Phase II randomized study of neoadjuvant everolimus plus letrozole compared with placebo plus letrozole in patients with estrogen receptor-positive breast cancer

Phase II study of capecitabine and the oral mTOR inhibitor everolimus in patients with advanced pancreatic cancer

Purpose

The combination of an mTOR inhibitor with 5-fluorouracil-based anticancer therapy is attractive because of preclinical evidence of synergy between these drugs. According to our phase I study, the combination of capecitabine and everolimus is safe and feasible, with potential activity in pancreatic cancer patients.

Methods

Patients with advanced adenocarcinoma of the pancreas were enrolled. Eligible patients had a WHO performance status 0–2 and adequate hepatic and renal functions. The treatment regimen consisted of capecitabine 1000 mg/m² BID day 1–14 and everolimus 10 mg daily (5 mg BID) in a continuous 21-day schedule. Tumor assessment was performed with CT-scan every three cycles. Primary endpoint was response rate (RR) according to RECIST 1.0. Secondary endpoints were progression-free survival, overall survival and 1-year survival rate.

Results

In total, 31 patients were enrolled. Median (range) treatment duration with everolimus was 76 days (1–431). Principal grade 3/4 toxicities were hyperglycemia (45 %), hand-foot syndrome (16 %), diarrhea (6 %) and mucositis (3 %). Prominent grade 1/2 toxicities were anemia (81 %), rash (65 %), mucositis (58 %) and fatigue (55 %). RR was 6 %. Ten patients (32 %) had stable disease resulting in a disease control rate of 38 %. Median overall survival was 8.9 months (95 % CI 4.6–13.1). Progression-free survival was 3.6 months (95 % CI 1.9–5.3).

Conclusions

The oral regimen with the combination of capecitabine and everolimus is a moderately active treatment for patients with advanced pancreatic cancer, with an acceptable toxicity profile at the applied dose level.

Validation of p27KIP1 expression levels as a candidate predictive biomarker of response to rapalogs in patient-derived breast tumor xenografts

Blockade of mammalian target of rapamycin (mTOR) is a promising area in breast cancer therapy. However, in clinical trials, objective response rate with mTOR inhibitor monotherapy in breast cancer was modest. Biomarker studies designed to identify the responders of rapalogs are of increasing interest. We validated p27KIP1 expression levels as a candidate predictive biomarker of response to rapalogs. We also analyzed the correlation between rapamycin activity and p27KIP1 expression in the primary breast cancer cells and the patient-derived breast tumor xenograft models. The cells isolated from the breast tumor tissues expressing high levels of p27KIP1 were sensitive to rapamycin, whereas the cells from the tissues expressing low levels of p27KIP1 exhibited resistance to rapamycin. The correlation between p27KIP1 expression and rapamycin antitumor activity was also observed in the patient-derived breast tumor xenograft models. Moreover, we also found rapamycin significantly decreased phosphorylated p70S6K1 and phosphorylated 4EBP1 in both samples. It seemed that the different sensitivity of tumor cells to rapamycin did not owe to its different potency against mTOR activity. We further propose p27KIP1 expression level may be also a candidate predictive biomarker of rapalogs for breast cancer therapy, which requires additional clinical validation.

Management of locally advanced breast cancer-perspectives and future directions

Locally advanced breast cancer (LABC) constitutes a heterogeneous entity that includes advanced-stage primary tumours, cancers with extensive nodal involvement and inflammatory breast carcinomas. Although the definition of LABC can be broadened to include some large operable breast tumours, we use this term to strictly refer to inoperable cancers that are included in the above-mentioned categories. The prognosis of such tumours is often unfavourable; despite aggressive treatment, many patients eventually develop distant metastases and die from the disease. Advances in systemic therapy, including radiation treatment, surgical techniques and the development of new targeted agents have significantly improved clinical outcomes for patients with this disease. Notwithstanding these advances, LABC remains an important clinical problem, particularly in developing countries and those without widely adapted breast cancer awareness programmes. The optimal management of LABC requires a multidisciplinary approach, a well-coordinated treatment schedule and close cooperation between medical, surgical and radiation oncologists. In this Review, we discuss the current state of the art and possible future treatment strategies for patients with LABC.

