Auger emitter in combination with Olaparib suppresses tumor growth via promoting antitumor immune responses in pancreatic cancer.

The present study aimed to clarify the hypothesis that auger emitter 125I particles in combination with PARP inhibitor Olaparib could inhibit pancreatic cancer progression by promoting antitumor immune response. Pancreatic cancer cell line (Panc02) and mice subcutaneously inoculated with Panc02 cells were employed for the in vitro and in vivo experiments, respectively, followed by 125I and Olaparib administrations. The apoptosis and CRT exposure of Panc02 cells were detected using flow cytometry assay. QRT-PCR, immunofluorescence, immunohistochemical analysis, and western blot were employed to examine mRNA and protein expression. Experimental results showed that 125I combined with Olaparib induced immunogenic cell death and affected antigen presentation in pancreatic cancer. 125I in combination with Olaparib influenced T cells and dendritic cells by up-regulating CD4, CD8, CD69, Caspase3, CD86, granzyme B, CD80, and type I interferon (IFN)-γ and down-regulating Ki67 in vivo. The combination also activated the cyclic GMP-AMP synthase stimulator of IFN genes (Sting) pathway in Panc02 cells. Moreover, Sting knockdown alleviated the effect of the combination of 125I and Olaparib on pancreatic cancer progression. In summary, 125I in combination with Olaparib inhibited pancreatic cancer progression through promoting antitumor immune responses, which may provide a potential treatment for pancreatic cancer.

Design, synthesis, and biological evaluation of pyrido[2,3-d]pyrimidin-7(8H)-one derivatives as potent USP1 inhibitors.

USP1 has emerged as a novel and potential target for drug discovery in single therapeutic agents or combination with chemotherapy and molecular targeted therapy. In this study, based on the disclosed structure of ML323 and KSQ-4279, we designed and synthesized a series of pyrido[2,3-d]pyrimidin-7(8H)-one derivatives as potent USP1 inhibitors by cyclization strategy and the systematic structure-activity relationship exploration was conducted. The representative compounds 1k, 1m and 2d displayed excellent USP1/UAF inhibition and exhibited strong antiproliferation effect in NCI-H1299 cells. Further flow cytometry analysis revealed that they could arrest breast cancer cells MDA-MB-436 in the S phase. Inhibition mechanism study of compound 1m indicated these derivatives acted as reversible and noncompetitive USP1 inhibitors. Of note, the combination of compound 1m with PARP inhibitor olaparib generated enhanced cell killing in olaparib-resistant MDA-MB-436/OP cells, and compound 1m exhibited excellent oral pharmacokinetic properties in mice. Overall, our efforts may provide a reliable basis for the development of novel USP1 inhibitor as a single therapeutic agent and in combination with PARP inhibitors.

Olaparib in recurrent isocitrate dehydrogenase mutant high-grade glioma: A phase 2 multicenter study of the POLA Network.

Background: Based on preclinical studies showing that IDH-mutant (IDHm) gliomas could be vulnerable to PARP inhibition we launched a multicenter phase 2 study to test the efficacy of olaparib monotherapy in this population. Methods: Adults with recurrent IDHm high-grade gliomas (HGGs) after radiotherapy and at least one line of alkylating chemotherapy were enrolled. The primary endpoint was a 6-month progression-free survival rate (PFS-6) according to response assessment in neuro-oncology criteria. Pre-defined threshold for study success was a PFS-6 of at least 50%. Results: Thirty-five patients with recurrent IDHm HGGs were enrolled, 77% at ≥ 2nd recurrence. Median time since diagnosis and radiotherapy were 7.5 years and 33 months, respectively. PFS-6 was 31.4% (95% CI [16.9; 49.3%]). Two patients (6%) had an objective response and 14 patients (40%) had a stable disease as their best response. Median PFS and median overall survival were 2.05 and 15.9 months, respectively. Oligodendrogliomas (1p/19q codeleted) had a higher PFS-6 (53.4% vs. 15.7%, P = .05) than astrocytomas while an initial diagnosis of grade 4 astrocytoma tended to be associated with a lower PFS-6 compared to grade 2/3 gliomas (0% vs 31.4%, P = .16). A grade 2 or 3 treatment-related adverse event was observed in 15 patients (43%) and 5 patients (14%), respectively. No patient definitively discontinued treatment due to side effects. Conclusions: Although it did not meet its primary endpoint, the present study shows that in this heavily pretreated population, olaparib monotherapy was well tolerated and resulted in some activity, supporting further PARP inhibitors evaluation in IDHm HGGs, especially in oligodendrogliomas.

