CDK4/6 inhibition triggers anti-tumour immunity.

Cyclin-dependent kinases 4 and 6 (CDK4/6) are fundamental drivers of the cell cycle and are required for the initiation and progression of various malignancies. Pharmacological inhibitors of CDK4/6 have shown significant activity against several solid tumours. Their primary mechanism of action is thought to be the inhibition of phosphorylation of the retinoblastoma tumour suppressor, inducing G1 cell cycle arrest in tumour cells. Here we use mouse models of breast carcinoma and other solid tumours to show that selective CDK4/6 inhibitors not only induce tumour cell cycle arrest, but also promote anti-tumour immunity. We confirm this phenomenon through transcriptomic analysis of serial biopsies from a clinical trial of CDK4/6 inhibitor treatment for breast cancer. The enhanced anti-tumour immune response has two underpinnings. First, CDK4/6 inhibitors activate tumour cell expression of endogenous retroviral elements, thus increasing intracellular levels of double-stranded RNA. This in turn stimulates production of type III interferons and hence enhances tumour antigen presentation. Second, CDK4/6 inhibitors markedly suppress the proliferation of regulatory T cells. Mechanistically, the effects of CDK4/6 inhibitors both on tumour cells and on regulatory T cells are associated with reduced activity of the E2F target, DNA methyltransferase 1. Ultimately, these events promote cytotoxic T-cell-mediated clearance of tumour cells, which is further enhanced by the addition of immune checkpoint blockade. Our findings indicate that CDK4/6 inhibitors increase tumour immunogenicity and provide a rationale for new combination regimens comprising CDK4/6 inhibitors and immunotherapies as anti-cancer treatment.

Palbociclib with adjuvant endocrine therapy in early breast cancer (PALLAS): interim analysis of a multicentre, open-label, randomised, phase 3 study.

BACKGROUND: Palbociclib added to endocrine therapy improves progression-free survival in hormone-receptor-positive, HER2-negative, metastatic breast cancer. The PALLAS trial aimed to investigate whether the addition of 2 years of palbociclib to adjuvant endocrine therapy improves invasive disease-free survival over endocrine therapy alone in patients with hormone-receptor-positive, HER2-negative, early-stage breast cancer. METHODS: PALLAS is an ongoing multicentre, open-label, randomised, phase 3 study that enrolled patients at 406 cancer centres in 21 countries worldwide with stage II-III histologically confirmed hormone-receptor-positive, HER2-negative breast cancer, within 12 months of initial diagnosis. Eligible patients were aged 18 years or older with an Eastern Cooperative Oncology Group performance score of 0 or 1. Patients were randomly assigned (1:1) in permuted blocks of random size (4 or 6), stratified by anatomic stage, previous chemotherapy, age, and geographical region, by use of central telephone-based and web-based interactive response technology, to receive either 2 years of palbociclib (125 mg orally once daily on days 1-21 of a 28-day cycle) with ongoing standard provider or patient-choice adjuvant endocrine therapy (tamoxifen or aromatase inhibitor, with or without concurrent luteinising hormone-releasing hormone agonist), or endocrine therapy alone, without masking. The primary endpoint of the study was invasive disease-free survival in the intention-to-treat population. Safety was assessed in all randomly assigned patients who started palbociclib or endocrine therapy. This report presents results from the second pre-planned interim analysis triggered on Jan 9, 2020, when 67% of the total number of expected invasive disease-free survival events had been observed. The trial is registered with ClinicalTrials.gov (NCT02513394) and EudraCT (2014-005181-30). FINDINGS: Between Sept 1, 2015, and Nov 30, 2018, 5760 patients were randomly assigned to receive palbociclib plus endocrine therapy (n=2883) or endocrine therapy alone (n=2877). At the time of the planned second interim analysis, at a median follow-up of 23·7 months (IQR 16·9-29·2), 170 of 2883 patients assigned to palbociclib plus endocrine therapy and 181 of 2877 assigned to endocrine therapy alone had invasive disease-free survival events. 3-year invasive disease-free survival was 88·2% (95% CI 85·2-90·6) for palbociclib plus endocrine therapy and 88·5% (85·8-90·7) for endocrine therapy alone (hazard ratio 0·93 [95% CI 0·76-1·15]; log-rank p=0·51). As the test statistic comparing invasive disease-free survival between groups crossed the prespecified futility boundary, the independent data monitoring committee recommended discontinuation of palbociclib in patients still receiving palbociclib and endocrine therapy. The most common grade 3-4 adverse events were neutropenia (1742 [61·3%] of 2840 patients on palbociclib and endocrine therapy vs 11 [0·3%] of 2903 on endocrine therapy alone), leucopenia (857 [30·2%] vs three [0·1%]), and fatigue (60 [2·1%] vs ten [0·3%]). Serious adverse events occurred in 351 (12·4%) of 2840 patients on palbociclib plus endocrine therapy versus 220 (7·6%) of 2903 patients on endocrine therapy alone. There were no treatment-related deaths. INTERPRETATION: At the planned second interim analysis, addition of 2 years of adjuvant palbociclib to adjuvant endocrine therapy did not improve invasive disease-free survival compared with adjuvant endocrine therapy alone. On the basis of these findings, this regimen cannot be recommended in the adjuvant setting. Long-term follow-up of the PALLAS population and correlative studies are ongoing. FUNDING: Pfizer.

