Deleterious BRCA Mutations Research Articles

Olaparib plus trastuzumab in HER2-positive advanced breast cancer patients with germline BRCA1/2 mutations: The OPHELIA phase 2 study

PurposeTo evaluate the efficacy and safety of the combination of olaparib plus trastuzumab in patients with HER2-positive advanced breast cancer (ABC) and germinal BRCA mutations (gBRCAm). MethodsOPHELIA (NCT03931551) was a single-arm, open-label, phase 2 clinical trial. Patients aged ≥18 years diagnosed with HER2-positive ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease were enrolled. Patients received olaparib plus trastuzumab until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was investigator-assessed clinical benefit rate for at least 24 weeks as per RECIST v.1.1. Key secondary endpoints included overall response rate (ORR) and safety profile. ResultsA total of 68 pre-treated HER2-positive ABC patients were screened. Due to slow accrual the trial was stopped after enrolling 5 patients instead of the planned sample size of 20. Four patients achieved clinical benefit (80.0 %, 95 % CI; 28.4–99.5, p < 0.001) and the primary endpoint was met. The ORR was 60.0 % (95 % CI; 14.7–94.7), including one complete response. Four (80.0 %) patients experienced at least one treatment-related treatment-emergent adverse event (TEAE). Most TEAEs were grade 1 or 2. There were no treatment-related deaths and no new safety signals were identified. ConclusionsThis study suggests that the combination of olaparib plus trastuzumab may be effective and safe in pre-treated patients with HER2-positive gBRCAm ABC. This ABC patient population should be further studied and not be pre-emptively excluded from clinical trials of targeted therapy for BRCA1/2-driven cancers.

Prevalence of homologous recombination biomarkers in multiple tumor types: an observational study.

Aim: To determine the prevalence of deleterious mutations in BRCA1 and BRCA2 and in 13 genes involved in homologous recombination repair (HRR), the prevalence of genomic loss of heterozygosity and the allelic and hereditary status of BRCA1, BRCA2 and other HRR gene mutations in multiple solid tumor types. Patients & methods: This was a retrospective observational study of patients with an advanced/metastatic diagnosis in one of 15 solid tumor types, who were identified in a real-world clinico-genomic database. Results: Tumor tissue samples from 9457 patients were analyzed, among which 4.7% had known or suspected deleterious BRCA1/2 mutations. The prevalence (range) of mutations in HRR genes was 13.6% (2.4%-26.0%) and genomic loss of heterozygosity ≥16% was 20.6% (2.6-34.4%) across all tumor types. Conclusion: The prevalence of mutations varied significantly depending on the type of tumor.

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

DNA damage response (DDR) pathways are responsible for repairing endogenous or exogenous DNA damage to maintain the stability of the cellular genome, including homologous recombination repair (HRR) pathway, mismatch repair (MMR) pathway, etc. In ovarian cancer, current studies are focused on HRR genes, especially BRCA1/2, and the results show regional and population differences. To characterize germline mutations in DDR genes in ovarian cancer in Southwest China, 432 unselected ovarian cancer patients underwent multi-gene panel testing from October 2016 to October 2020. Overall, deleterious germline mutations in DDR genes were detected in 346 patients (80.1%), and in BRCA1/2 were detected in 126 patients (29.2%). The prevalence of deleterious germline mutations in BRCA2 is higher than in other studies (patients are mainly from Eastern China), and so is the mismatch repair genes. We identified three novel BRCA1/2 mutations, two of which probably deleterious (BRCA1 p.K1622* and BRCA2 p.L2987P). Furthermore, we pointed out that deleterious mutations of FNACD2 and RECQL4 are potential ovarian cancer susceptibility genes and may predispose carriers to ovarian cancer. In conclusion, our study highlights the necessity of comprehensive germline mutation detection of DNA damage response genes in ovarian cancer patients, which is conducive to patient management and genetic counseling.

Comprehensive genomic evaluation of advanced and recurrent breast cancer patients for tailored precision treatments

AimThe aim of this study was to investigate genetic alterations within breast cancer in the setting of recurrent or de novo stage IV disease.Patients and methods: This study included 22 patients with recurrent breast cancer (n = 19) and inoperable de novo stage IV breast cancer (n = 3). For next generation sequencing, FoundationOneCDx (F1CDx) (Foundation Medicine Inc., Cambridge, MA, USA) was performed in 21 patients and FoundationOneLiquid CDx was performed in 1 patient.ResultsMedian age was 62.9 years (range, 33.4–82.1). Pathological diagnoses of specimens included invasive ductal carcinoma (n = 19), invasive lobular carcinoma (n = 2), and invasive micropapillary carcinoma (n = 1). F1CDx detected a median of 4.5 variants (range, 1–11). The most commonly altered gene were PIK3CA (n = 9), followed by TP53 (n = 7), MYC (n = 4), PTEN (n = 3), and CDH1 (n = 3). For hormone receptor-positive patients with PIK3CA mutations, hormonal treatment plus a phosphoinositide 3-kinase inhibitor was recommended as the treatment of choice. Patients in the hormone receptor-negative and no human epidermal growth factor receptor 2 expression group had significantly higher tumor mutational burden than patients in the hormone receptor-positive group. A BRCA2 reversion mutation was revealed by F1CDx in a patient with a deleterious germline BRCA2 mutation during poly ADP ribose polymerase inhibitor treatment.ConclusionGuidance on tailored precision therapy with consideration of genomic mutations was possible for some patients with information provided by F1CDx. Clinicians should consider using F1CDx at turning points in the course of the disease.

