Palbociclib Rechallenge for Hormone Receptor-Positive/HER-Negative Advanced Breast Cancer: Findings from the Phase II BioPER Trial.

PURPOSE: To assess the efficacy and exploratory biomarkers of continuing palbociclib plus endocrine therapy (ET) beyond progression on prior palbociclib-based regimen in patients with hormone receptor-positive/HER2-negative (HR+/HER2-) advanced breast cancer (ABC). PATIENTS AND METHODS: The multicenter, open-label, phase II BioPER trial included women who had experienced a progressive disease (PD) after having achieved clinical benefit on the immediately prior palbociclib plus ET regimen. Palbociclib (125 mg, 100 mg, or 75 mg daily orally for 3 weeks and 1 week off as per prior palbociclib-based regimen) plus ET of physician's choice were administered in 4-week cycles until PD or unacceptable toxicity. Coprimary endpoints were clinical benefit rate (CBR) and percentage of tumors with baseline loss of retinoblastoma (Rb) protein expression. Additional endpoints included safety and biomarker analysis. RESULTS: Among 33 patients enrolled, CBR was 34.4% [95% confidence interval (CI), 18.6-53.2; P < 0.001] and 13.0% of tumors (95% CI, 5.2-27.5) showed loss of Rb protein expression, meeting both coprimary endpoints. Median progression-free survival was 2.6 months (95% CI, 1.8-6.7). No new safety signals were reported. A signature that included baseline mediators of therapeutic resistance to palbociclib and ET (low Rb score, high cyclin E1 score, ESR1 mutation) was independently associated with shorter median progression-free survival (HR, 22.0; 95% CI, 1.71-282.9; P = 0.018). CONCLUSIONS: Maintaining palbociclib after progression on prior palbociclib-based regimen seems to be a reasonable, investigational approach for selected patients. A composite biomarker signature predicts a subset of patients who may not derive a greater benefit from palbociclib rechallenge, warranting further validation in larger randomized controlled trials.

Role of germline variants in the metastasis of breast carcinomas.

Most cancer-related deaths in breast cancer patients are associated with metastasis, a multistep, intricate process that requires the cooperation of tumour cells, tumour microenvironment and metastasis target tissues. It is accepted that metastasis does not depend on the tumour characteristics but the host's genetic makeup. However, there has been limited success in determining the germline genetic variants that influence metastasis development, mainly because of the limitations of traditional genome-wide association studies to detect the relevant genetic polymorphisms underlying complex phenotypes. In this work, we leveraged the extreme discordant phenotypes approach and the epistasis networks to analyse the genotypes of 97 breast cancer patients. We found that the host's genetic makeup facilitates metastases by the dysregulation of gene expression that can promote the dispersion of metastatic seeds and help establish the metastatic niche-providing a congenial soil for the metastatic seeds.

A clinical calculator to predict disease outcomes in women with hormone receptor-positive advanced breast cancer treated with first-line endocrine therapy.

PURPOSE: Endocrine therapy (ET) is an effective strategy to treat hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) but nearly all patients eventually progress. Our goal was to develop and validate a web-based clinical calculator for predicting disease outcomes in women with HR+ABC who are candidates for receiving first-line single-agent ET. METHODS: The meta-database comprises 891 patient-level data from the control arms of five contemporary clinical trials where patients received first-line single-agent ET (either aromatase inhibitor or fulvestrant) for ABC. Risk models were constructed for predicting 24-months progression-free survival (PFS-24) and 24-months overall survival (OS-24). Final models were internally validated for calibration and discrimination using ten-fold cross-validation. RESULTS: Higher number of sites of metastases, measurable disease, younger age, lower body mass index, negative PR status, and prior endocrine therapy were associated with worse PFS. Final PFS and OS models were well-calibrated and associated with cross-validated time-dependent area under the curve (AUC) of 0.61 and 0.62, respectively. CONCLUSIONS: The proposed ABC calculator is internally valid and can accurately predict disease outcomes. It may be used to predict patient prognosis, aid planning of first-line treatment strategies, and facilitate risk stratification for future clinical trials in patients with HR+ABC. Future validation of the proposed models in independent patient cohorts is warranted.

Phase III Trial of Adjuvant Capecitabine After Standard Neo-/Adjuvant Chemotherapy in Patients With Early Triple-Negative Breast Cancer (GEICAM/2003-11_CIBOMA/2004-01).

