by inducing an exhausted T-cell phenotype.

Germline BRCA variants, lifestyle and ovarian cancer survival

OBJECTIVE

Women with ovarian cancer who have a pathogenic germline variant in BRCA1 or BRCA2 (BRCA) have been shown to have better 5-year survival after diagnosis than women who are BRCA-wildtype (non-carriers). Modifiable lifestyle factors, including smoking, physical activity and body mass index (BMI) have previously been associated with ovarian cancer survival; however, it is unknown whether these associations differ by germline BRCA status.

METHODS

We investigated measures of lifestyle prior to diagnosis in two cohorts of Australian women with invasive epithelial ovarian cancer, using Cox proportional hazards regression to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

In the combined studies (n = 1923), there was little association between physical activity, BMI or alcohol intake and survival, and no difference by BRCA status. However, the association between current smoking status before diagnosis and poorer survival was stronger for BRCA variant carriers (HR 1.98; 95% CI 1.20-3.27) than non-carriers (HR 1.18; 95% CI 0.96-1.46; p-interaction 0.02). We saw a similar differential association with smoking when we pooled results from two additional cohorts from the USA and UK (n = 2120). Combining the results from all four studies gave a pooled-HR of 1.94 (95% CI 1.28-2.94) for current smoking among BRCA variant carriers compared to 1.08 (0.90-1.29) for non-carriers.

CONCLUSIONS

Our results suggest that the adverse effect of smoking on survival may be stronger for women with a BRCA variant than those without. Thus, while smoking cessation may improve outcomes for all women with ovarian cancer, it might provide a greater benefit for BRCA variant carriers.

Appropriate Selection of PARP Inhibitors in Ovarian Cancer

OPINION STATEMENT

Poly-ADP-ribose polymerase inhibitors (PARPi) are a class of anti-cancer drugs that target DNA repair pathways and have shown promising efficacy in patients with ovarian cancer in recent clinical trials. To date, there have been 9 FDA PARPi approvals/indications in ovarian cancer since 2014, highlighting the importance of this class of agents in the treatment of ovarian cancer. BRCA1/2-mutated tumors or other forms of homologous recombination deficient (HRD) tumors are particularly susceptible to PARP inhibition and have seen the greatest benefits of improvement in response rate and progression-free survival (PFS) in clinical trials. Patients with homologous recombination-proficient tumors also receive benefit, especially when a nice response to paltinum is noted, but to a lesser extent. PARP inhibitors now have FDA approval and indications in first-line and recurrent maintenance, and treatment. PARP inhibitor use as maintenance therapy in the front-line setting is now considered the standard of care in patients with BRCA1/2 mutations based on the SOLO-1/GOG-3004/ENGOT study. PARP inhibitors are also recommended per ASCO guidelines in all patients with ovarian cancer as front-line maintenance therapy based on the PRIMA/ENGOT-OV26/GOG-3012 trial. The combination of PARP inhibitor, olaparib, and the anti-angiogenesis inhibitor bevacizumab is also approved as maintenance therapy after front-line chemotherapy treatment in patients with HRD tumors and is an option for patients who have initiated bevacizumab with their chemotherapy treatment. PARPi are also FDA approved and can be utilized as a treatment in third-line and beyond in recurrent ovarian cancer patients with BRCA1/2 mutations and HRD tumors. In this review, we will cover in detail when PARP inhibitor use is appropriate in ovarian cancer, as well as the various clinical factors to take into consideration when selecting a PARP inhibitor regimen.

Poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of ovarian cancer

BACKGROUND

Ovarian cancer is the sixth most common cancer in women world-wide. Epithelial ovarian cancer (EOC) is the most common; three-quarters of women present when disease has spread outside the pelvis (stage III or IV). Treatment consists of a combination of  surgery and platinum-based chemotherapy. Although initial responses to chemotherapy are good, most women with advanced disease will relapse. PARP (poly (ADP-ribose) polymerase) inhibitors (PARPi), are a type of anticancer treatment that works by preventing cancer cells from repairing DNA damage, especially in those with breast cancer susceptibility gene (BRCA) variants. PARPi offer a different mechanism of anticancer treatment from conventional chemotherapy.

