QTc prolongation across CDK4/6 inhibitors: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Cyclin-dependent kinases (CDK) 4/6 inhibitors have significantly improved outcomes for patients with ER+/HER2- breast cancer. Nevertheless, they differ from each other in terms of chemical, biological, and pharmacological features, as well as toxicity profiles. We aim to determine whether QTc prolongation is caused by CDK4/6i in general or if it is associated with ribociclib only. METHODS: We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs) comparing the prevalence of QTc prolongation as an adverse event in HR+ breast cancer patients treated with CDK4/6i vs those without CDK4/6i. We pooled risk ratio (RR) and mean difference (MD) with 95% confidence interval (CI) for the binary endpoint of QT prolongation. RESULTS: We included 14 RCTs comprising 16,196 patients, of whom 8,576 underwent therapy with CDK4/6i. An increased risk of QTc prolongation was associated with the use of CDK4/6i (RR 2.35; 95% CI 1.67-3.29; p < .001; I2=44%). Subgroup analyses revealed a significant increase in the QTc interval for the ribociclib and palbociclib cohorts. The ribociclib subgroup showed a risk ratio of 3.12 (RR 3.12; 95% CI 2.09-4.65; p < .001; I2 = 12%) while the palbociclib subgroup had a risk ratio of 1.51 (RR 1.51; 95% CI 1.05-2.15; p = .025, I2=0%). CONCLUSION: Palbociclib was associated with QTc prolongation, however, the RR for any grade QTc was quantitively twice with ribociclib. Furthermore, grade 3 QTc prolongations were observed exclusively with ribociclib. These results are important for guiding clinical decision-making and provide reassurance regarding the overall safety profile of this drug class.

Prospective Study of Supplemental Screening With Contrast-Enhanced Mammography in Women With Elevated Risk of Breast Cancer: Results of the Prevalence Round.

PURPOSE: Contrast-enhanced mammography (CEM) and magnetic resonance imaging (MRI) have shown similar diagnostic performance in detection of breast cancer. Limited CEM data are available for high-risk breast cancer screening. The purpose of the study was to prospectively investigate the efficacy of supplemental screening CEM in elevated risk patients. MATERIALS AND METHODS: A prospective, single-institution, institutional review board-approved observational study was conducted in asymptomatic elevated risk women age 35 years or older who had a negative conventional two-dimensional digital breast tomosynthesis screening mammography (MG) and no additional supplemental screening within the prior 12 months. RESULTS: Four hundred sixty women were enrolled from February 2019 to April 2021. The median age was 56.8 (range, 35.0-79.2) years; 408 of 460 (88.7%) were mammographically dense. Biopsy revealed benign changes in 22 women (22/37, 59%), high-risk lesions in four women (4/37, 11%), and breast cancer in 11 women (11/37, 30%). Fourteen cancers (10 invasive, tumor size range 4-15 mm, median 9 mm) were diagnosed in 11 women. The overall supplemental cancer detection rate was 23.9 per 1,000 patients, 95% CI (12.0 to 42.4). All cancers were grade 1 or 2, ER+ ERBB2-, and node negative. CEM imaging screening offered high specificity (0.875 [95% CI, 0.844 to 0.906]), high NPV (0.998 [95% CI, 0.993 to 1.000), moderate PPV1 (0.164 [95% CI, 0.076 to 0.253), moderate PPV3 (0.275 [95% CI, 0.137 to 0.413]), and high sensitivity (0.917 [95% CI, 0.760 to 1.000]). At least 1 year of imaging follow-up was available on all patients, and one interval cancer was detected on breast MRI 4 months after negative screening CEM. CONCLUSION: A pilot trial demonstrates a supplemental cancer detection rate of 23.9 per 1,000 in women at an elevated risk for breast cancer. Larger, multi-institutional, multiyear CEM trials in patients at elevated risk are needed for validation.

Neoadjuvant talazoparib in patients with germline BRCA1/2 mutation-positive, early-stage triple-negative breast cancer: exploration of tumor BRCA mutational status.