Efficacy of Single-Agent Chemotherapy for Patients with Advanced Invasive Lobular Carcinoma: A Pooled Analysis from Three Clinical Trials.

BACKGROUND: Data on the efficacy of chemotherapy regimens in patients with advanced invasive lobular carcinoma (ILC) of the breast are limited. We investigated the efficacy of single-agent eribulin for the treatment of advanced ILC when compared with invasive ductal carcinoma (IDC). PATIENTS AND METHODS: Results from the eribulin arms of two phase III studies (305 [EMBRACE] and 301) and a single-arm, phase II study were pooled. The studies involved patients with metastatic breast cancer who had previously received treatment with an anthracycline and a taxane. In all three studies, the dose of eribulin mesylate was 1.4 mg/m2 given on days 1 and 8 of a 21-day cycle. Overall survival (OS), progression-free survival (PFS), and response rates in patients with ILC were assessed and compared with data from patients with IDC. RESULTS: In total, 1,152 patients were included in this analysis (118 patients with ILC and 1,034 patients with IDC). Median OS was similar in patients with ILC and IDC (13.4 vs. 13.5 months; hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.87-1.38); as was median PFS (4.1 vs. 3.6 months; HR, 0.91; 95% CI, 0.72-1.14). There were no major differences in response rates between the two groups. CONCLUSION: This retrospective analysis suggests that eribulin demonstrates similar efficacy in patients with ILC and IDC with metastatic disease who have previously received an anthracycline and a taxane. IMPLICATIONS FOR PRACTICE: Data on the efficacy of chemotherapy regimens in patients with advanced invasive lobular carcinoma (ILC) of the breast are limited. This pooled retrospective analysis of three clinical studies demonstrates that the magnitude of benefit of eribulin in the metastatic setting did not differ between patients with ILC versus invasive ductal carcinoma (IDC), even when restricting for patients with estrogen receptor-positive/HER2-negative IDC.

Mixed Invasive Ductal and Lobular Carcinoma of the Breast: Prognosis and the Importance of Histologic Grade.

BACKGROUND: The diagnosis of mixed invasive ductal and lobular carcinoma (IDC-L) in clinical practice is often associated with uncertainty related to its prognosis and response to systemic therapies. With the increasing recognition of invasive lobular carcinoma (ILC) as a distinct disease subtype, questions surrounding IDC-L become even more relevant. In this study, we took advantage of a detailed clinical database to compare IDC-L and ILC regarding clinicopathologic and treatment characteristics, prognostic power of histologic grade, and survival outcomes. MATERIALS AND METHODS: In this retrospective cohort study, we identified 811 patients diagnosed with early-stage breast cancer with IDC-L or ILC. Descriptive statistics were performed to compare baseline clinicopathologic characteristics and treatments. Survival rates were subsequently analyzed using the Kaplan-Meier method and compared using the Cox proportional hazards model. RESULTS: Patients with ILC had more commonly multifocal disease, low to intermediate histologic grade, and HER2-negative disease. Histologic grade was prognostic for patients with IDC-L but had no significant discriminatory power in patients with ILC. Among postmenopausal women, those with IDC-L had significantly better outcomes when compared with those with ILC: disease-free survival (DFS) and overall survival (OS; adjusted hazard ratio [HR], 0.54; 95% confidence interval [CI] 0.31-0.95). Finally, postmenopausal women treated with an aromatase inhibitor had more favorable DFS and OS than those treated with tamoxifen only (OS adjusted HR, 0.50; 95% CI, 0.29-0.87), which was similar for both histologic types (p = .212). CONCLUSION: IDC-L tumors have a better prognosis than ILC tumors, particularly among postmenopausal women. Histologic grade is an important prognostic factor in IDC-L but not in ILC. IMPLICATIONS FOR PRACTICE: This study compared mixed invasive ductal and lobular carcinoma (IDC-L) with invasive lobular carcinomas (ILCs) to assess the overall prognosis, the prognostic role of histologic grade, and response to systemic therapy. It was found that patients with IDC-L tumors have a better prognosis than ILC, particularly among postmenopausal women, which may impact follow-up strategies. Moreover, although histologic grade failed to stratify the risk of ILC, it showed an important prognostic power in IDC-L, thus highlighting its clinical utility to guide treatment decisions of IDC-L. Finally, the disease-free survival advantage of adjuvant aromatase inhibitors over tamoxifen in ILC was consistent in IDC-L.

