PARP inhibitors and metastatic castration-resistant prostate cancer: uture directions and pitfalls.
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ABSTRACT:
SUBMITTER: Franza A
PROVIDER: S-EPMC8591349 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The approval of upfront abiraterone for castration-sensitive prostate cancer and the approval of enzalutamide and apalutamide for non-metastatic castration-resistant prostate cancer have led to early utilization of potent androgen receptor (AR) signaling inhibitors in treating advanced prostate cancer. There is an unmet need to develop novel therapies beyond targeting AR signaling for metastatic castration-resistant prostate cancer (mCRPC). Poly (ADP-ribose) polymerase inhibitors (PARPi) belong to a class of targeted agents being developed for the treatment of homologous recombination repair (HRR) deficient tumors. Olaparib, rucaparib, niraparib, veliparib, and talazoparib were evaluated in early phase trials as a monotherapy for HRR-deficient mCRPC. Among them, olaparib and rucaparib have breakthrough designations for BRCA1/2-mutated mCRPC. Phase II studies also reported clinical activity of the PARPi and abiraterone combination and the PARPi checkpoint inhibitor combination in HRR-intact mCRPC. Ongoing phase III trials are testing these combinations as frontline or later line treatments for mCRPC. This review summarizes the critical clinical data as well as ongoing clinical trials for developing PARPi in treating mCRPC.
| S-EPMC6721701 | biostudies-literature
Project description:Metastatic castration-resistant prostate cancer (mCRPC) is an incurable malignancy with a poor prognosis. Up to 30% of patients with mCRPC have mutations in homologous recombination repair (HRR) genes. Poly (ADP-ribose) polymerase (PARP) inhibitors take advantage of HRR deficiency to kill tumor cells based on the concept of synthetic lethality. Several PARP inhibitors (PARPis) have been successful in various malignancies with HRR gene mutations including BRCA1/2, especially in breast cancer and ovarian cancer. More recently, olaparib and rucaparib were approved for mCRPC refractory to novel hormonal therapies, and other PARPis will likely follow. This article highlights the mechanism of action of PARPis at the cellular level, the preclinical data regarding a proposed mechanism of action and the effectiveness of PARPis in cancer cell lines and animal models. The article expands on the clinical development of PARPis in mCRPC, discusses potential biomarkers that may predict successful tumor control, and summarizes present and future clinical research on PARPis in the metastatic disease landscape.
| S-EPMC7700539 | biostudies-literature
Project description:Background: Poly(ADP-ribose) polymerase (PARP) inhibitors have breakthrough designations for metastatic castration-resistant prostate cancer (mCRPC). We performed a meta-analysis of current clinical trials to evaluate the efficacy of PARP inhibitors in mCRPC patients based on their genetic status. Methods: On August 2020, PubMed, Scopus, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were searched for phase II/III clinical studies on PARP inhibitors in mCRPC patients. Data were extracted independently by two investigators and analyzed using Review Manager software version 5.3. Primary endpoints included overall response rate (ORR) and progression-free survival (PFS). Results: Nine clinical trials were identified and analyzed for the clinical benefit of PARP inhibitors in mCRPC patients (n = 1,219). Pooled analyses demonstrated that PARP inhibitors could provide a significant improvement of ORR and PFS in patients with homologous recombination deficiency (HRD) when compared with non-HRD patients. Within the HRD subgroup, BRCA mutation patients achieved significantly higher ORR [odds ratio (OR): 9.97, 95% confidence interval (CI): 6.08-16.35] and PFS rates at 12 months (OR: 3.23, 95% CI: 1.71-6.10) when compared with BRCA wild-type patients. Furthermore, patients harboring HRD without BRCA mutations have a higher objective response after PARP inhibitor treatment compared with non-HRD patients. Conclusion: PARP inhibitor is an effective treatment option for mCRPC patients with mutations in genes related to the HR DNA repair pathway when compared with non-HRD patients. In addition to BRCA mutations, other HRD-related gene aberrations may also be used as novel biomarkers to predict the efficacy of PARP inhibitors.