Evaluating the pharmacokinetics and pharmacodynamics of everolimus for treating breast cancer

INTRODUCTION

The aberrant activation of the phosphoinositide 3-kinase-Akt-mTOR signaling pathway is a common mechanism of resistance to endocrine therapy and human epidermal growth factor receptor 2 (HER2)-targeted treatments in breast cancer. Data from large clinical trials have shown that the combination of everolimus , an orally bioavailable mTOR inhibitor with exemestane improves outcome of metastatic breast cancer resistant to non-steroidal aromatase inhibitors. On the other hand, the addition of everolimus to trastuzumab in order to overcome resistance did not show meaningful clinical benefit in recent reported Phase III clinical trials. Everolimus has a favorable pharmacokinetic (PK) profile in early breast cancer studies. The association of endocrine therapy and HER2-targeted agents did not influence the main PK parameters of the drugs.

AREAS COVERED

This review article focuses on the biological rationale of using everolimus in breast cancer and on latest advances in the field of everolimus-based combinations with an emphasis on the PK and pharmacodynamic parameters of the drug throughout different studies.

EXPERT OPINION

Better identification of patients who sustain benefit or who are resistant to everolimus-based combinations in the treatment of advanced breast cancer remains an unmet need. New combination strategies based on the understanding of resistance mechanisms and intracellular feedback loops should be studied further in the future.

Incidence and risk of high-grade stomatitis with mTOR inhibitors in cancer patients

BACKGROUND

Inhibitors of the mammalian target of rapamycin (mTOR) pathway including everolimus and temsirolimus have been used extensively in cancer patients. Their use is associated with stomatitis, an adverse event resulting in morbidity and treatment interruptions or discontinuation. This study was conducted to determine the overall incidence and risk of stomatitis in cancer patients treated with the mTOR inhibitors by a meta-analysis of randomized controlled clinical trials (RCTs).

PATIENTS AND METHODS

Databases from PubMed and abstracts presented at the American Society of Clinical Oncology annual meetings up to October 2013 were searched for relevant studies. Eligible studies included RCTs using everolimus and temsirolimus at approved doses in cancer patients. Summary incidences, relative risks (RR), and 95% confidence intervals (CI) were calculated using a random- or fixed-effects model depending on the heterogeneity of the included trials.

RESULTS

A total of 11 RCTs with 4,752 patients (mTORs: 2,725, controls: 2,027) with a variety of solid tumors were included in the analysis. The incidences of all-grade (grade 1-4) and high-grade stomatitis (grade 3-4) were 33.5% (95% CI: 21.9-47.6%) and 4.1% (95% CI: 2.6-6.3%), respectively. The incidence of high-grade stomatitis significantly varied with tumor types (p=.004), and mTOR inhibitors (temsirolimus vs. everolimus, p<.001). In comparison with controls, mTOR inhibitors significantly increased the risk for developing all-grade stomatitis (RR: 4.04, 95% CI: 3.13-5.22, p<.001) and high-grade stomatitis (RR: 8.84, 95% CI: 4.07-19.22, p<.001).

CONCLUSIONS

The mTOR inhibitors everolimus and temsirolimus significantly increased the risk of high-grade stomatitis in cancer patients. Efforts towards the prevention, treatment, and identification of individuals at risk may allow for improved quality of life and consistent dosing.

Incidence and risk of rash to mTOR inhibitors in cancer patients--a meta-analysis of randomized controlled trials

BACKGROUND

Inhibitors of the mammalian target of rapamycin (mTOR) are currently approved for the treatment of several cancers, and their use is associated with serious rash, which affects patient's quality of life and leads to undesirable dose reductions or interruptions. A meta-analysis of randomized controlled trials (RCTs) was performed to determine the overall risk of developing high-grade rash with mTOR inhibitors in cancer patients.

METHODS

We searched the PubMed database and abstracts presented at the American Society of Clinical Oncology (ASCO) meetings up to December 2013 for relevant studies. Eligible studies included RCTs in which everolimus or temsirolimus was compared to controls in cancer patients. The summary incidence, relative risk (RR), and 95% confidence intervals (CI) were calculated using a random- or fixed-effects model depending on the heterogeneity of the included trials.

RESULTS

A total of 11 RCTs with 4752 patients (mTORs: 2725, controls: 2027) with a variety of solid tumors were included in the analysis. The incidences of all-grade (grade 1-4) and high-grade rash (grade 3-4) were 27.3% (95% CI 21.0-34.7%) and 1.0% (95% CI 0.6-1.4%), respectively. In comparison with controls, mTOR inhibitors significantly increased the risk for developing all-grade rash (RR = 3.55, 95% CI 3.0-4.20, p < 0.001) and high-grade rash (RR = 4.25, 95% CI 1.63-11.10, p = 0.003). The increased risk of high-grade rash did not vary significantly among different tumors (p = 0.91). There was no significant difference between everolimus and temsirolimus (p = 0.60). There was also no significant difference between mTOR inhibitors alone and in combination with other agents (p = 0.57).