Addition of the PARP inhibitor veliparib plus carboplatin or carboplatin alone to standard neoadjuvant chemotherapy in triple-negative breast cancer (BrighTNess): a randomised, phase 3 trial.

BACKGROUND: Although several randomised trials in patients with triple-negative breast cancer have shown that the addition of carboplatin, with or without poly(ADP-ribose) polymerase (PARP) inhibitors, to neoadjuvant chemotherapy increases the likelihood of achieving a pathological complete response, the use of these therapies in this setting has remained controversial. The BrighTNess trial was designed to assess the addition of the PARP inhibitor veliparib plus carboplatin or carboplatin alone to standard neoadjuvant chemotherapy in triple-negative breast cancer. METHODS: We did a phase 3, randomised, double-blind, placebo-controlled trial (BrighTNess) across 145 sites in 15 countries. Patients aged 18 years and older with previously untreated histologically or cytologically confirmed clinical stage II-III triple-negative breast cancer, who were candidates for potentially curative surgery and had an Eastern Cooperative Oncology Group performance status of 0 or 1, were randomly assigned (2:1:1) by an interactive response technology system via permuted blocks (block size of four) within strata to receive one of three segment 1 regimens: paclitaxel (80 mg/m2 intravenously weekly for 12 doses) plus carboplatin (area under the curve 6 mg/mL per min, intravenously every 3 weeks, for four cycles) plus veliparib (50 mg orally, twice a day); paclitaxel plus carboplatin plus veliparib placebo (twice a day); or paclitaxel plus carboplatin placebo (every 3 weeks for four cycles) plus veliparib placebo. Following segment 1, all patients were assigned to segment 2 in which they received doxorubicin and cyclophosphamide every 2-3 weeks for four cycles. Randomisation for segment 1 was stratified by germline BRCA mutation status, nodal stage, and planned schedule of doxorubicin and cyclophosphamide administration. The primary endpoint was pathological complete response in breast and lymph nodes as determined by site pathologists following completion of neoadjuvant therapy. Efficacy analyses were done by intention to treat and safety analyses included all patients who received at least one dose of study treatment. These are the first results of an ongoing clinical trial; the data cutoff for the analyses presented was Dec 8, 2016. This study is registered with ClinicalTrials.gov, number NCT02032277. FINDINGS: Between April 4, 2014, and March 18, 2016, 634 patients were randomly assigned: 316 to paclitaxel plus carboplatin plus veliparib, 160 to paclitaxel plus carboplatin, and 158 to paclitaxel alone. The proportion of patients who achieved a pathological complete response was higher in the paclitaxel, carboplatin, and veliparib group than in patients receiving paclitaxel alone (168 [53%] of 316 patients vs 49 [31%] of 158, p<0·0001), but not compared with patients receiving paclitaxel plus carboplatin (92 [58%] of 160 patients, p=0·36). Grade 3 or 4 toxicities, and serious adverse events were more common in patients receiving carboplatin, whereas veliparib did not substantially increase toxicity. The most common grade 3 or 4 events overall were neutropenia (352 [56%] of 628 patients), anaemia (180 [29%]), and thrombocytopenia (75 [12%]) through complete treatment, and febrile neutropenia (88 [15%] of 601 patients) during segment 2. The most common serious adverse events were febrile neutropenia (80 [13%] of 628 patients) and anaemia (20 [3%]). INTERPRETATION: Although the addition of veliparib and carboplatin to paclitaxel followed by doxorubicin and cyclophosphamide improved the proportion of patients with triple-negative breast cancer who achieved a pathological complete response, the addition of veliparib to carboplatin and paclitaxel did not. Increased toxicities with the addition of carboplatin (with or without veliparib) to paclitaxel were manageable and did not substantially affect treatment delivery of paclitaxel followed by doxorubicin and cyclophosphamide. Given the consistent results with previous studies, the addition of carboplatin appears to have a favourable risk to benefit profile and might be considered as a potential component of neoadjuvant chemotherapy for patients with high-risk, triple-negative breast cancer. FUNDING: AbbVie.

Time trends in incidence rates and survival of newly diagnosed stage IV breast cancer by tumor histology: a population-based analysis.

