Deleterious BRCA Mutations Research Articles

Aromatase inhibitors and contralateral breast cancer in BRCA mutation carriers.

Deleterious BRCA mutations confer a significant lifetime risk of breast cancer (BC) as well as contralateral BC (CBC) in patients who do not undergo prophylactic mastectomy. Prior reports have suggested that tamoxifen reduces the risk of CBC in BRCA mutation carriers. Whether aromatase inhibitors (AI) have the same effect is unknown. This is a retrospective review of patients diagnosed with non-metastatic ER+ BC between 2004 and 2014 with known BRCA mutation status. Patients were followed from primary diagnosis until CBC diagnosis or death. Median follow-up was 11.5years. Risk of CBC was evaluated as time to event. 935 subjects were included in this analysis, with 53 BRCA1 mutation carriers, and 94 BRCA2 mutation carriers. Median age at diagnosis was 42.7years. Seventy-two percent (676) received tamoxifen and 43% (405) received AI. A total of 66 CBCs occurred, of which 10% (15/147) occurred in BRCA mutation carriers vs 6.5% (51/788) in BRCA wild type. Multivariate analyses indicated that BRCA status and AI use were significantly associated with CBC risk. AI use resulted in a significant reduction in risk of CBC (HR 0.44, p = 0.004) regardless of the BRCA mutation status. Tamoxifen use was not associated with reduced risk of CBC. This is the first report showing that AIs reduce the risk of CBC in BRCA mutation carriers. The potential role of AIs as chemoprevention should be validated in larger independent cohorts.

Emerging Role of PARP Inhibitors in Metastatic Prostate Cancer.

We highlight the clinical development of Poly (ADP-Ribose) polymerase (PARP) inhibitors in prostate cancer. Approximately 10 to 30% of metastatic prostate cancer patients carry germline or somatic mutations in DNA repair pathways. BRCA2 is the most commonly mutated gene in DNA damage repair pathways. Because of its critical function in homologous recombination repair (HRR) machinery, deleterious BRCA2 mutation enables synthetic lethality to a PARP inhibitor. Olaparib demonstrated clinical benefit in patients with deleterious mutations in HRR-related genes and most clearly in patients with BRCA2 mutations. Olaparib received the US FDA approval or mCRPC patients with a qualifying HRR gene mutation in May 2020. Rucaparib received an accelerated FDA approval for patients with BRCA1- or BRCA2-mutated mCRPC based on 43% objective response rate in a phase II study. To expand the application of a PARP inhibitor, several trials have evaluated various combination strategies with an androgen receptor signaling inhibitor, immunotherapy, radium-223, and others. While no PARP inhibitor combination regimen has been approved, promising data from a PARP inhibitor and an ASI combination have been reported. PARP inhibitor represents a standard treatment for patient with mCRPC with germline or somatic mutations in BRCA2 and other HRR pathway genes.

Efficacy of combining tumor treating fields (TTFields) with a PARP inhibitor in ovarian cell lines (300.5)

Objectives: PARP inhibition demonstrates clinical effectiveness in patients with solid tumors and deleterious BRCA mutations. The use of PARP inhibitors is specifically relevant in ovarian cancer, as one of three women with this malignancy harbor BRCA mutations. Tumor Treating Fields (TTFields) are alternating electric fields with antimitotic effects on cancerous cells, which are approved to treat patients with glioblastoma and malignant pleural mesothelioma. TTFields were shown to induce a state of BRCAness in several cancerous cell lines. The objective of this study was to explore the potential of combining TTFields with PARP inhibition for the treatment of ovarian cancer based on in vitro work. Methods: Ovarian carcinoma cells, A2780 (BRCA1/2 wild type) and OVCAR3 (BRCA1 wild type, BRCA2 mutated), were treated for 72 h with TTFields (at an intensity of 1.2 V/cm RMS and frequency of 200 kHz) using the in vitro system. The effectiveness of TTFields in combination with the PARP inhibitor niraparib was examined by measuring cell counts, clonogenic potential, overall effect (multiplicity product of cytotoxicity and clonogenicity), and apoptosis induction. Results: The application of TTFields to A2780 or OVCAR3 cells resulted in about 50% reduction in cell counts. Niraparib displayed a dose-dependent cytotoxic effect on both cell lines. Co-application of niraparib and TTFields resulted in enhanced cytotoxicity compared to the effect of niraparib or TTFields alone. TTFields also elevated the effects of niraparib on the colony-forming ability of the cells, the overall effect, and apoptosis. Conclusions: These results suggest a potential benefit for concomitant treatment of TTFields with niraparib in ovarian cancer. Additional experiments will examine the effect on the BRCA-FANC pathway in ovarian cancer. Objectives: PARP inhibition demonstrates clinical effectiveness in patients with solid tumors and deleterious BRCA mutations. The use of PARP inhibitors is specifically relevant in ovarian cancer, as one of three women with this malignancy harbor BRCA mutations. Tumor Treating Fields (TTFields) are alternating electric fields with antimitotic effects on cancerous cells, which are approved to treat patients with glioblastoma and malignant pleural mesothelioma. TTFields were shown to induce a state of BRCAness in several cancerous cell lines. The objective of this study was to explore the potential of combining TTFields with PARP inhibition for the treatment of ovarian cancer based on in vitro work. Methods: Ovarian carcinoma cells, A2780 (BRCA1/2 wild type) and OVCAR3 (BRCA1 wild type, BRCA2 mutated), were treated for 72 h with TTFields (at an intensity of 1.2 V/cm RMS and frequency of 200 kHz) using the in vitro system. The effectiveness of TTFields in combination with the PARP inhibitor niraparib was examined by measuring cell counts, clonogenic potential, overall effect (multiplicity product of cytotoxicity and clonogenicity), and apoptosis induction. Results: The application of TTFields to A2780 or OVCAR3 cells resulted in about 50% reduction in cell counts. Niraparib displayed a dose-dependent cytotoxic effect on both cell lines. Co-application of niraparib and TTFields resulted in enhanced cytotoxicity compared to the effect of niraparib or TTFields alone. TTFields also elevated the effects of niraparib on the colony-forming ability of the cells, the overall effect, and apoptosis. Conclusions: These results suggest a potential benefit for concomitant treatment of TTFields with niraparib in ovarian cancer. Additional experiments will examine the effect on the BRCA-FANC pathway in ovarian cancer.