CONCLUSIONS

Everolimus and temsirolimus significantly increased the risk of high-grade rash in cancer patients. Early recognition and appropriate treatment is recommended.

Risk of fatigue and hepatic and metabolic toxicities in patients with solid tumors treated with everolimus: a meta-analysis

ABSTRACT 

Background: We performed a systematic review and meta-analysis of fatigue, hepatic and metabolic toxicities associated with everolimus intake in patients with solid tumors. Methods: Eligible studies included randomized trials of patients with solid tumors on everolimus describing events of fatigue, hyperlipidemia, hyperglycemia and elevated alanine aminotransferase (ALT). Results: After the exclusion of ineligible studies, a total of ten clinical trials were considered eligible for the meta-analysis. The relative risks of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT were 1.31 (p < 0.002), 3.06 (p < 0.0001), 2.54 (p = 0.0001) and 2.96 (p < 0.003), respectively. Conclusion: Our meta-analysis demonstrates that everolimus is associated with a significantly increased risk of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT.

Phase II study evaluating efficacy and safety of everolimus with letrozole for management of advanced (unresectable or metastatic) non-small cell lung cancer after failure of platinum-based treatment: a preliminary analysis of toxicity

INTRODUCTION

Lung cancer is one of the most common malignancies worldwide. Non-small cell lung cancer (NSCLC) comprises the majority of the cases of lung cancer. Previous studies have demonstrated a role for both the estrogen pathway and mammalian target of rapamycin (mTOR) in NSCLC.

METHODS

This single-arm phase 2 study was designed to assess the safety and efficacy of combination treatment with aromatase inhibitor—letrozole—and mTOR inhibitor—everolimus—in the treatment of patients with advanced (unresectable stage III or stage IV) NSCLC who had failed at least one line of platinum-based chemotherapy.

RESULTS

The study was closed after enrolling five patients due to safety concerns. Of the five patients treated with the study combination, two patients developed grade 5 pulmonary toxicity and another patient developed reversible grade 4 pulmonary toxicity.

CONCLUSIONS

There is a probable causal relationship between the study medication and the reported serious adverse events. In the absence of additional clinical data in lung cancer patients, we recommend that extreme caution be exercised in the use of combined letrozole and everolimus regimens in patients with advanced lung cancers, active pulmonary pathologies, or both.

Overcoming endocrine resistance in metastatic breast cancer: Current evidence and future directions

About 75% of all breast cancers are estrogen receptor (ER)-positive. They generally have a more favorable clinical behavior, prognosis, and pattern of recurrence, and endocrine therapy forms the backbone of treatment. Anti-estrogens (such as tamoxifen and fulvestrant) and aromatase inhibitors (such as anastrozole, letrozole, and exemestane) can effectively control the disease and induce tumor responses in a large proportion of patients. However, the majority of patients progress during endocrine therapy (acquired resistance) and a proportion of patients may fail to respond to initial therapy (de novo resistance). Endocrine resistance is therefore of clinical concern and there is great interest in strategies that delay or circumvent it. A deeper knowledge of the molecular mechanisms that drive endocrine resistance has recently led to development of new strategies that have the promise to effectively overcome it. Many resistance mechanisms have been described, and the crosstalk between ER and growth factor receptor signaling pathways seems to represent one of the most relevant. Compounds that are able to inhibit key elements of these pathways and restore endocrine sensitivity have been studied and more are currently under development. The aim of this review is to summarize the molecular pathophysiology of endocrine resistance in breast cancer and its impact on current clinical management.

Everolimus plus exemestane for hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: overall survival results from BOLERO-2†

BACKGROUND

The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with hormone-receptor-positive (HR(+)), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.

PATIENTS AND METHODS

BOLERO-2 is a phase III, double-blind, randomized international trial comparing EVE 10 mg/day plus EXE 25 mg/day versus placebo (PBO) + EXE 25 mg/day in postmenopausal women with HR(+) advanced breast cancer with prior exposure to NSAIs. The primary end point was PFS by local investigator assessment; OS was a key secondary end point.