PURPOSE: Operable triple-negative breast cancers (TNBCs) have a higher risk of relapse than non-TNBCs with standard therapy. The GEICAM/2003-11_CIBOMA/2004-01 trial explored extended adjuvant capecitabine after completion of standard chemotherapy in patients with early TNBC. PATIENTS AND METHODS: Eligible patients were those with operable, node-positive-or node negative with tumor 1 cm or greater-TNBC, with prior anthracycline- and/or taxane-containing chemotherapy. After central confirmation of TNBC status by immunohistochemistry, patients were randomly assigned to either capecitabine or observation. Stratification factors included institution, prior taxane-based therapy, involved axillary lymph nodes, and centrally determined phenotype (basal v nonbasal, according to cytokeratins 5/6 and/or epidermal growth factor receptor positivity by immunohistochemistry). The primary objective was to compare disease-free survival (DFS) between both arms. RESULTS: Eight hundred seventy-six patients were randomly assigned to capecitabine (n = 448) or observation (n = 428). Median age was 49 years, 55.9% were lymph node negative, 73.9% had a basal phenotype, and 67.5% received previous anthracyclines plus taxanes. Median length of follow-up was 7.3 years. DFS was not significantly prolonged with capecitabine versus observation [hazard ratio (HR), 0.82; 95% CI, 0.63 to 1.06; P = .136]. In a preplanned subgroup analysis, nonbasal patients seemed to derive benefit from the addition of capecitabine with a DFS HR of 0.53 versus 0.94 in those with basal phenotype (interaction test P = .0694) and an HR for overall survival of 0.42 versus 1.23 in basal phenotype (interaction test P = .0052). Tolerance of capecitabine was as expected, with 75.2% of patients completing the planned 8 cycles. CONCLUSION: This study failed to show a statistically significant increase in DFS by adding extended capecitabine to standard chemotherapy in patients with early TNBC. In a preplanned subset analysis, patients with nonbasal phenotype seemed to obtain benefit with capecitabine, although this will require additional validation.

Survival impact of primary tumor resection in de novo metastatic breast cancer patients (GEICAM/El Alamo Registry).

The debate about surgical resection of primary tumor (PT) in de novo metastatic breast cancer (MBC) patients persists. We explored this approach's outcomes in patients included in a retrospective registry, named El Álamo, of breast cancer patients diagnosed in Spain (1990-2001). In this analysis we only included de novo MBC patients, 1415 of whom met the study's criteria. Descriptive, Kaplan-Meier and Cox regression analyses were carried out. Median age was 63.1 years, 49.2% of patients had single-organ metastasis (skin/soft tissue [16.3%], bone [33.8%], or viscera [48.3%]). PT surgery (S) was performed in 44.5% of the cases. S-group patients were younger, had smaller tumors, higher prevalence of bone and oligometastatic disease, and lower prevalence of visceral involvement. With a median follow-up of 23.3 months, overall survival (OS) was 39.6 versus 22.4 months (HR = 0.59, p < 0.0001) in the S- and non-S groups, respectively. The S-group OS benefit remained statistically and clinically significant regardless of metastatic location, histological type, histological grade, hormone receptor status and tumor size. PT surgery (versus no surgery) was associated with an OS benefit suggesting that loco-regional PT control may be considered in selected MBC patients. Data from randomized controlled trials are of utmost importance to confirm these results.

Triple negative breast cancer subtypes and pathologic complete response rate to neoadjuvant chemotherapy.

Triple negative breast cancer (TNBC) is a heterogeneous disease with distinct molecular subtypes that differentially respond to chemotherapy and targeted agents. The purpose of this study is to explore the clinical relevance of Lehmann TNBC subtypes by identifying any differences in response to neoadjuvant chemotherapy among them. We determined Lehmann subtypes by gene expression profiling in paraffined pre-treatment tumor biopsies from 125 TNBC patients treated with neoadjuvant anthracyclines and/or taxanes +/- carboplatin. We explored the clinicopathological characteristics of Lehmann subtypes and their association with the pathologic complete response (pCR) to different treatments. The global pCR rate was 37%, and it was unevenly distributed within Lehmann's subtypes. Basal-like 1 (BL1) tumors exhibited the highest pCR to carboplatin containing regimens (80% vs 23%, p=0.027) and were the most proliferative (Ki-67>50% of 88.2% vs. 63.7%, p=0.02). Luminal-androgen receptor (LAR) patients achieved the lowest pCR to all treatments (14.3% vs 42.7%, p=0.045 when excluding mesenchymal stem-like (MSL) samples) and were the group with the lowest proliferation (Ki-67≤50% of 71% vs 27%, p=0.002). In our cohort, only tumors with LAR phenotype presented non-basal-like intrinsic subtypes (HER2-enriched and luminal A). TNBC patients present tumors with a high genetic diversity ranging from highly proliferative tumors, likely responsive to platinum-based therapies, to a subset of chemoresistant tumors with low proliferation and luminal characteristics.

Limitations in predicting PAM50 intrinsic subtype and risk of relapse score with Ki67 in estrogen receptor-positive HER2-negative breast cancer.