Abstract B013: A quest for deeper understanding of BRCA2 Variants of Uncertain Significance (VUS)

Abstract Deleterious mutations in homology-directed repair pathway genes impact both future cancer risk and therapeutic intervention options for cancer diagnosis and prognosis. Homology-directed repair pathway is a high-fidelity DNA repair pathway for resolving double-strand breaks (DSBs) throughout the human genome. BRCA2, as a homology-directed repair factor, is essential to ensure genome integrity through an error-free process. Deleterious BRCA2 mutations increase the lifetime risk of breast, ovarian, melanoma, prostate, and pancreatic cancers. Deleterious BRCA2 mutations cover only 25% of the total BRCA2 mutations identified in the population by genetic testing whereas 60% are mutations with unknown connection to the disease called Variants of Uncertain Significance (VUS). The majority of BRCA2 VUS are missense mutations with one point mutation which could potentially alter BRCA2 cellular localization and/or nuclear functions. Thus, evaluating BRCA2 cellular localization and function in BRCA2 missense carriers and tumors is urgently needed to provide clinical guidance regarding cancer risk and treatment options. We have identified a paradoxical relationship between BRCA2 nuclear import and treatment. Deleterious missense mutations in the DNA binding domain of BRCA2 direct the protein to the cytosol which increase sensitivity to PARP inhibitors (PARPi) and platinum drugs. Therefore, although BRCA2 mislocalization might be a cause of cancer, keeping it out of the nucleus allows for much better treatment outcomes. Here, we present how BRCA2 cancer-driver missense mutations lead to cytosolic mislocalization and how BRCA2 localization can be used as a diagnostic tool to stratify patients. Our robust multi-step molecular approach will guide future clinical decision rules surrounding BRCA2 VUS. By providing reliable and accurate functional assays to correctly evaluate the pathogenicity of BRCA2 VUS, our goal is to improve personalized medicine by providing actionable information to patients and their physicians. Citation Format: Cole Niedmann, Judit Jimenez Sainz. A quest for deeper understanding of BRCA2 Variants of Uncertain Significance (VUS) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr B013.

Pharmacodynamic effects of the PARP inhibitor talazoparib (MDV3800, BMN 673) in patients with BRCA-mutated advanced solid tumors

PurposeTalazoparib is an inhibitor of the poly (ADP-ribose) polymerase (PARP) family of enzymes and is FDA-approved for patients with (suspected) deleterious germline BRCA1/2-mutated, HER2‑negative, locally advanced or metastatic breast cancer. Because knowledge of the pharmacodynamic (PD) effects of talazoparib in patients has been limited to studies of PARP enzymatic activity (PARylation) in peripheral blood mononuclear cells, we developed a study to assess tumoral PD response to talazoparib treatment (NCT01989546).MethodsWe administered single-agent talazoparib (1 mg/day) orally in 28-day cycles to adult patients with advanced solid tumors harboring (suspected) deleterious BRCA1 or BRCA2 mutations. The primary objective was to examine the PD effects of talazoparib; the secondary objective was to determine overall response rate (ORR). Tumor biopsies were mandatory at baseline and post-treatment on day 8 (optional at disease progression). Biopsies were analyzed for PARylation, DNA damage response (γH2AX), and epithelial‒mesenchymal transition.ResultsNine patients enrolled in this trial. Four of six patients (67%) evaluable for the primary PD endpoint exhibited a nuclear γH2AX response on day 8 of treatment, and five of six (83%) also exhibited strong suppression of PARylation. A transition towards a more mesenchymal phenotype was seen in 4 of 6 carcinoma patients, but this biological change did not affect γH2AX or PAR responses. The ORR was 55% with the five partial responses lasting a median of six cycles.ConclusionIntra-tumoral DNA damage response and inhibition of PARP enzymatic activity were confirmed in patients with advanced solid tumors harboring BRCA1/2 mutations after 8 days of talazoparib treatment.

Application of genetic counseling and preventive surgery in hereditary breast-ovarian cancer syndrome based on a rare family

Objective: To investigate the genetic, clinical and pathological characteristics of families with hereditary breast-ovarian cancer syndrome (HBOCS) and to explore the implementation of genetic counseling and preventive surgery. Methods: Four siblings with HBOCS in Cancer Hospital/Chinese Academy of Medical Sciences were selected as the study subjects. BRCA gene testing and genetic counseling were performed, family history was traced and family map was drawn. Results: There were 7 cancer patients (Ⅰ 2, Ⅱ 4, Ⅱ 8, Ⅲ 7, Ⅲ 10, Ⅲ 11, Ⅲ 12) in three generations in the family. One patient (Ⅲ 7) had breast cancer and ovarian cancer successively. The first generation (Ⅰ 2) developed cancer at age 60, the second generation (Ⅱ4 and Ⅱ8) developed cancer at 55. The third generation (Ⅲ 7, Ⅲ 10, Ⅲ 11, Ⅲ 12) developed cancer at the age of 42-50 years. Four HBOCS patients were treated in our hospital, and all of them were found to have deleterious BRCA1 mutation. Two had already developed ovarian cancer (Ⅲ 10, Ⅲ 12), while in one case (Ⅲ 11), tubal carcinoma was found during preventive total hysterectomy and pelvic lymph node metastasis was found after the supplementary staging surgery. The other patient without cancer underwent preventive bilateral salpingectomy(Ⅲ 15). Conclusion: The HBOCS family reported in this study is relatively rare, the onset time of tumor was younger generation by generation. It is very important to pay attention to the genetic counseling of ovarian cancer patients and to timely detect the HBOCS families for genetic testing and prophylactic surgery.