Management Strategies of Breast Cancer Patients with BRCA1 and BRCA2 Pathogenic Germline Variants.

Most of breast cancer cases are sporadic; however, 15–20% are associated with family history, and some are inherited. Among those, deleterious mutations in BRCA1 and BRCA2 tumor suppressor genes are the most commonly encountered pathogenic germline variants (PGVs). Given the availability and affordability of multi-gene panel sequencing technologies, testing for PGVs is commonly practiced. With our enhanced understanding of cancer genetics and specific molecular alterations, the better acceptance of risk-directed screening and prevention, and the recent introduction of novel targeted therapies, management of BRCA-positive breast cancers is taking a new direction, focusing more on risk-reducing interventions, including mastectomy and salpingo-oophorectomy, and incorporating special treatment regimens, including platinum-based chemotherapy, and the recently-introduced PARP (poly (ADP)-ribose polymerase) inhibitors. Given the recent advances in reproductive technology and molecular medicine, younger women with PGVs may have the option of embryo selection through preimplantation genetic testing and diagnosis, thus preventing the potential transmission of the implicated genes to the next generations. In this review, we cover the clinical implications of identifying a pathogenic germline mutation in BRCA1 and BRCA2 genes in breast cancer patients, and their relatives, across the continuum of care – from cancer prevention and early detection, through active treatment and up to survivorship issues.

Low BRCA1 and BRCA2 Germline Mutation Rates in a French-Canadian Population with a Diagnosis of Epithelial Tubo-Ovarian Carcinoma

ObjectiveUniversal genetic testing has become increasingly important in the management of epithelial tubo-ovarian and peritoneal carcinoma. Worldwide, reported incidences of deleterious BRCA mutations vary between 12% and 15%. We sought to evaluate the incidence in our population, given its specific genetic background (French-Canadian ancestry). MethodMainstream genetic testing was implemented in our service in May 2017 and offered to all patients with epithelial tubo-ovarian or peritoneal carcinomas, except mucinous and borderline tumours. Data were prospectively collected in a database and retrospectively analyzed. ResultsWe tested 222 patients in our centre, of whom 183 (82.4%) had high-grade serous carcinoma (HGSC). Overall, 139 patients had no identified mutation (62.6%). Deleterious BRCA1 and BRCA2 mutations were found in 12 patients (5.4%): 6 had BRCA1, and 6 BRCA2 mutations; 11 of these patients had HGSC. Other non–BRCA mutations (ATM, RAD51C, RAD51D, BRIP1, CDH1, MRE11, MSH6, MUTYH, PALB2, and PMS2) were observed in an additional 20 patients (9.0%), of whom 18 had HGSC. A total of 63 different variants of unknown significance (VUS) were found, of which 4 were in the BRCA1 and BRCA2 genes. Deleterious mutations were not identified in clear cell carcinomas, and only 1 was found in low-grade serous carcinoma. ConclusionIn our French-Canadian population, the incidence of deleterious germline BRCA mutations was surprisingly low at 5.4%—less than half that reported in the literature. This may affect patient response to poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) therapy. Mainstream genetic testing was successfully implemented in our service and facilitated access to genetic testing in our patient population.

Physical Activity in Young BRCA Carriers and Reduced Risk of Breast Cancer

A systematic literature review was conducted to determine whether physical activity levels during adolescent and young adult years were associated with a reduced lifetime risk of breast cancer among carriers of deleterious mutations in BRCA1 and BRCA2 genes. Ovid/MEDLINE, Embase, CENTRAL, WOS, and CINAHL were searched for articles including information about adolescent and young adult physical activity and breast cancer incidence among women carrying deleterious BRCA1 and BRCA2 gene mutations (search was initiated in October 2019; last update and full analyses were in March 2021). Independent reviewers screened articles at the title/abstract and full-text levels, resolving differences by consensus with lead authors. The NIH Quality Assessment Tools were used to assess sources of bias. A total of 1,957 unique articles were identified; 5 met inclusion criteria. Samples size ranged from 68 to 1,185. All studies relied on self-reported adolescent and young adult physical activity. One study measured sports involvement; the others measured recreational activity. One large study was null, whereas 4 others showed a reduction in breast cancer incidence later in life with higher adolescent and young adult physical activity (p≤0.05). However, the protection was limited to premenopausal breast cancer in 1 of the studies (OR=0.62; 95% CI=0.40, 0.96; p-trend=0.01). In addition, adolescent and young adult physical activity was associated with older age at breast cancer diagnosis in 1 study (p=0.03). A limited number of studies suggest that adolescent and young adult physical activity may reduce or delay the risk of breast cancer incidence among carriers of deleterious mutations in BRCA1 and BRCA2 genes.

Real-life data on treatment and outcomes in advanced ovarian cancer: An observational, multinational cohort study (RESPONSE trial).

