Sacituzumab Govitecan in Metastatic Triple-Negative Breast Cancer.

BACKGROUND: Patients with metastatic triple-negative breast cancer have a poor prognosis. Sacituzumab govitecan is an antibody-drug conjugate composed of an antibody targeting the human trophoblast cell-surface antigen 2 (Trop-2), which is expressed in the majority of breast cancers, coupled to SN-38 (topoisomerase I inhibitor) through a proprietary hydrolyzable linker. METHODS: In this randomized, phase 3 trial, we evaluated sacituzumab govitecan as compared with single-agent chemotherapy of the physician's choice (eribulin, vinorelbine, capecitabine, or gemcitabine) in patients with relapsed or refractory metastatic triple-negative breast cancer. The primary end point was progression-free survival (as determined by blinded independent central review) among patients without brain metastases. RESULTS: A total of 468 patients without brain metastases were randomly assigned to receive sacituzumab govitecan (235 patients) or chemotherapy (233 patients). The median age was 54 years; all the patients had previous use of taxanes. The median progression-free survival was 5.6 months (95% confidence interval [CI], 4.3 to 6.3; 166 events) with sacituzumab govitecan and 1.7 months (95% CI, 1.5 to 2.6; 150 events) with chemotherapy (hazard ratio for disease progression or death, 0.41; 95% CI, 0.32 to 0.52; P<0.001). The median overall survival was 12.1 months (95% CI, 10.7 to 14.0) with sacituzumab govitecan and 6.7 months (95% CI, 5.8 to 7.7) with chemotherapy (hazard ratio for death, 0.48; 95% CI, 0.38 to 0.59; P<0.001). The percentage of patients with an objective response was 35% with sacituzumab govitecan and 5% with chemotherapy. The incidences of key treatment-related adverse events of grade 3 or higher were neutropenia (51% with sacituzumab govitecan and 33% with chemotherapy), leukopenia (10% and 5%), diarrhea (10% and <1%), anemia (8% and 5%), and febrile neutropenia (6% and 2%). There were three deaths owing to adverse events in each group; no deaths were considered to be related to sacituzumab govitecan treatment. CONCLUSIONS: Progression-free and overall survival were significantly longer with sacituzumab govitecan than with single-agent chemotherapy among patients with metastatic triple-negative breast cancer. Myelosuppression and diarrhea were more frequent with sacituzumab govitecan. (Funded by Immunomedics; ASCENT ClinicalTrials.gov number, NCT02574455; EudraCT number, 2017-003019-21.).

Using Oncotype DX breast recurrence score® assay to define the role of neoadjuvant endocrine therapy in early-stage hormone receptor-positive breast cancer.

PURPOSE: The role of neoadjuvant endocrine therapy in the treatment of patients with early-stage, hormone receptor-positive (HR +) breast cancer is not well defined. Tools to better determine which patients may benefit from neoadjuvant endocrine therapy versus chemotherapy or upfront surgery remain an unmet need. METHODS: We assessed the rate of clinical and pathologic complete response (cCR, pCR) among a pooled cohort of patients with early-stage HR + breast cancer who had been randomized to neoadjuvant endocrine therapy or neoadjuvant chemotherapy in two earlier studies to understand better how outcomes varied by Oncotype DX Breast Recurrence Score® assay. RESULTS: We observed that patients with intermediate RS results had no statistically significant differences in pathologic outcomes at the time of surgery based on whether they received neoadjuvant endocrine therapy or neoadjuvant chemotherapy, suggesting that a subgroup of women with a RS 0-25 may omit chemotherapy without compromising outcomes. CONCLUSION: These data suggest that Recurrence Score® (RS) results may serve as a useful tool in treatment decision-making in the neoadjuvant setting.

Clinical Utility of Routine Cardiac Monitoring in Breast Cancer Patients Receiving Trastuzumab.