RESULTS

At the time of data cutoff (3 October 2013), 410 deaths had occurred and 13 patients remained on treatment. Median OS in patients receiving EVE + EXE was 31.0 months [95% confidence interval (CI) 28.0-34.6 months] compared with 26.6 months (95% CI 22.6-33.1 months) in patients receiving PBO + EXE (hazard ratio = 0.89; 95% CI 0.73-1.10; log-rank P = 0.14). Poststudy treatments were received by 84% of patients in the EVE + EXE arm versus 90% of patients in the PBO + EXE arm. Types of poststudy therapies were balanced across arms, except for chemotherapy (53% EVE + EXE versus 63% PBO + EXE). No new safety concerns were identified.

CONCLUSIONS

In BOLERO-2, adding EVE to EXE did not confer a statistically significant improvement in the secondary end point OS despite producing a clinically meaningful and statistically significant improvement in the primary end point, PFS (4.6-months prolongation in median PFS; P < 0.0001). Ongoing translational research should further refine the benefit of mTOR inhibition and related pathways in this treatment setting.

TRIAL REGISTRATION NUMBER

NCT00863655.

[New targeted therapies in breast cancer]

Trastuzumab improves care of patients with HER2+ breast cancer and allows a major gain in terms of survival. T-DM1 and pertuzumab are two new treatments, which give very encouraging results in metastatic breast cancer. Their place in neo-adjuvant and adjuvant setting still remains to be defined. Bevacizumab have its place in metastatic breast cancer. In adjuvant setting, results are disappointing and in neo-adjuvant setting, we need more studies on subgroups, which can benefit more. Development of the PARP inhibitors was slowed down by recent negative results in metastatic breast cancer but studies continue with more targeted patient's. Finally, everolimus, inhibitor of mTOR, allows to by pass the hormono-resistance in metastatic phase. Its toxicity must be taken into account in particular in adjuvant setting.

mTOR inhibitors: changing landscape of endocrine-resistant breast cancer

Most breast cancer (BC) patients have tumors that express hormone receptors (HRs). Although endocrine therapy, such as aromatase inhibitors, is very effective, most patients with metastatic HR-positive (HR(+)) BC become resistant to endocrine therapy at some point in their treatment and subsequently require chemotherapy. The PI3K/mTOR pathway is often upregulated in endocrine-resistant BC patients and, therefore, has been one of the targets for development of new agents. Recently, a Phase III trial (BOLERO-2) in aromatase inhibitor-resistant BC patients showed a significant improvement in time to progression with the combination of everolimus and exemestane compared with exemestane alone, confirming the importance of the PI3K/mTOR pathway in endocrine-resistant BC. Side effects from mTOR inhibitors are manageable, but early detection and proactive management are required to ensure patients' safety, compliance and continuity of treatment. Thus, mTOR inhibitors offer a new hope and promise for patients with HR(+) BC.

New agents in locally advanced breast cancer

PURPOSE OF REVIEW

Sequential anthracycline/taxane regimens are routinely used as neoadjuvant therapy (NAT) for locally advanced breast cancer. Unfortunately, the majority of patients do not achieve a pathological complete response (pCR). Efforts to improve pCR rates include the addition of novel targeted agents. The purpose of this article is to review recent developments in this area and to demonstrate the clinical and research advantages of a neoadjuvant platform for the evaluation of novel targeted therapy.

RECENT FINDINGS

Dual human epidermal growth factor 2 (HER2)-targeting concurrent with chemotherapy has demonstrated superiority over chemotherapy with trastuzumab alone. Bevacizumab appears to have a modest effect on pCR rates and its role in neoadjuvant treatment remains uncertain. Despite promising preclinical signals, mTOR inhibition in combination with chemotherapy has yet to yield a benefit in the neoadjuvant setting and trials are ongoing. In contrast, mTOR inhibition in combination with endocrine therapy has demonstrated potential as NAT.

SUMMARY

Dual HER2-targeting considerably improves pCR rates. Thus, far incorporation of non-HER2 targeted agents has been less successful. NAT provides an opportunity to evaluate novel agents, and thereby assist the development of a rationale adjuvant strategy, and facilitates the collection of samples for correlative research into breast cancer biology and predictive biomarkers/pathways.