BACKGROUND: Talazoparib monotherapy in patients with germline BRCA-mutated, early-stage triple-negative breast cancer (TNBC) showed activity in the neoadjuvant setting in the phase II NEOTALA study (NCT03499353). These biomarker analyses further assessed the mutational landscape of the patients enrolled in the NEOTALA study. METHODS: Baseline tumor tissue from the NEOTALA study was tested retrospectively using FoundationOne®CDx. To further hypothesis-driven correlative analyses, agnostic heat-map visualizations of the FoundationOne®CDx tumor dataset were used to assess overall mutational landscape and identify additional candidate predictive biomarkers of response. RESULTS: All patients enrolled (N = 61) had TNBC. In the biomarker analysis population, 75.0% (39/52) and 25.0% (13/52) of patients exhibited BRCA1 and BRCA2 mutations, respectively. Strong concordance (97.8%) was observed between tumor BRCA and germline BRCA mutations, and 90.5% (38/42) of patients with tumor BRCA mutations evaluable for somatic-germline-zygosity were predicted to exhibit BRCA loss of heterozygosity (LOH). No patients had non-BRCA germline DNA damage response (DDR) gene variants with known/likely pathogenicity, based on a panel of 14 non-BRCA DDR genes. Ninety-eight percent of patients had TP53 mutations. Genomic LOH, assessed continuously or categorically, was not associated with response. CONCLUSION: The results from this exploratory biomarker analysis support the central role of BRCA and TP53 mutations in tumor pathobiology. Furthermore, these data support assessing germline BRCA mutational status for molecular eligibility for talazoparib in patients with TNBC.

Factors influencing U.S. women's interest and preferences for breast cancer risk communication: a cross-sectional study from a large tertiary care breast imaging center.

BACKGROUND: Breast imaging clinics in the United States (U.S.) are increasingly implementing breast cancer risk assessment (BCRA) to align with evolving guideline recommendations but with limited uptake of risk-reduction care. Effectively communicating risk information to women is central to implementation efforts, but remains understudied in the U.S. This study aims to characterize, and identify factors associated with women's interest in and preferences for breast cancer risk communication. METHODS: This is a cross-sectional survey study of U.S. women presenting for a mammogram between January and March of 2021 at a large, tertiary breast imaging clinic. Survey items assessed women's interest in knowing their risk and preferences for risk communication if considered to be at high risk in hypothetical situations. Multivariable logistic regression modeling assessed factors associated with women's interest in knowing their personal risk and preferences for details around exact risk estimates. RESULTS: Among 1119 women, 72.7% were interested in knowing their breast cancer risk. If at high risk, 77% preferred to receive their exact risk estimate and preferred verbal (52.9% phone/47% in-person) vs. written (26.5% online/19.5% letter) communications. Adjusted regression analyses found that those with a primary family history of breast cancer were significantly more interested in knowing their risk (OR 1.5, 95% CI 1.0, 2.1, p = 0.04), while those categorized as "more than one race or other" were significantly less interested in knowing their risk (OR 0.4, 95% CI 0.2, 0.9, p = 0.02). Women 60 + years of age were significantly less likely to prefer exact estimates of their risk (OR 0.6, 95% CI 0.5, 0.98, p < 0.01), while women with greater than a high school education were significantly more likely to prefer exact risk estimates (OR 2.5, 95% CI 1.5, 4.2, p < 0.001). CONCLUSION: U.S. women in this study expressed strong interest in knowing their risk and preferred to receive exact risk estimates verbally if found to be at high risk. Sociodemographic and family history influenced women's interest and preferences for risk communication. Breast imaging centers implementing risk assessment should consider strategies tailored to women's preferences to increase interest in risk estimates and improve risk communication.

Testing Adaptive Therapy Protocols Using Gemcitabine and Capecitabine in a Preclinical Model of Endocrine-Resistant Breast Cancer.

