CDK4/6 inhibitors: The Devil is in the Detail.

PURPOSE OF REVIEW: Update on the most recent clinical evidence on CDK4/6 inhibitors (CDK4/6i) in the treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor (HER)2-negative breast cancer. RECENT FINDINGS: Over the past decade, CDK4/6i have become part of the standard of care treatment of patients with both metastatic and high-risk early HR + /HER2- breast cancers. The three available CDK4/6i (palbociclib, ribociclib and abemaciclib) have been extensively studied in combination with endocrine therapy (ET) in metastatic breast cancer (mBC) with consistent prolongation of progression free survival; however, ribociclib has emerged as the preferred first line agent in mBC given overall survival benefit over endocrine monotherapy. In early BC, abemaciclib is the only currently approved agent while ribociclib has early positive clinical trial data. Toxicities and financial burden limit the use of CDK4/6i in all patients and resource-poor settings, and optimal timing of their use in mBC remains unclear. There is considerable evidence for the use of CDK4/6i in metastatic and early HR + /HER2- breast cancer, but knowledge gaps remain, and further research is necessary to better define their optimal use.

Organizational Breast Cancer Data Mart: A Solution for Assessing Outcomes of Imaging and Treatment.

PURPOSE: In the United States, a comprehensive national breast cancer registry (CR) does not exist. Thus, care and coverage decisions are based on data from population subsets, other countries, or models. We report a prototype real-world research data mart to assess mortality, morbidity, and costs for breast cancer diagnosis and treatment. METHODS: With institutional review board approval and Health Insurance Portability and Accountability Act (HIPPA) compliance, a multidisciplinary clinical and research data warehouse (RDW) expert group curated demographic, risk, imaging, pathology, treatment, and outcome data from the electronic health records (EHR), radiology (RIS), and CR for patients having breast imaging and/or a diagnosis of breast cancer in our institution from January 1, 2004, to December 31, 2020. Domains were defined by prebuilt views to extract data denormalized according to requirements from the existing RDW using an export, transform, load pattern. Data dictionaries were included. Structured query language was used for data cleaning. RESULTS: Five-hundred eighty-nine elements (EHR 311, RIS 211, and CR 67) were mapped to 27 domains; all, except one containing CR elements, had cancer and noncancer cohort views, resulting in a total of 53 views (average 12 elements/view; range, 4-67). EHR and RIS queries returned 497,218 patients with 2,967,364 imaging examinations and associated visit details. Cancer biology, treatment, and outcome details for 15,619 breast cancer cases were imported from the CR of our primary breast care facility for this prototype mart. CONCLUSION: Institutional real-world data marts enable comprehensive understanding of care outcomes within an organization. As clinical data sources become increasingly structured, such marts may be an important source for future interinstitution analysis and potentially an opportunity to create robust real-world results that could be used to support evidence-based national policy and care decisions for breast cancer.

Treatment outcomes in older patients with metastatic breast cancer receiving palbociclib plus an aromatase inhibitor: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This summary describes an article published in the medical journal Frontiers in Oncology in September 2023. The article reports results from a study that looked at breast cancer treatments for older patients aged 75 years or older. The study focused on a type of cancer called HR+/HER2- metastatic breast cancer. HR+/HER2- stands for hormone receptorpositive/human epidermal growth factor receptor 2-negative. This study evaluated whether older patients with this type of cancer benefited from the combination of two medicines - palbociclib and an aromatase inhibitor - compared with taking an aromatase inhibitor alone. HOW WAS THE STUDY IN THIS SUMMARY CARRIED OUT?: The Flatiron database contains medical records for people with cancer in the US. This study used deidentified health care information from this database. 'Deidentified' means that all information that could identify an individual was removed to protect individuals' privacy. People in this study received treatment in routine care and not in a clinical trial. WHAT DO THE RESULTS MEAN?: Older patients who took palbociclib plus an aromatase inhibitor lived longer than those who took an aromatase inhibitor alone. Older patients who took palbociclib plus an aromatase inhibitor also lived longer without their cancer getting worse and started chemotherapy later than those who took an aromatase inhibitor alone. These results support using palbociclib plus an aromatase inhibitor as the first treatment for patients aged 75 years or older with HR+/HER2- metastatic breast cancer.