BackgroundThis study aimed to describe the treatment strategies and outcomes for women with newly diagnosed advanced high‐grade serous or endometrioid ovarian cancer (OC).MethodsThis observational study collected real‐world medical record data from eight Western countries on the diagnostic workup, clinical outcomes, and treatment of adult women with newly diagnosed advanced (Stage III–IV) high‐grade serous or endometrioid OC. Patients were selected backward in time from April 1, 2018 (the index date), with a target of 120 patients set per country, followed for ≥20 months.ResultsOf the 1119 women included, 66.9% had Stage III disease, 11.7% had a deleterious BRCA mutation, and 26.6% received bevacizumab; 40.8% and 39.3% underwent primary debulking surgery (PDS) and interval debulking surgery (IDS), respectively. Of the patients who underwent PDS, 55.5% had no visible residual disease (VRD); 63.9% of the IDS patients had no VRD. According to physician‐assessed responses (at the first assessment after diagnosis and treatment), 53.2% of the total population had a complete response and 25.7% had a partial response to first‐line chemotherapy after surgery. After ≥20 months of follow‐up, 32.9% of the patients were disease‐free, 46.4% had progressive disease, and 20.6% had died. Bevacizumab use had a significant positive effect on overall survival (hazard ratio [HR], 0.62; 95% CI, 0.42–0.91; p = .01). A deleterious BRCA status had a significant positive effect on progression‐free survival (HR, 0.60; 95% CI, 0.41–0.84; p < .01).ConclusionsWomen with advanced high‐grade serous or endometrioid OC have a poor prognosis. Bevacizumab use and a deleterious BRCA status were found to improve survival in this real‐world population.Lay summary Patients with advanced (Stage III or IV) ovarian cancer (OC) have a poor prognosis.The standard treatment options of surgery and chemotherapy extend life beyond diagnosis for 5 years or more in only approximately 45% of patients.This study was aimed at describing the standard of care in eight Western countries and estimating how many patients who are diagnosed with high‐grade serous or endometrioid OC could potentially be eligible for first‐line poly(adenosine diphosphate ribose) polymerase inhibitor (PARPi) maintenance therapy.The results highlight the poor prognosis for these patients and suggest that a significant proportion (79%) would potentially be eligible for first‐line PARPi maintenance treatment.

Abstract 5842: High resolution melting technique as an economic prognostic tool for identifying deleterious mutations in BRCA1, BRCA2, and P53 genes amongst breast cancer women

Abstract Introduction: The incidence of breast cancer (BC) has substantially increased among women younger than 50. Due to fragile economic situation in the middle east and lack of awareness, BC women are characterized by late diagnosis and thus, there is an urgent need for a cheap early prognostic tool. BC progression involves several genetic mutations via activating oncogenes or disrupting the functions of tumor suppressor genes, such as; BRCA1, BRCA2, P53. Mutation in these genes are associated with an increased risk of breast cancer and thereof, can be used as prognostic markers. High throughput technologies such as next generation sequencing (NGS) with help of different bioinformatic analysis tools give massive data about deleterious mutations in tumor suppressor genes. Therefore, in this study we aimed to establish High Resolution Melting (HRM) technique as an economic prognostic tool for identifying deleterious mutations in BRCA1/2 and P53 genes amongst familial and non-familial breast cancer patients. Patients and Methods: Forty-eight breast cancer patients (15 Familial and 33 non-familial) and 2 healthy volunteers were enrolled in the present study. Genomic DNA was extracted from breast cancer tissues and screened using NGS to identify types of mutations in both BRCA1/2 genes. All positive samples were screened for presence of mutations in BRCA 1(exon 19), BRCA2 (Exon 11F) and P53 (exon 5) using HRM. All samples were analyzed for identifying types of mutations using sanger sequencing. Results: Our results identified 57 different mutations in the three genes. Deleterious mutations are identified as follows; 13 frameshift (c.5345delA (36.3%), c.5321delC (36%), c.5337delA (27.2%)) and 8 missense mutations (c.T5320C (36.3%), c.T5330W(A/T) (27.2%)) in BRCA1 (Exon 19). 6 frameshift mutations (c.3528delA (27.2%)), 13 missense mutations (c.T3840G (72.7%), c.G3839K(G/T) (27.2%)) and 6 synonymous mutations (c.A3895R (A/G) (45.4%)) in BRCA2 (exon11F). Regarding P53 (exon 5), 10 frameshift mutations (c.813insC (63.6%)) were detected. Additionally, some of the sequences were sent to GenBank and obtained the following accession numbers; (OL512955 and OL512956 for BRCA1(Exon 19) and OL512957 for BRCA2 (Exon 11)). Moreover, mutations in the three high penetrance genes; BRCA1, BRCA2 and P53 were correlated with some clinical parameters and results showed that young age and family history were the most prominent ones. Conclusion: The present study successfully established HRM as an economic prognostic tool for identifying the presence of deleterious mutations in BRCA1/2 and P53 genes which will help correlate the presence of mutations on other affected exons when present with other risk factors as prognostic tool in BC women. STDF Acknowledgement: This project was funded by the Science and Technology Development Fund (STDF), Egypt Grant No.22944. Citation Format: Shaza Ahmed, Nasra F. Abdel Fattah, Shimaa A. Metwally, Marwa A. Abdelwahed, Hossam Taha Mohamed, Sara H. Agwa, AbdelWahab El Ghareeb, Gehan Safwat, Ahmed A. El Sherif, Mohamed M. Moneer, Samah A. Loutfy. High resolution melting technique as an economic prognostic tool for identifying deleterious mutations in BRCA1, BRCA2, and P53 genes amongst breast cancer women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5842.