The Landscape of BRCA Mutations among Egyptian Women with Breast Cancer.

Deleterious germline mutations in BRCA1 and BRCA2 genes are associated with a high risk of breast and ovarian cancer. In many developing countries, including Egypt, the prevalence of BRCA1/2 mutations amongwomen with breast cancer (BC) is unknown. We aimed to determine the prevalence of deleterious germline BRCA mutations in Egyptian patients with breast cancer. We report the results of a cohort study of 81 Egyptian patients with breast cancer who were tested for germline BRCA1/2 mutations during routine clinical practice, mostly for their young age of presentation, BC subtype, or presence of family history. In addition, we searched five databases to retrieve studies that reported the prevalence of BRCA1/2 mutation status in Egyptian women with BC. A systematic review of the literature was performed, including prospective and retrospective studies. In our patient cohort study, 12 patients (14.8%) were positive for either BRCA1/2 deleterious mutations. Moreover, 13 (16.1%) patients had a variant of unknown significance (VUS) of BRCA1/2 genes. Twelve studies were eligible for the systematic review, including 610 patients. A total of 19 deleterious germline mutations in BRCA1/2 were identified. The pooled prevalence of BRCA1/2 mutations was 40% (95% confidence interval 1-80%). The reported prevalence was highly variable among the small-sized published studies that adopted adequate techniques. In our patient cohort, there was a high incidence of VUS in BRCA1/2 genes. Accordingly, there is an actual demand to conduct a prospective well-designed national study to accurately estimate the prevalence of BRCA1/2 mutations among patients with BC in Egypt.

Combining next-generation hormonal therapy with PARP inhibition in metastatic castration-resistant prostate cancer

In a paradigm of precision oncology, elegant preclinical work showed that inhibition of poly(ADP-ribose) polymerase (PARP) proteins can exploit a deficiency of cancer cells to repair DNA double-strand breaks through homologous recombination repair (HRR), 1 Lord CJ Ashworth A PARP inhibitors: synthetic lethality in the clinic. Science. 2017; 355: 1152-1158 Crossref PubMed Scopus (1411) Google Scholar and the resulting synthetic lethality was first shown to be clinically effective in ovarian cancer carrying a germline deleterious mutation in BRCA1 or BRCA2, key HRR genes. 2 Banerjee S Moore KN Colombo N et al. Maintenance olaparib for patients with newly diagnosed advanced ovarian cancer and a BRCA mutation (SOLO1/GOG 3004): 5-year follow-up of a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet Oncol. 2021; 22: 1721-1731 Summary Full Text Full Text PDF PubMed Scopus (92) Google Scholar For prostate cancer, the discovery of alterations in BRCA2 and other HRR-related genes in up to 20% of advanced disease 3 Robinson D Van Allen EM Wu YM et al. Integrative clinical genomics of advanced prostate cancer. Cell. 2015; 161: 1215-1228 Summary Full Text Full Text PDF PubMed Scopus (2077) Google Scholar led to the development of several biomarker-driven trials of PARP inhibitors in patients with metastatic castration-resistant prostate cancer (mCRPC) 4 Abida W Patnaik A Campbell D et al. Rucaparib in men with metastatic castration-resistant prostate cancer harboring a BRCA1 or BRCA2 gene alteration. J Clin Oncol. 2020; 38: 3763-3772 Crossref PubMed Scopus (309) Google Scholar , 5 de Bono JS Mehra N Scagliotti GV et al. Talazoparib monotherapy in metastatic castration-resistant prostate cancer with DNA repair alterations (TALAPRO-1): an open-label, phase 2 trial. Lancet Oncol. 2021; 22: 1250-1264 Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar , 6 Hussain M Mateo J Fizazi K et al. Survival with olaparib in metastatic castration-resistant prostate cancer. N Engl J Med. 2020; 383: 2345-2357 Crossref PubMed Scopus (289) Google Scholar , 7 Smith MR Scher HI Sandhu S et al. Niraparib in patients with metastatic castration-resistant prostate cancer and DNA repair gene defects (GALAHAD): a multicentre, open-label, phase 2 trial. Lancet Oncol. 2022; 23: 362-373 Summary Full Text Full Text PDF PubMed Scopus (41) Google Scholar and to the regulatory approval of rucaparib and olaparib as monotherapy for the treatment of mCRPC harbouring mutations in BRCA2 and other HRR genes. Talazoparib plus enzalutamide in men with first-line metastatic castration-resistant prostate cancer (TALAPRO-2): a randomised, placebo-controlled, phase 3 trialTalazoparib plus enzalutamide resulted in clinically meaningful and statistically significant improvement in rPFS versus standard of care enzalutamide as first-line treatment for patients with mCRPC. Final overall survival data and additional long-term safety follow-up will further clarify the clinical benefit of the treatment combination in patients with and without tumour HRR gene alterations. Full-Text PDF

Pathologic complete response after neoadjuvant systemic therapy for breast cancer in BRCA mutation carriers and noncarriers.