Health-related quality of life over chemotherapy course among individuals with early-stage breast cancer: the association of social determinants of health and neighborhood socioeconomic disadvantage.

PURPOSE: This study aimed to examine relationships between health-related quality of life (HRQOL), social determinants of health, and neighborhood socioeconomic disadvantage in individuals with early-stage breast cancer (ESBC) during chemotherapy. METHODS: This is a longitudinal study that recruited Black and White women with ESBC receiving chemotherapy. Participants completed questionnaires recording their sociodemographic information at baseline and the Functional Assessment of Cancer Therapy-General (FACT-G) to report their HRQOL before each chemotherapy cycle. Linear mixed modeling was employed to examine the associations between FACT-G scores, self-reported race, and area deprivation index (ADI) before and at the last chemotherapy cycle, with the duration of chemotherapy treatment as a covariate. RESULTS: A total of 84 Black and 146 White women with ESBC completed the surveys. Linear mixed modeling results suggested that women with ESBC who reported being Black experienced significantly worse physical well-being than those who reported being White throughout chemotherapy, with a 0.22-point lower average (p = 0.02). Both Black and White women with ESBC experienced decreased functional well-being over the chemotherapy, and Black women consistently reported lower scores than White women, with the change in functional well-being over time differing between racial groups (p = 0.03). Participants' ADI national percentiles were not significantly associated with their HRQOL throughout chemotherapy. CONCLUSIONS: These findings underscore possible racial differences in some dimensions of HRQOL during chemotherapy among women with ESBC. Future research should consider further assessing life stressors and past experiences of discrimination and racism that may contribute to these disparities and guide proactive interventions.

Prolonging the lives of African-Americans with metastatic breast cancer by adding palbociclib to an aromatase inhibitor in routine clinical practice: a plain language summary of a real-world database study.

WHAT ARE THE KEY TAKEAWAYS?: This study used de-identified medical information from the Flatiron Database. This database contains healthcare information on people with cancer treated by doctors in the United States but personal information is removed to maintain privacy. Medical information for people who received certain treatments in routine clinical practice or real-world setting was included in the study. This study showed that in the real-world setting, African-Americans with HR+/HER2- MBC lived longer when receiving palbociclib with an AI than with an AI alone. Also, the study showed that African-Americans treated with palbociclib plus an AI lived longer without their cancer getting worse than those treated with an AI alone. WHAT WAS THE MAIN CONCLUSION REPORTED BY THE RESEARCHERS?: These results support the use of palbociclib with an AI as a first treatment for African-Americans with HR+/HER2- MBC. Clinical Trial Registration: NCT05361655 (ClinicalTrials.gov).

Activity and safety of enobosarm, a novel, oral, selective androgen receptor modulator, in androgen receptor-positive, oestrogen receptor-positive, and HER2-negative advanced breast cancer (Study G200802): a randomised, open-label, multicentre, multinational, parallel design, phase 2 trial.

