The impact of olaparib dose reduction and treatment interruption on treatment outcome in the SOLO2/ENGOT-ov21 platinum-sensitive recurrent ovarian cancer

Comparison of survival outcomes between olaparib and niraparib maintenance therapy in BRCA-mutated, newly diagnosed advanced ovarian cancer

INTRODUCTION

This multicenter retrospective cohort study aimed to compare survival outcomes and adverse events between maintenance therapy with two poly (ADP-ribose) polymerase (PARP) inhibitors, olaparib and niraparib, in patients with BRCA-mutated, newly diagnosed advanced epithelial ovarian cancer (EOC) who responded to platinum-based chemotherapy.

METHODS

We enrolled stage III-IV EOC patients with germline and/or somatic BRCA1/2 mutations that had received maintenance therapy with olaparib or niraparib. A 3:1 propensity score matching was conducted using two variables: residual disease size and the presence of germline variants. The primary outcome was progression-free survival (PFS), and the secondary outcomes were time to first subsequent therapy (TFST), overall survival (OS), and treatment-emergent adverse events (TEAEs).

RESULTS

In the propensity score-matched analysis, 80 patients who received olaparib and 31 patients who received niraparib were matched (3:1). In the propensity score-matched cohort, median PFS with olaparib vs. niraparib was not reached vs 31.5 months (HR, 1.08; 95% CI, 0.47-2.52; p = 0.854). The median TFST was not reached vs 31.8 months (HR, 1.20; 95% CI, 0.51-2.81; p = 0.682), and neither olaparib nor niraparib reached the median OS (HR, 0.42; 95% CI, 0.01-17.61; p = 0.649). In terms of the incidence rates of any-grade hematologic or non-hematologic TEAEs, higher rates of thrombocytopenia (p = 0.021) and neutropenia (p = 0.011) were observed in the niraparib group.

CONCLUSION

Advanced EOC patients with BRCA1/2 mutations exhibited no significant difference in OS between olaparib and niraparib, indicating the need to consider individualized strategies for selecting PARP inhibitors based on adverse event profiles.

Development and validation of a sensitive LC-MS/MS method for the assay of four PARP inhibitors in human plasma and its application in ovarian cancer patients

PARP inhibitors have demonstrated marked efficacy in ovarian cancer patients with BRCA1/2 loss-of-function mutations. In this study, we established and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) based method to simultaneously quantify the four frequently prescripted PARP inhibitors, namely niraparib, olaparib，fluzoparib, and pamiparib, in ovarian cancer. The mobile phase was 50 % methanol with 0.1 % formic acid at a flow rate of 0.3 mL/min, within 8 min run time. Four PARP inhibitors were separated on a Hypersil GOLD™ aQ C18 Polar Endcapped LC column (50 × 2.1 mm, 1.9 µm) at 35 ℃ and subjected to mass analysis using positive electro-spray ionization (ESI). The linear range of this method was 10-2000 ng/mL, 25-5000 ng/mL, and 50-10,000 ng/mL for niraparib, olaparib and fluzoparib, and pamiparib, respectively, with the correlation coefficients (r2) ≥ 0.99. Accuracies ranged from 93.12 %-110.71 and the inter- and intra-batch precisions were less than 15 % for all analytes in quality control samples. There was no significant matrix effect. Twenty-eight plasma samples were obtained from Sun Yat-sen University Cancer Center. The mean plasma concentrations (±SD) of niraparib and olaparib were 424.76 (±228.35) ng/mL and 1760.47 (±1739.69) ng/mL, respectively. The validated LC-MS/MS method allows the convient and efficient determination of four PARP inhibitors' exposure levels in ovarian cancer patients.

Pamiparib in combination with tislelizumab in patients with advanced solid tumours: results from the dose-expansion stage of a multicentre, open-label, phase I trial

BACKGROUND

The aim of this study was to investigate the antitumour activity, safety, and tolerability of pamiparib plus tislelizumab in patients with previously treated advanced solid tumours.

METHODS

In this study, patients were enrolled into eight arms by tumour type. All received pamiparib 40 mg orally twice daily plus tislelizumab 200 mg intravenously every 3 weeks. The primary endpoint was objective response rate (ORR), assessed by the investigator per Response Evaluation Criteria in Solid Tumours v1.1. Secondary endpoints included duration of response (DoR), safety, and tolerability.