544 Background: Distinct pathological characteristics and mutational signatures in BRCA-associated breast cancers may result in differential response to chemotherapy but understanding of treatment response after neoadjuvant chemotherapy (NAC) is limited. We describe a single-institutional experience to compare rates of pathologic complete response (pCR) after NAC in BRCA carriers (g BRCA1/2) and noncarriers. Methods: From 11/2013 to 01/2022, 1426 consecutive women with clinical stage I-III breast cancer were treated with NAC followed by surgery. Baseline disease characteristics were compared between g BRCA1/2 and noncarriers using two-sample non-parametric tests. Conditional logistic regression was used to evaluate the association between BRCA status and pCR (i.e., ypT0/is pN0) adjusting for variables selected using backward elimination. Results: 92 (6.5%) and 73 (5.1%) had deleterious mutations in BRCA1 and BRCA2, respectively. Compared to noncarriers, g BRCA1/2 were younger (p&lt;0.001) with clinical T1 (p=0.002) and triple negative disease (TN) (57% vs 25% noncarriers, p&lt;0.001). Almost all patients received doxorubicin/cyclophosphamide/paclitaxel therapy (93%) with g BRCA1/2 more likely to receive carboplatin (p&lt;0.001). pCR rate was 42% of g BRCA1, 21% of g BRCA2, and 26% of noncarriers (p=0.001). Among clinically node positive (cN+) patients, nodal pCR was higher in g BRCA1/2 compared to noncarriers (53/96 (55%) vs 371/856 (43%), p=0.012). This difference was seen in ER+/HER2- (36% gBRCA1/2 vs 20% noncarriers; p=0.027) and TN subtypes (79% g BRCA1/2 vs 45% noncarriers; p&lt;0.001). Poorly differentiated tumors (p&lt;0.001), cN+ (p=0.010), lower cT stage (p=0.028), ductal histology (p&lt;0.001), TN and HER2+ receptor status (p&lt;0.001), absence of lymphovascular invasion (p&lt;0.001), carboplatin receipt (p=0.041), and BRCA1 status (p=0.001) were also associated with pCR on univariate analysis. After adjusting for differentiation and molecular subtype, BRCA1 status remained independently associated with pCR. Conclusions: g BRCA1 undergoing NAC have higher pCR rates relative to g BRCA2 and patients with sporadic disease. Across breast cancer subtypes, g BRCA1/2 more frequently converted to pN0. Defining biological mechanism for these findings would allow customization of treatment based on germline genetics. [Table: see text]

Clinical predictors of survival in advanced epithelial ovarian cancer: Can we foresee the long-term survivors and develop a personalized treatment approach?

e17605 Background: While women with recurrent disease have a poor prognosis, a subset of women are long term survivors (LTS). We aimed to characterize the demographic and clinical characteristics associated with long and short-term survival of patients with advanced epithelial OC (EOC). Methods: We conducted a retrospective descriptive analysis of 822 patients diagnosed with advanced EOC (FIGO stage III/IV) and treated at a single institution, between 2002-2020. Characteristics of short-term survivors (STS), women who survived less than 2 years, were compared to LTS, patients who lived beyond 7 and 10 years from diagnosis. Descriptive statistics of the clinical, oncologic, and treatment parameters were performed using t-test, chi-square. We assessed the contribution of age and stage, BRCA carrier status, interval or primary debulking, optimal debulking, platinum sensitivity, and treatment scheduling upon oncological outcomes. Results: Among 822 patients with advanced EOC, 112 women (13.6%) died withing 24 months from diagnosis, while 139 (16.9%), and 64 (7.8%) survived beyond 7 and 10 years, respectively. Histology, CA125 level at diagnosis, and interval or primary debulking approach, were not significant among the STS and LTS. LTS were younger at diagnosis, (median age of 57, and 56.5 among women who lived &gt; 7 and 10 years, respectively vs. 70 in STS, p &lt; 0.0001). The majority of LTS were diagnosed with stage III disease, (95%, and 97%, &gt; 7 and &gt; 10 years, respectively vs. 67% of STS), in contrast to a greater proportion of STS diagnosed with stage IV (33.0% of STS vs. 5.0%, 3.1% of LTS &gt; 7 and &gt; 10 years, respectively, p &lt; 0.0001). BRCA mutation status was the strongest prognostic factor for LTS ( &gt; 7 and 10 years, OR = 17.8, 21.2 respectively, p &lt; 0.001). Almost half of LTS who were carriers of a deleterious BRCA mutation, (47.3%, 46.2% of LTS &gt; 7 and 10 years, respectively, p &lt; 0.0001), whereas most STS were not carriers of BRCA mutations (89.8%). LTS were predominantly platinum sensitive (99.3%, 98.4% &gt; 7 and &gt; 10 year, vs. 21.6% of STS, P &lt; 0.0001). Optimal cytoreductive surgery was performed in a smaller number of STS compared to the LTS (41.9% of STS vs. 83.5% and 88.7% of LTS &gt; 7 and 10 years, respectively, p &lt; 0.0001). A greater proportion of LTS received weekly treatment scheduling of paclitaxel and carboplatin compared to STS (50.8% and 49.2% of LTS &gt; 7 and 10 years, respectively vs. 31.6% of STS, p &lt; 0.01). Conclusions: The long and short-term survivors of advanced EOC may be identified early in the clinical assessment, based on distinct patient characteristics associated with survivorship, which are critical in developing a personalized treatment approach. Our work demonstrated that LTS are a distinct group of women diagnosed at a younger age, lower stage, optimally debulked, platinum sensitive disease, and BRCA mutation carriers.