Abstract 1024: The challenge of standardizing the measurement of an imprecise biomarker like HRD

Abstract Here we present data on the characterization and implementation of a set of reference materials for the standardization of homologous recombination deficiency (HRD) assessment. The safety and effectiveness profile of a drug can be improved by using it in patients where that drug is most likely to be effective. While PARP inhibitors are indicated for use in some patients with ovarian, breast, pancreatic, and prostate cancer, patients with other cancers that are deficient in homologous recombination repair (HRR) might also benefit from their use. However, determining whether a cancer is HRD-positive is neither trivial nor precise. While clinical trials have shown that patients with deleterious mutations in BRCA2 and BRCA1 are most likely to benefit from PARP inhibitors, determining that a given BRCA mutation (or set of such mutations) is in fact deleterious is frequently not straightforward. Therefore, assays are now looking for signs of HRD, such as genomic instability consistent with non-homologous end joining (NHEJ) being used for the repair of double-stranded breaks in DNA as opposed to HRR. For example, some assays look at the combination of loss of heterozygosity (LOH) and large-scale state transitions (LST) across chromosomes as well as telomeric allelic imbalance (TAI) when determining whether a cancer is HRD-positive, while other assays use alternative approaches. How those characteristics are measured, integrated, and distilled into a final determination of whether HRD is present or absent varies, which can create uncertainty around treatment options and enrollment into clinical trials. This also makes the path of follow-on companion diagnostics challenging because perfect agreement between imprecise measurements is unlikely. In order to enable more standardized reporting of HRD and to enable the assessment of HRD assays, we created a set of characterized reference materials composed of HRD negative, borderline, and positive tumor/normal matched cell lines that were analyzed using both array-based and next generation sequencing-based assays in order to characterize chromosomal changes across their genomes and obtain HRD scores. Because of differences in the results, assay imprecision should be taken into account in clinical trials that implement cutoffs in order to establish safety data for patients who are biomarker-negative but may be biomarker-positive in a future assay, which is similar to what is done for complementary diagnostics. Citation Format: Yves Konigshofer, Matthew G. Butler, Krystyna Nahlik, Dana Ruminski Lowe, Catherine Huang, Omoshile Clement, Russell K. Garlick. The challenge of standardizing the measurement of an imprecise biomarker like HRD [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1024.

Abstract 2601: Concomitant treatment of ovarian cell lines with Tumor Treating Fields (TTFields) and PARP inhibitors

Abstract Background: PARP inhibitors (PARPi) are an effective treatment option for ovarian cancer patients harboring deleterious BRCA mutations. While such mutations prevail in one third of ovarian cancer patients, most of the other patients gain little survival benefit by the use of PARPi. Tumor Treating Fields (TTFields) are alternating electric fields with antimitotic effects on cancerous cells, also shown to induce a state of BRCAness in several types of cancer cell lines. The current study aimed to explore the potential of combining TTFields with PARP inhibition for the treatment of ovarian cancer in vitro. Methods: Ovarian carcinoma cells A2780 (BRCA1/2 wild type) and OVCAR3 (BRCA1 wild type, BRCA2 deep deletion) were treated with TTFields using the inovitro system. Treatment was applied for 72 h at an intensity of 1.2 V/cm RMS and frequency of 200 kHz. The efficacy of concomitant application of TTFields with the PARP inhibitors niraparib and olaparib was examined via measurements of cell survival, colony forming ability, overall effect (multiplicity product of cytotoxicity and clonogenicity), and apoptosis induction. Results: A2780 or OVCAR3 cells treated with TTFields displayed about 50% reduction in cell counts. Co-application of TTFields with PARPi enhanced the cytotoxic effect compared to that demonstrated by TTFields or PARPi alone. Concomitant application also resulted in reduced clonogenicity, enhanced overall effect, and increased apoptosis. Conclusions: The results suggest potential benefits for TTFields concomitant with PARP inhibiting agents for treatment of ovarian cancer. Citation Format: Antonia Martinez-Conde, Eyal Dor-On, Adi Haber, Moshe Giladi, Uri Weinberg, Yoram Palti. Concomitant treatment of ovarian cell lines with Tumor Treating Fields (TTFields) and PARP inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2601.

Ethical, legal, and sociocultural challenges of genomic research in Jordan: a mixed methods study in patients with breast cancer with Jordanian–Palestinian heritage

BackgroundBreast cancer is a leading cause of morbidity and mortality in women worldwide. At King Hussein Cancer Center (KHCC), Amman, Jordan, 38% of breast cancer diagnoses are in women younger than 45 years, which might reflect a high prevalence of hereditary breast cancer. The aim of this study was to assess the contribution of germline mutations in BRCA1 and BRCA2 to breast cancer treated at KHCC. We also describe our experience in dealing with this delicate cultural issue in a tribal-based country with Palestinian–Jordanian family origins. MethodsPatients treated at KHCC with stage I–IV breast cancer, with a high-risk profile according to US National Comprehensive Cancer Network guidelines, were invited to participate. Patients were interviewed for consent and had full autonomy to decide whether they wanted to know their test result, inform their treating physician, or have a copy of the result placed in their charts. Charts were reviewed for clinical data and tumour pathology. A 10 mL blood sample was obtained for DNA extraction. A detailed three-generation family history was obtained. BRCA sequencing was done at the Myriad Genetics laboratory using BRCAnalysis. BRCA mutations were classified as deleterious, suspected deleterious, variant of uncertain significance (VUS), or favour polymorphism (harmless). The report received for each mutation result contained a detailed description of level of risk associated with the involved variant and estimated lifetime risk of breast and ovarian cancer, risk of second breast cancer or subsequent ovarian cancer, and risk of cancer to first, second, and third-degree family members. Patients were invited to an ad-hoc clinic with the treating physician for disclosure of results and counselling about estimated cancer risk to patient and relatives. Interviews with patients were summarised as text and qualitiative analysis for common themes was done. Challenges encountered during patient consent and disclosure of results were documented, as well as proposed solutions. Ethical approval was granted by the KHCC Institutional Review Board (no 11 KHCC 63). FindingsThe first 102 patients to meet inclusion criteria were invited to participate in the study, of whom 100 enrolled and provided written informed consent. Two patients declined to participate (a response rate of 98%). Six participants were residents of the West Bank and treated at KHCC, and 66 were from families of Palestinian origin residing in Jordan. The remaining patients were Jordanians. Median age was 40 years (range 22–75). 20 patients had deleterious mutations and seven had suspected deleterious mutations in BRCA1 and BRCA2 genes. Seven VUS were detected. All patients with BRCA1 and BRCA2 mutations had a significant family history of breast or ovarian cancer. Nevertheless, many patients with a significant family history (62 of 100) tested negative for BRCA1 and BRCA2 mutations. Many ethical dilemmas were highlighted during patient encounters, mainly relating to the guarantee of confidentiality and privacy in a tribal-based culture, fears of false reassurance, autonomy versus beneficence, and the bounds of physician–patient confidentiality when relatives are at genetic risk of cancer. Potential insurance, employment, and social discrimination implications were also addressed with the patients before testing and in more detail after disclosure of positive mutation results, which flagged a legal void in local genetic testing and data protection regulations. InterpretationOur cohort showed an important incidence of deleterious and suspected deleterious BRCA1 and BRCA2 mutations, suggesting that genetic testing should be discussed and offered to patients with high-risk features. Many high-risk patients tested negative for BRCA1 and BRCA2 mutations, therefore future studies should aim to test for mutations in other breast cancer susceptibility genes (eg, CHEK2, PALB2, and BRIP1). Running culturally sensitive genetic research in a country with limited resources is a challenging exercise and highlights the urgent need for guiding regulations. We recommend establishing a clinical cancer genetics programme, through which unaffected family members would benefit from early breast cancer screening and appropriate risk-reduction measures. FundingSister Institution Network Fund of MD Anderson Cancer Center and KHCC.