Adaptive therapy, an ecologically inspired approach to cancer treatment, aims to overcome resistance and reduce toxicity by leveraging competitive interactions between drug-sensitive and drug-resistant subclones, prioritizing patient survival and quality of life instead of killing the maximum number of cancer cells. In preparation for a clinical trial, we used endocrine-resistant MCF7 breast cancer to stimulate second-line therapy and tested adaptive therapy using capecitabine, gemcitabine, or their combination in a mouse xenograft model. Dose modulation adaptive therapy with capecitabine alone increased survival time relative to MTD but not statistically significantly (HR = 0.22, 95% CI = 0.043-1.1, p = 0.065). However, when we alternated the drugs in both dose modulation (HR = 0.11, 95% CI = 0.024-0.55, p = 0.007) and intermittent adaptive therapies, the survival time was significantly increased compared to high-dose combination therapy (HR = 0.07, 95% CI = 0.013-0.42, p = 0.003). Overall, the survival time increased with reduced dose for both single drugs (p < 0.01) and combined drugs (p < 0.001), resulting in tumors with fewer proliferation cells (p = 0.0026) and more apoptotic cells (p = 0.045) compared to high-dose therapy. Adaptive therapy favors slower-growing tumors and shows promise in two-drug alternating regimens instead of being combined.

Metastatic ER+ Breast Cancer: Mechanisms of Resistance and Future Therapeutic Approaches.

Endocrine therapy is the main treatment for hormone receptor-positive (HR+) breast cancer. However, advanced tumors develop resistance to endocrine therapy, rendering it ineffective as the disease progresses. There are several molecular mechanisms of primary and secondary endocrine resistance. Resistance can develop due to either alteration of the estrogen receptor pathway (e.g., ESR1 mutations) or upstream growth factors signaling pathways (e.g., PI3K/Akt/mTOR pathway). Despite progress in the development of molecularly targeted anticancer therapies, the emergence of resistance remains a major limitation and an area of unmet need. In this article, we review the mechanisms of acquired endocrine resistance in HR+ advanced breast cancer and discuss current and future investigational therapeutic approaches.

Testing Adaptive Therapy Protocols using Gemcitabine and Capecitabine on a Mouse Model of Endocrine-Resistant Breast Cancer.

Highly effective cancer therapies often face limitations due to acquired resistance and toxicity. Adaptive therapy, an ecologically inspired approach, seeks to control therapeutic resistance and minimize toxicity by leveraging competitive interactions between drug-sensitive and drug-resistant subclones, prioritizing patient survival and quality of life over maximum cell kill. In preparation for a clinical trial in breast cancer, we used large populations of MCF7 cells to rapidly generate endocrine-resistance breast cancer cell line. We then mimicked second line therapy in ER+ breast cancers by treating the endocrine-resistant MCF7 cells in a mouse xenograft model to test adaptive therapy with capecitabine, gemcitabine, or the combination of those two drugs. Dose-modulation adaptive therapy with capecitabine alone increased survival time relative to MTD, but not statistically significant (HR: 0.22, 95% CI 0.043- 1.1 P = 0.065). However, when we alternated the drugs in both dose modulation (HR = 0.11, 95% CI: 0.024 - 0.55, P = 0.007) and intermittent adaptive therapies significantly increased survival time compared to high dose combination therapy (HR = 0.07, 95% CI: 0.013 - 0.42; P = 0.003). Overall, survival time increased with reduced dose for both single drugs (P < 0.01) and combined drugs (P < 0.001). Adaptive therapy protocols resulted in tumors with lower proportions of proliferating cells (P = 0.0026) and more apoptotic cells (P = 0.045). The results show that Adaptive therapy outperforms high-dose therapy in controlling endocrine-resistant breast cancer, favoring slower-growing tumors, and showing promise in two-drug alternating regimens.

Genomic analysis of advanced breast cancer tumors from talazoparib-treated gBRCA1/2mut carriers in the ABRAZO study.