BACKGROUND: Trastuzumab targets the human epidermal growth factor receptor-2 (HER2). Cardiotoxicity is a potential adverse effect, manifesting as either an asymptomatic decline in left-ventricular ejection fraction or infrequently as largely reversible symptomatic heart failure (HF). Monitoring recommendations differ between product labeling and 2012 guidelines, and the clinical utility of serial cardiac monitoring in patients with metastatic breast cancer remains controversial. OBJECTIVE: The objectives of this study were to describe the frequency of monitoring, incidence of symptomatic or asymptomatic HF, overall effect on treatment, and cost of monitoring for cardiotoxicity. METHODS: We preformed an institutional review board-approved retrospective chart review of breast cancer patients receiving trastuzumab from January 1, 2009, through January 1, 2014, at an academic medical center. RESULTS: Out of 154 treatments, 72% were adjuvant, and 28% were metastatic. In the adjuvant setting, a mean of 4.5 (interquartile range [IQR] = 4-5) echocardiograms (echos) over a mean of 11.5 (IQR = 11-12) months were performed. In the metastatic setting, a mean of 3.1 (IQR = 1-5) echos over a mean of 20.2 (IQR = 9-31) months were performed. Symptomatic HF events occurred in 4 adjuvant (3.6%) and 2 metastatic patients (6.5%); 10 patients (6.5%) had a treatment interruption, with 9 (90%) tolerating restart of trastuzumab. Two patients (1.3%) changed treatment as a result of cardiotoxicity. Using population incidence of HER2-positive breast cancer, $13 million could be saved if monitoring were reduced by 1 echo per patient. CONCLUSIONS: Given the low incidence of clinically significant HF and cost of monitoring, less frequent monitoring may be justified.

Management of patients with HER2-positive metastatic breast cancer: is there an optimal sequence of HER2-directed approaches?

The successful development of therapies targeting the human epidermal growth factor receptor 2 (HER2) has altered the natural progression of disease among patients with HER2-positive metastatic breast cancer. The monoclonal antibody trastuzumab was the first HER2-directed agent and it was associated with significantly improved outcomes for patients. Subsequently, other HER2-directed agents such as the monoclonal antibody pertuzumab, the tyrosine kinase receptor inhibitor lapatinib, and the immunoconjugate trastuzumab emtansine were developed to overcome resistance to trastuzumab and provide additional treatment options for patients. Recent data have demonstrated that the use of these HER2-directed agents improves outcomes. However, with the emergence of new HER2-targeted agents, the optimal sequencing of treatment remains unclear. Ongoing research is investigating new HER2 combinations, the role of sequencing, novel HER2-directed agents, and combinations with other targeted agents to overcome resistance.

The 21-gene recurrence score and locoregional recurrence in breast cancer patients.

PURPOSE: Although the 21-gene recurrence score (RS) assay has been validated to assess the risk of distant recurrence in hormone receptor-positive breast cancer patients, the relationship between RS and the risk of locoregional recurrence (LRR) remains unclear. The purpose of this study was to determine if RS is associated with LRR in breast cancer patients and whether this relationship varies based on the type of local treatment [mastectomy or breast-conserving therapy (BCT)]. METHODS: 163 consecutive estrogen receptor-positive breast cancer patients at our institution had an RS generated from the primary breast tumor between August 2006 and October 2009. Patients were treated with lumpectomy and radiation (BCT) (n = 110) or mastectomy alone (n = 53). Patients were stratified using a pre-determined RS of 25 and then grouped according to local therapy type. RESULTS: Median follow-up was 68.2 months. Patients who developed an LRR had stage I or IIA disease, >2 mm surgical margins, and received chemotherapy as directed by RS. While an RS > 25 did not predict for a higher rate of LRR, an RS > 24 was associated with LRR in our subjects. Among mastectomy patients, the 5-year LRR rate was 27.3 % in patients with an RS > 24 versus 10.7 % (p = 0.04) in those whose RS was ≤ 24. RS was not associated with LRR in patients who received BCT. CONCLUSIONS: Breast cancer patients treated with mastectomy for tumors that have an RS > 24 are at high risk of LRR and may benefit from post-mastectomy radiation.

Optimizing Endocrine Therapy for Breast Cancer.