Assessing homologous recombination deficiency (HRD) in ovarian cancer: Optimizing concordance of the regulatory-approved companion diagnostic and a next-generation sequencing (NGS) assay kit.

e17571 Background: Olaparib + bevacizumab is approved as first-line maintenance treatment of ovarian cancer that is HRD positive, defined as the presence of a deleterious/suspected deleterious BRCA mutation (BRCAm) and/or genomic instability. HRD genomic instability score (GIS) has been assessed in clinical trials using a regulatory-approved companion diagnostic, Myriad myChoice® CDx. We evaluated the performance of an in-development NGS assay kit that identifies BRCA variants based on genomic content from Illumina’s TruSight™ Oncology 500 research assay, and, with additional genomic content, measures HRD GIS in tumor tissue (Illumina test) in parallel. Analytic concordance of the Illumina test versus the Myriad myChoice® PLUS assay (Myriad test) under improved algorithms for calculating GIS scores is reported. Methods: Ovarian cancer tissue samples were analyzed with the Illumina (40 ng DNA; N = 227) and Myriad (200 ng DNA; N = 254) tests. Agreement rates for BRCA analysis, HRD GIS, and overall HRD status (includes BRCAm and HRD GIS [cutoff, 42]) were analyzed. For the overall and the non-BRCAm analysis cohorts, Pearson correlation between the continuous HRD GIS of the Illumina and Myriad tests was determined. Analytic sensitivity and specificity of the Illumina-derived HRD GIS to classify HRD GIS (cutoff, 42) were evaluated using AUROC. After initial concordance calculations, modifications were made to increase the quality of the Illumina preprocessing data (ie, reducing allele dosage noise and allele bias) upstream of the GIS calling algorithm. Reprocessing of the existing raw data led to further improvement in the point estimates of positive and negative percent agreement. Results: Prevalence using the Illumina and Myriad tests was 51.2% and 49.2% (overall HRD positive) and 27.6% and 25.5% (BRCAm), respectively. Agreement rates are reported in the Table. Correlation of the Illumina HRD GIS with Myriad HRD GIS was 0.980 (all samples) and 0.976 (non-BRCAm cohort); AUROCs were 0.995 and 0.992, respectively. Conclusions: Comparison between the Illumina and Myriad tests showed that overall HRD status, BRCA analysis, and HRD GIS detection results were &gt; 90% concordant; HRD GIS was highly correlated (r &gt; 0.98); and prevalence estimates were similar. These data suggest that a distributable kit solution, such as the Illumina test under development, will approach the performance of the Myriad myChoice HRD assay.[Table: see text]

Exploratory hrd and PD-L1 analysis of l-MOCA study: Olaparib maintenance monotherapy in Asian patients with platinum-sensitive relapsed ovarian cancer.

e17578 Background: Olaparib demonstrated its efficacy to prolong progression-free survival (PFS) in platinum-sensitive relapsed ovarian cancer (PSROC) patients (L-MOCA study). Almost half of OC patients harbor homologous recombination deficiencies (HRD). However, there is lack of the HRD prevalence in Asian PSR population. Meanwhile, Immunological processes play a key role in tumorigenesis and PD-L1 status may hinder an effective antitumor immune response in OC. Herein, we analyzed HRD and PD-L1 status in Asian patients with PSROC, and explored Olaparib response to different HRD status. Methods: In this exploratory analysis of L-MOCA trial, HRD and PD-L1 status were analyzed from patients with PSROC. Residual DNA samples of 193 patients were analyzed for HRD status with a local developed HRD assay (Teddy Laboratory, Shanghai, China, which determines two major components, tBRCA1/2 status and LOH score, HRD positive indicates the presence of a deleterious or suspected deleterious BRCA mutation or LOH score ≥0.4). The remaining formalin fixation and paraffin embedded samples were used for PD-L1 expression analysis by immunohistochemistry with SP263. Descriptive statistics were summarized for HRD status, PD-L1 expression status and PFS by different HRD status subgroups. Results: 193 of 224 patients had residual DNA for HRD test. Patients clinical characteristics were similar between those with and without residual DNA for HRD test, in terms of age (mean age 55.5y Vs 54.2y), FIGO stage (stage III 68.9% Vs 61.3%, stage IV 12.4% Vs 22.65%), and time to disease progression to Last prior Platinum Based Chemotherapy (6-12m: 39.9% Vs 41.9%; &gt; 12m: 59.6% Vs 54.8%). Among 193 patients with HRD test conducted, proportion of HRD+ BRCAm, HRD+ BRCAwt, HRD- and HRD unknown were 37.3%, 28.0%, 14.5% and 20.2%, separately. mPFS of the above subgroups was 20.1 months, 15.8 months, 9.2 months and 16.4 months, respectively (Table1). 200 of 224 patients were available for PD-L1 expression analysis. 184 (92%) with TC＜1%, 12 (6%) with TC among 1-25%. These results showed TC expression in all patients were less than 25%, suggesting that ovarian cancer may be an immunologically cold tumor. Conclusions: This is firstly showing the HRD and PD-L1 status in Asian OC patients. The results showed all the PSR patients could benefit from Olaparib treatment, regardless of HRD status. Meanwhile the numerically different mPFS observed across different HRD status subgroups also indicated potential clinical utility of locally developed HRD assay. Clinical trial information: NCT03534453. [Table: see text]