Few contemporary data are available that compare incidence and survival of metastatic breast cancer between ductal and lobular carcinomas. Using the Surveillance, Epidemiology, and End Results-9 registries, we identified 10,639 patients with de novo metastatic breast cancer diagnosed from 1990 to 2011. Annual age-adjusted incidence rates and annual percent changes (APCs) were analyzed. Multivariable Cox regression models were used to investigate the impact of year of diagnosis and histology on overall survival. 9250 (86.9 %) patients had ductal and 1389 (13.1 %) had lobular carcinomas. Metastatic breast cancer incidence increased slightly over time for ductal (APC = +1.7, 95 % confidence interval (CI) = +1.0 to +2.4) and lobular carcinomas (APC = +3.0, 95 % CI = +1.8 to +4.3). Median overall survival was 22 months among the whole cohort. More recent year of diagnosis was associated with better overall survival only for patients with ductal carcinomas (interaction p value = 0.006), with an adjusted hazard ratio of death for every five-year increment in the date of diagnosis of 0.93 (95 % CI =  0.91-0.95) among ductal carcinomas, compared with 1.05 (95 % CI = 0.95-1.10) among lobular carcinomas. Overall survival was longer for lobular versus ductal carcinomas (28 versus 21 months, respectively; adjusted hazard ratio of death = 0.93, 95 % CI = 0.87-0.99), but the magnitude of this effect was attenuated among the cohort restricted to hormone receptor-positive tumors. In this population-based analysis, incidence rates of metastatic breast cancer at presentation increased slightly over time for both histologies, and particularly for lobular tumors. A modest improvement in metastatic breast cancer median overall survival was observed, but was apparently limited to ductal carcinomas.

Trastuzumab re-treatment following adjuvant trastuzumab and the importance of distant disease-free interval: the HERA trial experience.

This retrospective analysis conducted using data from patients enrolled onto the Herceptin Adjuvant has two objectives: The first is to evaluate the impact of the time interval between the end of adjuvant trastuzumab and distant recurrence (TDRI) upon overall survival (OS). The second is to describe the duration of trastuzumab-based regimens in the metastatic setting for patients previously treated with adjuvant trastuzumab. The first objective included 187 patients treated with adjuvant trastuzumab and diagnosed with distant recurrence at 4-year median follow-up. The second objective included data from questionnaires sent to investigators retreating patients with trastuzumab upon distant recurrence: 144 of 156 questionnaires were returned (93 %), and 90 patients were selected based on available clinical information and consent for subsequent studies. There was no statistically significant relationship between TDRI following 1 year of adjuvant trastuzumab and OS from distant recurrence: hazard ratio 0.991, p = 0.46. The median OS from distant recurrence was numerically longer among patients with a TDRI of ≥12 months (n = 103) than <12 months (n = 84) but not statistically significant (23.7 vs. 17.8 months, p = 0.47). The median duration of first-line trastuzumab-based regimens for patients previously treated with adjuvant trastuzumab and diagnosed with distant disease recurrence was 8.8 months (n = 88). This retrospective, exploratory study suggests that TDRI did not impact on OS measured from distant recurrence. We argue that prospective collection of treatment information beyond disease progression should be included in future clinical studies.

Surgical Options and Locoregional Recurrence in Patients Diagnosed with Invasive Lobular Carcinoma of the Breast.

PURPOSE: Recent consensus guidelines on margins for breast-conserving surgery (BCS) recommend the use of "no ink on tumor" as the standard for an adequate margin. The recommendations extend to invasive lobular carcinoma (ILC), but the data on this subset are limited. We reviewed our modern dataset on margin status with outcomes of ILC. METHODS: We performed a retrospective cohort study on 736 patients with a diagnosis of stage I-III ILC treated at our cancer center between May 1997 and December 2007. Clinicopathologic data were extracted from the Clinical Research Information Systems Database. Margin status was defined using the latest ASCO/ASTRO/SSO consensus guideline criteria. RESULTS: The initial surgery performed was mastectomy in 352 patients (48 %) and BCS in 384 patients (52 %). In multivariate analysis, tumor size and multifocality were significantly associated with high rates of mastectomy and positive surgical margins at initial BCS. After initial BCS, additional surgery was performed in 92 patients (24 %). During a 72-month median follow-up period, 12 (3.1 %) ipsilateral breast tumor recurrences (IBTR) and 5 (1.3 %) other locoregional recurrences (LRR) were observed. Patients with margins with ink on tumor who did not receive further surgery were found to have significantly increased LRR [odds ratio (OR) 5.5; p = 0.02] and IBTR (OR 8.5; p = 0.006), whereas patients with close margins (1-3 mm) and margins within 1 mm were not. CONCLUSIONS: Our study supports the validity of using "no ink on tumor" as the standard for a negative margin for pure and mixed ILC treated with multimodality therapy.