BACKGROUND: The androgen receptor is a tumour suppressor in oestrogen receptor-positive breast cancer. The activity and safety of enobosarm, an oral selective androgen receptor modulator, was evaluated in women with oestrogen receptor (ER)-positive, HER2-negative, and androgen receptor (AR)-positive disease. METHODS: Women who were postmenopausal (aged ≥18 years) with previously treated ER-positive, HER2-negative, locally advanced or metastatic breast cancer with an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled in a randomised, open-label, multicentre, multinational, parallel design, phase 2 trial done at 35 cancer treatment centres in nine countries. Participants were stratified on the setting of immediately preceding endocrine therapy and the presence of bone-only metastasis and randomly assigned (1:1) to 9 mg or 18 mg oral enobosarm daily using an interactive web response system. The primary endpoint was clinical benefit rate at 24 weeks in those with centrally confirmed AR-positive disease (ie, the evaluable population). This trial is registered with ClinicalTrials.gov (NCT02463032). FINDINGS: Between Sept 10, 2015, and Nov 28, 2017, 136 (79%) of 172 patients deemed eligible were randomly assigned to 9 mg (n=72) or 18 mg (n=64) oral enobosarm daily. Of these 136 patients, 102 (75%) patients formed the evaluable population (9 mg, n=50; 18 mg, n=52). The median age was 60·5 years (IQR 52·3-69·3) in the 9 mg group and 62·5 years (54·0-69·3) in the 18 mg group. The median follow-up was 7·5 months (IQR 2·9-14·1). At 24 weeks, 16 (32%, 95% CI 20-47) of 50 in the 9 mg group and 15 (29%, 17-43) of 52 in the 18 mg group had clinical benefit. Six (8%) of 75 patients who received 9 mg and ten (16%) of 61 patients who received 18 mg had grade 3 or grade 4 drug-related adverse events, most frequently increased hepatic transaminases (three [4%] of 75 in the 9 mg group and two [3%] of 61 in the 18 mg group), hypercalcaemia (two [3%] and two [3%]), and fatigue (one [1%] and two [3%]). Four deaths (one in the 9 mg group and three in the 18 mg group) were deemed unrelated to the study drug. INTERPRETATION: Enobosarm has anti-tumour activity in patients with ER-positive, HER2-negative advanced breast cancer, showing that AR activation can result in clinical benefit, supporting further clinical investigation of selective AR activation strategies for the treatment of AR-positive, ER-positive, HER2-negative advanced breast cancer. FUNDING: GTx.

Final Results From the Randomized Phase III ASCENT Clinical Trial in Metastatic Triple-Negative Breast Cancer and Association of Outcomes by Human Epidermal Growth Factor Receptor 2 and Trophoblast Cell Surface Antigen 2 Expression.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Sacituzumab govitecan (SG), a first-in-class anti-trophoblast cell surface antigen 2 (Trop-2) antibody-drug conjugate, demonstrated superior efficacy over single-agent chemotherapy (treatment of physician's choice [TPC]) in patients with metastatic triple-negative breast cancer (mTNBC) in the international, multicenter, phase III ASCENT study.Patients were randomly assigned 1:1 to receive SG or TPC until unacceptable toxicity/progression. Final efficacy secondary end point analyses and post hoc analyses of outcomes stratified by Trop-2 expression and human epidermal growth factor receptor 2 status are reported. Updated safety analyses are provided.In this final analysis, SG (n = 267) improved median progression-free survival (PFS; 4.8 v 1.7 months; hazard ratio (HR), 0.41 [95% CI, 0.33 to 0.52]) and median overall survival (OS; 11.8 v 6.9 months; HR, 0.51 [95% CI, 0.42 to 0.63]) over TPC (n = 262). SG improved PFS over TPC in each Trop-2 expression quartile (n = 168); a trend was observed for improved OS across quartiles. Overall, SG had a manageable safety profile, with ≤5% of treatment-related discontinuations because of adverse events and no treatment-related deaths. The safety profile was consistent across all subgroups.These data confirm the clinical benefit of SG over chemotherapy, reinforcing SG as an effective treatment option in patients with mTNBC in the second line or later.

Breast Cancer Index and Prediction of Extended Aromatase Inhibitor Therapy Benefit in Hormone Receptor-Positive Breast Cancer from the NRG Oncology/NSABP B-42 Trial.