Chemo-phosphoproteomic profiling with ATR inhibitors berzosertib and gartisertib uncovers new biomarkers and DNA damage response regulators.

The ATR kinase protects cells against DNA damage and replication stress and represents a promising anti-cancer drug target. The ATR inhibitors (ATRi) berzosertib and gartisertib are both in clinical trials for the treatment of advanced solid tumours as monotherapy or in combination with genotoxic agents. We carried out quantitative phospho-proteomic screening for ATR biomarkers that are highly sensitive to berzosertib and gartisertib, using an optimized mass spectrometry pipeline. Screening identified a range of novel ATR-dependent phosphorylation events, which were grouped into three broad classes: i) targets whose phosphorylation is highly sensitive to ATRi and which could be the next generation of ATR biomarkers; ii) proteins with known genome maintenance roles not previously known to be regulated by ATR; iii) novel targets whose cellular roles are unclear. Class iii targets represent candidate DNA damage response proteins and, with this in mind, proteins in this class were subjected to secondary screening for recruitment to DNA damage sites. We show that one of the proteins recruited, SCAF1, interacts with RNAPII in a phospho-dependent manner and recruitment requires PARP activity and interaction with RNAPII. We also show that SCAF1 deficiency partly rescues RAD51 loading in cells lacking the BRCA1 tumour suppressor. Taken together these data reveal potential new ATR biomarkers and new genome maintenance factors.

Triple Combinations of Histone Lysine Demethylase Inhibitors with PARP1 Inhibitor-Olaparib and Cisplatin Lead to Enhanced Cytotoxic Effects in Head and Neck Cancer Cells.

PARP inhibitors are used to treat cancers with a deficient homologous recombination (HR) DNA repair pathway. Interestingly, recent studies revealed that HR repair could be pharmacologically impaired by the inhibition of histone lysine demethylases (KDM). Thus, we investigated whether KDM inhibitors could sensitize head and neck cancer cells, which are usually HR proficient, to PARP inhibition or cisplatin. Therefore, we explored the effects of double combinations of KDM4-6 inhibitors (ML324, CPI-455, GSK-J4, and JIB-04) with olaparib or cisplatin, or their triple combinations with both drugs, on the level of DNA damage and apoptosis. FaDu and SCC-040 cells were treated with individual compounds and their combinations, and cell viability, apoptosis, DNA damage, and gene expression were assessed using the resazurin assay, Annexin V staining, H2A.X activation, and qPCR, respectively. Combinations of KDM inhibitors with cisplatin enhanced cytotoxic effects, unlike combinations with olaparib. Triple combinations of KDM inhibitors with cisplatin and olaparib exhibited the best cytotoxic activity, which was associated with DNA damage accumulation and altered expression of genes associated with apoptosis induction and cell cycle arrest. In conclusion, triple combinations of KDM inhibitors (especially GSK-J4 and JIB-04) with cisplatin and olaparib represent a promising strategy for head and neck cancer treatment.

BUB1 Inhibition Sensitizes TNBC Cell Lines to Chemotherapy and Radiotherapy.