CNS relapses in patients with HER2-positive early breast cancer who have and have not received adjuvant trastuzumab: a retrospective substudy of the HERA trial (BIG 1-01).

BACKGROUND: Several randomised trials have confirmed the benefit of adjuvant trastuzumab for patients with HER2-positive early breast cancer. However, concern has been expressed that adjuvant trastuzumab might be associated with an increased frequency of CNS relapses. We assessed the frequency and course of CNS relapses, either as first event or at any time, using data from the HERA trial. METHODS: We estimated the cumulative incidence of first disease-free survival (DFS) events in the CNS versus other sites by competing risks analysis in patients with HER2-positive early breast cancer who had been randomly assigned to receive 1 year of trastuzumab or to observation in the HERA trial after a median follow-up of 4 years (IQR 3·5-4·8). To obtain further information about CNS relapse at any time before death, we circulated a data collection form to investigators to obtain standardised information about CNS events that occurred in all patients who had died before July, 2009. We estimated the cumulative incidence of CNS relapse at any time with a competing risks analysis. RESULTS: Of 3401 patients who had been assigned to receive 1 year of trastuzumab or to observation, 69 (2%) had a CNS relapse as first DFS event and 747 (22%) had a first DFS event not in the CNS. The frequency of CNS relapses as first DFS event did not differ between the group given 1 year of trastuzumab (37 [2%] of 1703 patients) and the observation group (32 [2%] of 1698; p=0·55 [Gray's test]). 481 data collection forms were distributed, of which 413 (86%) were returned. The proportion of patients who had died and experienced a CNS relapse was numerically higher in the observation group (129 [57%] of 227) than in the group given trastuzumab for 1 year (88 [47%] of 186; p=0·06 [Gray's test]). Most CNS relapses were symptomatic (189 [87%] of 217). CONCLUSION: Adjuvant trastuzumab does not increase the risk of CNS relapse in patients with HER2-positive early breast cancer. FUNDING: None.

Axillary Nodal Response to Neoadjuvant T-DM1 Combined with Pertuzumab in a Prospective Phase II Multi-Institution Clinical Trial.

BACKGROUND: Patients with ERBB2 (HER2)-positive breast cancer experience high pathologic complete response (pCR) rates after standard neoadjuvant anti-HER2 systemic therapy. We examined axillary pathologic nodal response to neoadjuvant dual HER2-targeted therapy alone, based on breast pathologic response, in a multi-institution clinical trial. STUDY DESIGN: Patients with HER2-positive breast cancer were enrolled to a phase II single-arm trial, which administered 6 cycles of neoadjuvant trastuzumab emtansine (T-DM1) plus pertuzumab. Rates of pathologic nodal disease (ypN) in patients who were clinically node-negative (cN0) and node-positive (cN1) were analyzed, by residual breast disease (pCR and residual cancer burden [RCB] I to III). RESULTS: One hundred fifty-eight patients completed preoperative treatment and proceeded to surgery. Of 92 patients who were cN0, 48 (52.2%) and 10 (10.9%) experienced breast pCR and RCB I, respectively. Of these, 100% were ypN0. Of 34 with RCB II to III, 26 (76.5%) were ypN0. Of 30 patients who were cN1 with breast pCR, 100% were ypN0; of the 12 patients who were cN1 with RCB I, 66.7% were ypN0; and of the 24 patients who were cN1 with RCB II to III, 25% were ypN0. ypN0 rates were significantly different between patients who did and did not experience a pCR, in both cN0 (p = 0.002) and cN1 (p < 0.001) subgroups. CONCLUSIONS: Patients with HER2-positive breast cancer treated with dual HER2-targeted therapy who experienced a breast pCR or RCB I response were frequently ypN0. These findings support future trials considering omission of axillary surgical staging for patients with HER2-positive breast cancer in neoadjuvant trials of active HER2-targeted regimens, particularly if they experience breast pCR or RCB I.

HER2 heterogeneity and treatment response-associated profiles in HER2-positive breast cancer in the NCT02326974 clinical trial.