These analyses explore the impact of homologous recombination repair gene mutations, including BRCA1/2 mutations and homologous recombination deficiency (HRD), on the efficacy of the poly(ADP-ribose) polymerase (PARP) inhibitor talazoparib in the open-label, two-cohort, Phase 2 ABRAZO trial in germline BRCA1/2-mutation carriers. In the evaluable intent-to-treat population (N = 60), 58 (97%) patients harbor ≥1 BRCA1/2 mutation(s) in tumor sequencing, with 95% (53/56) concordance between germline and tumor mutations, and 85% (40/47) of evaluable patients have BRCA locus loss of heterozygosity indicating HRD. The most prevalent non-BRCA tumor mutations are TP53 in patients with BRCA1 mutations and PIK3CA in patients with BRCA2 mutations. BRCA1- or BRCA2-mutated tumors show comparable clinical benefit within cohorts. While low patient numbers preclude correlations between HRD and efficacy, germline BRCA1/2 mutation detection from tumor-only sequencing shows high sensitivity and non-BRCA genetic/genomic events do not appear to influence talazoparib sensitivity in the ABRAZO trial.ClinicalTrials.gov identifier: NCT02034916.

Neoadjuvant Talazoparib in Patients With Germline BRCA1/2 Mutation-Positive, Early-Stage Triple-Negative Breast Cancer: Results of a Phase II Study.

BACKGROUND: The undetermined efficacy of the current standard-of-care neoadjuvant treatment, anthracycline/platinum-based chemotherapy, in patients with early-stage triple-negative breast cancer (TNBC) and germline BRCA mutations emphasizes the need for biomarker-targeted treatment, such as poly(ADP-ribose) polymerase inhibitors, in this setting. This phase II, single-arm, open-label study evaluated the efficacy and safety of neoadjuvant talazoparib in patients with germline BRCA1/2-mutated early-stage TNBC. PATIENTS AND METHODS: Patients with germline BRCA1/2-mutated early-stage TNBC received talazoparib 1 mg once daily for 24 weeks (0.75 mg for moderate renal impairment) followed by surgery. The primary endpoint was pathologic complete response (pCR) by independent central review (ICR). Secondary endpoints included residual cancer burden (RCB) by ICR. Safety and tolerability of talazoparib and patient-reported outcomes were assessed. RESULTS: Of 61 patients, 48 received ≥80% talazoparib doses, underwent surgery, and were assessed for pCR or progressed before pCR assessment and considered nonresponders. pCR rate was 45.8% (95% confidence interval [CI], 32.0%-60.6%) and 49.2% (95% CI, 36.7%-61.6%) in the evaluable and intent-to-treat (ITT) population, respectively. RCB 0/I rate was 45.8% (95% CI, 29.4%-63.2%) and 50.8% (95% CI, 35.5%-66.0%) in the evaluable and ITT population, respectively. Treatment-related adverse events (TRAE) were reported in 58 (95.1%) patients. Most common grade 3 and 4 TRAEs were anemia (39.3%) and neutropenia (9.8%). There was no clinically meaningful detriment in quality of life. No deaths occurred during the reporting period; 2 deaths due to progressive disease occurred during long-term follow-up (>400 days after first dose). CONCLUSIONS: Neoadjuvant talazoparib monotherapy was active despite pCR rates not meeting the prespecified threshold; these rates were comparable to those observed with combination anthracycline- and taxane-based chemotherapy regimens. Talazoparib was generally well tolerated. CLINICALTRIALS.GOV IDENTIFIER: NCT03499353.

Comparison of PARPi efficacy according to homologous recombination deficiency biomarkers in patients with ovarian cancer: a systematic review and meta-analysis.