PAM50/Prosigna gene expression-based assay identifies three categorical risk of relapse groups (ROR-low, ROR-intermediate and ROR-high) in post-menopausal patients with estrogen receptor estrogen receptor-positive (ER+)/ HER2-negative (HER2-) early breast cancer. Low risk patients might not need adjuvant chemotherapy since their risk of distant relapse at 10-years is below 10% with endocrine therapy only. In this study, 517 consecutive patients with ER+/HER2- and node-negative disease were evaluated for Ki67 and Prosigna. Most of Luminal A tumors (65.6%) and ROR-low tumors (70.9%) had low Ki67 values (0-10%); however, the percentage of patients with ROR-medium or ROR-high disease within the Ki67 0-10% group was 42.7% (with tumor sizes ≤2 cm) and 33.9% (with tumor sizes > 2 cm). Finally, we found that the optimal Ki67 cutoff for identifying Luminal A or ROR-low tumors was 14%. Ki67 as a surrogate biomarker in identifying Prosigna low-risk outcome patients or Luminal A disease in the clinical setting is unreliable. In the absence of a well-validated prognostic gene expression-based assay, the optimal Ki67 cutoff for identifying low-risk outcome patients or Luminal A disease remains at 14%.

Nab-Paclitaxel in Metastatic Breast Cancer: Defining the Best Patient Profile.

Around 40% of patients with breast cancer will present with a recurrence of the disease. Chemotherapy is recommended for patients with recurrent hormone-independent or hormone-refractory breast cancer and almost all patients with metastatic breast cancer (MBC) receive chemotherapy during their medical history. Nanoparticle albuminbound (nab)-paclitaxel is a solvent-free, 130-nanometer particle formulation of paclitaxel. Nab-paclitaxel can be administered to all patients for whom the treatment choice is a taxane. In this review, 6 patient profiles for which nabpaclitaxel may be particularly useful are described and analyzed: (i) as first-line treatment of MBC, (ii) as second-line treatment of MBC after oral chemotherapy, (iii) after a standard taxane, (iv) as third-line treatment after a standard taxane and oral chemotherapy, (v) for patients with HER2-positive MBC and (vi) for patients with intolerance to standard taxanes. Nab-paclitaxel is a rational treatment choice for patients with MBC in different settings, as well as for those with prior exposure to a standard taxane.

Standard versus continuous administration of capecitabine in metastatic breast cancer (GEICAM/2009-05): a randomized, noninferiority phase II trial with a pharmacogenetic analysis.

BACKGROUND: The approved capecitabine regimen as monotherapy in metastatic breast cancer (MBC) is 1,250 mg/m(2) twice daily for 2 weeks on and 1 week off (Cint). Dose modifications are often required because of severe hand-foot syndrome (HFS). We tested a continuous regimen with a lower daily dose but a similar cumulative dose in an attempt to reduce the severity of adverse events (AEs) while maintaining efficacy. METHODS: We randomized 195 patients with HER-2/neu-negative MBC to capecitabine 800 mg/m(2) twice daily throughout the 21-day cycle (Ccont) or to Cint to assess noninferiority in the percentage of patients free of progression at 1 year. Secondary endpoints included efficacy and safety. Associations between polymorphisms in capecitabine metabolism-related genes and drug response were assessed. RESULTS: The percentage of patients free of progression at 1 year was 27.3% with Cint versus 25.3% with Ccont (difference of -2.0%; 95% confidence interval: -15.5% to 11.5%, exceeding the 15% deemed noninferior). Differences regarding other efficacy variables were also not found. Grade 3-4 HFS was the most frequent AE (41.1% in Cint vs. 42.3% in Ccont). Grade 3-4 neutropenia, thrombocytopenia, diarrhea, and stomatitis were more frequent with Cint. A 5' untranslated region polymorphism in the carboxylesterase 2 gene was associated with HFS. One polymorphism in cytidine deaminase and two in thymidine phosphorylase were associated with survival. CONCLUSION: Our study was unable to show noninferiority with the continuous capecitabine regimen (Ccont) compared with the approved intermittent regimen (Cint). Further investigation is required to improve HFS. Polymorphisms in several genes might contribute to interindividual differences in response to capecitabine.

Practical prognostic index for patients with metastatic recurrent breast cancer: retrospective analysis of 2,322 patients from the GEICAM Spanish El Alamo Register.