BUB1 is overexpressed in most human solid cancers, including breast cancer. Higher BUB1 levels are associated with a poor prognosis, especially in patients with triple-negative breast cancer (TNBC). Women with TNBC often develop resistance to chemotherapy and radiotherapy, which are still the mainstay of treatment for TNBC. Our previous studies demonstrated that a BUB1 kinase inhibitor (BAY1816032) reduced tumor cell proliferation and significantly enhanced radiotherapy efficacy in TNBC. In this study, we evaluated the effectiveness of BAY1816032 with a PARP inhibitor (olaparib), platinum agent (cisplatin), and microtubule poison (paclitaxel) alone or in combination with radiotherapy using cytotoxicity and clonogenic survival assays. BUB1 inhibitors sensitized BRCA1/2 wild-type SUM159 and MDA-MB-231 cells to olaparib, cisplatin, and paclitaxel synergistically (combination index; CI < 1). BAY1816032 significantly increased the radiation sensitization of SUM159 and MDA-MB-231 by olaparib, cisplatin, or paclitaxel at non-toxic concentrations (doses well below the IC50 concentrations). Importantly, the small molecular inhibitor of BUB1 synergistically (CI < 1) sensitized the BRCA mutant TNBC cell line HCC1937 to olaparib. Furthermore, the BUB1 inhibitor significantly increased the radiation enhancement ratio (rER) in HCC1937 cells (rER 1.34) compared to either agent alone (BUB1i rER 1.19; PARPi rER 1.04). The data presented here are significant as they provide proof that inhibition of BUB1 kinase activity sensitizes TNBC cell lines to a PARP inhibitor and radiation, irrespective of BRCA1/2 mutation status. Due to the ability of the BUB1 inhibitor to sensitize TNBC to different classes of drugs (platinum, PARPi, microtubule depolarization inhibitors), this work strongly supports the role of BUB1 as a novel molecular target to improve chemoradiation efficacy in TNBC and provides a rationale for the clinical evaluation of BAY1816032 as a chemosensitizer and chemoradiosensitizer in TNBC.

A phase 2 trial exploring the significance of homologous recombination status in patients with platinum sensitive or platinum resistant relapsed ovarian cancer receiving combination cediranib and olaparib.

OBJECTIVE: Combination cediranib/olaparib has reported activity in relapsed ovarian cancer. This phase 2 trial investigated the activity of cediranib/olaparib in relapsed ovarian cancer and its association with homologous recombination deficiency (HRD). METHODS: Seventy patients were enrolled to cohorts of either platinum-sensitive or platinum-resistant ovarian cancer and received olaparib tablets 200 mg twice daily and cediranib tablets 30 mg once daily under a continuous dosing schedule. HRD testing was performed on pre-treatment, on-treatment and archival biopsies by sequencing key homologous recombination repair (HRR) genes and by genomic LOH analysis. The primary objective for the platinum-sensitive cohort was the association of HRD, defined as presence of HRR gene mutation, with progression-free survival (PFS). The primary objective for the platinum-resistant cohort was objective response rate (ORR), with a key secondary endpoint evaluating the association of HRD status with activity. RESULTS: In platinum-sensitive ovarian cancer (N = 35), ORR was 77.1% (95% CI 59.9-89.6%) and median PFS was 16.4 months (95% CI 13.2-18.6). Median PFS in platinum-sensitive HRR-HRD cancers (N = 22) was 16.8 months (95% CI 11.3-18.6), and 16.4 months (95% CI 9.4-NA) in HRR-HR proficient cancers (N = 13; p = 0.57). In platinum-resistant ovarian cancer (N = 35), ORR was 22.9% (95% CI 10.4-40.1%) with median PFS 6.8 months (95% CI 4.2-9.1). Median PFS in platinum-resistant HRR-HRD cancers (N = 7) was 10.5 months (95% CI 3.6-NA) and 5.6 months (95% CI 3.6-7.6) in HRR-HR proficient cancers (N = 18; p = 0.23). CONCLUSIONS: Cediranib/olaparib had clinical activity in both platinum-sensitive and -resistant ovarian cancer. Presence of HRR gene mutations was not associated with cediranib/olaparib activity in either setting.

Uncovering miRNA-mRNA Regulatory Networks Related to Olaparib Resistance and Resensitization of BRCA2MUT Ovarian Cancer PEO1-OR Cells with the ATR/CHK1 Pathway Inhibitors.