BACKGROUND: Mutations in the BRCA1/2 (BRCA) genes are associated with response to poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi). In addition, there are different homologous recombination deficiency (HRD) biomarkers available in clinical practice [e.g., genome-wide loss-of-heterozygosity (gLOH) and myChoice® score] that identify patients who can benefit from PARPi. Inconsistencies in biomarkers used in PARPi clinical trials make it challenging to identify clinically relevant predictive biomarkers. This study aims to compare clinically available HRD biomarkers in terms of benefits from PARPi. METHODS: We performed database search for phase II or III randomized clinical trials comparing PARPi versus chemotherapy, and meta-analysis using generic inverse variance and a Random Effects model. Patients were classified according to their HRD status: (I) BRCAm (patients with BRCA mutation of germline or somatic origin); (II) non-BRCA HRD [patients BRCA wild-type (wt) with another HRD biomarker-gLOH or myChoice®]; and (III) homologous recombination proficiency (HRP) (BRCAwt and without HRD biomarkers). From those that were BRCAwt, we compared myChoice®+ with gLOH-high. RESULTS: Five studies (3,225 patients) analyzing PARPi in first line setting were included. Patients with BRCAmut had progression-free survival (PFS) with hazard ratio (HR) 0.33 [95% confidence interval (CI): 0.30-0.43]; patients with non-BRCA HRD had a PFS HR 0.49 (95% CI: 0.37-0.65), and patients with HRP had a PFS HR 0.78 (95% CI: 0.58-1.03). Eight studies (5,529 patients) with PARPi including first line and recurrence settings were included. BRCAmut had PFS HR 0.37 (95% CI: 0.30-0.48), BRCAwt & HRD 0.45 (95% CI: 0.37-0.55) and HRP 0.70 (95% CI: 0.57-0.85). Patients with BRCAwt & myChoice® ≥42 had PFS HR 0.43 (95% CI: 0.34-0.56), similar to patients with BRCAwt & gLOH-high with PFS HR 0.42 (95% CI: 0.28-0.62). CONCLUSIONS: Patients with HRD derived significantly more benefit from PARPi when compared to patients with HRP. The benefit of PARPi in patients with HRP tumors was limited. Careful cost-effectiveness analysis, and alternative therapies or clinical trial enrollment should strongly be considered for patients with HRP tumors. Among patients with BRCAwt, a similar benefit was found in patients with gLOH-high and those myChoice®+. The clinical development of further HRD biomarkers (e.g., Sig3) may help identify more patients who benefit from PARPi.

PARP Inhibitors for Breast Cancer: Germline BRCA1/2 and Beyond.

Poly-adenosine diphosphate ribose polymerase (PARP) inhibitors (PARPi) are approved for BRCA1/2 carriers with HER2-negative breast cancer in the adjuvant setting with a high risk of recurrence as well as the metastatic setting. However, the indications for PARPi are broader for patients with other cancer types (e.g., prostate and ovarian cancer), involving additional biomarkers (e.g., ATM, PALB2, and CHEK) and genomic instability scores. Herein, we summarize the data on PARPi and breast cancer and discuss their use beyond BRCA carriers.

Determinants of Response to Talazoparib in Patients with HER2-Negative, Germline BRCA1/2-Mutated Breast Cancer.

PURPOSE: PARP inhibitors (PARPi) have demonstrated efficacy in tumors with germline breast cancer susceptibility genes (gBRCA) 1 and 2 mutations, but further factors influencing response to PARPi are poorly understood. EXPERIMENTAL DESIGN: Breast cancer tumor tissue from patients with gBRCA1/2 mutations from the phase III EMBRACA trial of the PARPi talazoparib versus chemotherapy was sequenced using FoundationOne CDx. RESULTS: In the evaluable intent-to-treat population, 96.1% (296/308) had ≥1 tumor BRCA (tBRCA) mutation and there was strong concordance (95.3%) between tBRCA and gBRCA mutational status. Genetic/genomic characteristics including BRCA loss of heterozygosity (LOH; identified in 82.6% of evaluable patients), DNA damage response (DDR) gene mutational burden, and tumor homologous recombination deficiency [assessed by genomic LOH (gLOH)] demonstrated no association with talazoparib efficacy. CONCLUSIONS: Overall, BRCA LOH status, DDR gene mutational burden, and gLOH were not associated with talazoparib efficacy; however, these conclusions are qualified by population heterogeneity and low patient numbers in some subgroups. Further investigation in larger patient populations is warranted.

A Breast Radiology Department-operated, Proactive Same-day Program Identifies Pathogenic Breast Cancer Mutations in Unaffected Women.