Neoadjuvant therapy for breast cancer

Neoadjuvant treatment of breast cancer refers to the use of different treatment modalities prior to surgical excision of the tumor. It has been accepted as a treatment option for patients with nonmetastatic disease, because it renders inoperable tumors operable and increases the rates of breast-conserving surgery, while achieving similar long-term clinical outcomes as adjuvant treatment. The neoadjuvant setting is being increasingly perceived as a research platform, where the biologic effects of traditional anticancer agents can be delineated, prognostic and predictive biomarkers can be identified, and the development of targeted agents can be expedited. Surrogate endpoints that can predict long-term clinical outcome and are evaluable early on, such as the pathologic complete response, offer valuable opportunities for rapid assessment of anticancer agents. Additionally, efforts for molecular profiling of the post-neoadjuvant residual disease hold the potential to lead to personalized therapy for breast cancer patients with early-stage high-risk disease.

Standard of care and promising new agents for triple negative metastatic breast cancer

Triple negative breast cancer (TNBC) is a cluster of heterogeneous diseases, all of them sharing the lack of expression of estrogen and progesterone receptors and HER2 protein. They are characterized by different biological, molecular and clinical features, including a poor prognosis despite the increased sensitivity to the current cytotoxic therapies. Several studies have identified important molecular features which enable further subdivision of this type of tumor. We are drawing from genomics, transcription and translation analysis at different levels, to improve our knowledge of the molecular alterations along the pathways which are activated during carcinogenesis and tumor progression. How this information should be used for the rational selection of therapy is an ongoing challenge and the subject of numerous research studies in progress. Currently, the vascular endothelial growth factor (VEGF), poly (ADP-ribose) polymerase (PARP), HSP90 and Aurora inhibitors are most used as targeting agents in metastatic setting clinical trials. In this paper we will review the current knowledge about the genetic subtypes of TNBC and their different responses to conventional therapeutic strategies, as well as to some new promising molecular target agents, aimed to achieve more tailored therapies.

Role of inflammation and oxidative stress in post-menopausal oestrogen-dependent breast cancer

Weight gain and obesity are among the most important risk factors for post-menopausal oestrogen-dependent breast cancer (EDBC). Weight gain is associated with oxidative stress, which in turn promotes breast cancer progression. We carried out a prospective study in 216 consecutive post-menopausal breast cancer patients aiming to examine the correlations between traditional prognostic factors (tumour size, T, nodal, N, grading, G, and metastasis status, M), and body mass index (BMI), leptin, pro-inflammatory cytokines (Interleukin, IL,-6 and tumour necrosis factor-alpha, TNF-α), and oxidative stress (reactive oxygen species, ROS, glutathione peroxidase, GPx, superoxide dismutase, SOD) among patients with oestrogen receptor (ER)+ and ER− breast cancers. Distribution of T, N and M categories did not differ between ER+ and ER− breast cancer patients. ER− patients showed a higher incidence of G3 tumours. Weight, BMI, leptin, IL-6 and ROS were higher in ER+ compared with ER− patients. Among ER+ patients, BMI, leptin, IL-6 and ROS correlated with T and M. Leptin, IL-6 and ROS were positively correlated also with N. Among ER− patients, BMI and leptin did not correlate with any of prognostic parameters, whereas a positive correlation between IL-6, ROS and M was found. Multivariate regression analysis showed that BMI, leptin, IL-6 and ROS were predictive for T, N and M in ER+ patients. Weight gain, inflammation and oxidative stress are involved in EDBC prognosis. Their modulation through antidiabetic, anti-inflammatory and antioxidants drugs combined with endocrine therapy may constitute a targeted approach in post-menopausal EDBC.

Update on adjuvant chemotherapy for early breast cancer

Breast cancer is the second most common cancer in women worldwide. Although most women are diagnosed with early breast cancer, a substantial number recur due to persistent micro-metastatic disease. Systemic adjuvant chemotherapy improves outcomes and has advanced from first-generation regimens to modern dose-dense combinations. Although chemotherapy is the cornerstone of adjuvant therapy, new biomarkers are identifying patients who can forego such treatment. Neo-adjuvant therapy is a promising platform for drug development, but investigators should recognize the limitations of surrogate endpoints and clinical trials. Previous decades have focused on discovering, developing, and intensifying adjuvant chemotherapy. Future efforts should focus on customizing therapy and reducing chemotherapy for patients unlikely to benefit. In some cases, it may be possible to replace chemotherapy with treatments directed at specific genetic or molecular breast cancer subtypes. Yet, we anticipate that chemotherapy will remain a critical component of adjuvant therapy for years to come.