Resistance to olaparib is the major obstacle in targeted therapy for ovarian cancer (OC) with poly(ADP-ribose) polymerase inhibitors (PARPis), prompting studies on novel combination therapies to enhance olaparib efficacy. Despite identifying various mechanisms, understanding how OC cells acquire PARPi resistance remains incomplete. This study investigated microRNA (miRNA) expression in olaparib-sensitive (PEO1, PEO4) and previously established olaparib-resistant OC cell lines (PEO1-OR) using high-throughput RT-qPCR and bioinformatic analyses. The role of miRNAs was explored regarding acquired resistance and resensitization with the ATR/CHK1 pathway inhibitors. Differentially expressed miRNAs were used to construct miRNA-mRNA regulatory networks and perform functional enrichment analyses for target genes with miRNet 2.0. TCGA-OV dataset was analyzed to explore the prognostic value of selected miRNAs and target genes in clinical samples. We identified potential processes associated with olaparib resistance, including cell proliferation, migration, cell cycle, and growth factor signaling. Resensitized PEO1-OR cells were enriched in growth factor signaling via PDGF, EGFR, FGFR1, VEGFR2, and TGFßR, regulation of the cell cycle via the G2/M checkpoint, and caspase-mediated apoptosis. Antibody microarray analysis confirmed dysregulated growth factor expression. The addition of the ATR/CHK1 pathway inhibitors to olaparib downregulated FGF4, FGF6, NT-4, PLGF, and TGFß1 exclusively in PEO1-OR cells. Survival and differential expression analyses for serous OC patients revealed prognostic miRNAs likely associated with olaparib resistance (miR-99b-5p, miR-424-3p, and miR-505-5p) and resensitization to olaparib (miR-324-5p and miR-424-3p). Essential miRNA-mRNA interactions were reconstructed based on prognostic miRNAs and target genes. In conclusion, our data highlight distinct miRNA profiles in olaparib-sensitive and olaparib-resistant cells, offering molecular insights into overcoming resistance with the ATR/CHK1 inhibitors in OC. Moreover, some miRNAs might serve as potential predictive signature molecules of resistance and therapeutic response.

Olaparib for childhood tumors harboring defects in DNA damage repair genes: arm H of the NCI-COG Pediatric MATCH trial.

BACKGROUND: The National Cancer Institute-Children's Oncology Group Pediatric Molecular Analysis for Therapy Choice (MATCH) precision oncology platform trial enrolled children aged 1-21 years with treatment-refractory solid tumors and predefined actionable genetic alterations. Patients with tumors harboring alterations in DNA damage repair (DDR) genes were assigned to receive olaparib. METHODS: Tumor and blood samples were submitted for centralized molecular testing. Tumor and germline sequencing were conducted in parallel. Olaparib was given twice daily for 28-day cycles starting at a dose 30% lower than the adult recommended phase 2 dose (RP2D). The primary endpoint was the objective response. RESULTS: Eighteen patients matched (1.5% of those screened) based on the presence of a deleterious gene alteration in BRCA1/2, RAD51C/D, or ATM detected by tumor sequencing without germline subtraction or analysis of loss of heterozygosity (LOH). Eleven (61%) harbored a germline mutation, with only one exhibiting LOH. Six patients enrolled and received the olaparib starting dose of 135 mg/m2/dose. Two participants were fully evaluable; 4 were inevaluable because <85% of the prescribed dose was administered during cycle 1. There were no dose-limiting toxicities or responses. Minimal hematologic toxicity was observed. CONCLUSION: Most DDR gene alterations detected in Pediatric MATCH were germline, monoallelic, and unlikely to confer homologous recombination deficiency predicting sensitivity to olaparib monotherapy. The study closed due to poor accrual. CLINICALTRIALS.GOV IDENTIFIER: NCT03233204. IRB approved: initial July 24, 2017.

Olaparib maintenance therapy for platinum-sensitive relapsed ovarian cancer at a single institution: A retrospective study.

AIM: In this study, we aimed to investigate patient characteristics, efficacy, prognostic factors, and safety of olaparib maintenance therapy for platinum-sensitive recurrent ovarian cancer at our institution. METHODS: Patients responding to platinum-based therapy and starting olaparib maintenance therapy for recurrent epithelial ovarian, fallopian tube, or peritoneal cancer at Kurume University Hospital between January 2018 and November 2021 were enrolled in the study. Their data were extracted retrospectively from medical records. RESULTS: In all, 50 patients were included. The median (range) age of the patients, follow-up time, and duration of olaparib maintenance therapy were 62 (39-87) years, 21.6 (2.2-45.9) months, and 7.2 (2-45.9) months, respectively. Among the 29 patients tested for homologous recombination (HR) status, 22 (75.9%) were positive for HR deficiency (HRD), 12 (54.5%) of whom had BRCA-positive tumors. The median progression-free survival was 8.9 months (95% confidence interval: 6.2-12.6), and the median overall survival was 27.1 months (95% confidence interval: 22.5-40.3). Multivariate analysis of prognostic factors revealed that HRD was an independent prognostic factor for both progression-free survival and overall survival. The most common adverse event was nausea (any grade, n = 30, 60%), resulting in drug interruption (n = 23, 46%), dose reduction (n = 17, 34%), and discontinuation of treatment (n = 1, 2%). CONCLUSION: Olaparib maintenance therapy for recurrent platinum-sensitive ovarian cancer at our institution was effective, with acceptable adverse events. HRD was the most significant prognostic factor for patients with recurrent platinum-sensitive ovarian cancer.