Endocrine therapy has significantly improved outcomes for patients with early- and advanced-stage hormone-receptor (HR)-positive breast cancer. Despite the success of adjuvant endocrine therapy, some patients with early-stage disease will experience relapse. Additionally, all patients with advanced disease will eventually experience disease progression on endocrine therapy due to resistance. Improved understanding of the mechanisms associated with resistance to endocrine agents has recently led to the approval of new therapeutics. Multiple questions remain unanswered, including the optimal duration of adjuvant therapy, the role of ovarian ablation in early-stage breast cancer in premenopausal women, and how to best incorporate targeted agents with endocrine therapy in the metastatic setting. This article reviews the optimization of endocrine therapy in patients with HR-positive breast cancer, focusing on these controversial areas.

Everolimus: side effect profile and management of toxicities in breast cancer.

Everolimus is an orally available inhibitor of the mammalian target of rapamycin (mTOR), which has been approved in combination with exemestane for hormone receptor-positive (HR) breast cancer after failure of treatment with non-steroidal aromatase inhibitors. Everolimus is generally very well tolerated with most common side effects including stomatitis, rash, fatigue, hyperglycemia, hyperlipidemia, and myelosuppression. Most of these side effects are mild and resolve with dose interruptions or dose reductions. Symptomatic non-infectious pneumonitis is a relatively uncommon class effect of mTOR inhibitors, which can be life threatening. Given the efficacy of everolimus in HR-positive metastatic breast cancer, it is crucial for physicians to recognize toxicities related to everolimus and start timely interventions. This review will focus on the adverse events reported with everolimus in breast cancer trials and will provide practical guidelines for the management of these adverse events.

Genomic subtypes in choosing adjuvant therapy for breast cancer.

The use of gene expression profiling has impacted our understanding of breast cancer biology and increasingly has played a role in guiding clinical decisions. We have used hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status for years to guide selection of therapy. More recently, gene expression analysis has facilitated the identification of at least five intrinsic subtypes of breast cancer. Potential therapeutic targets have also been identified using genomic profiling. Several tests, such as the 21-gene recurrence score assay (Oncotype DX) and the 70-gene prognosis signature (MammaPrint), have been well validated as prognostic tools for early-stage breast cancer, and have aided in adjuvant therapy decisions for early-stage, HR-positive breast cancer patients. Genomic profiling has the potential to provide additional insight into drug discovery and clinical trial design by identifying appropriate targeted therapies for subtypes of breast cancer.

Tucatinib vs Placebo, Both in Combination With Trastuzumab and Capecitabine, for Previously Treated ERBB2 (HER2)-Positive Metastatic Breast Cancer in Patients With Brain Metastases: Updated Exploratory Analysis of the HER2CLIMB Randomized Clinical Trial.

Importance: It is estimated that up to 50% of patients with ERBB2 (HER2)-positive metastatic breast cancer (MBC) will develop brain metastases (BMs), which is associated with poor prognosis. Previous reports of the HER2CLIMB trial have demonstrated that tucatinib in combination with trastuzumab and capecitabine provides survival and intracranial benefits for patients with ERBB2-positive MBC and BMs. Objective: To describe overall survival (OS) and intracranial outcomes from tucatinib in combination with trastuzumab and capecitabine in patients with ERBB2-positive MBC and BMs with an additional 15.6 months of follow-up. Design, Setting, and Participants: HER2CLIMB is an international, multicenter, randomized, double-blind, placebo-controlled clinical trial evaluating tucatinib in combination with trastuzumab and capecitabine. The 612 patients, including those with active or stable BMs, had ERBB2-positive MBC previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine. The study was conducted from February 23, 2016, to May 3, 2019. Data from February 23, 2016, to February 8, 2021, were analyzed. Interventions: Patients were randomized 2:1 to receive tucatinib (300 mg orally twice daily) or placebo (orally twice daily), both in combination with trastuzumab (6 mg/kg intravenously or subcutaneously every 3 weeks with an initial loading dose of 8 mg/kg) and capecitabine (1000 mg/m2 orally twice daily on days 1-14 of each 3-week cycle). Main Outcomes and Measures: Evaluations in this exploratory subgroup analysis included OS and intracranial progression-free survival (CNS-PFS) in patients with BMs, confirmed intracranial objective response rate (ORR-IC) and duration of intracranial response (DOR-IC) in patients with measurable intracranial disease at baseline, and new brain lesion-free survival in all patients. Only OS was prespecified before the primary database lock. Results: At baseline, 291 of 612 patients (47.5%) had BMs. Median age was 52 years (range, 22-75 years), and 289 (99.3%) were women. At median follow-up of 29.6 months (range, 0.1-52.9 months), median OS was 9.1 months longer in the tucatinib-combination group (21.6 months; 95% CI, 18.1-28.5) vs the placebo-combination group (12.5 months; 95% CI, 11.2-16.9). The tucatinib-combination group showed greater clinical benefit in CNS-PFS and ORR-IC compared with the placebo-combination group. The DOR-IC was 8.6 months (95% CI, 5.5-10.3 months) in the tucatinib-combination group and 3.0 months (95% CI, 3.0-10.3 months) in the placebo-combination group. Risk of developing new brain lesions as the site of first progression or death was reduced by 45.1% in the tucatinib-combination group vs the placebo-combination group (hazard ratio, 0.55 [95% CI, 0.36-0.85]). Conclusions and Relevance: This subgroup analysis found that tucatinib in combination with trastuzumab and capecitabine improved OS while reducing the risk of developing new brain lesions, further supporting the importance of this treatment option for patients with ERBB2-positive MBC, including those with BMs. Trial Registration: ClinicalTrials.gov Identifier: NCT02614794.

