scholarly journals Gynecologic Cancers: Emerging Novel Strategies for Targeting DNA Repair Deficiency

2016 ◽  
pp. e259-e268 ◽  
Author(s):  
Rebecca S. Kristeleit ◽  
Rowan E. Miller ◽  
Elise C. Kohn
Keyword(s):  
Ovarian Cancer ◽  
Dna Repair ◽  
Brca Mutation ◽  
Parp Inhibitor ◽  
Inhibitor Therapy ◽  
Molecular Therapy ◽  
Parp Inhibition ◽  
Gynecologic Cancers ◽  
Brca Mutations ◽  
Individual Gene

The presence of a BRCA mutation, somatic or germline, is now established as a standard of care for selecting patients with ovarian cancer for treatment with a PARP inhibitor. During the clinical development of the PARP inhibitor class of agents, a subset of women without BRCA mutations were shown to respond to these drugs (termed “ BRCAness”). It was hypothesized that other genetic abnormalities causing a homologous recombinant deficiency (HRD) were sensitizing the BRCA wild-type cancers to PARP inhibition. The molecular basis for these other causes of HRD are being defined. They include individual gene defects (e.g., RAD51 mutation, CHEK2 mutation), homozygous somatic loss, and whole genome properties such as genomic scarring. Testing this knowledge is possible when selecting patients to receive molecular therapy targeting DNA repair, not only for patients with ovarian cancer but also endometrial and cervical cancers. The validity of HRD assays and multiple gene sequencing panels to select a broader population of patients for treatment with PARP inhibitor therapy is under evaluation. Other non-HRD targets for exploiting DNA repair defects in gynecologic cancers include mismatch repair (MMR), checkpoint signaling, and nonhomologous end-joining (NHEJ) DNA repair. This article describes recent evidence supporting strategies in addition to BRCA mutation for selecting patients for treatment with PARP inhibitor therapy. Additionally, the challenges and opportunities of exploiting DNA repair pathways other than homologous recombination for molecular therapy in gynecologic cancers is discussed.

scholarly journals PARP Inhibitors in Ovarian Cancer: The Route to “Ithaca”

Diagnostics ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 55 ◽  
Author(s):  
Boussios ◽  
Karathanasi ◽  
Cooke ◽  
Neille ◽  
Sadauskaite ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Brca Mutation ◽  
Parp Inhibitor ◽  
Parp Inhibitors ◽  
Parp Inhibition ◽  
Current Evidence ◽  
Repair Pathway ◽  
Significant Efficacy

Poly (ADP-ribose) polymerase (PARP) inhibitors are a novel class of therapeutic agents that target tumors with deficiencies in the homologous recombination DNA repair pathway. Genomic instability characterizes high-grade serous ovarian cancer (HGSOC), with one half of all tumors displaying defects in the important DNA repair pathway of homologous recombination. Early studies have shown significant efficacy for PARP inhibitors in patients with germline breast related cancer antigens 1 and 2 (BRCA1/2) mutations. It has also become evident that BRCA wild-type patients with other defects in the homologous recombination repair pathway benefit from this treatment. Companion homologous recombination deficiency (HRD) scores are being developed to guide the selection of patients that are most likely to benefit from PARP inhibition. The choice of which PARP inhibitor is mainly based upon the number of prior therapies and the presence of a BRCA mutation or HRD. The identification of patients most likely to benefit from PARP inhibitor therapy in view of HRD and other biomarker assessments is still challenging. The aim of this review is to describe the current evidence for PARP inhibitors in ovarian cancer, their mechanism of action, and the outstanding issues, including the rate of long-term toxicities and the evolution of resistance.

scholarly journals Efficacy of PARP Inhibitors in the Treatment of Ovarian Cancer: A Literature-Based Review

2019 ◽  
Vol 05 (01) ◽  
pp. 01-18
Author(s):  
Vikas Goswami ◽  
Venkata Pradeep Babu Koyyala ◽  
Sumit Goyal ◽  
Manish Sharma ◽  
Varun Goel ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Germ Line ◽  
Brca Mutation ◽  
Parp Inhibitor ◽  
Parp Inhibitors ◽  
Parp Inhibition ◽  
Repair Mechanism ◽  
Selection Of