RATIONALE AND OBJECTIVES: Pathogenic mutations in some genes elevate women's breast cancer risk, necessitating risk-reduction strategies. Unfortunately, women are underscreened for cancer risk, and when identified as potentially high risk, women seldom pursue genetic counseling or testing. To improve cancer risk management, this project determined the feasibility of radiology-operated, proactive, same-day risk assessment and genetic testing programs to diagnose high-risk women undergoing breast imaging. MATERIALS AND METHODS: The Comprehensive Assessment, Risk & Education Program launched on June 5, 2019. Data was tracked through July 22, 2020. Women undergoing breast imaging completed questionnaires that calculated Tyrer-Cuzick risk and assessed genetic testing eligibility using National Comprehensive Cancer Network criteria. To encourage eligible women's genetic testing adherence, pretest counseling and saliva sample collection occurred that same day in the imaging center. Samples were tested by a 34-multigene panel. Genetic counselors called women with positive results. Women with negative results or variants of uncertain significance were mailed notifications. Summary statistics were calculated. RESULTS: A total of 3345 women completed questionnaires. 1080 (32.3%) met genetic testing criteria. 468/1080 (43.3%) submitted genetic samples, and 416/1080 (38.5%) completed testing. Of 416 completed tests, 269 (64.7%) tested negative, 109 (26.2%) had variants of uncertain significance, and 38 (9.1%) diagnosed pathogenic mutations. 13/38 (34.2%) women with pathogenic mutations implemented risk-reduction strategies at our institution. CONCLUSION: Breast imaging centers can operate same-day cancer risk assessment and genetic testing programs, identifying high-risk women that conventional risk assessment methods may not have diagnosed. These proactive programs add value to radiology departments' cancer care beyond traditional imaging services.

Personalized Breast Cancer Risk Assessment: Incorporation of Genetic and High-Risk Factorson Breast Cancer Risk and Management.

Breast cancer remains the second most diagnosed cancer in women worldwide and the number one cause of cancer in women in the United States. It is unfortunately the primary cause of cancerrelated deaths among women, with 14% of all cancer deaths attributed to it. Over the past decade, screening methods have matured, and imaging modalities are continuously improving. Screening mammograms remain the only modality that have been shown to improve breast cancer survival, however, more modalities like MRI, abbreviated MRI, and CT mammography are gaining in momentum. Now more than ever, providers need to identify the patient population that is at an elevated risk for breast cancer to offer them a personalized screening approach specific to their empiric risk. In this paper we shed light on risk factors of breast cancer and summarize risk assessment tools that have been recently incorporated in assessing a woman's risk of breast cancer. We also summarize new genetic testing strategies and their implications in prevention of breast cancer. And finally, we offer a personalized approach to management of women with agenetic predisposition as well as to women at elevated risk but without a genetic mutation. The hope is to identify women at increased risk and perfect a "personalized screening approach" for breast cancer.

Relations of Mindfulness and Illness Acceptance With Psychosocial Functioning in Patients With Metastatic Breast Cancer and Caregivers.

OBJECTIVES: To examine relationships in mindfulness and illness acceptance and psychosocial functioning in patients with metastatic breast cancer and their family caregivers. SAMPLE & SETTING: 33 dyads from an academic cancer center in the United States. METHODS & VARIABLES: Participants completed questionnaires on mindfulness, illness acceptance, relationship quality, anxiety, and depressive symptoms. Dyadic, cross-sectional data were analyzed using actor-partner interdependence models. RESULTS: Greater nonjudging, acting with awareness, and illness acceptance among caregivers were associated with patients' and caregivers' perceptions of better relationship quality. Higher levels of these processes were associated with reduced anxiety and depressive symptoms in patients and caregivers. IMPLICATIONS FOR NURSING: Aspects of mindfulness and illness acceptance in dyads confer benefits that are primarily intrapersonal in nature. Nurses may consider introducing mindfulness and acceptance-based interventions to patients and caregivers with adjustment difficulties.

Outcomes in Clinically Relevant Patient Subgroups From the EMBRACA Study: Talazoparib vs Physician's Choice Standard-of-Care Chemotherapy.