PURPOSE: BCI (H/I) has been shown to predict extended endocrine therapy (EET) benefit. We examined BCI (H/I) for EET benefit prediction in NSABP B-42, which evaluated extended letrozole therapy (ELT) in patients with hormone receptor-positive breast cancer after 5 years of ET. EXPERIMENTAL DESIGN: A stratified Cox model was used to analyze RFI as the primary endpoint, with DR, BCFI, and DFS as secondary endpoints. Because of a nonproportional effect of ELT on DR, time-dependent analyses were performed. RESULTS: The translational cohort included 2,178 patients (45% BCI (H/I)-High, 55% BCI (H/I)-Low). ELT showed an absolute 10-year RFI benefit of 1.6% (P = 0.10), resulting in an underpowered primary analysis (50% power). ELT benefit and BCI (H/I) did not show a significant interaction for RFI (BCI (H/I)-Low: 10 years absolute benefit 1.1% [HR, 0.70; 95% confidence interval (CI), 0.43-1.12; P = 0.13]; BCI (H/I)-High: 2.4% [HR, 0.83; 95% CI, 0.55-1.26; P = 0.38]; Pinteraction = 0.56). Time-dependent DR analysis showed that after 4 years, BCI (H/I)-High patients had significant ELT benefit (HR = 0.29; 95% CI, 0.12-0.69; P < 0.01), whereas BCI (H/I)-Low patients were less likely to benefit (HR, 0.68; 95% CI, 0.33-1.39; P = 0.29; Pinteraction = 0.14). Prediction of ELT benefit by BCI (H/I) was more apparent in the HER2- subset after 4 years (ELT-by-BCI (H/I) Pinteraction = 0.04). CONCLUSIONS: BCI (H/I)-High versus BCI (H/I)-Low did not show a statistically significant difference in ELT benefit for the primary endpoint (RFI). However, in time-dependent DR analysis, BCI (H/I)-High patients experienced statistically significant benefit from ELT after 4 years, whereas (H/I)-Low patients did not. Because BCI (H/I) has been validated as a predictive marker of EET benefit in other trials, additional follow-up may enable further characterization of BCI's predictive ability.

Long-Term Follow-Up of the Anthracyclines in Early Breast Cancer Trials (USOR 06-090, NSABP B-46-I/USOR 07132, and NSABP B-49 [NRG Oncology]).

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The primary joint efficacy analysis of the Anthracyclines in Early Breast Cancer (ABC) trials reported in 2017 failed to demonstrate nonanthracycline adjuvant therapy was noninferior to anthracycline-based regimens in high-risk, early breast cancer. Full analyses of the studies had proceeded when the prespecified futility boundary was crossed at a planned futility analysis for the ability to demonstrate noninferiority of a nonanthracycline regimen with continued follow-up. These results were presented with 3.3 years of median follow-up. This manuscript reports results of the final analyses of the study efficacy end points conducted with 6.9 years of median follow-up. Long-term analysis of invasive disease-free survival (IDFS), the primary end point of the ABC trials, remains consistent with the original results, as noninferiority of the nonanthracycline regimens could not be declared on the basis of the original criteria. The secondary end point of recurrence-free interval, which excluded deaths not due to breast cancer as events, favored anthracycline-based regimens, and tests for heterogeneity were significant for hormone receptor status (P = .02) favoring anthracycline regimens for the hormone receptor-negative cohorts. There was no difference in overall survival, and review of the type of IDFS events in the groups suggested reductions in cancer recurrences achieved with anthracycline regimens were offset by late leukemias and deaths unrelated to breast cancer.

Entinostat, nivolumab and ipilimumab for women with advanced HER2-negative breast cancer: a phase Ib trial.

We report the results of 24 women, 50% (N = 12) with hormone receptor-positive breast cancer and 50% (N = 12) with advanced triple-negative breast cancer, treated with entinostat + nivolumab + ipilimumab from the dose escalation (N = 6) and expansion cohort (N = 18) of ETCTN-9844 ( NCT02453620 ). The primary endpoint was safety. Secondary endpoints were overall response rate, clinical benefit rate, progression-free survival and change in tumor CD8:FoxP3 ratio. There were no dose-limiting toxicities. Among evaluable participants (N = 20), the overall response rate was 25% (N = 5), with 40% (N = 4) in triple-negative breast cancer and 10% (N = 1) in hormone receptor-positive breast cancer. The clinical benefit rate was 40% (N = 8), and progression-free survival at 6 months was 50%. Exploratory analyses revealed that changes in myeloid cells may contribute to responses; however, no correlation was noted between changes in CD8:FoxP3 ratio, PD-L1 status and tumor mutational burden and response. These findings support further investigation of this treatment in a phase II trial.