AbstractPoly (ADP-ribose) polymerase (PARP) inhibitors are a unique class of therapeutic agents that focus on tumors with deficiencies in the homologous recombination DNA repair mechanism. Genomic instability outlines high-grade serous ovarian cancer, with 50% of all tumors displaying defects in the important DNA repair mechanism of homologous recombination. Earlier research studies have demonstrated considerable efficiency for PARP inhibitors in patients with germ line breast-related cancer antigens 1 and 2 (BRCA-1/BRCA-2) mutations. It has also been observed that BRCA wild-type patients with other defects in the homologous recombination repair mechanism get benefited from this therapy. Companion homologous recombination deficiency (HRD) scores are being developed to guide the selection of patients that are most likely to benefit from PARP inhibition. The selection of PARP inhibitor is mainly dependent upon the number of prior therapies and the presence of a BRCA mutation or HRD. The identification of cases which are most likely to get benefited from PARP inhibitor therapy in view of HRD and other biomarker assessments is still challenging. The purpose of this review is to focus and describe the current evidences for PARP inhibitors in ovarian malignancy, their mechanism of action, and the outstanding issues, including the rate of long-term toxicities and the evolving resistance.

scholarly journals The evolving role of PARP inhibitors in advanced ovarian cancer

2021 ◽  
Vol 12 (1) ◽  
pp. 82-104
Author(s):  
Sofia Levva ◽  
Aglaia Skolariki ◽  
Eleni Sogka ◽  
Alexandros Bokas ◽  
Avraam Assi ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Repair ◽  
Parp Inhibitor ◽  
Advanced Ovarian Cancer ◽  
Parp Inhibitors ◽  
Parp Inhibition ◽  
Primary Analysis ◽  
Serious Adverse Events ◽  
Adverse Event Data ◽  
Inhibitor Resistance

Abstract The field of ovarian cancer has been revolutionized with the use of poly (ADP-ribose) polymerase (PARP) inhibitors, which present greater inhibition effect in epithelial subtype due to high rates of homologous recombination deficiency. PARP inhibition exploits this cancer pitfall by disrupting DNA repair, leading to genomic instability and apoptosis. Three PARP inhibitors (olaparib, niraparib, and rucaparib) are now approved for use in women with epithelial ovarian cancer, while others are under development. Among women with BRCA1/2 mutations, maintenance PARP therapy has led to a nearly fourfold prolongation of PFS, while those without BRCA1/2 mutations experience an approximately twofold increase in PFS. Differences in trial design, patient selection and primary analysis population affect the conclusions on PARP inhibitors. Limited OS data have been published and there is also limited experience regarding long-term safety. With regard to toxicity profile, there are no differences in serious adverse events between the experimental and control groups. However, combining adverse event data from maintenance phases, a trend towards more events in the experimental group, compared with controls, has been shown. The mechanisms of PARP-inhibitor resistance include restoration of HR through reversion mutations in HR genes, leading to resumed HR function. Other mechanisms that sustain sufficient DNA repair are discussed as well. PARP inhibitors play a pivotal role in the management of ovarian cancer, affecting the future treatment choices. Defining exactly which patients will benefit from them is a challenge and the need for HRD testing to define ‘BRCA-ness’ will add additional costs to treatment.

No Association of BRCA Mutations with Therapy-Related Myelodysplastic Syndrome or Acute Myeloid Leukemia in Patients Treated for Breast or Ovarian Cancer

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4259-4259
Author(s):  
Aaron S. Mansfield ◽  
Mark A Lewis ◽  
Mrinal M. Patnaik ◽  
Noralane M Lindor ◽  
Matthew P Goetz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Ovarian Cancer ◽  
Dna Repair ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Brca Mutation ◽  
Seer Database ◽  
Brca Mutations ◽  
Acute Myeloid