Women with recurrent metastatic breast cancer from a Spanish hospital registry (El Alamo, GEICAM) were analyzed in order to identify the most helpful prognostic factors to predict survival and to ultimately construct a practical prognostic index. The inclusion criteria covered women patients diagnosed with operable invasive breast cancer who had metastatic recurrence between 1990 and 1997 in GEICAM hospitals. Patients with stage IV breast cancer at initial diagnosis or with isolated loco-regional recurrence were excluded from this analysis. Data from 2,322 patients with recurrent breast cancer after primary treatment (surgery, radiation and systemic adjuvant treatment) were used to construct the prognostic index. The prognostic index score for each individual patient was calculated by totalling up the scores of each independent variable. The maximum score obtainable was 26.1. Nine-hundred and sixty-two patients who had complete data for all the variables were used in the computation of the prognostic index score. We were able to stratify them into three prognostic groups based on the prognostic index score: 322 patients in the good risk group (score < or =13.5), 308 patients in the intermediate risk group (score 13.51-15.60) and 332 patients in the poor risk group (score > or =15.61). The median survivals for these groups were 3.69, 2.27 and 1.02 years, respectively (P < 0.0001). In conclusion, risk scores are extraordinarily valuable tools, highly recommendable in the clinical practice.

Prognostic and predictive factors and genetic analysis of early breast cancer.

The great heterogeneity of breast cancer makes it impossible to firmly predict which patients with early-stage tumours will or will not need systemic treatments according to the conventional prognostic factors currently employed. In fact, a substantial percentage of patients receive medical treatment for a disease that will not relapse, while another proportion of patients regarded as having good prognostic factors according to the classic criteria do not receive treatment and suffer disease relapse. Considering that most oncological treatments have short- and long-term toxic effects, new methods capable of offering a more precise prognosis need to be developed. The individualisation of the diagnosis of patients with breast cancer based on molecular and gene expression studies is bringing about a veritable revolution in our understanding of the biology of the disease. The new molecular classification of breast cancer, based on these profiles, allows us to establish a prognosis according to the genetic characteristics of each tumour. Such individualisation of the diagnosis of patients with breast cancer will lead to the application of more specific treatments, thereby improving patient survival with lesser toxicity and increased economic savings. Of the different genetic analytical tests available, MammaPrint has been shown to be the option offering the most information on the behaviour of early breast cancer; as a result, it is the most useful technique in deciding the need for oncological treatment as a complement to surgery.

A phase II study of weekly vinorelbine and trastuzumab in patients with HER2-positive metastatic breast cancer.

BACKGROUND: Trastuzumab combined with cytotoxic agents presents encouraging results in metastatic breast cancer (MBC), but cardiac toxicity limits some combinations. The synergism shown with trastuzumab and the favorable tolerability profile of vinorelbine provided the rationale for investigating this combination. PATIENTS AND METHODS: Patients with HER2-positive MBC who had received <2 lines of chemotherapy for metastatic disease were included. Vinorelbine (25 mg/m2 on day 2, then weekly on day 1) and trastuzumab (4 mg/kg on day 1, then 2 mg/kg weekly) were administered for a maximum of 6 cycles (1 cycle=3 weeks). RESULTS: A total of 52 patients were enrolled. The median age was 50 years (range, 26-79 years). Ninety percent of the patients had received adjuvant chemotherapy, 42% received a first line of chemotherapy for MBC, and 69% had disease at visceral sites. The overall response rate was 58% (95% CI, 43%-71%). The median time to progression and overall survival were 7 months (95% CI, 5-9 months) and 26 months (95% CI, 20-32 months), respectively. Grade 4 neutropenia was present in 3 courses; neutropenic fever was not reported. The main grade 3 nonhematologic toxicities were asthenia, neuropathy, diarrhea, alopecia, and nausea/vomiting. No patients experienced serious cardiac toxicity. CONCLUSION: These results confirm that weekly vinorelbine/trastuzumab is an active and safe regimen in patients with HER2-positive MBC with an unfavorable prognosis.

Neoadjuvant endocrine therapy for breast cancer: past, present and future.

Combined treatments together with surgery, radiotherapy, chemotherapy, and endocrine therapy have contributed substantially to the improved survival rate in breast cancer. For more than 2 decades, tamoxifen has been the standard endocrine agent for hormone receptor-positive tumors. Third-generation aromatase inhibitors have, however, now proven to be superior to tamoxifen in the adjuvant and, more recently, the neoadjuvant treatment of postmenopausal patients. They have especially improved the surgical management of large or inoperable locally advanced breast tumors. Other advantages of neoadjuvant endocrine therapy are just emerging, but there are still many unanswered questions regarding its optimal use in this setting. A need to define how to select the patients who will benefit most from these therapies, the optimal duration of treatment, the best method to evaluate the treatment response achieved, the existence of predictive factors for response, or the superiority of certain endocrine agents over others has been observed. Other questions regarding which complementary local and systemic treatments should be administered after neoadjuvant endocrine therapy or which efficacy endpoints should be evaluated in clinical trials are also of interest. To answer as many of these questions as possible, we have carried out a critical analysis of the current literature on the use of endocrine therapy in the neoadjuvant setting of breast cancer. In this review, we outline the rationale for its use, and consider data published to date to further clarify how to optimize its administration.