Poziotinib treatment in patients with HER2-positive advanced breast cancer who have received prior anti-HER2 regimens.

PURPOSE: Poziotinib is an irreversible pan-inhibitor of the human epidermal growth factor receptor (HER) that has shown acceptable tolerability and antitumor activity in phase I and II trials in patients with advanced solid tumors. In the present open-label, multicenter phase II study, we demonstrate safety, tolerability, and preliminary efficacy data from two different dosing schedules in patients with HER2-positive advanced breast cancer. PATIENTS AND METHODS: Patients who had received at least two prior HER2-directed therapy lines for advanced disease, received 24 mg poziotinib on an intermittent dosing schedule (cohort 1) or 16 mg poziotinib once daily on a continuous dosing schedule (cohort 2). The primary endpoint was overall response rate (ORR). Secondary endpoints were progression-free survival (PFS), disease control rate (DCR), and time to progression (TTP). Secondary endpoints additionally included safety and pharmacokinetics. RESULTS: A total of 67 patients were enrolled. The ORR was 30% in both groups (p = 0.98). DCR was 60% vs 78% (p = 0.15) and median PFS and TTP were 4.1 vs 4.9 months (both p = 0.30) for cohorts 1 and 2, respectively. The most common treatment related adverse events (AEs) of any grade included diarrhea (88% vs 85%, p = 0.76), rash (88% vs 88%, p = 0.96), and stomatitis (64% vs 56%, p = 0.52), with grade 3-4 diarrhea occurring in 33% vs 32% of patients (p = 0.93) and grade 3-4 rash in 27% vs 35% of patients (p = 0.48) in cohort 1 vs cohort 2, respectively. CONCLUSION: Poziotinib demonstrated evidence of clinical activity in patients with pre-treated HER2-positive advanced breast cancer, although high levels of toxicity may preclude further studies at this time.

Real-world treatment patterns for palbociclib plus an aromatase inhibitor, or an aromatase inhibitor alone, for patients with metastatic breast cancer in the Flatiron Database.

There are limited real-world comparative effectiveness data for palbociclib plus an aromatase inhibitor (AI) as a first-line (1L) treatment examining endpoints that require long term follow-up and post 1L progression. The Flatiron Health Analytic Database was used to characterize treatment and dosing patterns in patients with hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) receiving palbociclib plus an AI vs an AI alone in routine US clinical practice. In addition, time to chemotherapy (TTC) and real-world progression-free survival (rwPFS) when combining 1L and second-line of therapy (rwPFS2) were assessed. Of 1324 patients who received palbociclib plus an AI between February 3, 2015 and March 31, 2020, 1110 (83.8%) started palbociclib at the recommended 125 mg/day dose. After stabilized inverse probability treatment-weighting (sIPTW), median TTC in patients treated with palbociclib plus an AI and AI alone was 37.4 months (95% confidence interval [CI], 33.7-40.7) and 29.2 months (95% CI, 26.8-33.5), respectively (hazard ratio [HR] = 0.77 [95% CI, 0.69-0.86], P < .0001); median rwPFS2 was 32.6 months (95% CI, 29.4-35.2) and 20.7 months (95% CI, 18.9-22.6), respectively (HR = 0.62 [95% CI, 0.54-0.70], P < .0001). Sensitivity analyses with propensity score matching showed similar results to sIPTW analyses. Results from this large real-world study examining additional effectiveness outcomes beyond 1L rwPFS and overall survival support the use of palbociclib plus an AI as a 1L treatment for patients with HR+/HER2- mBC.