Predictors of olaparib discontinuation owing to adverse drug events in patients with ovarian, peritoneal, or fallopian tube cancer: a retrospective observational study.

We investigated predictors of olaparib discontinuation owing to adverse effects. Patients with ovarian, peritoneal, or fallopian tube cancers treated with olaparib at Osaka Medical and Pharmaceutical University Hospital between April 2018 and September 2022 were included in this study. The exclusion criteria were as follows: discontinuation of treatment due to disease progression, use of anaemia medications, and use of cytochrome P450 (CYP3A4) inhibitors. The follow-up period was 90 d. Of the 46 eligible patients, 21 patients discontinued olaparib, including 15 patients with grade 3 or higher anaemia, eight patients with grade 3 or higher neutropenia, and four patients with non-haematological toxicity (including multiple onset). Multivariate logistic regression analysis showed that grade 4 neutropenia and anaemia progression to grades 2-3 due to chemotherapy administered before olaparib administration were predictors of olaparib discontinuation. The severity of neutropenia and anaemia due to chemotherapy before olaparib administration may be a potential marker for its discontinuation.

BRCA testing and management of BRCA-mutated early-stage breast cancer: a comprehensive statement by expert group from GCC region.

BReast CAncer (BRCA)1 and BRCA2 gene pathogenic variants account for most hereditary breast cancers (BC). Identification of BRCA mutations can significantly influence both prognosis and treatment outcomes. Furthermore, it enables the identification of individuals who are at heightened risk of developing BC due to inherited genetic mutations. Many developing countries rely on western guidelines for BRCA testing and BC management; however, there exist wide disparities in the prevalence of risk factors, availability of medical resources, and practice patterns. Guidelines tailored to specific regions can help mitigate healthcare variations, promote consistency in treatment, and aid healthcare providers in identifying effective therapies for improving patient outcomes. Hence, oncologists from the Gulf Cooperation Council (GCC) congregated virtually in March 2023 and reviewed existing data on the epidemiology of BC, BRCA mutations, practices and challenges associated with BRCA testing and management of BRCA mutated early-stage BC in the GCC region. They also provided insights on the real-world diagnostic and treatment practices and challenges in the GCC region in the BRCA-mutated early-stage BC domain and suggested some variations to international guidelines to aid their uptake in this region.

Combining inotuzumab ozogamicin with PARP inhibitors olaparib and talazoparib exerts synergistic cytotoxicity in acute lymphoblastic leukemia by inhibiting DNA strand break repair.

Inotuzumab ozogamicin (IO), a novel therapeutic drug for relapsed or refractory acute lymphoblastic leukemia (RR)­(ALL), is a humanized anti­cluster of differentiation (CD) 22 monoclonal antibody conjugated with calicheamicin that causes DNA single­ and double­strand breaks. Although the efficacy of IO is significantly improved compared with that of conventional chemotherapies, the prognosis for RR­ALL remains poor, highlighting the need for more effective treatment strategies. The present study examined the role of DNA damage repair inhibition using the poly (ADP­ribose) polymerase (PARP) inhibitors olaparib or talazoparib on the enhancement of the antitumor effects of IO on B­ALL cells in vitro. The Reh, Philadelphia (Ph)­B­ALL and the SUP­B15 Ph+ B­ALL cell lines were used for experiments. Both cell lines were ~90% CD22+. The half­maximal inhibitory concentration (IC50) values of IO were 5.3 and 49.7 ng/ml for Reh and SUP­B15 cells, respectively. The IC50 values of IO combined with minimally toxic concentrations of olaparib or talazoparib were 0.8 and 2.9 ng/ml for Reh cells, respectively, and 36.1 and 39.6 ng/ml for SUP­B15 cells, respectively. The combination index of IO with olaparib and talazoparib were 0.19 and 0.56 for Reh cells and 0.76 and 0.89 for SUP­B15 cells, demonstrating synergistic effects in all combinations. Moreover, the addition of minimally toxic concentrations of PARP inhibitors augmented IO­induced apoptosis. The alkaline comet assay, which quantitates the amount of DNA strand breaks, was used to investigate the degree to which DNA damage observed 1 h after IO administration was repaired 6 h later, reflecting successful repair of DNA strand breaks. However, DNA strand breaks persisted 6 h after IO administration combined with olaparib or talazoparib, suggesting inhibition of the repair processes by PARP inhibitors. Adding olaparib or talazoparib thus synergized the antitumor effects of IO by inhibiting DNA strand break repair via the inhibition of PARP.