RESULTS

Overall, 180 patients were enrolled. In the overall population, the ORR was 20.0% (range: 0-47.4 across study arms), with median DoR of 17.1 months (95% confidence interval [CI]: 6.2, not estimable [NE]). The highest ORR was observed in the triple-negative breast cancer (TNBC) arm (patients with BRCA1/2 mutations and/or homologous recombination deficiency) (ORR: 47.4%; median DoR: 17.1 months [95% CI: 3.0, NE]). Treatment-emergent adverse events (TEAEs) of ≥Grade 3 occurred in 61.7% of patients. Serious TEAEs occurred in 50.0% of patients.

CONCLUSIONS

Pamiparib plus tislelizumab showed a variable level of antitumour activity in patients with advanced solid tumours, with the highest ORR in TNBC and was associated with a manageable safety profile.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.gov: NCT02660034.

Managing Adverse Effects Associated With Poly (ADP-ribose) Polymerase Inhibitors in Ovarian Cancer: A Synthesis of Clinical Trial and Real-World Data

The use of poly (ADP-ribose) polymerase (PARP) inhibitor therapy is standard care in the management of patients with various malignancies including ovarian, breast, prostate, and pancreatic cancers. PARP inhibitors have been approved in different settings for patients with specific hereditary pathogenic variants, most notably homologous recombination repair pathways such as BRCA1 and BRCA2 genes. The vast experience with PARP inhibitors (olaparib, niraparib, rucaparib) has been in the management of epithelial ovarian cancer. There have not been any head-to-head comparisons of PARP inhibitors in randomized trials, and we can only perform cross-comparison on the basis of the reported literature. The three approved PARP inhibitors share several common adverse effects because of a class effect including nausea, fatigue, and anemia, but there are notable differences likely because of variations in their poly-pharmacology and off-target effects. Finally, patients included in clinical trials are often younger with a good performance status and less comorbidities than the real-world population, and hence, the potential benefits and adverse effects may not be superimposable. In this review, we describe these differences and discuss strategies to mitigate and manage adverse side effects effectively.

Targeted therapy and immunotherapy: Diamonds in the rough in the treatment of epithelial ovarian cancer

Currently, for ovarian cancer, which has the highest mortality rate among all gynecological cancers, the standard treatment protocol is initial tumor cytoreductive surgery followed by platinum-based combination chemotherapy. Although the survival rate after standard treatment has improved, the therapeutic effect of traditional chemotherapy is very limited due to problems such as resistance to platinum-based drugs and recurrence. With the advent of the precision medicine era, molecular targeted therapy has gradually entered clinicians' view, and individualized precision therapy has been realized, surpassing the limitations of traditional therapy. The detection of genetic mutations affecting treatment, especially breast cancer susceptibility gene (BRCA) mutations and mutations of other homologous recombination repair defect (HRD) genes, can guide the targeted drug treatment of patients, effectively improve the treatment effect and achieve a better patient prognosis. This article reviews different sites and pathways of targeted therapy, including angiogenesis, cell cycle and DNA repair, and immune and metabolic pathways, and the latest research progress from preclinical and clinical trials related to ovarian cancer therapy.

Corrected Allele Frequency of BRCA1/2 Mutations Is an Independent Prognostic Factor for Treatment Response to PARP-Inhibitors in Ovarian Cancer Patients

PARP inhibitors (PARPi) have increased treatment options in ovarian cancer, particularly in patients with BRCA1/2 mutations, although there are still marked differences in the duration of patients’ response to this targeted therapy. BRCA testing is routinely performed in tumor tissue of ovarian cancer patients. The resulting molecular pathological findings include the genetic nomenclature of the mutation, the frequency of the mutated allele (variant allele frequency, VAF), and the tumor cell content. VAF measures the percentage of mutated alleles from the total alleles in the cells of the examined tissue. The aim of this study was to investigate the significance of VAF on the therapeutic response to PARPis in ovarian cancer patients. Epithelial ovarian cancer patients harboring BRCA1/2 tumor mutations, who underwent germline testing and received PARPi therapy at the Medical University of Vienna (n = 41) were included in the study. Corrected VAF (cVAF) was calculated based on VAF, tumor cell content, and germline mutation. Patients were divided into two groups based on their cVAF. Median PFS under PARPi in patients with low cVAF was 13.0 months (IQR [10.3-not reached]) and was not reached in the high cVAF group. High cVAF was significantly associated with longer PFS in the multivariate analysis (HR = 0.07; 95% CI [0.01–0.63]; p = 0.017). In conclusion, high cVAF was associated with a significantly better response to PARPi in this study population.