Abstract P4-07-29: Olaparib plus Trastuzumab in HER2[+] BRCA-Mutated Advanced Breast Cancer Patients: The OPHELIA Study

Abstract Background: Olaparib (O) is approved for the treatment of HER2[-] patients (pts) with early or metastatic breast cancer and a germline BRCA mutation. Nevertheless, there is no evidence that HER2[+] tumors are resistant to PARPi. Preclinical data support that HER2[+] cells are sensitive to PARPi and strongly suggest that PARP inhibition augments the efficacy of trastuzumab (T). To test whether PARPi is synergistic with anti-HER2 therapy, the OPHELIA study has assessed the efficacy and safety of O in combination with T in pts with HER2[+] germinal BRCA-mutated advanced breast cancer (ABC). Methods: OPHELIA (NCT03931551) is an open-label, multicenter, single-arm, phase II trial. The study enrolled pts aged ≥18 years diagnosed of HER2[+] ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease (including a pertuzumab- or trastuzumab emtansine based regimen). Pts received O (300 mg oral, twice daily) plus T (either loading dose of 8 mg/kg IV infusion, and subsequent 3-weekly doses of 6 mg/kg IV infusion; or 600 mg SC injection, on day 1 of every 21-day cycle) until disease progression, unacceptable toxicity, or consent withdrawal. Primary endpoint was investigator-assessed clinical benefit rate (CBR) for at least 24 weeks as per RECIST v.1.1. Secondary endpoints included overall response rate (ORR), duration of response (DoR), progression-free survival (PFS), overall survival (OS); and safety and tolerability as per NCI-CTCAE v.5.0. The primary analysis evaluated CBR (H0: ≤5%; H1: ≥30%) based on exact binomial test. Sample size was designed to attain a 90% power at 10% one-sided alpha level. Results: From Mar 25, 2019, through Mar 2, 2022, 5 pts (from a total of 42 pts evaluated) were enrolled at 17 sites in Spain. Median age was 37.0 (range 32–54) years, 1 (20.0%) patient was male, 4 (80.0%) pts carried germinal BRCA2 mutations, 4 (80.0%) pts had received ≥ 3 advanced disease treatments lines, and 4 (80.0%) pts presented ≥ 2 metastatic sites. At data cutoff (Mar 2, 2022), with a median follow-up of 18.7 months (min: 11.7; max: 22.1), 40.0% of pts remained on therapy. CBR at 24 weeks was 80.0% meeting the primary endpoint (4 of 5 pts; 95% CI, 28.4% to 99.5%, p&amp;lt; 0.001). ORR (1 complete and 2 partial responses) was 60.0% (95% CI, 17.4% to 94.7%), and median DoR was 3.8 months (95% CI, 2.5 to 8.3 months). Two (40.0%) pts had PFS events due to disease progression at 5.2 and 1.2 months, respectively. Rest of pts were treated for 5.5, 11.2, and 19.0 months. There were 2 (40.0%) deaths at 14.0 and 18.5 months. The most common non-hematological treatment emergent adverse events (TEAEs) of any grade (G) were fatigue (60.0%; 0% G≥3), nausea (60.0%; 0% G≥3), vomiting (40.0%; 0% G≥3), and back pain (40.0%; 0% G≥3). Anemia (40.0%; 20.0% G≥3) and lymphopenia (40.0%; 20.0% G≥3) were the most frequent hematological TEAEs. One (20.0%) patient discontinued treatment because of a drug-related TEAE (leukopenia). A dose reduction of O was reported in 1 (20.0%) patient. No treatment-related deaths were reported. Conclusions: HER2 overexpression in germline BRCA-mutated ABC is infrequent. The activity observed in these 5 pts indicates that O+T combination might be of help in this group of pts. We strongly believe that randomized data are not needed, and RWE studies might help us to understand the real activity of this combination. Toxicity was as expected. Citation Format: José E. Alés-Martínez, Judith Balmaña, Pedro Sánchez-Rovira, Francisco Javier Salvador Bofill, José Ángel García-Sáenz, Isabel Pimentel, Serafin Morales Murillo, Adela Fernández, Ainhara Lahuerta Martínez, Neus Ferrer, Pilar Zamora, Begoña Bermejo, Tamara Díaz-Redondo, María Helena Lopez-Ceballos, María Galán, Andrea Malfettone, Laura Calabuig, Miguel Sampayo-Cordero, José Manuel Pérez-García, Javier Cortés, Antonio Llombart-Cussac. Olaparib plus Trastuzumab in HER2[+] BRCA-Mutated Advanced Breast Cancer Patients: The OPHELIA Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-29.

Abstract OT2-09-01: TBCRC-055: A Phase II Study of NirAparib, Dostarlimab, and Radiotherapy in Metastatic, PD-L1 Negative or Immunotherapy-Refractory Triple-Negative Breast Cancer (NADiR) – NCT04837209

