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Abstract Background In PAOLA-1/ENGOT-ov25, the addition of olaparib to bevacizumab maintenance improved overall survival in patients with newly diagnosed advanced ovarian cancer. We describe the safety profile and quality of life (QoL) of this combination in older patients in PAOLA-1. Methods Safety (CTCAE v4.03) and QoL (EORTC QoL Questionnaires Core 30 and Ovarian 28) data were collected. We compared safety by age (≥70 vs <70 years) in the olaparib-containing arm. QoL by treatment arm was assessed in older patients. Geriatric features, including Geriatric Vulnerability Score (GVS), were also gathered. Results Of 806 patients randomized, 142 were ≥70 years old (olaparib-containing arm: n = 104; placebo arm: n = 38). Older patients treated with olaparib exhibited a similar safety profile to younger patients, except for higher rates of all grades of lymphopenia and grade ≥3 hypertension (31.7% vs 21.6%, P =.032 and 26.9% vs 16.7%, P =.019, respectively). No hematological malignancy was reported. Two years after randomization, mean Global Health Status and cognitive functioning seemed better with olaparib than bevacizumab alone (adjusted mean difference: +4.47 points [95% CI, −0.49 to 9.42] and +4.82 [−0.57 to 10.21], respectively), and other QoL items were similar between arms. In the olaparib-containing arm, older patients with baseline GVS ≥ 1 (n = 48) exhibited increased toxicity and poorer QoL than those with GVS of 0 (n = 34). Conclusion Among older patients in PAOLA-1, olaparib plus bevacizumab had a manageable safety profile and no adverse impact on QoL. Additional data are required to confirm these results in more vulnerable patients. (ClinicalTrials.gov Identifier: NCT02477644).

Background Olaparib is poorly soluble, requiring advanced drug delivery technologies for adequate bioavailability. Sixteen capsules/day are required for the approved 400 mg twice-daily dose; a tablet formulation was developed to reduce pill burden. This clinical trial evaluated the optimal dose and administration schedule of the tablet formulation. Patients and Methods Two stages of sequentially enrolled cohorts: stage 1, pharmacokinetic properties of tablet and capsule formulations were compared in patients with advanced solid tumours; stage 2, tablet dose escalation with expansion cohorts at doses/schedules of interest in patients with solid tumours and BRCA m breast/ovarian cancers. Results Olaparib 200 mg tablets displayed similar C max,ss , but lower AUC ss and C min,ss than 400 mg capsules. Following multiple dosing, steady-state exposure with tablets ≥300 mg matched or exceeded that of 400 mg capsules. After dose escalation, while 400 mg twice daily was the tablet maximum tolerated dose based on haematological toxicity, 65 % of patients in the randomized expansion phase eventually required dose reduction to 300 mg. Intermittent tablet administration did not significantly improve tolerability. Tumour shrinkage was similar for 300 and 400 mg tablet and 400 mg capsule cohorts. Conclusions The recommended monotherapy dose of olaparib tablet for Phase III trials was 300 mg twice daily, simplifying drug administration from 16 capsules to four tablets per day. Clinical Trial Number NCT00777582 (ClinicalTrials.gov)

BACKGROUNDClinical trials have suggested antitumor activity from PARP inhibition beyond homologous recombination deficiency (HRD). RNASEH2B loss is unrelated to HRD and preclinically sensitizes to PARP inhibition. The current study reports on RNASEH2B protein loss in advanced prostate cancer and its association with RB1 protein loss, clinical outcome, and clonal dynamics during treatment with PARP inhibition in a prospective clinical trial.METHODSWhole tumor biopsies from multiple cohorts of patients with advanced prostate cancer were interrogated using whole-exome sequencing (WES), RNA-Seq (bulk and single nucleus), and IHC for RNASEH2B and RB1. Biopsies from patients treated with olaparib in the TOPARP-A and TOPARP-B clinical trials were used to evaluate RNASEH2B clonal selection during olaparib treatment.RESULTSShallow codeletion of RNASEH2B and adjacent RB1 - colocated at chromosome 13q14 - was common, deep codeletion infrequent, and gene loss associated with lower mRNA expression. In castration-resistant prostate cancer (CRPC) biopsies, RNASEH2B and RB1 mRNA expression correlated, but single nucleus RNA-Seq indicated discordant loss of expression. IHC studies showed that loss of the 2 proteins often occurred independently, arguably due to stochastic second allele loss. Pre- and posttreatment metastatic CRPC (mCRPC) biopsy studies from BRCA1/2 WT tumors, treated on the TOPARP phase II trial, indicated that olaparib eradicated RNASEH2B-loss tumor subclones.CONCLUSIONPARP inhibition may benefit men suffering from mCRPC by eradicating tumor subclones with RNASEH2B loss.TRIAL REGISTRATIONClinicaltrials.gov NCT01682772.FUNDINGAstraZeneca; Cancer Research UK; Medical Research Council; Cancer Research UK; Prostate Cancer UK; Movember Foundation; Prostate Cancer Foundation.