Avelumab Plus Talazoparib in Patients With BRCA1/2- or ATM-Altered Advanced Solid Tumors: Results From JAVELIN BRCA/ATM, an Open-Label, Multicenter, Phase 2b, Tumor-Agnostic Trial.

Importance: Nonclinical studies suggest that the combination of poly(ADP-ribose) polymerase and programmed cell death 1/programmed cell death-ligand 1 inhibitors has enhanced antitumor activity; however, the patient populations that may benefit from this combination have not been identified. Objective: To evaluate whether the combination of avelumab and talazoparib is effective in patients with pathogenic BRCA1/2 or ATM alterations, regardless of tumor type. Design, Setting, and Participants: In this pan-cancer tumor-agnostic phase 2b nonrandomized controlled trial, patients with advanced BRCA1/2-altered or ATM-altered solid tumors were enrolled into 2 respective parallel cohorts. The study was conducted from July 2, 2018, to April 12, 2020, at 42 institutions in 9 countries. Interventions: Patients received 800 mg of avelumab every 2 weeks and 1 mg of talazoparib once daily. Main Outcomes and Measures: The primary end point was confirmed objective response (OR) per RECIST 1.1 by blinded independent central review. Results: A total of 200 patients (median [range] age, 59.0 [26.0-89.0] years; 132 [66.0%] women; 15 [7.5%] Asian, 11 [5.5%] African American, and 154 [77.0%] White participants) were enrolled: 159 (79.5%) in the BRCA1/2 cohort and 41 (20.5%) in the ATM cohort. The confirmed OR rate was 26.4% (42 patients, including 9 complete responses [5.7%]) in the BRCA1/2 cohort and 4.9% (2 patients) in the ATM cohort. In the BRCA1/2 cohort, responses were more frequent (OR rate, 30.3%; 95% CI, 22.2%-39.3%, including 8 complete responses [6.7%]) and more durable (median duration of response: 10.9 months [95% CI, 6.2 months to not estimable]) in tumor types associated with increased heritable cancer risk (ie, BRCA1/2-associated cancer types, such as ovarian, breast, prostate, and pancreatic cancers) and in uterine leiomyosarcoma (objective response in 3 of 3 patients and with ongoing responses greater than 24 months) compared with non-BRCA-associated cancer types. Responses in the BRCA1/2 cohort were numerically higher for patients with tumor mutational burden of 10 or more mutations per megabase (mut/Mb) vs less than 10 mut/Mb. The combination was well tolerated, with no new safety signals identified. Conclusions and Relevance: In this phase 2b nonrandomized controlled trial, neither the BRCA1/2 nor ATM cohort met the prespecified OR rate of 40%. Antitumor activity for the combination of avelumab and talazoparib in patients with BRCA1/2 alterations was observed in some patients with BRCA1/2-associated tumor types and uterine leiomyosarcoma; benefit was minimal in non-BRCA-associated cancer types. Trial Registration: ClinicalTrials.gov Identifier: NCT03565991.