Abstract Abstract 4259 Background: Patients with defective DNA repair mechanisms are at higher risk for developing cancer. BRCA1 and BRCA2 are proteins that coordinate DNA repair by homologous-recombination. Mutations in BRCA1 and BRCA2 are associated with an increased risk of cancers, namely breast, ovarian, and pancreatic, thus making these patients more likely to receive chemo- or radiation therapy. Additionally, secondary malignancies can be an unfortunate consequence of treatment with chemo- or radiation therapy. Although tumors with defective DNA repair mechanisms may be more susceptible to therapy, we hypothesized that patients with BRCA mutations that underwent chemotherapy or radiotherapy for treatment of breast or ovarian cancer would be at a higher risk of developing therapy- related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML). Methods: We accessed patient data from our institution maintained by the Mayo Clinic Life Sciences System using the Data Discovery and Query Builder. We searched for patients whose notes and diagnoses included the terms BRCA, and breast or ovarian cancer, and myelodysplastic syndrome or acute myeloid leukemia. We searched our records from 1/1/1995–7/15/2011. We cross-referenced our findings to a database of patients who were diagnosed with a BRCA mutation through our department of medical genetics. Secondly, we searched the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database for female patients who developed AML after the diagnosis or breast or ovarian cancer from the years 1973–2008 using ratio and multiple primaries standardized incidence ratios sessions. Results: We identified 220 patients with a BRCA mutation, of which 73 received chemotherapy. There were two patients with BRCA mutations that developed t-AML following treatment for breast cancer, and one patient with a BRCA mutation who developed t-AML following treatment for ovarian cancer (Table 1). Manual data extraction from the list of patients with BRCA mutations diagnosed at our institution only identified one of these patients, as two obtained their testing through another institution. We did not identify any patients with BRCA mutations who developed t-MDS following treatment for breast or ovarian cancer. The latency between diagnosis of the primary cancer and the diagnosis or t-AML was 24 months for two patients, and 22 years for the other. From our search of the SEER database we found 649 patients who developed AML after a diagnosis of breast cancer, and 98 patients who developed AML after a diagnosis of ovarian cancer. These patients represented 0.1% and 0.2% of evaluable breast and ovarian cases respectively. The latency from time of diagnosis of the primary cancer to that of AML was 58 months (29–113 interquartile range) for breast cancer and 47 months (29–91) for ovarian cancer. The observed number of patients with AML following the diagnosis of breast or ovarian cancer was 1.68 and 4.74 times higher than that expected of the general population, respectively (both p<0.05). We were not able to stratify patients based on the presence of a BRCA mutation due to the limitations of the database. Conclusions: We identified three patients with confirmed BRCA mutations and t-AML at our institution. Although this does not represent a strong association, patients at risk for BRCA mutations do not always undergo testing. Thus, our results may not fully represent whether there is an association with BRCA mutations and t-MDS or t-AML. Using the SEER database, we confirmed that patients who were diagnosed with breast or ovarian cancer subsequently had a higher incidence of AML than the general population, although we were not able to test if patients with BRCA mutations are at higher risk of t-MDS or t-AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Landscape and Therapeutic Implications of Molecular Profiles in Epithelial Ovarian Cancer

2020 ◽  
Vol 9 (7) ◽  
pp. 2239
Author(s):  
Ludivine Dion ◽  
Isis Carton ◽  
Sylvie Jaillard ◽  
Krystel Nyangoh Timoh ◽  
Sébastien Henno ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Epithelial Ovarian Cancer ◽  
Brca Mutation ◽  
Parp Inhibitor ◽  
Parp Inhibitors ◽  
Genetic Alterations ◽  
High Grade ◽  
Dna Breaks ◽  
Brca Mutations ◽  
Platinum Based Chemotherapy

Epithelial ovarian cancer (EOC) affects 43,000 women worldwide every year and has a five-year survival rate of 30%. Mainstay treatment is extensive surgery and chemotherapy. Outcomes could be improved by molecular profiling. We conducted a review of the literature to identify relevant publications on molecular and genetic alterations in EOC. Approximately 15% of all EOCs are due to BRCA1 or BRCA2 mutations. Four histologic subtypes characterized by different mutations have been described: serous, endometrioid, mucinous, and clear-cell. Between 20–30% of high-grade serous EOCs have a BRCA mutation. Tumors with BRCA mutations are unable to repair double-strand DNA breaks, making them more sensitive to platinum-based chemotherapy and to PolyAdenosine Diphosphate-Ribose Polymerase (PARP) inhibitors. Olaparib is a PARP inhibitor with proven efficacy in BRCA-mutated ovarian cancer, but its effectiveness remains to be demonstrated in tumors with a BRCAness (breast cancer) profile (i.e., also including sporadic tumors in patients with deficient DNA repair genes). A universally accepted molecular definition of BRCAness is required to identify optimal theranostic strategies involving PARP inhibitors. Gene expression analyses have led to the identification of four subgroups of high-grade serous EOC: mesenchymal, proliferative, differentiated, and immunoreactive. These subtypes are not mutually exclusive but are correlated with prognosis. They are not yet used in routine clinical practice. A greater understanding of EOC subtypes could improve patient management.

scholarly journals Combined Strategies with Poly (ADP-Ribose) Polymerase (PARP) Inhibitors for the Treatment of Ovarian Cancer: A Literature Review

Diagnostics ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 87 ◽  
Author(s):  
Stergios Boussios ◽  
Peeter Karihtala ◽  
Michele Moschetta ◽  
Afroditi Karathanasi ◽  
Agne Sadauskaite ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Dna Repair ◽  
Synthetic Lethality ◽  
Excision Repair ◽  
Parp Inhibitor ◽  
Advanced Ovarian Cancer ◽  
Pegylated Liposomal Doxorubicin ◽  
Parp Inhibitors ◽  
Parp Inhibition ◽  
Biologic Agent