Treatment-related fatigue with everolimus and temsirolimus in patients with cancer-a meta-analysis of clinical trials

Mammalian target of rapamycin (mTOR) inhibitors, everolimus and temsirolimus, are approved for the treatment of a variety of malignancies. Fatigue has been described with these agents as a common side effect, although the overall incidence and risk remain unclear. We performed a meta-analysis to calculate the overall incidence of fatigue in cancer patients treated with everolimus and temsirolimus and to compare the differences in incidence with placebo. The electronic databases PubMed, Embase, Web of Science, and Cochrane databases were searched for studies to include in the meta-analysis. Eligible studies were phase II and III prospective clinical trials of cancer patients treated with single drug everolimus or temsirolimus with toxicity data on fatigue. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed or random effects models depending on the heterogeneity of the included studies. A total of 9,760 patients with a variety of malignancies from 56 prospective clinical trials were included for the meta-analysis. The overall incidences of all-grade and high-grade fatigue in cancer patients treated with mTOR inhibitor (everolimus or temsirolimus) were 45.4% (95% CI 36.9-55.8%) and 8.7% (95% CI 7.2-10.4%), respectively. The relative risks of fatigue of mTOR inhibitor compared to placebo were increased for all-grade (RR = 1.22, 95% CI 1.08-1.38, P = 0.002) and high-grade (RR = 1.82, 95% CI 1.24-2.69, P = 0.002) fatigue. The incidence of all-grade fatigue of patients treated with everolimus was higher than those with temsirolimus (RR = 1.85, 95% CI 1.71-2.01, P < 0.001). No significant difference was detected with between everolimus and temsirolimus in terms of high-grade fatigue (RR = 1.15, 95% CI 0.94-1.41, P = 0.18). Treatment with mTOR inhibitor, everolimus and temsirolimus, is associated with an increased incidence of fatigue in patients with cancer. Early detection and management of fatigue is needed.

PI3K/AKT signaling pathway and cancer: an updated review

Despite development of novel agents targeting oncogenic pathways, matching targeted therapies to the genetic status of individual tumors is proving to be a daunting task for clinicians. To improve the clinical efficacy and to reduce the toxic side effects of treatments, a deep characterization of genetic alterations in different tumors is required. The mutational profile often evidences a gain of function or hyperactivity of phosphoinositide 3-kinases (PI3Ks) in tumors. These enzymes are activated downstream tyrosine kinase receptors (RTKs) and/or G proteins coupled receptors (GPCRs) and, via AKT, are able to induce mammalian target of rapamycin (mTOR) stimulation. Here, we elucidate the impact of class I (p110α, β, γ, and δ) catalytic subunit mutations on AKT-mediated cellular processes that control crucial mechanisms in tumor development. Moreover, the interrelation of PI3K signaling with mTOR, ERK, and RAS pathways will be discussed, exploiting the potential benefits of PI3K signaling inhibitors in clinical use.

The role of Ki-67 in the proliferation and prognosis of breast cancer molecular classification subtypes

The Ki-67 antigen was identified in the early steps of polymerase I-dependent ribosomal RNA synthesis. Although it seems that this protein has an important function in cell division, its exact role is still unclear and there is little published work on its overall function. The aim of the present study was to evaluate the contribution of the level of Ki-67 with respect to tumor recurrence in molecularly classified groups of breast cancer patients. Ki-67 was divided into the percentage levels up to and including 20% and over 20%. Immunohistochemistry and fluorescence in-situ hybridization are described for the results of estrogen receptor, progesterone receptor, c-erb-B2, and Ki-67 biomarkers. Formaldehyde-fixed breast samples were paraffin wax embedded and processed for paraffin sections. The protocol of the present study started in 1995 and finished in 2010. Nine hundred and sixteen patients with breast cancer were examined: 291 were grouped as luminal A, 228 as luminal B, 221 as the Her-2 subtype, and 107 as basal cell (triple negative). Follow-up ranged from 3 to 15 years following diagnosis. It was found that in luminal A patients, only one had a Ki-67 level higher than 20%. In luminal B, the Ki-67 was higher than 20% in 51.16% of the patients and recurrence occurred in 23.68%. In the Her-2 subtype, the Ki-67 level was more than 20% in 48.63%. In basal cell triple-negative patients, Ki-67 was more than 20% in 63.86%. The data presented here indicate that the level of Ki-67 may be considered one of the valuable biomarkers in breast cancer patients with respect to process and recurrence.

Risk of mucocutaneous toxicities in patients with solid tumors treated with everolimus; a systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis of mucocutaneous toxicities associated with the use of everolimus in solid tumors.