Abstract Background: Metastatic triple negative breast cancer (mTNBC) is associated with high recurrence and mortality rates. Prior studies have shown an immune checkpoint inhibitor (ICI) + chemotherapy improves progression-free survival for patients with PD-L1 positive mTNBC. There remains a need for treatment options in patients who do not respond to ICI or are PD-L1 negative. Preclinical data suggests that a PARP inhibitor (PARPi) may promote innate immune signaling, and combination with an ICI has shown a positive response in patients with mTNBC. Radiotherapy (RT) is a potent immune stimulator and used for local control in the setting of metastatic breast cancer. This phase II study (NCT04837209) proposes combination of PARPi, ICI, and RT to combat ICI resistance and improve response rates in patients with mTNBC who are PD-L1 negative or who have progressed on prior ICI. Methods: 32 patients with mTNBC defined as ER&amp;lt; 1%, PR&amp;lt; 1%, HER-2-neu 0-1+ by IHC or non-FISH-amplified or patients with metastatic HR+/HER2- breast cancer are anticipated to participate. Eligibility criteria for mTNBC patients includes those who are PD-L1 negative or have progressed on prior ICI. Eligibility criteria for HR+/HER2- patients is specific to those who harbor a deleterious BRCA1 or BRCA2 mutation with or without high tumor mutational burden (TMB). All trial patients should have at least 1 lesion amenable to RT and at least 1 measurable lesion that will not be radiated. Study treatment consists of 3-week cycles, with 500mg dostarlimab given on day 1 of each cycle through cycle 5, then 1000mg given every 6 weeks. RT (24 Gy) is delivered in 3 consecutive fractions starting day 1 of cycle 1. Niraparib (200mg) is dosed orally daily. Tumor biopsies are taken within 28 days pre-treatment, and at C3D1-8. Blood samples are taken at baseline and every odd cycle for cfDNA and PBMC analysis. The primary endpoint is to assess overall response rate as measured by RECIST v1.1 of the combination of niraparib, dostarlimab, and RT. Secondary objectives include assessing safety and toxicity, overall survival, progression free survival, and quality of life. Results: To date, this study has accrued 4 subjects, including 3 with mTNBC, and 1 with HR+/HER2-/BRCA mutant + TMB high mBC. The study is currently open at MGH and Sibley, and the addition of UPenn, Johns Hopkins, and Duke are in progress. Funding for this study was provided by GSK. GSK was provided the opportunity to review a preliminary version of this abstract for factual accuracy, but the authors are solely responsible for final content and interpretation. People with specific interest in the trial should reach out to Elizabeth Scott, Clinical Research Coordinator, at ecscott@mgh.harvard.edu. Citation Format: Elizabeth Scott, Steven J. Isakoff, Alphonse G. Taghian, Jean Wright, Cesar Augusto Santa-Maria, Payal Shah, Neil Taunk, Carey Anders, Rachel Blitzblau, Gaorav Gupta, Alice Ho. TBCRC-055: A Phase II Study of NirAparib, Dostarlimab, and Radiotherapy in Metastatic, PD-L1 Negative or Immunotherapy-Refractory Triple-Negative Breast Cancer (NADiR) – NCT04837209 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-09-01.

Genetic Counseling, Screening and Risk-Reducing Surgery in Patients with Primary Breast Cancer and Germline BRCA Mutations: Unmet Needs in Low- and Middle-Income Countries.

Worldwide genetic counseling practices are variable and often not reported in low- and middle-income countries (LMICs). We present the follow-up genetic counseling, breast screening, risk-reducing salpingo-oophorectomy (RRSO) and contralateral prophylactic mastectomy (CPM) in a cohort of study patients with either BRCA pathogenic mutations or BRCA variant of unknown significance (VUS). Chart review and phone calls for the collection of information. Out of a cohort of 250 patients, 14 had deleterious mutations and 31 had a VUS, of whom 19 had primary early breast cancer. We collected information about genetic counseling, screening, CPM and RRSO. Fourteen patients with deleterious mutations (7 BRCA1 and 7 BRCA2) and 19 patients with VUS mutations (20 VUS, 4 BRCA1, 16 BRCA2; 1 patient had both) were surveyed. Of 14 patients with deleterious BRCA mutations, 57.14% (8/14 patients) received genetic counseling from their oncologist. Subsequently 85.71% (12/14) are undergoing mammography screening and 35.71% (5/14) breast screening magnetic resonance imaging (MRI). Furthermore, 50% of them underwent CPM and 57.14% underwent RRSO. Of 19 patients with VUS mutations, 10.5% received genetic counseling from their oncologist; 78.9% were undergoing regular screening mammogram and 31.5% were undergoing breast MRI; one patient underwent CPM and two patients RRSO. Within three years from knowing they have a mutation, 50% of patients with germline BRCA mutations had undergone CPM and 60% RRSO, the majority of them had screening mammography surveillance but only 50% had screening MRI. Follow-up of patients with VUS with mammography was 78% but MRI was only 31%. Lack of MRI surveillance reflects both limited resources and insufficient counseling. Genetic counseling was done by medical oncologists, which reflects a trend in LMIC. Our Data shows the importance of the need for professional genetic counselors and optimal surveillance in Lebanon and other LMICs.

Rucaparib cocrystal: Improved solubility and bioavailability over camsylate

Rucaparib (Ruc) is a drug used to treat advanced ovarian cancer associated with deleterious BRCA mutations. Its commercial form, the camsylate salt (Ruc-Cam), suffers from poor aqueous solubility and thus causes low and erratic oral bioavailability. In this work, we aimed to improve the oral exposure of Ruc through cocrystallization. Liquid-assisted grinding, slurry, and solvent evaporation methods were employed to prepare new solid forms of Ruc. Cocrystals of rucaparib-theophylline monohydrate (Ruc-Thp MH), rucaparib-maltol (Ruc-Mal), and rucaparib-ethyl maltol (Ruc-Emal) were obtained. Powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamic vapor sorption were utilized to characterize these multi-component systems. All cocrystals dissolve faster than Ruc-Cam at pH 2.0 and 4.5, and Ruc-Thp MH displays the highest apparent solubility in pH 4.5 and 6.8 buffers. Pharmacokinetic studies in rats show that Ruc-Thp MH exhibits 2.4 times the Cmax and 1.4 times the AUC0-24h at a single dose compared with Ruc-Cam. The enhanced solubility and bioavailability of Ruc-Thp MH showcase the power of cocrystallization in addressing absorption issues in drug development.