Poly (ADP-ribose) polymerase (PARP) inhibitors are the first clinically approved drugs designed to exploit synthetic lethality, and were first introduced as a cancer-targeting strategy in 2005. They have led to a major change in the treatment of advanced ovarian cancer, and altered the natural history of a disease with extreme genetic complexity and defective DNA repair via homologous recombination (HR) pathway. Furthermore, additional mechanisms apart from breast related cancer antigens 1 and 2 (BRCA1/2) mutations can also result in HR pathway alterations and consequently lead to a clinical benefit from PARP inhibitors. Novel combinations of PARP inhibitors with other anticancer therapies are challenging, and better understanding of PARP biology, DNA repair mechanisms, and PARP inhibitor mechanisms of action is crucial. It seems that PARP inhibitor and biologic agent combinations appear well tolerated and clinically effective in both BRCA-mutated and wild-type cancers. They target differing aberrant and exploitable pathways in ovarian cancer, and may induce greater DNA damage and HR deficiency. The input of immunotherapy in ovarian cancer is based on the observation that immunosuppressive microenvironments can affect tumour growth, metastasis, and even treatment resistance. Several biologic agents have been studied in combination with PARP inhibitors, including inhibitors of vascular endothelial growth factor (VEGF; bevacizumab, cediranib), and PD-1 or PD-L1 (durvalumab, pembrolizumab, nivolumab), anti-CTLA4 monoclonal antibodies (tremelimumab), mTOR-(vistusertib), AKT-(capivasertib), and PI3K inhibitors (buparlisib, alpelisib), as well as MEK 1/2, and WEE1 inhibitors (selumetinib and adavosertib, respectively). Olaparib and veliparib have also been combined with chemotherapy with the rationale of disrupting base excision repair via PARP inhibition. Olaparib has been investigated with carboplatin and paclitaxel, whereas veliparib has been tested additionally in combination with temozolomide vs. pegylated liposomal doxorubicin, as well as with oral cyclophosphamide, and topoisomerase inhibitors. However, overlapping myelosuppression observed with PARP inhibitor and chemotherapy combinations requires further investigation with dose escalation studies. In this review, we discuss multiple clinical trials that are underway examining the antitumor activity of such combination strategies.

scholarly journals Homologous recombination deficiency in epithelial ovarian cancer

2020 ◽  
Vol 13 (4) ◽  
pp. 367-370 ◽  
Author(s):  
Thomas Bartl ◽  
Valentina Paspalj ◽  
Christoph Grimm
Keyword(s):  
Ovarian Cancer ◽  
Homologous Recombination ◽  
Epithelial Ovarian Cancer ◽  
Therapeutic Option ◽  
Parp Inhibitor ◽  
Therapy Response ◽  
Inhibitor Therapy ◽  
Parp Inhibition ◽  
Double Blind ◽  
Strand Breaks

SummarySince the introduction of poly-ADP-ribose polymerase (PARP) inhibitor therapy for epithelial ovarian cancer (EOC) patients, testing for aberrations of homologous recombination (HR) repair as a predictive biomarker of therapy response has become an area of particular clinical interest. As HR represents a crucial repair pathway of otherwise possibly lethal DNA double strand breaks, its deficiency triggers a phenotypic behavior of tumor cells resulting in the accumulation of genetic damage. PARP inhibitors target this emerging genomic instability by fostering DNA strand breaks. Whereas testing for mutations of the tumor-suppressor genes BRCA 1 and BRCA 2 as a pivotal part of the HR apparatus has entered clinical routine, approximately 30% more high-grade EOC patients harbor aberrations of the HR pathway other than BRCA mutations and may therefore respond to PARP inhibition therapy. In recent years, several double-blind, placebo-controlled trials investigating sizeable patient cohorts have reported positive results of PARP inhibitor therapy response in HR-positive patient subgroups. Therefore, introducing HR testing in both the primary and recurrent setting as a biomarker for PARP inhibitor response may expand the range of patients who may profit from this therapeutic option beyond BRCA-mutated tumors.

scholarly journals Veliparib Is an Effective Radiosensitizing Agent in a Preclinical Model of Medulloblastoma

2021 ◽  
Vol 8 ◽  
Author(s):  
Jessica Buck ◽  
Patrick J. C. Dyer ◽  
Hilary Hii ◽  
Brooke Carline ◽  
Mani Kuchibhotla ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Combination Therapy ◽  
Cellular Response ◽  
Molecular Subtype ◽  
Parp Inhibitor ◽  
Single Agent ◽  
Parp Inhibition ◽  
Preclinical Model ◽  
Radiation Induced