Summary Olaparib (AZD2281) is an oral poly(ADP-ribose) polymerase (PARP) inhibitor with antitumour activity in cancer patients with BRCA1/2 germline mutations and in patients with homologous recombination deficiency. In this dose-finding study, patients were randomized to olaparib 10, 30, 100, 200 or 400 mg (capsule formulation) twice daily for the 4–5 days preceding breast cancer surgery. The primary objective was to identify an effective biological dose of olaparib for future trials. Secondary endpoints included evaluation of PARP-1 inhibition dose/exposure-response, and safety. Olaparib plasma pharmacokinetics (PK) and the pharmacodynamics (PD) in tumour and peripheral blood mononuclear cells (PBMCs) were evaluated. Population PK/PD modelling was performed on pooled data from this study and a previously reported study. Sixty patients were randomized ( n  = 12, each dose). Dose-dependent increases in exposure to olaparib were observed, but at ~50 % lower plasma exposure levels than seen in advanced disease studies. The mean maximal extent of PARP inhibition in PBMCs and tumour tissue was 50.6 % and 70.0 %, respectively, and was similar to inhibitory levels reported previously. No PARP inhibition-dose relationship was observed. Due to the unexpectedly low olaparib exposure, we were unable to determine an effective biological dose. Common adverse events included procedural pain ( n  = 31 patients), nausea, asthenia, malaise and increased blood creatinine ( n  = 6, each); these were of mild-to-moderate intensity, and all were manageable. Despite low olaparib exposure, PARP inhibition was consistent with previous reports. Reasons for the inter-study differences in exposure are unclear. The tolerability profile of olaparib was consistent with previous studies.

Bioluminescence imaging has previously been used to monitor the formation of grafted tumors in vivo and measure cell number during tumor progression and response to therapy. The development and optimization of successful cancer therapy strategies may well require detailed and specific assessment of biological processes in response to mechanistic intervention. Here, we use bioluminescence imaging to monitor the cell cycle in a genetically engineered, histologically accurate model of glioma in vivo . In these platelet-derived growth factor (PDGF)-driven oligodendrogliomas, G1 cell-cycle arrest is generated by blockade of either the PDGF receptor or mTOR using small-molecule inhibitors.

This research presents the design and synthesis of a novel series of phthalazine derivatives as Topo II inhibitors, DNA intercalators, and cytotoxic agents. In vitro testing of the new compounds against HepG-2, MCF-7, and HCT-116 cell lines confirmed their potent cytotoxic activity with low IC 50 values. Topo II inhibition and DNA intercalating activities were evaluated for the most cytotoxic members. IC 50 values determination demonstrated Topo II inhibitory activities and DNA intercalating affinities of the tested compounds at a micromolar level. Amongst, compound 9d was the most potent member. It inhibited Topo II enzyme at IC 50 value of 7.02 ± 0.54 µM with DNA intercalating IC 50 of 26.19 ± 1.14 µM. Compound 9d was then subjected to an in vivo antitumor examination. It inhibited tumour proliferation reducing solid tumour volume and mass. Additionally, it restored liver enzymes, proteins, and CBC parameters near-normal, indicating a remarkable amelioration in their functions along with histopathological examinations.