BACKGROUNDHER2-targeting therapies have great efficacy in HER2-positive breast cancer, but resistance, in part due to HER2 heterogeneity (HET), is a significant clinical challenge. We previously described that in a phase II neoadjuvant trastuzumab emtansine (T-DM1) and pertuzumab (P) clinical trial in early-stage HER2-positive breast cancer, none of the patients with HER2-HET tumors had pathologic complete response (pCR).METHODSTo investigate cellular and molecular differences among tumors according to HER2 heterogeneity and pCR, we performed RNA sequencing and ERBB2 FISH of 285 pretreatment and posttreatment tumors from 129 patients in this T-DM1+P neoadjuvant trial. A subset of cases was also subject to NanoString spatial digital profiling.RESULTSPretreatment tumors from patients with pCR had the highest level of ERBB2 mRNA and ERBB signaling. HER2 heterogeneity was associated with no pCR, basal-like features, and low ERBB2 expression yet high ERBB signaling sustained by activation of downstream pathway components. Residual tumors showed decreased HER2 protein levels and ERBB2 copy number heterogeneity and increased PI3K pathway enrichment and luminal features. HET tumors showed minimal treatment-induced transcriptomic changes compared with non-HET tumors. Immune infiltration correlated with pCR and HER2-HET status.CONCLUSIONResistance mechanisms in HET and non-HET tumors are distinct. HER2-targeting antibodies have limited efficacy in HET tumors. Our results support the stratification of patients based on HET status and the use of agents that target downstream components of the ERBB signaling pathway in patients with HET tumors.TRIAL REGISTRATIONClinicalTrials.gov NCT02326974.FUNDINGThis study was funded by Roche and the National Cancer Institute.

Analysis of regional timelines to set up a global phase III clinical trial in breast cancer: the adjuvant lapatinib and/or trastuzumab treatment optimization experience.

PURPOSE: This study measured the time taken for setting up the different facets of adjuvant lapatinib and/or trastuzumab treatment optimization (ALTTO), an nternational phase III study being conducted in 44 participating countries. METHODS: Time to regulatory authority (RA) approval, time to ethics committee/institutional review board (EC/IRB) approval, time from study approval by EC/IRB to first randomized patient, and time from first to last randomized patient were prospectively collected in the ALTTO study. Analyses were conducted by grouping countries into either geographic regions or economic classes as per the World Bank's criteria. RESULTS: South America had a significantly longer time to RA approval (median: 236 days, range: 21-257 days) than Europe (median: 52 days, range: 0-151 days), North America (median: 26 days, range: 22-30 days), and Asia-Pacific (median: 62 days, range: 37-75 days). Upper-middle economies had longer times to RA approval (median: 123 days, range: 21-257 days) than high-income (median: 47 days, range: 0-112 days) and lower-middle income economies (median: 57 days, range: 37-62 days). No significant difference was observed for time to EC/IRB approval across the studied regions (median: 59 days, range 0-174 days). Overall, the median time from EC/IRB approval to first recruited patient was 169 days (range: 26-412 days). CONCLUSION: This study highlights the long time intervals required to activate a global phase III trial. Collaborative research groups, pharmaceutical industry sponsors, and regulatory authorities should analyze the current system and enter into dialogue for optimizing local policies. This would enable faster access of patients to innovative therapies and enhance the efficiency of clinical research.

Targeted therapies in breast cancer: are heart and vessels also being targeted?

The concept of 'targeted' therapies implies that such drugs only act on cells that specifically express the particular target, therefore giving rise to a low incidence of side effects. However, targeted therapies currently approved for the treatment of breast cancer have demonstrated a relatively high incidence of cardiovascular events. The anti-HER2 agents trastuzumab and lapatinib may cause left ventricular dysfunction or even congestive heart failure. Bevacizumab, an antiangiogenic drug, has been shown to increase the risk of hypertension, cardiovascular dysfunction and thromboembolic events. In addition, several anti-human epidermal growth factor receptor 2 (HER2) and antiangiogenic agents plus their combinations are currently being developed and evaluated for the treatment of breast cancer. In this review, we aim to assess the incidence of cardiac adverse events associated with targeted therapies designed to block HER2 and angiogenic pathways.

Pregnancy occurring during or following adjuvant trastuzumab in patients enrolled in the HERA trial (BIG 01-01).

Only few case reports describe the pregnancy course and outcome of breast cancer patients, who were under treatment with trastuzumab at the time of conception or who have completed trastuzumab therapy before becoming pregnant. The HERA trial is a large phase III randomized clinical trial in which patients with early HER2-positive breast cancer were randomized to receive 1 or 2 years of trastuzumab or observation following completion of primary chemotherapy. To examine the effect of trastuzumab on pregnancy outcome, we report all pregnancy events that occurred until March 2010 in patients enrolled in the study. For the sake of this analysis, patients were assigned to three groups: (1) pregnancy occurring during and up to 3 months after trastuzumab exposure (group 1); (2) pregnancy occurring >3 months of last trastuzumab dose (group 2); and (3) pregnancy occurring in patients without prior exposure to trastuzumab (group 3). Sixteen, 45 and 9 pregnancies took place in groups 1, 2, and 3, respectively. 25 and 16% of patients in groups 1 and 2 experienced spontaneous abortion, the former being higher than figures reported in the general population. However, short-term fetal outcome appeared normal across the three groups. Only 2 congenital anomalies were reported, one in group 2 and one in group 3. No congenital anomalies were reported in those exposed to trastuzumab in utero. This is the first report from a large randomized trial assessing the effect of trastuzumab on pregnancy course and outcome. Based on our results, trastuzumab does not appear to affect fetal outcome in patients who manage to complete their pregnancy. We are currently initiating a collaboration to collect similar data from the other large adjuvant trastuzumab trials to confirm these findings.