Characteristics of germline DNA damage response gene mutations in ovarian cancer in Southwest China.

e17606 Background: DNA damage response (DDR) pathway is responsible for repairing endogenous or exogenous DNA damage to maintain the stability of the cell genome. Germline mutations of DDR genes are potentially predictive and prognostic biomarkers for oncotherapy and may predispose carries to some malignancies. We aimed to profile the characteristics of germline DDR gene mutations in ovarian cancer treated in our center to provide highlight on regional disparity and susceptibility genes. Methods: We retrospectively and unselectively enrolled a cohort of patients diagnosed as advanced epithelial ovarian cancer from October 2016 to October 2020, who had complete clinicopathological data and signed informed consent for gene testing. In total, peripheral blood samples from 432 patients were collected in our center and evaluated on specific germline alterations. This study was approved by the Medical Ethics Committee of West China Second University Hospital, Sichuan University (Ethical Lot Number 20200076). Results: The most observed mutated genes were FANCD2 (47%), BRCA1 (27%), BRCA2 (27%), ERCC5 (18%) and RECQL4 (17%). The frequency of missense mutation was higher than other mutation types in most genes, except FANCD2, TSC2 and PHOX2B. Deleterious DDR gene mutations and deleterious homologous recombination repair gene mutations were detected in 346 patients (80.1%) and 240 patients (55.6%), respectively. The most observed genes with deleterious mutation were BRCA1 (18.5%), BRCA2 (12.5%), ERCC5 (6%), MLH1 (5.8%), PALB2 (3.7%) and ERCC4 (3.7%). The prevalence of BRCA2 deleterious mutations is higher than other studies (patients mainly from Eastern China), and so are the mismatch repair genes. Furthermore, we pointed out that deleterious mutations of FNACD2 and RECQL4 are potential ovarian cancer susceptibility genes and may predispose carriers to ovarian cancer. Conclusions: Our study presented here showed the germline DDR gene mutation spectrum of ovarian cancer patients in Southwest China, which is different from other regions of China in some genes. And we found germline FANCD2 and RECQL4 deleterious mutations were likely ovarian cancer susceptibility sites, which should draw more attention in patient management and genetic counseling.

A phase I study of pharmacokinetic (PK)-driven sequential dosing of rucaparib (RUB) with irinotecan liposome (nal-IRI) and fluorouracil (5FU) in metastatic gastrointestinal (mGI) and pancreas (PANC) cancers.

563 Background: RUB is an oral PARP1,2,3 inhibitor that demonstrated efficacy in patients (pts) with ovarian and prostate cancers harboring deleterious BRCA mutations. RUB exerts synergistic anti-tumor effect with IRI preclinically though the combination has overlapping toxicities. We previously published on the population PK of nal-IRI (Adiwijaya, Ma et al, Clin Pharm Ther 2017). We conducted a phase I study to evaluate a novel sequential dosing of RUB with nal-IRI/5FU in mGI cancer pts. Methods: Eligible pts had incurable mGI cancer previously received &gt; 1 line of therapy (rx), ECOG PS 0-1, had RECIST measurable disease, adequate organ reserves and not received IRI for metastatic disease. Previous PARPi rx was excluded. The endpoints included dose limiting toxicity (DLT), maximum tolerated dose (MTD) and toxicity profile. The dose escalation utilized the 3+3 design. RUB was given oral bid on Day 4 to 13 and 18 to 27 with nal-IRI i.v. and 5FU i.v. 2400 mg/m2 over 46 hr on Day 1 and 15, every 28 day. Planned dose levels were RUB 400 mg/nal-IRI 50 mg/m2 (DL1), 400 mg/70 mg/m2 (DL2) and 600 mg/70 mg/m2 (DL3). Adverse events (AEs) were scored per CTCAE v4.03. Molecular profile was evaluated by CLIA-certified NGS testing. Results: Eighteen pts including 11 colorectal (CRC), 6 PANC, 1 gastroesophageal (GE) were enrolled and 12 were evaluable for DLTs. DL2 was not tolerable (DLT: G3 diarrhea, nausea and vomiting) and DL2A was added (RUB 600 mg/nal-IRI 50 mg/m2). DL2A enrolled 6 pts with no DLT and was determined as the MTD. Of DLT-evaluable pts, G3 and worse treatment-related AEs from all cycles were diarrhea (33%), fatigue (25%), leukopenia (25%), neutropenia (25%), anemia (8%) and nausea (8%). Four of 12 response evaluable pts had partial response: 2 CRC (1 had ATM mut), 1 PANC ( ATM mut), 1 GE ( BRCA2 mut) whilst 3 responders previously had platinum (PLA). Five pts had stable disease beyond 16 weeks (range 18.9 to 100.7 weeks), and all had prior PLA. Conclusions: The study successfully determined the MTD of RUB in combination with nal-IRI and 5FU. Encouraging efficacy was observed in PLA-treated mGI cancers including responses in those harboring ATM and BRCA alterations. The study is proceeding to evaluate the efficacy of the combination in metastatic pancreas cancer pts with and without BRCA1/2 or PALB2 alterations. Clinical trial information: NCT03337087.