OBJECTIVES

To determine the benefits and risks of poly (ADP-ribose) polymerase) inhibitors (PARPi) for the treatment of epithelial ovarian cancer (EOC).

SEARCH METHODS

We identified randomised controlled trials (RCTs) by searching the Cochrane Central Register of Controlled Trials (Central 2020, Issue 10), Cochrane Gynaecological Cancer Group Trial Register, MEDLINE (1990 to October 2020), Embase (1990 to October 2020), ongoing trials on www.controlled-trials.com/rct, www.clinicaltrials.gov, www.cancer.gov/clinicaltrials, the National Research Register (NRR), FDA database and pharmaceutical industry biomedical literature.

SELECTION CRITERIA

We included trials that randomised women with EOC to PARPi with no treatment, or PARPi versus conventional chemotherapy, or PARPi together with conventional chemotherapy versus conventional chemotherapy alone.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. Two review authors independently assessed whether studies met the inclusion criteria. We contacted investigators for additional data. Outcomes included overall survival (OS), objective response rate (ORR), quality of life (QoL) and rate of adverse events.

MAIN RESULTS

We included 15 studies (6109 participants); four (3070 participants) with newly-diagnosed, advanced EOC and 11 (3039 participants) with recurrent EOC. The studies varied in types of comparisons and evaluated PARPi. Eight studies were judged as at low risk of bias in most of the domains. Quality of life data were generally poorly reported. Below we present six key comparisons.  The majority of participants had BRCA mutations, either in their tumour (sBRCAmut) and/or germline (gBRCAmut), or homologous recombination deficiencies (HRD) in their tumours. Newly diagnosed EOC Overall, four studies evaluated the effect of PARPi in newly-diagnosed, advanced EOC. Two compared PARPi with chemotherapy and chemotherapy alone. OS data were not reported. The combination of PARPi with chemotherapy may have little to no difference in progression-free survival (PFS) (two studies, 1564 participants; hazard ratio (HR) 0.82, 95% confidence interval (CI 0).49 to 1.38; very low-certainty evidence)(no evidence of disease progression at 12 months' 63% with PARPi versus 69% for placebo).  PARPi with chemotherapy likely increases any severe adverse event (SevAE) (grade 3 or higher) slightly (45%) compared with chemotherapy alone (51%) (two studies, 1549 participants, risk ratio (RR) 1.13, 95% CI 1.07 to 1.20; high-certainty evidence). PARPi combined with chemotherapy compared with chemotherapy alone likely results in little to no difference in the QoL (one study; 744 participants, MD 1.56 95% CI -0.42 to 3.54; moderate-certainty evidence).  Two studies compared PARPi monotherapy with placebo as maintenance after first-line chemotherapy in newly diagnosed EOC. PARPi probably results in little to no difference in OS (two studies, 1124 participants; HR 0.81, 95%CI 0.59 to 1.13; moderate-certainty evidence) (alive at 12 months 68% with PARPi versus 62% for placebo). However, PARPi may increase PFS (two studies, 1124 participants; HR 0.42, 95% CI 0.19 to 0.92; low-certainty evidence) (no evidence of disease progression at 12 months' 55% with PARPi versus 24% for placebo). There may be an increase in the risk of experiencing any SevAE (grade 3 or higher) with PARPi (54%) compared with placebo (19%)(two studies, 1118 participants, RR 2.87, 95% CI 1.65 to 4.99; very low-certainty evidence), but the evidence is very uncertain. There is probably a slight reduction in QoL with PARPi, although this may not be clinically significant (one study, 362 participants; MD -3.00, 95%CI -4.48 to -1.52; moderate-certainty evidence).  Recurrent, platinum-sensitive EOC Overall, 10 studies evaluated the effect of PARPi in recurrent platinum-sensitive EOC. Three studies compared PARPi monotherapy with chemotherapy alone. PARPi may result in little to no difference in OS (two studies, 331 participants; HR 0.95, 95%CI 0.62 to 1.47; low-certainty evidence) (percentage alive at 36 months 18% with PARPi versus 17% for placebo). Evidence is very uncertain about the effect of PARPi on PFS (three studies, 739 participants; HR 0.88, 95%CI 0.56 to 1.38; very low-certainty evidence)(no evidence of disease progression at 12 months 26% with PARPi versus 22% for placebo). There may be little to no difference in rates of any SevAE (grade 3 or higher) with PARPi (50%) than chemotherapy alone (47%) (one study, 254 participants; RR 1.06, 95%CI 0.80 to 1.39; low-certainty evidence). Four studies compared PARPi monotherapy as maintenance with placebo. PARPi may result in little to no difference in OS (two studies, 560 participants; HR 0.88, 95%CI 0.65 to 1.20; moderate-certainty evidence)(percentage alive at 36 months 21% with PARPi versus 17% for placebo). However, evidence suggests that PARPi as maintenance therapy results in a large PFS (four studies, 1677 participants; HR 0.34, 95% CI 0.28 to 0.42; high-certainty evidence)(no evidence of disease progression at 12 months 37% with PARPi versus 5.5% for placebo). PARPi maintenance therapy may result in a large increase in any SevAE (51%) (grade 3 or higher) than placebo (19%)(four studies, 1665 participants, RR 2.62, 95%CI 1.85 to 3.72; low-certainty evidence). PARPi compared with chemotherapy may result in little or no change in QoL (one study, 229 participants, MD 1.20, 95%CI -1.75 to 4.16; low-certainty evidence). Recurrent, platinum-resistant EOC Two studies compared PARPi with chemotherapy. The certainty of evidence in both studies was graded as very low. Overall, there was minimal information on the QoL and adverse events.