PATIENTS AND METHODS

Eligible studies included randomized Phase II and III trials of patients with solid tumors on everolimus; describing events of stomatitis, skin rash, pruritus and mouth ulceration.

RESULTS

Our search strategy yielded 380 potentially relevant citations on everolimus from Pubmed/Medline, CENTRAL Cochrane registry and American Society of Clinical Oncology meeting library. After exclusion of ineligible studies, a total of 10 clinical trials were considered eligible for the meta-analysis, including eight Phase III trials and two Phase II trials. The relative risk of all-grade stomatitis, skin rash, pruritus and mouth ulceration were 3.86(95% CI: 2.23-6.68; p < 0.001); 3.49(95% CI: 2.39-5.08; p < 0.0001); 2.85(95% CI: 2.04-3.97; p = 0.0001); 3.31 (95% CI: 1.46-7.50; p = 0.004); respectively. Exploratory subgroup analysis showed no effect of tumor types or treatment regimen on the relative risk of the relevant adverse events.

CONCLUSION

Our meta-analysis has demonstrated that everolimus is associated with a significantly increased risk of all-grade stomatitis, skin rash, and pruritus and mouth ulceration. Clinicians should be aware of these risks and perform early clinical assessment and intervene accordingly.

Current clinical regulation of PI3K/PTEN/Akt/mTOR signalling in treatment of human cancer

PURPOSE

PTEN is an essential tumour suppressor gene which encodes a phosphatase protein that antagonises the PI3K/Akt/mTOR antiapoptotic pathway. Impairment of this tumour suppressor pathway potentially becomes a causal factor for development of malignancies. This review aims to assess current understanding of mechanisms of dysfunction involving the PI3K/PTEN/Akt/mTOR pathway linked to tumorigenesis and evaluate the evidence for targeted therapy directed at this signalling axis.

METHODS

Relevant articles in scientific databases were identified using a combination of search terms, including "malignancies", "targeted therapy", "PTEN", and "combination therapy". These databases included Medline, Embase, Cochrane Review, Pubmed, and Scopus.

RESULTS

PI3K/PTEN expression is frequently deregulated in a majority of malignancies through genetic, epigenetic, and post-transcriptional modifications. This contributes to the upregulation of the PI3K/Akt/mTOR pathway which has been the focus of intense clinical studies. Targeted agents aimed at this pathway offer a novel treatment approach in a variety of haematologic malignancies and solid tumours. Compared to single-agent use, greater response rates were obtained in combination regimens, supporting further investigation of suitable drug combinations in a broad spectrum of malignancies.

CONCLUSION

Activation of the PI3K/PTEN/Akt/mTOR pathway is implicated both in the pathogenesis of malignancies and development of resistance to anticancer therapies. Therefore, PI3K/Akt/mTOR inhibitors are a promising therapeutic option, in association with systemic cytotoxic and biological therapies, to enable sustained clinical outcomes in cancer treatment. Therapeutic strategies could be tailored according to appropriate biomarkers and patient-specific mutation profiles to maximise benefit of combination therapies.

Current treatment of early breast cancer: adjuvant and neoadjuvant therapy

Breast cancer is the most commonly diagnosed cancer in women. The latest world cancer statistics calculated by the International Agency for Research on Cancer (IARC) revealed that 1,677,000 women were diagnosed with breast cancer in 2012 and 577,000 died. The TNM classification of malignant tumor (TNM) is the most commonly used staging system for breast cancer. Breast cancer is a group of very heterogeneous diseases. The molecular subtype of breast cancer carries important predictive and prognostic values, and thus has been incorporated in the basic initial process of breast cancer assessment/diagnosis. Molecular subtypes of breast cancers are divided into human epidermal growth factor receptor 2 positive (HER2 +), hormone receptor positive (estrogen or progesterone +), both positive, and triple negative breast cancer. By virtue of early detection via mammogram, the majority of breast cancers in developed parts of world are diagnosed in the early stage of the disease. Early stage breast cancers can be completely resected by surgery. Over time however, the disease may come back even after complete resection, which has prompted the development of an adjuvant therapy. Surgery followed by adjuvant treatment has been the gold standard for breast cancer treatment for a long time. More recently, neoadjuvant treatment has been recognized as an important strategy in biomarker and target evaluation. It is clinically indicated for patients with large tumor size, high nodal involvement, an inflammatory component, or for those wish to preserve remnant breast tissue. Here we review the most up to date conventional and developing treatments for different subtypes of early stage breast cancer.