Differential responses to taxanes and PARP inhibitors in ATM-versus BRCA2-mutated metastatic castrate-resistant prostate cancer.

PARP(poly(ADP-ribose) polymerase) inhibitors (PARPi) are now standard of care in metastatic castrate-resistant prostate cancer (mCRPC) patients with select mutations in DNA damage repair (DDR) pathways, but patients with ATM- and BRCA2 mutations may respond differently to PARPi. We hypothesized that differences may also exist in response to taxanes, which may inform treatment sequencing decisions. mCRPC patients (N = 158) with deleterious ATM or BRCA2 mutations who received taxanes, PARPi, or both were retrospectively identified from 11 US academic centers. Demographic, treatment, and survival data were collected. Kaplan-Meier analyses were performed and Cox hazard ratios (HR) were calculated for progression-free survival (PFS) as well as overall survival (OS), from time of first taxane or PARPi therapy. Fifty-eight patients with ATM mutations and 100 with BRCA2 mutations were identified. Fourty-four(76%) patients with ATM mutations received taxane only or taxane before PARPi, while 14 (24%) received PARPi only or PARPi before taxane. Patients with ATM mutations had longer PFS when taxane was given first versus PARPi given first (HR: 0.74 [95% confidence interval[CI]: 0.37-1.50]; p = 0.40). Similarly, OS was longer in patients with ATM mutations who received taxane first (HR: 0.56 [CI: 0.20-1.54]; p = 0.26). Among patients with BRCA2 mutations, 51 (51%) received taxane first and 49 (49%) received PARPi first. In contrast, patients with BRCA2 mutations had longer PFS when PARPi was given first versus taxane given first (HR: 0.85 [CI: 0.54-1.35]; p = 0.49). Similarly, OS was longer in patients with BRCA2 mutations who received PARPi first (HR: 0.75 [CI: 0.41-1.37]; p = 0.35). Our retrospective data suggest differential response between ATM and BRCA2 mutated prostate cancers in terms of response to PARPi and to taxane chemotherapy. When considering the sequence of PARPi versus taxane chemotherapy for mCRPC with DDR mutations, ATM, and BRCA2 mutation status may be helpful in guiding choice of initial therapy.

Reproductive risk factors associated with breast cancer in young women by molecular subtype

BackgroundFew studies have examined detailed features of pregnancy and the postpartum period as potential risk factors for early onset breast cancer (BC) by molecular subtype. These data may have value for improving risk assessment and prevention. MethodsWe surveyed parous enrollees in the prospective Mayo Clinic Breast Disease Registry (MCBDR) who had been diagnosed with BC at age <55 years between 2015 and 2020. Summary statistics were used to describe survey responses and reproductive risk factors by BC subtype (defined by estrogen/progesterone receptors and human epidermal growth factor receptor expression, nurse-abstracted from the medical record). Associations were assessed with Kruskal-Wallis and Chi-Square tests, followed by age-adjusted linear and logistic regression models. We compared results from this parous cohort to those from a separate cohort of nulliparous MCBDR participants with BC diagnosed at age <55 years. ResultsIn 436 parous respondents with subtype data abstracted, we identified a higher frequency of BRCA1 mutation, earlier age at diagnosis, and lower BI in patients with triple negative BC. Comparing parous to nulliparous young women with breast cancer, the proportion with TNBC was larger in the latter (12.2% vs. 15.1%, p = 0.03). ConclusionsEarly age at diagnosis and deleterious BRCA1 mutation were more frequent among TNBC patients. In addition, parous young women with TNBC had a lower BI than those with other BC subtypes, a hypothesis-generating finding that supports the need for additional research on the cycle of pregnancy-lactation-postpartum involution and BC etiology.

Tumor Treating Fields (TTFields) Concomitant with PARP Inhibitors for Treatment of Ovarian Cancer Cell Lines

<h3>Purpose/Objective(s)</h3> TTFields are electric fields that disrupt cellular processes critical for cancer cell viability and tumor progression. Recently, TTFields have also been shown to induce a state of BRCAness in various cancer types. PARP inhibitors (PARPi) demonstrate clinical efficacy in patients with solid tumors and deleterious BRCA mutations; however, 3 of 4 patients with ovarian cancer do not harbor BRCA mutations, and thus may experience limited benefit from PARP inhibition. TTFields have shown in vitro and in vivo efficacy in ovarian cancer models. The objective of this study was to examine the effect of TTFields concomitant with PARPi on ovarian cancer cell lines. <h3>Materials/Methods</h3> A2780 (BRCA1/2 wild type) and OVCAR3 (BRCA1 wild type, BRCA2 deep deletion) ovarian carcinoma cells were treated for 72 h with TTFields at an intensity of 1 V/cm RMS and frequency of 200 kHz, alone or with concomitant application of the PARP inhibitors niraparib or olaparib. Efficacy was examined via measurements of cell survival, colony forming ability, and induction of apoptosis. Formation of DNA double strand breaks was examined by fluorescence staining for ɣH2AX. <h3>Results</h3> Application of TTFields or PARPi to A2780 or OVCAR3 cells resulted in cytotoxicity, anti-clonogenic effect, and induction of apoptosis. Concomitant application of TTFields with PARPi displayed synergistic interaction in the BRCA wild type A2780 cells and additively in the BRCA mutant OVCAR-3 cells. Co-application of TTFields and PARPi also resulted in increased levels of DNA double strand breaks in both cell lines relative to each modality alone. <h3>Conclusion</h3> The results support that TTFields induce a state of BRCAness, which together with PARP inhibition can possibly lead to synthetic lethality. Collectively, the data suggest potential benefits for TTFields concomitant application with PARP inhibition for treatment of ovarian cancer even in the absence of background BRCA mutations.