Medulloblastoma is the most common malignant childhood brain tumor, and 5-year overall survival rates are as low as 40% depending on molecular subtype, with new therapies critically important. As radiotherapy and chemotherapy act through the induction of DNA damage, the sensitization of cancer cells through the inhibition of DNA damage repair pathways is a potential therapeutic strategy. The poly-(ADP-ribose) polymerase (PARP) inhibitor veliparib was assessed for its ability to augment the cellular response to radiation-induced DNA damage in human medulloblastoma cells. DNA repair following irradiation was assessed using the alkaline comet assay, with veliparib inhibiting the rate of DNA repair. Veliparib treatment also increased the number of γH2AX foci in cells treated with radiation, and analysis of downstream pathways indicated persistent activation of the DNA damage response pathway. Clonogenicity assays demonstrated that veliparib effectively inhibited the colony-forming capacity of medulloblastoma cells, both as a single agent and in combination with irradiation. These data were then validated in vivo using an orthotopic implant model of medulloblastoma. Mice harboring intracranial D425 medulloblastoma xenografts were treated with vehicle, veliparib, 18 Gy multifractionated craniospinal irradiation (CSI), or veliparib combined with 18 Gy CSI. Animals treated with combination therapy exhibited reduced tumor growth rates concomitant with increased intra-tumoral apoptosis observed by immunohistochemistry. Kaplan–Meier analyses revealed a statistically significant increase in survival with combination therapy compared to CSI alone. In summary, PARP inhibition enhanced radiation-induced cytotoxicity of medulloblastoma cells; thus, veliparib or other brain-penetrant PARP inhibitors are potential radiosensitizing agents for the treatment of medulloblastoma.

The impact of live education on the competence and performance of oncology practitioners who care for patients with ovarian cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e23010-e23010
Author(s):  
Vanessa Carranza ◽  
Bryan Carson Taylor ◽  
Susan H. Gitzinger ◽  
Joan B. Fowler ◽  
Jessica Hall
Keyword(s):  
Ovarian Cancer ◽  
Genetic Testing ◽  
Cancer Patients ◽  
Parp Inhibitor ◽  
Inhibitor Therapy ◽  
Community Based ◽  
Educational Initiatives ◽  
Post Test ◽  
Chi Square Analysis

e23010 Background: About a third of ovarian cancer patients in the US have limited access to a gynecologic oncologist (GO) due to geographic disparities. A survey by The Society of Gynecologic Oncology (SGO) found that the majority of GOs found it was vital to coordinate local access to care, from diagnosis to survivorship, for patients living in areas of disparity. This allows rural/underserved patients broader access to novel therapies, as they increasingly become standard of care. It is critical for not only GOs to be current on the latest ovarian cancer data, but all clinicians who care for these patients. Methods: CEC Oncology developed two educational initiatives focused on PARP inhibitor therapy in ovarian cancer, which was targeted to all US healthcare professionals caring for ovarian cancer patients. Evaluations were collected from attendees attending an SGO Symposium and Ground Round (GR) series to assess impact on practice, increased competency, and intent to make a change in practice. Learning, knowledge, and competence was objectively assessed by analyzing pre-test, post-test, and follow-up survey data (sent 4-6 weeks post-activity). Chi-square analysis was conducted with a priori significance set at 0.05. Results: A total of 830 clinicians were educated, with SGO attendees primarily practicing in academic settings and GR attendees mostly from community practices. SGO attendees were asked case questions at baseline, immediately after the activity, and 4-6 weeks after the activity. Knowledge increased from pre- to post-test regarding current genetic testing recommendations (23% increase; P= .004) and appropriate selection of PARP inhibitor therapy (25% increase; P= .017). Knowledge was sustained at follow-up analysis. At follow-up, 90% of SGO and 84% of GR attendees made a change as a result of attending the activities. More attendees were able to incorporate germline multigene testing into practice, than originally intended; increase of 29% for SGO and 7% for GR audiences. All attendees experienced the barrier lack of patient education about the importance of genetic testing/counseling more than anticipated; increase of 7% for SGO and 13% for GR audiences. At follow-up, there was a 9% increase in GR attendees listing staying current with trial data and practice guidelines as a barrier. Conclusions: There were some notable differences seen in competence/performance among attendees of the two ovarian cancer educational initiatives. Differences may be attributed to practice setting (SGO primarily academic; GR primarily community.) Overall, GR attendees were more likely to face barriers, suggesting that community-based clinicians have fewer resources and experience more barriers to implementing best practices. Thus, it is vital to offer education for clinicians in community-based practices, particularly in areas that are considered ‘geographically disparate’.

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