Olaparib with or without bevacizumab versus bevacizumab plus a fluoropyrimidine as maintenance therapy in advanced colorectal cancer: The randomized phase 3 LYNK-003 study.

BACKGROUND: The randomized, open-label, phase III LYNK-003 study assessed the efficacy of first-line maintenance olaparib, alone or in combination with bevacizumab, versus bevacizumab plus a fluoropyrimidine in participants with unresectable or metastatic colorectal cancer (mCRC). We present results of the prespecified interim futility analysis. METHODS: Eligible participants were ≥18 years of age with unresectable or mCRC that had not progressed after induction with first-line bevacizumab plus 5-fluorouracil plus oxaliplatin plus leucovorin (FOLFOX) or capecitabine plus oxaliplatin (CAPOX). Participants were randomly assigned 1:1:1 to olaparib plus bevacizumab, olaparib alone, or bevacizumab plus a fluoropyrimidine (5-fluorouracil or capecitabine). The primary end point was progression-free survival (PFS) per RECIST v1.1 by central review. RESULTS: Between August 2020 and May 2022, 309 participants were assigned to olaparib plus bevacizumab (n = 104), olaparib (n = 107), or bevacizumab plus fluoropyrimidine (n = 98). At interim analysis, with a median follow-up of 7.6 months (range 0.1-19.7 months), the median PFS was 3.7 months (95% CI 2.8-5.3) with olaparib plus bevacizumab (HR 1.52; 95% CI 1.02-2.27; P = 0.982) and 3.5 months (95% CI 2.0-3.7) with olaparib (HR 2.11; 95% CI 1.39-3.18; P = 0.999) versus 5.6 months (95% CI 3.8-5.9) with bevacizumab plus fluoropyrimidine. Treatment-related adverse events occurred in 64 (62%), 52 (50%), and 57 (59%) participants, respectively. There were no treatment-related deaths. CONCLUSION: The LYNK-003 study was stopped prematurely as criteria for futility were met. Maintenance olaparib with or without bevacizumab did not demonstrate clinical efficacy compared with bevacizumab plus a fluoropyrimidine. GOV REGISTRATION: NCT04456699.

Exploratory biomarker analysis in the phase III L-MOCA study of olaparib maintenance therapy in patients with platinum-sensitive relapsed ovarian cancer.

BACKGROUND: The prospective phase III multi-centre L-MOCA trial (NCT03534453) has demonstrated the encouraging efficacy and manageable safety profile of olaparib maintenance therapy in the Asian (mainly Chinese) patients with platinum-sensitive relapsed ovarian cancer (PSROC). In this study, we report the preplanned exploratory biomarker analysis of the L-MOCA trial, which investigated the effects of homologous recombination deficiency (HRD) and programmed cell death ligand 1 (PD-L1) expression on olaparib efficacy. METHODS: HRD status was determined using the ACTHRD assay, an enrichment-based targeted next-generation sequencing assay. PD-L1 expression was assessed by SP263 immunohistochemistry assay. PD-L1 expression positivity was defined by the PD-L1 expression on ≥ 1% of immune cells. Kaplan-Meier method was utilised to analyse progression-free survival (PFS). RESULTS: This exploratory biomarker analysis included 225 patients and tested HRD status [N = 190; positive, N = 125 (65.8%)], PD-L1 expression [N = 196; positive, N = 56 (28.6%)], and BRCA1/2 mutation status (N = 219). The HRD-positive patients displayed greater median PFS than the HRD-negative patients [17.9 months (95% CI: 14.5-22.1) versus 9.2 months (95% CI: 7.5-13.8)]. PD-L1 was predominantly expressed on immune cells. Positive PD-L1 expression on immune cells was associated with shortened median PFS in the patients with germline BRCA1/2 mutations [14.5 months (95% CI: 7.4-18.2) versus 22.2 months (95% CI: 18.3-NA)]. Conversely, positive PD-L1 expression on immune cells was associated with prolonged median PFS in the patients with wild-type BRCA1/2 [20.9 months (95% CI: 13.9-NA) versus 8.3 months (95% CI: 6.7-13.8)]. CONCLUSIONS: HRD remained an effective biomarker for enhanced olaparib efficacy in the Asian patients with PSROC. Positive PD-L1 expression was associated with decreased olaparib efficacy in the patients with germline BRCA1/2 mutations but associated with improved olaparib efficacy in the patients with wild-type BRCA1/2. TRIAL REGISTRATION: NCT03534453. Registered at May 23, 2018.