Although PARP inhibitors (PARPi) target homologous recombination defective tumours, drug resistance frequently emerges, often via poorly understood mechanisms. Here, using genome-wide and high-density CRISPR-Cas9 “tag-mutate-enrich” mutagenesis screens, we identify close to full-length mutant forms of PARP1 that cause in vitro and in vivo PARPi resistance. Mutations both within and outside of the PARP1 DNA-binding zinc-finger domains cause PARPi resistance and alter PARP1 trapping, as does a PARP1 mutation found in a clinical case of PARPi resistance. This reinforces the importance of trapped PARP1 as a cytotoxic DNA lesion and suggests that PARP1 intramolecular interactions might influence PARPi-mediated cytotoxicity. PARP1 mutations are also tolerated in cells with a pathogenic BRCA1 mutation where they result in distinct sensitivities to chemotherapeutic drugs compared to other mechanisms of PARPi resistance ( BRCA1 reversion, 53BP1 , REV7 ( MAD2L2 ) mutation), suggesting that the underlying mechanism of PARPi resistance that emerges could influence the success of subsequent therapies. The mechanisms of PARP inhibitor (PARPi) resistance are poorly understood. Here the authors employ a CRISPR mutagenesis approach to identify PARP1 mutants causing PARPi resistance and find that PARP1 mutations are tolerated in BRCA1 mutated cells, suggesting alternative resistance mechanisms.

DNA-dependent protein kinase (DNA-PK) is a critical player in the DNA damage response (DDR) and instrumental in the non-homologous end-joining pathway (NHEJ) used to detect and repair DNA double-strand breaks (DSBs). We demonstrate that the potent and highly selective DNA-PK inhibitor, AZD7648, is an efficient sensitizer of radiation- and doxorubicin-induced DNA damage, with combinations in xenograft and patient-derived xenograft (PDX) models inducing sustained regressions. Using ATM-deficient cells, we demonstrate that AZD7648, in combination with the PARP inhibitor olaparib, increases genomic instability, resulting in cell growth inhibition and apoptosis. AZD7648 enhanced olaparib efficacy across a range of doses and schedules in xenograft and PDX models, enabling sustained tumour regression and providing a clear rationale for its clinical investigation. Through its differentiated mechanism of action as an NHEJ inhibitor, AZD7648 complements the current armamentarium of DDR-targeted agents and has potential in combination with these agents to achieve deeper responses to current therapies. DNA-dependent protein kinase (DNA-PK) plays a major role in the DNA damage response upon double-strand break formation. Here, the authors show that the DNA-PK inhibitor AZD7648, enhances the activity of radiotherapy, chemotherapy and the PARP inhibitor olaparib in multiple mouse tumour models.

Programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) interaction plays a crucial role in tumor-associated immune escape. Here, we verify that triple-negative breast cancer (TNBC) has higher PD-L1 expression than other subtypes. We then discover that nucleophosmin (NPM1) binds to PD-L1 promoter specifically in TNBC cells and activates PD-L1 transcription, thus inhibiting T cell activity in vitro and in vivo. Furthermore, we demonstrate that PARP1 suppresses PD-L1 transcription through its interaction with the nucleic acid binding domain of NPM1, which is required for the binding of NPM1 at PD-L1 promoter. Consistently, the PARP1 inhibitor olaparib elevates PD-L1 expression in TNBC and exerts a better effect with anti-PD-L1 therapy. Together, our research has revealed NPM1 as a transcription regulator of PD-L1 in TNBC, which could lead to potential therapeutic strategies to enhance the efficacy of cancer immunotherapy. PD-L1 is highly expressed in triple-negative breast cancers (TNBC). Here, the authors show that nucleophosmin 1 (NPM1) transcriptionally activates PD-L1 expression and inhibits T cell activity in TNBC.

Olaparib (Lynparza ™ ) is an oral, small molecule, poly (ADP-ribose) polymerase inhibitor being developed by AstraZeneca for the treatment of solid tumours. The primary indication that olaparib is being developed for is BRCA mutation-positive ovarian cancer. A capsule formulation of the drug has received approval for use in this setting in the EU and USA, and a tablet formulation is in global phase III trials (including in the USA, EU, Australia, Brazil, Canada, China, Israel, Japan, Russia and South Korea). In addition, phase III trials in breast, gastric and pancreatic cancer are underway/planned, and phase I/II investigation is being conducted in other malignancies, including prostate cancer, non-small cell lung cancer, Ewing’s sarcoma and advanced cancer. This article summarizes the milestones in the development of olaparib leading to this first approval for ovarian cancer.