| S-EPMC8718674 | biostudies-literature
Project description:The management of men with metastatic castration-resistant prostate cancer (CRPC) has taken several leaps forward in the last 2 years, with the demonstration of improved overall survival with three novel agents (sipuleucel-T, cabazitaxel, and abiraterone acetate), and a significant delay in skeletal-related events observed with denosumab. The pipeline of systemic therapies in prostate cancer remains strong, as multiple agents with a diverse array of mechanisms of action are demonstrating preliminary signs of clinical benefit, leading to more definitive phase III confirmatory trials. In this review, we will discuss the evolving landscape of treatment options for men with CRPC, with a particular focus on currently approved and emerging treatment options for these patients. Knowledge of these evolving standards will help to optimize delivery of care and long term outcomes in men with advanced CRPC.
| S-EPMC3685202 | biostudies-literature
Project description:Since 2010, several treatment options have been available for men with metastatic castration-resistant prostate cancer (mCRPC), including immunotherapeutic agents, although the clinical benefit of these agents remains inconclusive in unselected mCRPC patients. In recent years, however, immunotherapy has re-emerged as a promising therapeutic option to stimulate antitumor immunity, particularly with the use of immune checkpoint inhibitors (ICIs), such as PD-1/PD-L1 and CTLA-4 inhibitors. There is increasing evidence that ICIs may be especially beneficial in specific subgroups of patients with high PD-L1 tumor expression, high tumor mutational burden, or tumors with high microsatellite instability/mismatch repair deficiency. If we are to improve the efficacy of ICIs, it is crucial to have a better understanding of the mechanisms of resistance to ICIs and to identify predictive biomarkers to determine which patients are most likely to benefit. This review focuses on the current status of ICIs for the treatment of mCRPC (either as monotherapy or in combination with other drugs), mechanisms of resistance, potential predictive biomarkers, and future challenges in the management of mCRPC.
| S-EPMC8124759 | biostudies-literature
Project description:IntroductionTherapeutic options for metastatic castration-resistant prostate cancer (mCRPC) patients are continuously advancing. We described mCRPC treatment patterns in the US from 2013 to 2019.MethodsPatients with a confirmed mCRPC diagnosis and adenocarcinoma histology were included in the US Flatiron Health Electronic Health Record-derived de-identified database. Treatment patterns [including treatment per lines of therapies (LOTs), LOT sequences, and time on treatment] and overall survival (OS) have been described in mCRPC settings.ResultsOf 5213 patients (mean age: 72.6 years), 4374 (83.9%) were treated with ≥ 1 LOT post-mCRPC diagnosis (among those with ≥ 1 LOT, 55.3%, 29.5%, 14.7%, and 6.7% had ≥ 2, 3, 4, and 5 LOTs, respectively). In first line (1L), the main treatment class was next-generation hormonal agents (NHA; 62.5% of patients with ≥ 1 LOT), while the shortest and longest time on 1L were observed for chemotherapy (median 2.8 months) and NHA (median 5.1 months), respectively. The most common LOT sequences were NHA → NHA (29.4% of patients with ≥ 2 LOTs) and NHA → NHA → chemotherapy (16.7% of patients with ≥ 3 LOTs). In Kaplan-Meier analyses, the median OS was 19.4, 14.6, and 11.1 months post-1L, 2L, and 3L start, respectively. Patients who moved rapidly through LOTs had an increased risk of death.ConclusionsNHA were widely used as 1L therapy in mCRPC patients from 2013 to 2019, but time on 1L NHA treatment was on average < 6 months. While NHA → NHA was the most observed 1L → 2L LOT sequence, a plethora of other LOT sequences were observed. OS was poor, highlighting an unmet need for life-prolonging treatments.