First-line combination treatment with PARP and androgen receptor-signaling inhibitors in HRR-deficient mCRPC: Applying clinical study findings to clinical practice in the United States.

INTRODUCTION: Metastatic castration-resistant prostate cancer (mCRPC) remains incurable and develops from biochemically recurrent PC treated with androgen deprivation therapy (ADT) following definitive therapy for localized PC, or from metastatic castration-sensitive PC (mCSPC). In the mCSPC setting, treatment intensification of ADT plus androgen receptor (AR)-signaling inhibitors (ARSIs), with or without chemotherapy, improves outcomes vs ADT alone. Despite multiple phase 3 trials demonstrating a survival benefit of treatment intensification in PC, there remains high use of ADT monotherapy in real-world clinical practice. Prior studies indicate that co-inhibition of AR and poly(ADP-ribose) polymerase (PARP) may result in enhanced benefit in treating tumors regardless of alterations in DNA damage response genes involved either directly or indirectly in homologous recombination repair (HRR). Three recent phase 3 studies evaluated the combination of a PARP inhibitor (PARPi) with an ARSI as first-line treatment for mCRPC: TALAPRO-2, talazoparib plus enzalutamide; PROpel, olaparib plus abiraterone acetate and prednisone (AAP); and MAGNITUDE, niraparib plus AAP. Results from these studies have led to the recent approval in the United States of talazoparib plus enzalutamide for the treatment of mCRPC with any HRR alteration, and of both olaparib and niraparib indicated in combination with AAP for the treatment of mCRPC with BRCA alterations. SUMMARY: Here, we review the newly approved PARPi plus ARSI treatments within the context of the mCRPC treatment landscape, provide an overview of practical considerations for the combinations in clinical practice, highlight the importance of HRR testing, and discuss the benefits of treatment intensification for patients with mCRPC.

Real-world data of poly (ADP-ribose) polymerase inhibitor response in Japanese patients with ovarian cancer.

BACKGROUND: Poly (ADP-ribose) polymerase (PARP) inhibitors have been increasingly used in the treatment of ovarian cancer, with BRCA positivity and homologous recombination deficiency (HRD) being common biomarkers used for predicting their efficacy. However, given the limitations of these biomarkers, new ones need to be explored. METHODS: This retrospective study included 181 ovarian cancer patients who received olaparib or niraparib at two independent hospitals in Japan between May 2018 and December 2022. Clinical information and blood sampling data were collected. Patient characteristics, treatment history, and predictability of treatment duration based on blood data before treatment initiation were examined. RESULTS: High-grade serous carcinoma, BRCA positivity, HRD, and maintenance therapy after recurrence treatment were observed more frequently in the olaparib group than in the niraparib group. The most common reasons for treatment interruption were anemia, fatigue, and nausea in the olaparib group and thrombocytopenia in the niraparib group. Regarding response to olaparib treatment, complete response to the most recent treatment, maintenance therapy after the first chemotherapy, high-grade serous carcinoma, and germline BRCA positivity were observed significantly more frequently among responders than among non-responders. Furthermore, neutrophil counts were significantly higher among responders than among non-responders. CONCLUSIONS: Inflammation-related blood data, such as neutrophil count, obtained at the initial pre-treatment visit might serve as potential predictors for prolonged olaparib treatment. While this study offers valuable insights into potential indicators for prolonged olaparib treatment, it underscores the need for more expansive research to strengthen our understanding of PARP inhibitors and optimize treatment strategies in ovarian cancer.