Randomized Phase II Trial of Endocrine Therapy With or Without Ribociclib After Progression on Cyclin-Dependent Kinase 4/6 Inhibition in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: MAINTAIN Trial.

PURPOSE: Cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) with endocrine therapy (ET) improves progression-free survival (PFS) and overall survival (OS) in hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). Although preclinical and clinical data demonstrate a benefit in changing ET and continuing a CDK4/6i at progression, no randomized prospective trials have evaluated this approach. METHODS: In this investigator-initiated, phase II, double-blind placebo-controlled trial in patients with HR+/HER2- MBC whose cancer progressed during ET and CDK4/6i, participants switched ET (fulvestrant or exemestane) from ET used pre-random assignment and randomly assigned 1:1 to the CDK4/6i ribociclib versus placebo. PFS was the primary end point, defined as time from random assignment to disease progression or death. Assuming a median PFS of 3.8 months with placebo, we had 80% power to detect a hazard ratio (HR) of 0.58 (corresponding to a median PFS of at least 6.5 months with ribociclib) with 120 patients randomly assigned using a one-sided log-rank test and significance level set at 2.5%. RESULTS: Of the 119 randomly assigned participants, 103 (86.5%) previously received palbociclib and 14 participants received ribociclib (11.7%). There was a statistically significant PFS improvement for patients randomly assigned to switched ET plus ribociclib (median, 5.29 months; 95% CI, 3.02 to 8.12 months) versus switched ET plus placebo (median, 2.76 months; 95% CI, 2.66 to 3.25 months) HR, 0.57 (95% CI, 0.39 to 0.85); P = .006. At 6 and 12 months, the PFS rate was 41.2% and 24.6% with ribociclib, respectively, compared with 23.9% and 7.4% with placebo. CONCLUSION: In this randomized trial, there was a significant PFS benefit for patients with HR+/HER2- MBC who switched ET and received ribociclib compared with placebo after previous CDK4/6i and different ET.

21-Gene recurrence scores: racial differences in testing, scores, treatment, and outcome.

BACKGROUND: African American (AA) women experience higher breast cancer mortality than white (W) women. These differences persist even among estrogen receptor (ER)-positive breast cancers. The 21-gene recurrence score (RS) predicts recurrence in patients with ER-positive/lymph node-negative breast cancer according to RS score-low risk (RS, 0-18), intermediate risk (RS, 19-31), and high risk (RS, >31). The high-risk group is most likely to benefit from chemotherapy, to achieve minimal benefit from hormonal therapy, and to exhibit lower ER levels (intrinsically luminal B cancers). In the current study, the authors investigated racial differences in RS testing, scores, treatment, and outcome. METHODS: Tumor registry data from 3 Atlanta hospitals identified women who were diagnosed with breast cancers during 2005 through 2009. Medical record abstraction provided information on RS and other tumor/treatment factors. Statistical analyses used chi-square/exact tests and logistic regression. RESULTS: Of 2186 patients, including 1192 AA women and 992 W women, 853 women had stage I or II, ER-positive/lymph node-negative disease and, thus, were eligible for RS testing (AA = 372 [31.2%]; W = 481 [48.5%]; P < .0001); and 272 women (31.8%) received testing (AA = 76 [20.4%]; W = 196 [40.7%]; P < .0001). Tumors were distributed into the following groups according to risk: low risk (n = 133), medium risk (n = 113), and high risk (n = 26). The mean RS did not differ by race, but risk groups did (low-risk group: 46.1% vs 50% for AA women and W women, respectively; high-risk group: 15.8% vs 7.1%, respectively; P = .043). In multivariate analyses, AA race (odds ratio, 3.6) was associated independently with high risk scores. CONCLUSIONS: AA women were half as likely as W women to receive 21-gene RS testing but were 2-fold more likely to be categorized as high risk. The current data suggested that testing guidelines are not applied equivalently, testing bias may attenuate racial differences in RS, and disparate outcomes may be explained in part by differences in RS, although compliance and pharmacogenomics also may play a role.

Treatment adherence and outcome in women with inflammatory breast cancer: does race matter?