BRCA Mutation Status in Triple-Negative Breast Cancer Patients Treated with Neoadjuvant Chemotherapy: A Pivotal Role for Treatment Decision-Making.

Simple SummaryIn this retrospective observational study, we evaluated data from patients with triple-negative breast cancer (TNBC) treated with neoadjuvant chemotherapy (NACT) in order to better define the impact of germline BRCA1/2 (gBRCA1/2) mutation status on outcomes in this patient population. Our results show that patients with BRCA1/2 mutation had a higher pathologic complete response (pCR) rate than non-mutated patients; nevertheless, the benefit was confirmed only in the subset of patients who received a platinum-based NACT. Furthermore, pCR was associated with improved Event Free Survival (EFS) and Overall Survival (OS), regardless of BRCA1/2 mutation status and type of NACT received. Long-term follow-up analyses are needed to further define the impact of gBRCA mutation status in patients with early-TNBC.Triple-negative breast cancer (TNBC) is characterized by earlier recurrence and shorter survival compared with other types of breast cancer. Moreover, approximately 15 to 25% of all TNBC patients harbor germline BRCA (gBRCA) 1/2 mutations, which confer a more aggressive phenotype. However, TNBC seems to be particularly sensitive to chemotherapy, the so-called ‘triple negative paradox’. Therefore, Neoadjuvant chemotherapy (NACT) is currently considered the preferred approach for early-stage TNBC. BRCA status has also been studied as a predictive biomarker of response to platinum compounds. Although several randomized trials investigated the addition of carboplatin to standard NACT in early-stage TNBC, the role of BRCA status remains unclear. In this retrospective analysis, we evaluated data from 136 consecutive patients with Stage I-III TNBC who received standard NACT with or without the addition of carboplatin, in order to define clinical features and outcomes in BRCA 1/2 mutation carriers and non-carrier controls. Between January 2013 and February 2021, 67 (51.3%) out of 136 patients received a standard anthracyclines/taxane regimen and 69 (50.7%) patients received a platinum-containing chemotherapy regimen. Deleterious germline BRCA1 or BRCA2 mutations were identified in 39 (28.7%) patients. Overall, patients with deleterious gBRCA1/2 mutation have significantly higher pCR rate than non-carrier patients (23 [59%] of 39 vs. 33 [34%] of 97; p = 0.008). The benefit of harboring a gBRCA mutation was confirmed only in the subset of patients who received a platinum-based NACT (17 [65.4%] of 26 vs. 13 [30.2%] of 43; p = 0.005) while no differences were found in the platinum-free subgroup. Patients who achieved pCR after NACT had significantly better EFS (OR 4.5; 95% CI 1.9–10.7; p = 0.001) and OS (OR 3.3; 95% CI 1.3–8.9; p = 0.01) than patients who did not, regardless of BRCA1/2 mutation status and type of NACT received. Our results based on real-world evidence show that TNBC patients with the gBRCA1/2 mutation who received platinum-based NACT have a higher pCR rate than non-carrier patients, supporting the use of this chemotherapy regimen in this patient population. Long-term follow-up analyses are needed to further define the role of gBRCA mutation status on clinical outcomes in patients with early-TNBC.

Clinical Pharmacokinetics and Pharmacodynamics of Rucaparib.

Rucaparib is an oral small-molecule poly(ADP-ribose) polymerase inhibitor indicated for patients with recurrent ovarian cancer in the maintenance and treatment settings and for patients with metastatic castration-resistant prostate cancer associated with a deleterious BRCA1 or BRCA2 mutation. Rucaparib has a manageable safety profile; the most common adverse events reported were fatigue and nausea in both indications. Accumulation in plasma exposure occurred after repeated administration of the approved 600-mg twice-daily dosage. Steady state was achieved after continuous twice-daily dosing for a week. Rucaparib has moderate oral bioavailability and can be dosed with or without food. Although a high-fat meal weakly increased maximum concentration and area under the curve, the effect was not clinically significant. A mass balance analysis indicated almost a complete dose recovery of rucaparib over 12 days, with metabolism, renal, and hepatic excretion as the elimination routes. A population pharmacokinetic analysis of rucaparib revealed no effect of age, sex, race, or body weight. No starting dose adjustments were necessary for patients with mild-to-moderate hepatic or renal impairment; the effect of severe organ impairment on rucaparib exposure has not been evaluated. In patients, rucaparib moderately inhibited cytochrome P450 (CYP) 1A2 and weakly inhibited CYP3As, CYP2C9, and CYP2C19. Rucaparib weakly increased systemic exposures of oral contraceptives and oral rosuvastatin and marginally increased the exposure of oral digoxin (a P-glycoprotein substrate). In vitro studies suggested that rucaparib inhibits transporters MATE1, MATE2-K, OCT1, and OCT2. No clinically meaningful drug interactions with rucaparib as a perpetrator were observed. An exposure-response analysis revealed dose-dependent changes in selected clinical efficacy and safety endpoints. Overall, this article provides a comprehensive review of the clinical pharmacokinetics, pharmacodynamics, drug-drug interactions, effects of intrinsic and extrinsic factors, and exposure-response relationships of rucaparib.