BACKGROUND: Talazoparib is a poly(adenosine diphosphate-ribose) polymerase inhibitor that causes death in cells with breast cancer susceptibility gene 1 or 2 (BRCA1/2) mutations. METHODS: EMBRACA (NCT01945775) was a randomized phase III study comparing efficacy, safety, and patient-reported outcomes (PROs) of talazoparib (1 mg) with physician's choice of chemotherapy (PCT: capecitabine, eribulin, gemcitabine, vinorelbine) in locally advanced or metastatic breast cancer with a germline BRCA1/2 (gBRCA1/2) mutation. Prespecified patient subgroups were analyzed for progression-free survival, objective response, clinical benefit, duration of response, and safety. PROs were evaluated in hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) or triple-negative breast cancer (TNBC) subgroups. RESULTS: Of 431 patients, 287 were randomly assigned to talazoparib and 144 to PCT. Prespecified subgroup analyses showed prolonged progression-free survival with talazoparib (HR+/HER2-: hazard ratio = 0.47, 95% confidence interval = 0.32 to 0.71; TNBC: hazard ratio = 0.60, 95% confidence interval = 0.41 to 0.87) and greater objective response rate (odds ratio = 1.97 to 11.89), clinical benefit rate (odds ratio = 2.05 to 7.77), and duration of response with talazoparib in all subgroups. PROs in HR+/HER2- and TNBC subgroups showed consistent overall improvement and delay in time to definitive clinically meaningful deterioration with talazoparib vs PCT. Across subgroups, common adverse events included anemia, fatigue, and nausea with talazoparib and neutropenia, fatigue, and nausea with PCT. Seven patients (2.4%) receiving talazoparib had grade II alopecia and 22.7% had grade I alopecia. CONCLUSIONS: Across all patient subgroups with gBRCA-mutated advanced breast cancer, talazoparib demonstrated clinically significant superiority in outcomes compared with PCT.

Talazoparib in Patients with a Germline BRCA-Mutated Advanced Breast Cancer: Detailed Safety Analyses from the Phase III EMBRACA Trial.

BACKGROUND: In the EMBRACA phase III study (NCT01945775), talazoparib was associated with a significantly prolonged progression-free survival (PFS) compared with physician's choice of chemotherapy (PCT) in germline BRCA1/2-mutated HER2-negative advanced breast cancer (ABC). Herein, the safety profile of talazoparib is explored in detail. MATERIALS AND METHODS: Overall, 412 patients received ≥1 dose of talazoparib (n = 286) or PCT (n = 126). Adverse events (AEs) were evaluated, including timing, duration, and potential overlap of selected AEs. The relationship between talazoparib plasma exposure and grade ≥3 anemia was analyzed. Time-varying Cox proportional hazard models assessed the impact of dose reductions on PFS. Patient-reported outcomes (PROs) in patients with common AEs and health resource utilization (HRU) were assessed in both treatment arms. RESULTS: The most common AEs with talazoparib were hematologic (195 [68.2%] patients) and typically occurred within the first 3-4 months of receiving talazoparib. Grade 3-4 anemia lasted approximately 7 days for both arms. Overlapping grade 3-4 hematologic AEs were infrequent with talazoparib. Higher talazoparib exposure was associated with grade ≥3 anemia. Permanent discontinuation of talazoparib due to hematologic AEs was low (<2%). A total of 150 (52.4%) patients receiving talazoparib had AEs associated with dose reduction. Hematologic toxicities were managed by supportive care medication (including transfusion) and dose modifications. Among patients with anemia or nausea and/or vomiting AEs, PROs favored talazoparib. After accounting for the treatment-emergent period, talazoparib was generally associated with a lower rate of hospitalization and supportive care medication use compared with chemotherapy. CONCLUSION: Talazoparib was associated with superior efficacy, favorable PROs, and lower HRU rate versus chemotherapy in gBRCA-mutated ABC. Toxicities were manageable with talazoparib dose modification and supportive care. IMPLICATIONS FOR PRACTICE: Talazoparib was generally well tolerated in patients with germline BRCA-mutated HER2-negative advanced breast cancer in the EMBRACA trial. Common toxicities with talazoparib were primarily hematologic and infrequently resulted in permanent drug discontinuation (<2% of patients discontinued talazoparib due to hematologic toxicity). Hematologic toxicities typically occurred during the first 3-4 months of treatment and were managed by dose modifications and supportive care measures. A significant efficacy benefit, improved patient-reported outcomes, lower rate of health resource utilization and a tolerable safety profile support incorporating talazoparib into routine management of germline BRCA-mutated locally advanced/metastatic breast cancer.