BACKGROUND: The authors compared treatment adherence rates and outcome in Caucasian and African American patients with inflammatory breast cancer (IBC). METHODS: The records of 55 (25 Caucasian and 30 African American) IBC patients treated with curative intent from 1995 to 2009 were reviewed. All patients received neoadjuvant doxorubicin (Adriamycin) and/or taxane-based chemotherapy, and mastectomy with or without radiotherapy. The median follow-up period for Caucasian and African American patients was similar (39.5 months and 36.1 months, respectively). RESULTS: There was no difference between races in median age, tumor size, grade, and receptor status at diagnosis. The number of patients who completed neoadjuvant chemotherapy, surgery, and radiotherapy did not differ by race (84% of Caucasians vs 86.7% of African Americans) nor did the median length of time to complete trimodality treatment (263 [range, 207-422] days for Caucasians vs 262 [range, 165-371] days for African Americans). There was a trend toward slightly higher pathological complete response rates in Caucasian than African American women (20% in Caucasians vs 6.7% in African Americans, P = .23). Despite slightly better response rates to neoadjuvant chemotherapy, Caucasian patients did not have higher 3-year local control rates (70% in Caucasians vs 64% in African Americans, P = .73). However, there was a trend toward higher 3-year overall survival in Caucasian versus African American patients (73% in Caucasians vs 55% in African Americans, P = .09) and higher distant metastasis-free survival (60% in Caucasians vs 40% in African Americans, P = .19). CONCLUSIONS: This study is among the largest to examine patients with IBC by race. Being Caucasian or African American did not appear to impact treatment adherence. However, African American patients tended to have poorer response to standard treatment and worse outcome than Caucasian patients.

Improving on national quality indicators of breast cancer care in a large public hospital as a means to decrease disparities for African American women.

BACKGROUND: In April 2007, the National Quality Forum (NQF) endorsed the first nationally recognized hospital-based performance measures for stage I, II, and III breast cancer. The purpose of this study was to document compliance with the 3 NQF breast quality indicators during 2 time intervals in a metropolitan public hospital. MATERIALS AND METHODS: Tumor registry and medical records were used to identify patient demographics and treatments before (2005-2006) and after (2008) implementations in 2007 as a result of the NQF audit. Program changes included: hiring a dedicated medical oncology nurse practitioner, requiring the radiation oncology case manager to attend weekly multidisciplinary conferences, educating Patient Navigators of the importance of multimodal care, and providing support groups for patients addressing importance of completion of all treatment options. RESULTS: A total of 213 female patients were diagnosed with and treated for stage I, II, or III breast cancer in 2005-2006 and 2008. Of these, 189 (89%) were African American (AA) women. Also, 70 patients of 86 (81.3%) received radiation therapy, 60 of 77 (77.9%) received or were considered for adjuvant chemotherapy, and 124 of 144 (86.1%) for hormonal therapy according to NQF indicators. After 2007, patients receiving radiation therapy increased from 75.8 to 95.8%. Patients receiving or considered for adjuvant chemotherapy or hormonal therapy increased from 73.7 to 93.7% and from 84.1 to 90.0%, respectively. CONCLUSIONS: NQF breast cancer indicators provided a mechanism to improve compliance of multimodal treatment in our center. Raising awareness of these indicators in the multidisciplinary conference, hiring dedicated personnel, and educating patients has led to major improvements in breast cancer care.

Phase I/II Trial of Exemestane, Ribociclib, and Everolimus in Women with HR+/HER2- Advanced Breast Cancer after Progression on CDK4/6 Inhibitors (TRINITI-1).