Assessing frequency and clinical outcomes of BRCA mutated ovarian cancer in Saudi women

PurposeBRCA gene mutations (BRCAm) have an impact on patients’ characteristics and clinical outcomes of ovarian cancer (OC). The frequency and patterns of BRCAm vary among countries and ethnicities. There are limited data from Saudi Arabia (SA); thus, this study aims to determine the frequency, pattern, and impact on patient characteristics and outcomes of BRCAm OC compared to wild-type BRCA (BRCAw) in Saudi women.MethodsThis retrospective study evaluated women diagnosed with non-mucinous OC, fallopian tube, or peritoneal carcinoma who had BRCA status tested in an accredited lab between January 2016 and December 2017. The associations between various parameters and BRCAm were estimated using logistic regression. Statistical analysis performed with SPSS (Version 27).ResultSixty-one women with a median age of 52 at diagnosis were analyzed. Germline BRCA mutations were found in 41% of cases (25/61). The most common deleterious germline BRCA1 mutation was c.1140dupG (39%). Most women (72%) had no family history of cancers and 82% had advanced stage. Regardless of BRCA mutations, an optimal overall response rate (ORR) to first-line treatment has been achieved although most cases relapsed (84%) and the majority were platinum-sensitive relapse (85%). Higher ORR to subsequent lines and better survival were obtained in women with BRCA-mutation.ConclusionThe prevalence of BRCAm of OC was higher in Saudi women compared to regional and most of the international figures. The better clinical outcomes of BRCAm women agreed with the reported evidence. Further studies on BRCA mutations of OC and genetic counseling are highly recommended.Trial registrationTrial approved by the Institutional Review Board of King Faisal Specialist Hospital and Research Center (RAC # 2171137) and conducted at King Faisal Specialist Hospital and Research Center, PO Box 3354, Riyadh 11,211, Saudi Arabia.

Abstract P058: Anti-tumor activity of ATR inhibitor BAY 1895344 in patient-derived xenograft (PDX) models with DNA damage response (DDR) pathway alterations

Abstract Introduction: The ATR (ataxia-telangiectasia and Rad3 related protein) kinase inhibitor BAY 1895344 is currently in clinical development for the treatment of advanced solid tumors and has demonstrated promising antitumor activity in heavily pretreated patients with various advanced solid tumors, particularly those with ATM deleterious mutations and/or loss of ATM protein. There is further need to identify robust predictive biomarkers to optimize patient selection for ATR inhibitors. For that purpose, we tested the antitumor activity of BAY 1895344 in patient-derived xenograft (PDX) models that are characterized by a variety of DDR alterations. Methods: PDX models were characterized by genomic sequencing and ATM loss by immunohistochemistry (IHC). PDX models with deleterious ATM, BRCA1 or BRCA2 mutations or loss derived from a variety of histologies were tested. BAY1895344 treatment was tested with two monotherapy regimens 20 mg/kg and 40 mg/kg PO BID both 3 days on/4 days off. For in vivo studies, the percent tumor volume change per time point was calculated as a relative level of tumor growth change from baseline: , where is the tumor volume at time and is the tumor volume at baseline. T/C ratio was defined as the ratio of tumor volume change in treated vs control group. An event in each animal was defined as a doubling of tumor volume from initial tumor volume. Event free survival was analyzed by Kaplan-Meier survival analysis. Results: Seventeen PDX models from sixteen patients were treated with BAY 1895344. The PDX models spanned multiple tumor types: breast, colon, pancreas, and cholangiocarcinoma. BAY 1895344 has shown potent and dose-dependent antitumor activity. Strongest activity was observed with BAY 1895344 at 40 mg/kg PO BID applied for 3 days on and 4 days off treatment, achieving a regression or T/C ratio &amp;lt;0.4 in 6 of 17 models. Eleven models showed statistically significant prolongation of event-free survival. BAY 1895344 had anti-tumor activity in PDX models with ATM loss as well as BRCA alterations. Notably BAY 1895344 had antitumor activity in an ATM-deleted PDX model with acquired PARP inhibitor resistance generated in the lab as well as a PDX model generated from a BRCA-mutant patient with clinically acquired PARP resistance. Conclusion: ATR inhibition via treatment with BAY 1895344 shows potent antitumor activity as monotherapy in selected models that are characterized by certain DDR alterations and even those that have developed resistance to PARP inhibition. Further analyses are ongoing to define predictors of sensitivity to BAY 1895344 as well as pharmacodynamic markers of efficacy/response as a single agent or in rational combinations Citation Format: Christian X. Cruz Pico, Dali Li, Christopher D. Lanier, Kurt Evans, Maria G. Raso, Timothy DiPeri, Yasmeen Rizvi, Min Jin Ha, Huiqin Chen, Ming Zhao, Argun Akcakanat, Xiaofeng Zheng, Gokce Toruner, Erkan Yuca, Stephen Scott, Antje M. Wengner, Timothy A. Yap, Funda Meric-Bernstam. Anti-tumor activity of ATR inhibitor BAY 1895344 in patient-derived xenograft (PDX) models with DNA damage response (DDR) pathway alterations [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P058.

261P Survival outcomes of triple-negative breast cancer (TNBC) patients in the pre-immunotherapy age: An analysis of Gruppo Italiano Mammella (GIM) 14 BIOMETA study with a focus on biological subtypes

TNBC is a subtype of Breast Cancer (BC) associated with an overall survival (OS) of around 19 months (ms). Before immunotherapy, no specific systemic treatment apart from chemotherapy (CT) was available. ER low disease is characterized by low ER and PgR staining (both <10%) and negative Her2. It’s considered as having a survival and a biological behavior comparable to that of TNBC. Deleterious germline BRCA mutations were the only predictive biomarker available in the past years for TNBC.