AUTHORS' CONCLUSIONS

PARPi maintenance treatment after chemotherapy may improve PFS in women with newly-diagnosed and recurrent platinum-sensitive EOC; there may be little to no effect on OS, although OS data are immature. Overall, this is likely at the expense of an increase in SevAE. It is  disappointing that data on quality of life outcomes  are relatively sparse. More research is needed to determine whether PARPi have a role to play in platinum-resistant disease.

Poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors as maintenance therapy in women with newly diagnosed ovarian cancer: a systematic review and meta-analysis

PURPOSE

To investigate the efficacy and safety of poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors (including their different types) as maintenance therapy in women with newly diagnosed ovarian cancer, and to explore whether this therapy produces a survival benefit in a subgroup population with specific clinical characteristics.

METHODS

We searched MEDLINE, EMBASE, the Cochrane Library, Web of Science and relevant clinical research registry platforms on October 1, 2019, and included randomized controlled trials (RCTs) that compared PARP inhibitors with placebo in women (aged ≥ 18 years) with newly diagnosed epithelial ovarian cancer.

RESULTS

We identified four RCTs with 3,070 participants. Compared with placebo, PARP inhibitor maintenance therapy showed a clinically significant benefit on progression free survival (PFS) in homologous recombination deficiency (HRD) positive population (hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.29-0.53). In contrast, no clear differences were identified between the groups in the HRD negative population (HR, 0.83; 95% CI 0.67-1.03). Further, there was no clear difference between the groups in terms of other outcomes (overall survival, health-related quality of life, and adverse events).

CONCLUSIONS

PARP inhibitor maintenance therapy significantly prolongs the PFS of patients with newly diagnosed ovarian cancer, especially in HRD positive patients. The diagnostic test used to determine HRD status plays an important role in guiding PARP inhibitor maintenance therapy. Compared with placebo, the effect of PARP inhibitors on ovarian cancer was probably not affected by the International Federation of Gynecology and Obstetrics stage status, response to first-line chemotherapy, and residual macroscopic disease after debulking surgery.