Tolerability of Olaparib Combined with Abiraterone in Patients with Metastatic Castration-resistant Prostate Cancer: Further Results from the Phase 3 PROpel Trial.

BACKGROUND: The PROpel study (NCT03732820) demonstrated a statistically significant progression-free survival benefit with olaparib plus abiraterone versus placebo plus abiraterone in the first-line metastatic castration-resistant prostate cancer (mCRPC) setting, irrespective of homologous recombination repair mutation status. OBJECTIVE: We report additional safety analyses from PROpel to increase clinical understanding of the adverse-event (AE) profiles of olaparib plus abiraterone versus placebo plus abiraterone. DESIGN, SETTING, AND PARTICIPANTS: A randomised (1:1), double-blind, placebo-controlled trial was conducted at 126 centres in 17 countries (October 2018-January 2020). Patients had mCRPC and no prior systemic mCRPC treatment. INTERVENTION: Olaparib (300 mg bid) or placebo with abiraterone (1000 mg od) plus prednisone/prednisolone (5 mg bid). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The data cut-off date was July 30, 2021. Safety was assessed by AE reporting (Common Terminology Criteria for Adverse Events v4.03) and analysed descriptively. RESULTS AND LIMITATIONS: The most common AEs (all grades) for olaparib plus abiraterone versus placebo plus abiraterone were anaemia (46.0% vs 16.4%), nausea (28.1% vs 12.6%), and fatigue (27.9% vs 18.9%). Grade ≥3 anaemia occurred in 15.1% versus 3.3% of patients in the olaparib plus abiraterone versus placebo plus abiraterone arm. The incidences of the most common AEs for olaparib plus abiraterone peaked early, within 2 mo, and were managed typically by dose modifications or standard medical practice. Overall, 13.8% versus 7.8% of patients discontinued treatment with olaparib plus abiraterone versus placebo plus abiraterone because of an AE; 3.8% versus 0.8% of patients discontinued because of anaemia. More venous thromboembolism events were observed in the olaparib plus abiraterone arm (any grade, 7.3%; grade ≥3, 6.8%) than in the placebo plus abiraterone arm (any grade, 3.3%; grade ≥3, 2.0%), most commonly pulmonary embolism (6.5% vs 1.8% for olaparib plus abiraterone vs placebo plus abiraterone). CONCLUSIONS: Olaparib plus abiraterone has a manageable and predictable safety profile. PATIENT SUMMARY: The PROpel trial showed that in patients who had not received any previous treatment for metastatic castration-resistant prostate cancer, olaparib combined with abiraterone was more effective in delaying progression of the disease than abiraterone alone. Most side effects caused by combining olaparib with abiraterone could be managed with supportive care methods, by pausing olaparib administration for a short period of time and/or by reducing the dose of olaparib.

Case report: Emerging BRCA mutation confers benefit from olaparib after chemotherapy intolerance in advanced triple-negative breast cancer.

Key Clinical Message: In a patient with metastatic breast cancer, an acquired BRCA mutation in the BRCA gene was detected, resulting in benefits from olaparib treatment. This underscores the importance of ongoing genetic phenotype testing after paclitaxel chemotherapy. Abstract: Triple-negative breast cancer (TNBC) is associated with a poor prognosis and elevated mortality risk. BRCA mutations are commonly regarded as prevalent mutations in TNBC patients, strongly associated with congenital familial heredity. Dynamic changes in mutation sites, however, are rarely reported. In this case report, we report a 59-year-old TNBC patient who developed pulmonary metastases post-chemoradiotherapy. No BRCA mutations were detected through NGS. After 7.6 months of nab-paclitaxel treatment, the patient experienced progression of lung metastases, and BRCA mutations were detected through NGS testing. Subsequent administration of olaparib resulted in a reduction in lung metastasis, demonstrating significant therapeutic efficacy. This case underscores the infrequent occurrence of treatment-induced BRCA mutations and emphasizes the significance of dynamic NGS genetic testing for real-time assessment of a patient's mutational status.