Landscape of homologous recombination-related (HRR) genes mutations in colon cancer.

e15525 Background: Homologous recombination deficiency (HRD) might serve as a biomarker of immunotherapy and chemotherapy response. In addtion, HRD is associated with sensitivity to PARP inhibitor (PARPi) therapy. The HRD phenotype has been defined as the presence of a non-silent somatic mutation in homologous recombination-related (HRR) genes. Here, we focused on mutational landscape of HRR genes and the relationship between HRR-related genes and clinical outcomes in colon cancer. Methods: We prospectively sequenced 784 Chinese patients with colon cancer using next-generation sequencing techniques with 808 cancer-related genes. 290 patients with somatic mutation from the TCGA project were included. The 15 HRR genes were selected on clinical evidence of sensitivity to PARP inhibitors and immunotherapy. TCGA datasets were performed to identify the correlations between HRR gene mutations and clinical outcomes. Results: In the Chinese cohort, 11.5% (90/784) patients exhibited deleterious somatic mutation in HRR genes, including ATM (3.3%), BRCA2 (2.4%), CDK12 (2.4%), BRCA1 (1.0%), BRIP1 (1.0%), CHEK2 (0.5%), BARD1 (0.4%), RAD54L (0.4%), PALB2 (0.3%), and RAD51B (0.3%). In TCGA cohort, 28.6% (83/290) patients had at least one deleterious somatic mutation in HRR genes, including ATM (14.8%), BRCA2 (9.0%), CDK12 (7.9%), BRIP1 (3.8%), BRCA1 (3.4%), FANCL (3.1%), CHEK2 (2.4%), PALB2 (2.1%), PPP2R2A (2.1%), RAD54L (2.1%), CHEK1 (1.7%), BARD1 (1.4%), RAD51C (1.4%), RAD51B (1.0%), and RAD51D (0.3%). Overall, the mutational frequency of HRR genes in the Chinese cohort was lower than that in the TCGA cohort (p &lt; 0.001). In the TCGA cohort, colon patients with HRR-mut had significantly higher tumor mutational burden and incidence of microsatellite instability high and enhanced immune activity than patients with HRR-wt. Furthermore, In the MSK-IMPACT cohort treated by immune checkpoint inhibitor, patients with HRR-mut had significantly better OS (p = 0.009) and increased immune activities, such as infiltration of cytotoxic cells (p &lt; 0.05) and exhausted CD8+ T cells (p &lt; 0.01), and increased the IFN-γ scores (p &lt; 0.05) than patients with HRR-wt. Conclusions: Our data suggest that detection of somatic mutations in HRR genes might contribute to identify patients who might benefit from immune checkpoint blockade therapy and PARP inhibitors. In addition, the molecular features of HRR provide new opportunities to predict the tumor response to multiple treatments. Exploring other biomarkers of HRD to predict the response to PARPi and immunotherapeutic in colon cancer is necessary.

Genomic profiling of KRAS wide-type pancreatic ductal adenocarcinomas identifies targetable genetic alterations.

4121 Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and the 5-year survival of PDAC patients is below 10%. The oncogenic KRASmutations account for about 90% of PDAC cases. Unfortunately, there is no FDA-approved targeted therapy for KRAS mutations. Therefore, the genomic profiling of KRAS wide-type PDACs can provide invaluable sights to the etiology of these patients and offer them the opportunity of precision therapy trials. Methods: To characterize actionable targets in 521 Chinese PDAC patients, deep sequencing of a 831-gene panel (OncoPanscan, Genetronhealth) was applied to assess somatic mutations of their tumor tissues including SNV, insertions/deletions, CNV and re-arrangements, as well as possible pathogenic germline variants of paired genomic DNA sample. Results: There were 89% (463/521) of patients in our PDAC cohort harbored KRAS mutations. Among the remaining 58 patients in KRAS wild-type subgroup, 33% (19/58) carried activating mutations in the RTK/Ras/MAPK pathway. Targetable BRAF mutations were seen in five (9%) patients: V600E (1/5), G464V (1/5), N486_P490del (2/5) and BRAF fusion (1/5). The frequency of BRAF mutations was 9% (5/58) in KRAS wild-type PDACs but only 0.4% (2/463) in KRAS-mutated PDACs (P &lt; 0.001). We found one classic EGFR activing mutation (L747_A750delinsP) and one MAP2K1 activating mutation (F53_Q58delinsL), which can be targeted by EGFR-TKIs and MEK inhibitor trametinib, respectively. An oncogenic ERBB3 mutation (V104L) was seen in one patient, who was eligible for HER2-targeted therapy clinical trials. We also found STK11/TSC2 inactivating mutations and a dominant-negative mutation of PTEN (R130Q) which could be targeted by mTOR inhibitor everolimus and AKT inhibitor capivasertib, respectively. Additionally, we observed a patient with high level amplification of MET and another patient with the NCOA4-RET fusion gene which can be targeted by MET inhibitor carbozantinib. Interestingly, we also identified two patients with inactivating mutations in ELF3 (one frameshift and one in splicing-site), which is a driver gene of ampullary carcinoma. Lastly, two patients carried deleterious germline mutations in BRCA1 and PALB2, which may be targeted with PARP inhibitors. Overall, at least 29% (17/58) KRAS wide-type patients harbored potentially actionable genomic alterations to currently used anticancer drugs. Conclusions: The mutational landscape of our PDAC cohort provided compelling evidence that targetable driver mutations accounted for a significant portion of KRAS wide-type tumors. Our findings demonstrated that genomic profiling of PDAC patients can enable physicians to optimize their clinical management and enroll them into genomically matched clinical trials.