Clinical development of insulin-like growth factor receptor--1 (IGF-1R) inhibitors: at the crossroad?

Insulin like growth factor receptor (IGF-1R) targeting became one of the most investigated areas in anticancer drug development during the last decade. Strategies aiming to block IGF-1R activity include monoclonal antibodies, tyrosine kinase inhibitors and anti-ligands antibodies. Initial enthusiasm quickly encountered challenges. Unfortunately the validation of the efficacy of IGF-1R targeted agents in large clinical trials failed, however anecdotal single agent activity was seen in early studies. Consequently, questions regarding the selection of right target population and the appropriate trial design are arising. Despite the plethora of clinical trials conducted no predictive biomarker has been validated so far and resistance mechanisms to IGF-1R inhibitors remain unclear. The other issue to be addressed is how to best combine IGF-1R inhibitors with other therapeutic approaches. This review highlights the most relevant clinical data emphasizing the main tumor types where IGF-1R inhibition showed potential interest. We also tried to extract based on clinical and translational data some candidate biomarkers that could help better to select patient population who potentially could benefit most from this therapeutic approach.

The natural history of hormone receptor-positive breast cancer.

Abstract: Approximately 70% of human breast tumors express hormone receptors (HRs), comprising the estrogen receptor (ER) and/or progesterone receptor (PR).The ER is the primary transcription factor driving oncogenesis in HR-positive (HR+) breast cancers; it is both a target of, and predictor of response to, antiestrogen therapy. Unlike in other breast cancer subtypes, more than half of all disease recurrences in HR+ breast cancer occur 6 years or more after diagnosis, particularly following 5 years of adjuvant anti-estrogen therapy. Late relapses in HR+ breast cancer thus represent a significant clinical challenge. There is considerable molecular and clinical heterogeneity underlying HR+ breast cancers, and a limited understanding of the mechanisms underlying treatment resistance and late relapse. In this review, we describe the long natural history of HR+ breast cancer and discuss relapse patterns in relation to their clinicopathological and molecular characteristics. We highlight the relationship between tumor relapse and anti-estrogen therapy resistance, and we describe the concept of tumor dormancy. Finally, we review novel translational research strategies utilizing preclinical models and patient tumor samples, and current clinical strategies that address this increasingly common challenge in breast cancer.

Luminal androgen receptor breast cancer subtype and investigation of the microenvironment and neoadjuvant chemotherapy response.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low overall survival rates and high molecular heterogeneity; therefore, few targeted therapies are available. The luminal androgen receptor (LAR) is the most consistently identified TNBC subtype, but the clinical utility has yet to be established. Here, we constructed a novel genomic classifier, LAR-Sig, that distinguishes the LAR subtype from other TNBC subtypes and provide evidence that it is a clinically distinct disease. A meta-analysis of seven TNBC datasets (n = 1086 samples) from neoadjuvant clinical trials demonstrated that LAR patients have significantly reduced response (pCR) rates than non-LAR TNBC patients (odds ratio = 2.11, 95% CI: 1.33, 2.89). Moreover, deconvolution of the tumor microenvironment confirmed an enrichment of luminal epithelium corresponding with a decrease in basal and myoepithelium in LAR TNBC tumors. Increased immunosuppression in LAR patients may lead to a decreased presence of cycling T-cells and plasma cells. While, an increased presence of myofibroblast-like cancer-associated cells may impede drug delivery and treatment. In summary, the lower levels of tumor infiltrating lymphocytes (TILs), reduced immune activity in the micro-environment, and lower pCR rates after NAC, suggest that new therapeutic strategies for the LAR TNBC subtype need to be developed.

Treatment Exposure and Discontinuation in the PALbociclib CoLlaborative Adjuvant Study of Palbociclib With Adjuvant Endocrine Therapy for Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast Cancer (PALLAS/AFT-05/ABCSG-42/BIG-14-03).