| S-EPMC8342357 | biostudies-literature
Project description:Purpose of the studyReduced levels of the tumor suppressor protein CCDC6 sensitize cancer cells to the treatment with PARP-inhibitors. The turnover of CCDC6 protein is regulated by the de-ubiquitinase USP7, which also controls the androgen receptor (AR) stability. Here, we correlated the expression levels of CCDC6 and USP7 proteins in primary prostate cancers (PC). Moreover, we tested the efficacy of the USP7 inhibitors, in combination with PARP-inhibitors as a novel therapeutic option in advanced prostate cancer.Experimental techniques: PC cells were exposed to USP7 inhibitor, P5091, together with cycloheximide, to investigate the turnover of the USP7 substrates, AR and CCDC6. As outcome of the AR downregulation, transcription targets of AR and its variant V7 were examined by qPCR. As a result of CCDC6 degradation, the induction of PARP inhibitors sensitivity was evaluated by analyzing PC cells viability and foci formation. We scored and correlated CCDC6 and USP7 expression levels in a prostate cancer tissue microarray (TMA).ResultsP5091 accelerated the degradation of AR and V7 isoform affecting PSA, UBE2C, CDC20 transcription and PC cells proliferation. Moreover, P5091 accelerated the degradation of CCDC6 sensitizing the cells to PARP-inhibitors, that acted sinergistically with genotoxic agents. The immunohistochemical analysis of both CCDC6 and USP7 proteins exhibited significant correlation for the intensity of staining (p ? 0.05).Data interpretation: Thus, CCDC6 and USP7 represent predictive markers for the combined treatment of the USP7-inhibitors and PARP-inhibitors in advanced prostate cancer.
| S-EPMC5458250 | biostudies-literature
Project description:The majority of prostate cancer (PCa) cases are diagnosed as a localized disease. Definitive treatment, active surveillance or watchful waiting are employed as therapeutic paradigms. The current standard of care for the treatment of metastatic PCa is either medical or surgical castration. Once PCa progresses in spite of castrate androgen levels it is termed 'castration-resistant prostate cancer' (CRPC). Patients may even exhibit rising PSA levels with possible bone, lymph node or solid organ metastases. In 2010, the only agent approved for the treatment of CRPC was docetaxel, a chemotherapeutic agent. It is now known that cells from patients with CRPC express androgen receptors (AR) and remain continuously influenced by androgens. As such, treatments with novel hormonal agents that specifically target the biochemical conversion of cholesterol to testosterone have come to the forefront. The use of cytochrome P450c17 (CYP17A1) inhibitor underlies one of the most recent advances in the treatment of CRPC. Abiraterone acetate (AA) was the first CYP17A1 inhibitor approved in the United States. This review will discuss CRPC in general with a specific focus on AA and novel CYP17A1 inhibitors. AA clinical trials will be reviewed along with other novel adjunct treatments that may enhance the effectiveness of abiraterone therapy. Furthermore, the most recently identified CYP17A1 inhibitors Orteronel, Galeterone, VT-464, and CFG920 will also be explored.
| S-EPMC4323677 | biostudies-literature
Project description:The arrival of several new agents--cabazitaxel, abiraterone acetate, enzalutamide, and radium-223--is changing the treatment options and management of patients with metastatic castration-resistant prostate cancer (mCRPC). Many other novel agents are also being investigated. As new drugs become approved, new treatment strategies and markers to best select which patients will best respond to which drug are needed. This review article is a summary of a European Treatment Practices Meeting, which was convened to discuss these latest data on novel agents and current treatment strategies in the mCRPC setting.
| S-EPMC3662847 | biostudies-other
Project description:To review and evaluate current literature on the US Food and Drug Administration (FDA)-approved drug enzalutamide (XTANDI(®)) in metastatic castration-resistant prostate cancer.Literature search was done through PubMed using the terms enzalutamide, MDV3100, abiraterone, and castration-resistant prostate cancer. Data from FDA product labels were also used.Recent and relevant studies were included in the review. Collected clinical trials were screened and evaluated.Enzalutamide is an androgen receptor (AR) inhibitor with high selectivity and affinity to the AR. It was approved by the FDA to treat metastatic castration-resistant prostate cancer in patients previously treated with docetaxel, after a Phase III trial (AFFIRM) that showed a 4.8-month survival benefit in this population. Recently, the FDA expanded the approval of enzalutamide as first-line therapy for metastatic castration-resistant prostate cancer (mCRPC) who did not receive chemotherapy. Moreover, enzalutamide is shown to be associated with an acceptable safety profile.Enzalutamide has been shown to be both safe and effective in improving overall survival in metastatic castration-resistant prostate cancer postchemotherapy with docetaxel and as a first line treatment before initiation of chemotherapy. However, additional studies and head-to-head trials are needed.
| S-EPMC4407758 | biostudies-other