The Effect of Race and Area Deprivation on Symptom Profiles over the Course of Early-Stage Breast Cancer.

Purpose: This study compared common symptoms (fatigue, pain), overall physical functioning and changes over time between Black and White women receiving early-stage breast cancer (ESBC) chemotherapy. Methods: A longitudinal, repeated measures comparative design was employed. Time points of symptom measurement (PROMIS domains) at baseline, mid and end point were adjusted as per patient chemotherapy schedule. Analyses: Linear mixed models were applied. Results: There were 147 patients, 36% Black 64% White (54±12 years) recommended to receive early-stage breast cancer chemotherapy with adequate data for symptom analysis. Pain: Main effect of race was significant (F(1, 390) = 29.43, p<.001) for pain with Black patients experiencing significantly higher pain scores compared to White patients at pretherapy (Mean Difference; MD=3.7, p=.034), midpoint (MD=5.8, p=.002), and endpoint (MD=7.8, p<.001). Fatigue: Fatigue significantly increased (deteriorated) at endpoint (MDT1-T3= 8.7, p<.001) for Black patients. Among White patients, fatigue significantly increased at midpoint (MDT1-T2= 5.7) and at endpoint (MDT1-T3=10.1, p<.001; MDT2-T3=4.3, p= .017). Physical function: Black patients had significantly lower physical function scores compared to White patients at midpoint (MD=4.0, p=.027). Physical function decreased by endpoint in Black (MDT1-T3=7.8, p<.001), and White patients (MDT1-T3=7.7, p<.001). Conclusion: Symptom burden significantly increased over the course of chemotherapy for all patients. Scores for pain and physical function were higher overall for Black patients and deteriorated at a greater rate for Black vs. White women over the course of chemotherapy. This assessment holds implication for proactive assessment and mitigation strategies.

Phase Ib study of HSP90 inhibitor, onalespib (AT13387), in combination with paclitaxel in patients with advanced triple-negative breast cancer.

Background: Heat shock protein 90 (HSP90) is a molecular chaperone required for stabilization of client proteins over-activated in triple-negative breast cancer (TNBC). Over-expression of HSP90 client proteins has been implicated in paclitaxel resistance. Onalespib (AT13387) is a potent inhibitor of HSP90 that could improve paclitaxel efficacy when administered in combination. Design: This phase Ib trial administered onalespib with paclitaxel in patients with advanced TNBC to assess safety and establish a recommended phase II dose (RP2D). Objectives: The primary objectives were determining the dose-limiting toxicities and maximum tolerated dose of combination therapy. Secondary objectives included pharmacokinetic (PK) analysis and determination of overall response rate (ORR), duration of response (DOR), and progression-free survival (PFS). Methods: Patients with advanced TNBC were treated with standard dose intravenous paclitaxel in combination with intravenous onalespib at doses ranging from 120 to 260 mg/m2 administered on days 1, 8, and 15 of a 28-day cycle using a standard 3 + 3 design. A total of 15 patients were enrolled to dose expansion cohort at RP2D to confirm safety profile. Results: Thirty-one patients were enrolled in the study, of which over 90% had received prior taxane therapy. Paclitaxel was given for metastatic disease in 23% of patients. Adverse events (AEs) included anemia (grade 3: 20%), lymphopenia (grade 3: 17%), and neutropenia (grade 3: 33%, grade 4: 4%). The most frequent grade ⩾3 non-hematologic AE was diarrhea (7%). The established RP2D was 260 mg/m2 onalespib when given with paclitaxel at 80 mg/m2. PK analysis revealed a modest drug interaction profile for onalespib in the combination regimen. ORR was 20%. Three patients achieved complete responses, all of whom had received prior taxane therapy. Median DOR was 5.6 months; median PFS was 2.9 months. Conclusion: Combination treatment with onalespib and paclitaxel had an acceptable toxicity profile and RP2D was determined to be 260 mg/m2 of onalespib. Combination therapy showed antitumor activity in patients with advanced TNBC. Trial registration: Onalespib and paclitaxel in treating patients with advanced TNBC https://clinicaltrials.gov/ct2/show/NCT02474173.