PURPOSE: Standard-of-care treatment for metastatic hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer includes endocrine therapy (ET) combined with a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i). Optimal treatment after progression on CDK4/6i is unknown. The TRINITI-1 trial investigated ribociclib, a CDK4/6i that has recently demonstrated significant overall survival benefit in two phase III trials, in combination with everolimus and exemestane in patients with HR+, HER2- advanced breast cancer (ABC) after progression on a CDK4/6i. PATIENTS AND METHODS: This multicenter, open-label, single-arm, phase I/II study included patients with locally advanced/metastatic HR+/HER2- breast cancer. The primary endpoint was clinical benefit rate (CBR) at week 24 among patients with ET-refractory disease with progression on a CDK4/6i. Other endpoints included safety and biomarker analysis. RESULTS: Of 104 patients enrolled (phases I and II), 96 had prior CDK4/6i. Recommended phase II doses (all once daily days 1-28 of 28-day cycle) were ribociclib 300 mg, everolimus 2.5 mg, and exemestane 25 mg (group 1) and ribociclib 200 mg, everolimus 5 mg, and exemestane 25 mg (group 2). CBR among 95 efficacy-evaluable patients (phases I and II) at week 24 was 41.1% (95% confidence interval, 31.1-51.6), which met the primary endpoint (predetermined threshold: 10%). Common adverse events included neutropenia (69.2%) and stomatitis (40.4%). No new safety signals were observed; no grade 3/4 QTc prolongation was reported. CONCLUSIONS: Preliminary TRINITI-1 safety and efficacy results support further investigation of CDK4/6 blockade and targeting of the PI3K/AKT/mTOR signaling pathway in patients with ET-refractory HR+/HER2- ABC after progression on a CDK4/6i.

Preservation of quality of life in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer treated with tucatinib or placebo when added to trastuzumab and capecitabine (HER2CLIMB trial).

AIMS: In HER2CLIMB, tucatinib significantly improved progression-free and overall survival in patients with human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer. We evaluated the impact of tucatinib on health-related quality of life (HR-QoL) in HER2CLIMB. METHODS: Patients were randomised 2:1 to tucatinib or placebo combined with trastuzumab and capecitabine. Starting with protocol version 7, the EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) questionnaire and EQ visual analogue scale (VAS) were administered at day 1 of cycle 1, every two cycles during cycles 3-9, every three cycles during cycle 12 and thereafter and at each patient's 30-day follow-up visit. RESULTS: Among 364 patients eligible for HR-QoL assessment, 331 (91%) completed ≥1 assessment. EQ-VAS scores were similar for both arms at baseline and maintained throughout treatment. EQ-5D-5L scores were similar between the treatment arms, stable throughout therapy and worsened after discontinuing treatment. Risk of meaningful deterioration (≥7 points) on EQ-VAS was reduced 19% in the tucatinib vs. placebo arm (hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.55, 1.18); the median (95% CI) time to deterioration was not reached in the tucatinib arm and was 5.8 months (4.3, -) in the placebo arm. Among patients with brain metastases (n = 164), risk of meaningful deterioration on EQ-VAS was reduced 49% in the tucatinib arm (HR: 0.51; 95% CI: 0.28, 0.93); the median (95% CI) time to deterioration was not reached in the tucatinib arm and was 5.5 months (4.2, -) in the placebo arm. CONCLUSIONS: HR-QoL was preserved for patients with HER2+ metastatic breast cancer who were treated with tucatinib added to trastuzumab and capecitabine and maintained longer with tucatinib therapy than without it among those with brain metastases. CLINICAL TRIAL REGISTRATION: NCT02614794.

Overcoming taxane and anthracycline resistance.

With more and more breast cancer (BC) patients receiving taxanes and anthracyclines in the adjuvant setting, the number of patients resistant to these drugs is rising. Herein, we review cellular mechanisms (e.g., overexpression of drug efflux pumps) that are associated with clinical anthracycline and/or taxane-resistant BC. We also discuss therapeutic approaches that have received Food and Drug Administration approval in this setting or are in clinical development, including targeted agents that do not employ a cytotoxic mechanism, as well as novel chemotherapeutics such as the epothilones, a class of microtubule stabilizers less susceptible to common cellular resistance mechanisms.

Intracranial Efficacy and Survival With Tucatinib Plus Trastuzumab and Capecitabine for Previously Treated HER2-Positive Breast Cancer With Brain Metastases in the HER2CLIMB Trial.