PURPOSE: The PALLAS study investigated whether the addition of palbociclib, an oral CDK4/6 inhibitor, to adjuvant endocrine therapy (ET) improves invasive disease-free survival (iDFS) in early hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer. In this analysis, we evaluated palbociclib exposure and discontinuation in PALLAS. METHODS: Patients with stage II-III HR+, HER2- disease were randomly assigned to 2 years of palbociclib with adjuvant ET versus ET alone. The primary objective was to compare iDFS between arms. Continuous monitoring of toxicity, dose modifications, and early discontinuation was performed. Association of baseline covariates with time to palbociclib reduction and discontinuation was analyzed with multivariable competing risk models. Landmark and inverse probability weighted per-protocol analyses were performed to assess the impact of drug persistence and exposure on iDFS. RESULTS: Of the 5,743 patient analysis population (2,840 initiating palbociclib), 1,199 (42.2%) stopped palbociclib before 2 years, the majority (772, 27.2%) for adverse effects, most commonly neutropenia and fatigue. Discontinuation of ET did not differ between arms. Discontinuations for non-protocol-defined reasons were greater in the first 3 months of palbociclib, and in the first calendar year of accrual, and declined over time. No significant relationship was seen between longer palbociclib duration or ≥ 70% exposure intensity and improved iDFS. In the weighted per-protocol analysis, no improvement in iDFS was observed in patients receiving palbociclib versus not (hazard ratio 0.89; 95% CI, 0.72 to 1.11). CONCLUSION: Despite observed rates of discontinuation in PALLAS, analyses suggest that the lack of significant iDFS difference between arms was not directly related to inadequate palbociclib exposure. However, the discontinuation rate illustrates the challenge of introducing novel adjuvant treatments, and the need for interventions to improve persistence with oral cancer therapies.

A Distinct Chromatin State Drives Therapeutic Resistance in Invasive Lobular Breast Cancer.

Most invasive lobular breast cancers (ILC) are of the luminal A subtype and are strongly hormone receptor-positive. Yet, ILC is relatively resistant to tamoxifen and associated with inferior long-term outcomes compared with invasive ductal cancers (IDC). In this study, we sought to gain mechanistic insights into these clinical findings that are not explained by the genetic landscape of ILC and to identify strategies to improve patient outcomes. A comprehensive analysis of the epigenome of ILC in preclinical models and clinical samples showed that, compared with IDC, ILC harbored a distinct chromatin state linked to gained recruitment of FOXA1, a lineage-defining pioneer transcription factor. This resulted in an ILC-unique FOXA1-estrogen receptor (ER) axis that promoted the transcription of genes associated with tumor progression and poor outcomes. The ILC-unique FOXA1-ER axis led to retained ER chromatin binding after tamoxifen treatment, which facilitated tamoxifen resistance while remaining strongly dependent on ER signaling. Mechanistically, gained FOXA1 binding was associated with the autoinduction of FOXA1 in ILC through an ILC-unique FOXA1 binding site. Targeted silencing of this regulatory site resulted in the disruption of the feed-forward loop and growth inhibition in ILC. In summary, ILC is characterized by a unique chromatin state and FOXA1-ER axis that is associated with tumor progression, offering a novel mechanism of tamoxifen resistance. These results underscore the importance of conducting clinical trials dedicated to patients with ILC in order to optimize treatments in this breast cancer subtype. SIGNIFICANCE: A unique FOXA1-ER axis in invasive lobular breast cancer promotes disease progression and tamoxifen resistance, highlighting a potential therapeutic avenue for clinical investigations dedicated to this disease. See related commentary by Blawski and Toska, p. 3668.

Adjuvant Palbociclib for Early Breast Cancer: The PALLAS Trial Results (ABCSG-42/AFT-05/BIG-14-03).

PURPOSE: Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor-positive breast cancer has not been confirmed. PATIENTS AND METHODS: In the prospective, randomized, phase III PALLAS trial, patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer were randomly assigned to receive 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle) with adjuvant endocrine therapy or adjuvant endocrine therapy alone (for at least 5 years). The primary end point of the study was invasive disease-free survival (iDFS); secondary end points were invasive breast cancer-free survival, distant recurrence-free survival, locoregional cancer-free survival, and overall survival. RESULTS: Among 5,796 patients enrolled at 406 centers in 21 countries worldwide over 3 years, 5,761 were included in the intention-to-treat population. At the final protocol-defined analysis, at a median follow-up of 31 months, iDFS events occurred in 253 of 2,884 (8.8%) patients who received palbociclib plus endocrine therapy and in 263 of 2,877 (9.1%) patients who received endocrine therapy alone, with similar results between the two treatment groups (iDFS at 4 years: 84.2% v 84.5%; hazard ratio, 0.96; CI, 0.81 to 1.14; P = .65). No significant differences were observed for secondary time-to-event end points, and subgroup analyses did not show any differences by subgroup. There were no new safety signals for palbociclib in this trial. CONCLUSION: At this final analysis of the PALLAS trial, the addition of adjuvant palbociclib to standard endocrine therapy did not improve outcomes over endocrine therapy alone in patients with early hormone receptor-positive breast cancer.