Phase 1b study of HSP90 inhibitor called onalespib in combination with paclitaxel in patients with advanced triple-negative breast cancer This Phase 1b study demonstrated that treatment with a combination of onalespib and paclitaxel was reasonably well tolerated by most patients. Onalespib at 260 mg/m² given intravenously on days 1, 8 and 15 on 28-day cycles in combination with standard dose and schedule of paclitaxel was established as the recommended phase 2 dose for further clinical development. Despite minor drug-drug interactions between these 2 agents, onalespib did not alter paclitaxel exposure and paclitaxel did not affect exposure to onalespib. While onalespib with paclitaxel combination therapy did not yield durable objective responses or prolonged progression-free survival, there were several patients with long-lasting benefit from this combination including patients who previously experienced progression on taxane therapy.

Palbociclib Combined with an Aromatase Inhibitor in Patients with Breast Cancer with Lung or Liver Metastases in US Clinical Practice.

A cyclin-dependent kinase 4/6 inhibitor combined with endocrine therapy is the standard of care for patients with hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC), but real-world effectiveness data for patients with lung or liver metastases are limited. This retrospective study included data from the US Flatiron Health database of patients with HR+/HER2- mBC and lung or liver metastases treated with first-line palbociclib (PAL) plus an aromatase inhibitor (AI) or an AI alone in routine clinical practice. Overall survival (OS) and real-world progression-free survival (rwPFS) were assessed. A total of 891 patients were included (622 with lung metastasis, 376 with liver metastasis, and 107 with both lung and liver metastasis). After stabilized inverse probability of treatment weighting to balance patient characteristics, PAL + AI versus AI alone was associated with significantly prolonged OS (HR = 0.62; p < 0.001) and rwPFS (HR = 0.55; p < 0.001) in patients with lung metastases and numerically longer OS (HR = 0.73; p = 0.056) and significantly longer rwPFS (HR = 0.57, p < 0.001) for those with liver metastases. Overall, PAL + AI versus AI alone was associated with prolonged OS and rwPFS in routine clinical practice, supporting the use of first-line PAL + AI for patients with HR+/HER2- mBC with lung and/or liver metastases.

Effects of socioeconomic status and race on survival and treatment in metastatic breast cancer.

Race and socioeconomic factors affect outcomes in breast cancer. We aimed to assess the effect of race and neighborhood socioeconomic status (SES) on overall survival and treatment patterns in patients with metastatic breast cancer (MBC). This is a retrospective cohort study involving patients (N = 1246) with distant breast cancer metastases diagnosed at UPMC Magee Women's Breast Cancer Clinic from 2000-2017. Overall survival and treatment patterns were compared between races (Blacks and whites) and SES groups (defined using Area Deprivation Index). Low SES, but not tumor characteristics, was associated with Black race (P < 0.001) in the study population. Low SES (Median [Interquartile Range, IQR] survival 2.3[2.2-2.5] years vs high SES 2.7[2.5-3.1] years, P = 0.01) and Black race (Median [IQR] survival 1.8[1.3-2.3] years, vs white 2.5[2.3-2.7] years P = 0.008) separately were associated with worse overall survival in patients with MBC. In the Cox Proportional Hazard model with SES, race, age, subtype, number of metastases, visceral metastasis, and year of diagnosis as covariates, low SES (Hazard ratio 1.19[1.04-1.35], P = 0.01), but not Black race (Hazard ratio 1.19[0.96-1.49], P = 0.12), independently predicted overall survival in MBC. Moreover, patients from low SES neighborhoods and Black race received fewer lines of chemotherapy than high SES and whites. In conclusion, low neighborhood SES is associated with worse outcomes in patients with MBC. Poor outcomes in Black patients with MBC, at least in part is driven by socioeconomic factors. Future studies should delineate the interplay between neighborhood SES, race, and their effects on tumor biology in MBC.