PURPOSE: In the HER2CLIMB study, patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer with brain metastases (BMs) showed statistically significant improvement in progression-free survival (PFS) with tucatinib. We describe exploratory analyses of intracranial efficacy and survival in participants with BMs. PATIENTS AND METHODS: Patients were randomly assigned 2:1 to tucatinib or placebo, in combination with trastuzumab and capecitabine. All patients underwent baseline brain magnetic resonance imaging; those with BMs were classified as active or stable. Efficacy analyses were performed by applying RECIST 1.1 criteria to CNS target lesions by investigator assessment. CNS-PFS (intracranial progression or death) and overall survival (OS) were evaluated in all patients with BMs. Confirmed intracranial objective response rate (ORR-IC) was evaluated in patients with measurable intracranial disease. RESULTS: There were 291 patients with BMs: 198 (48%) in the tucatinib arm and 93 (46%) in the control arm. The risk of intracranial progression or death was reduced by 68% in the tucatinib arm (hazard ratio [HR], 0.32; 95% CI, 0.22 to 0.48; P < .0001). Median CNS-PFS was 9.9 months in the tucatinib arm versus 4.2 months in the control arm. Risk of death was reduced by 42% in the tucatinib arm (OS HR, 0.58; 95% CI, 0.40 to 0.85; P = .005). Median OS was 18.1 versus 12.0 months. ORR-IC was higher in the tucatinib arm (47.3%; 95% CI, 33.7% to 61.2%) versus the control arm (20.0%; 95% CI, 5.7% to 43.7%; P = .03). CONCLUSION: In patients with HER2-positive breast cancer with BMs, the addition of tucatinib to trastuzumab and capecitabine doubled ORR-IC, reduced risk of intracranial progression or death by two thirds, and reduced risk of death by nearly half. To our knowledge, this is the first regimen to demonstrate improved antitumor activity against BMs in patients with HER2-positive breast cancer in a randomized, controlled trial.

Use of Everolimus and Trastuzumab in Addition to Endocrine Therapy in Hormone-Refractory Metastatic Breast Cancer.

BACKGROUND: Increased signaling through growth factor receptor pathways, including HER2, plays a role in resistance to endocrine therapy (ET) in patients with hormone receptor (HR)-positive metastatic breast cancer (MBC). Inhibition of mechanistic target of rapamycin improves outcomes when used in addition to ET in patients with HR-positive MBC, who previously received ET. We hypothesized that the additional use of trastuzumab (T) or everolimus (E) could restore sensitivity to ET in patients with endocrine-resistant, HR-positive, HER2-negative MBC. PATIENTS AND METHODS: Patients with endocrine-resistant HR-positive, HER2-negative MBC continued the ET during which they had experienced disease progression, and were randomized to receive T or E. At disease progression, patients could continue the therapy they were receiving and have E or T used in addition. RESULTS: Fifty-four patients were randomized to the additional use of E (n = 30) or T (n = 24) with existing ET. Progression-free survival (PFS) was 5.7 months, and 2.2 months, respectively, and clinical benefit rate at 24 weeks was 48% and 11% for patients receiving E or T, respectively. PFS was 4.5 months and 3.1 months for patients in whom E (n = 16) or T (n = 12) was used post progression, respectively. There were no new safety signals apart from 2 patients who had a decreased ejection fraction while receiving E with ET. CONCLUSION: These results suggest that E, but not T, can potentially reverse resistance to ET in patients with endocrine-resistant HR-positive, HER2-negative MBC. Further, the additional use of E with an ET to which the cancer has already been exposed might offer the possibility of delaying time to use of chemotherapy.

Targeting angiogenesis in advanced breast cancer.

Angiogenesis, the process of new blood vessel formation, is required for tumor growth and metastasis. There is substantial preclinical and clinical evidence supporting the central role of angiogenesis in tumor formation and metastasis. Thus, the inhibition of angiogenesis may provide more effective treatment for patients with advanced breast cancer. Several chemotherapeutic and hormonal agents routinely used in the treatment of advanced breast cancer have antiangiogenic properties. Novel antiangiogenic agents targeting the vascular endothelial growth factor (VEGF) ligand and receptor tyrosine kinase inhibitors are being developed. Recently, a large phase III clinical trial demonstrated a significant benefit in progression-free survival with the addition of anti-VEGF monoclonal antibody bevacizumab to paclitaxel for first-line treatment of advanced breast cancer. This study established that antiangiogenic therapy is effective in breast cancer, and additional studies of bevacizumab and other antiangiogenic agents are underway. This article reviews the evidence for the role of angiogenesis in breast cancer pathogenesis, the challenges of developing antiangiogenic agents, and current agents in clinical trials.