Real-world treatment patterns and effectiveness of palbociclib plus an aromatase inhibitor in patients with metastatic breast cancer aged 75 years or older.

Background: Elderly patients are generally underrepresented in oncology clinical trials; therefore, real-world data are needed to inform clinical management of elderly patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC). This subanalysis of the P-REALITY X study (NCT05361655) evaluated palbociclib treatment patterns and comparative effectiveness of palbociclib plus an aromatase inhibitor (AI) versus an AI alone among patients with HR+/HER2- mBC aged ≥ 75 years treated in routine clinical practice in the United States. Methods: This retrospective observational cohort study used electronic health records from the Flatiron Health Analytic Database. Palbociclib treatment patterns, overall survival (OS), real-world progression-free survival (rwPFS), and time to chemotherapy (TTC) were evaluated. Three methods were used for comparative analyses: (1) an unadjusted analysis, (2) stabilized inverse probability treatment weighting (sIPTW; primary analysis), and (3) propensity score matching (PSM; sensitivity analysis). Results: A total of 961 patients aged ≥ 75 years with HR+/HER2- mBC were identified who started palbociclib plus an AI (n = 313) or an AI alone (n = 648) as first-line (1L) therapy between February 2015 and March 2020 (data cut-off: September 30, 2020). Among patients in the palbociclib plus an AI group with a documented palbociclib starting dose (n = 306), approximately 75% started palbociclib at 125 mg/day, and approximately 40% experienced dose adjustment. After sIPTW, patients treated with palbociclib plus an AI versus an AI alone had significantly improved OS (median of 43.0 vs. 32.4 months; hazard ratio [HR], 0.66 [95% confidence interval (CI), 0.51-0.84]; P = 0.0007), rwPFS (median of 20.0 vs. 15.0 months; HR, 0.72 (0.59-0.89); P = 0.0021), and TTC (median of 40.2 vs. 27.4 months; HR, 0.69 [0.55-0.87]; P = 0.0014). These significant improvements in OS, rwPFS, and TTC remained consistent in the unadjusted analysis and after PSM. Conclusion: This real-world comparative analysis demonstrated that 1L palbociclib plus an AI is associated with improved effectiveness compared with an AI alone among patients with HR+/HER2- mBC aged ≥ 75 years. These findings support palbociclib plus an AI as a standard-of-care 1L treatment for elderly patients with HR+/HER2- mBC.

Twenty-Year Follow-Up of a Phase II Trial of Taxotere/Carboplatin/Herceptin in Patients With Metastatic HER2-Positive Breast Cancer.

BACKGROUND: As the implementation of trastuzumab, several studies have investigated new agents and regimens to treat human epidermal growth factor 2-positive (HER2+) metastatic breast cancer (MBC). However, long-term survival analyses from HER2-targeted therapies are lacking. This is a 20-year follow-up study of a phase II trial that evaluated the activity and safety of docetaxel in combination with carboplatin and trastuzumab (TCH) in patients with HER2+ MBC. MATERIALS AND METHODS: This is a follow-up of a phase II, single-arm, open-label study. The primary objective was the activity from the combination of TCH in terms of response rate (RR). Secondary objectives included the activity from TCH in terms of response duration (RD), time to progression (TTP), overall survival (OS), and percent one-year survival. RESULTS: Between 11/1999 and 10/2002, 40 women were enrolled. Most patients (67.5%) had visceral metastasis on enrollment. After 2 decades and 3 months from first enrollment, there were 4 (10%) survivors (median follow-up of 3.2 years). The RR for complete response (CR) or partial response (PR) was 72.5%. The RR for CR was 42.5%. RD was 8 months. Median TTP was 10.8 months. Participants achieved a median OS of 39.8 months. Percent one-year survival was 92.5%. CONCLUSION: A subset of patients (10%) receiving trastuzumab in the metastatic setting have achieved long-term survival beyond 20 years.