Mechanisms and therapeutic advances in the management of endocrine-resistant breast cancer

The estrogen receptor (ER) pathway plays a critical role in breast cancer development and progression. Endocrine therapy targeting estrogen action is the most important systemic therapy for ER positive breast cancer. However its efficacy is limited by intrinsic and acquired resistance. Mechanisms responsible for endocrine resistance include deregulation of the ER pathway itself, including loss of ER expression, post-translational modification of ER, deregulation of ER co-activators; increased receptor tyrosine kinase signaling leading to activation of various intracellular pathways involved in signal transduction, proliferation and cell survival, including growth factor receptor tyrosine kinases human epidermal growth factor receptor-2, epidermal growth factor receptor, PI3K/AKT/mammalian target of rapamycin (mTOR), Mitogen activated kinase (MAPK)/ERK, fibroblast growth factor receptor, insulin-like growth factor-1 receptor; alterations in cell cycle and apoptotic machinery; Epigenetic modification including dysregulation of DNA methylation, histone modification, and nucleosome remodeling; and altered expression of specific microRNAs. Functional genomics has helped us identify a catalog of genetic and epigenetic alterations that may be exploited as potential therapeutic targets and biomarkers of response. New treatment combinations targeting ER and such oncogenic signaling pathways which block the crosstalk between these pathways have been proven effective in preclinical models. Results of recent clinical studies suggest that subsets of patients benefit from the combination of inhibitor targeting certain oncogenic signaling pathway with endocrine therapy. Especially, inhibition of the mTOR signaling pathway, a key component implicated in mediating multiple signaling cascades, offers a promising approach to restore sensitivity to endocrine therapy in breast cancer. We systematically reviewed important publications cited in PubMed, recent abstracts from ASCO annual meetings and San Antonio Breast Cancer Symposium, and relevant trials registered at ClinicalTrials.gov. We present the molecular mechanisms contributing to endocrine resistance, in particular focusing on the biological rationale for the clinical development of novel targeted agents in endocrine resistant breast cancer. We summarize clinical trials utilizing novel strategies to overcome therapeutic resistance, highlighting the need to better identify the appropriate patients whose diseases are most likely to benefit from these specific strategies.

Signaling pathways in breast cancer: therapeutic targeting of the microenvironment

Breast cancer is the most common cancer in women worldwide. Understanding the biology of this malignant disease is a prerequisite for selecting an appropriate treatment. Cell cycle alterations are seen in many cancers, including breast cancer. Newly popular targeted agents in breast cancer include cyclin dependent kinase inhibitors (CDKIs) which are agents inhibiting the function of cyclin dependent kinases (CDKs) and agents targeting proto-oncogenic signaling pathways like Notch, Wnt, and SHH (Sonic hedgehog). CDKIs are categorized as selective and non-selective inhibitors of CDK. CDKIs have been tried as monotherapy and combination therapy. The CDKI Palbocyclib is now a promising therapeutic in breast cancer. This drug recently entered phase III trial for estrogen receptor (ER) positive breast cancer after showing encouraging results in progression free survival in a phase II trials. The tumor microenvironment is now recognized as a significant factor in cancer treatment response. The tumor microenvironment is increasingly considered as a target for combination therapy of breast cancer. Recent findings in the signaling pathways in breast cancer are herein summarized and discussed. Furthermore, the therapeutic targeting of the microenvironment in breast cancer is also considered.

The PI3K/AKT/mTOR pathway in breast cancer: targets, trials and biomarkers

The phosphoinositide 3 kinase (PI3K)/Akt/mammalian (or mechanistic) target of rapamycin (mTOR) pathway is a complicated intracellular pathway, which leads to cell growth and tumor proliferation and plays a significant role in endocrine resistance in breast cancer. Multiple compounds targeting this pathway are being evaluated in clinical trials. These agents are generally well tolerated and can be used in combination with targeted therapies, endocrine therapy or cytotoxic agents. The identification of subtypes of tumors more likely to respond to these therapeutics cannot be overemphasized, since breast cancer is a very heterogeneous malignancy. Activation of pathways such as KRAS and MEK can act as escape mechanisms that lead to resistance, thus a combination of agents targeting multiple steps of the intracellular machinery is promising. There is evidence that tumors with PIK3CA mutations are more sensitive to inhibitors of the PI3K pathway but this has yet to be validated. Large clinical trials with correlative studies are necessary to identify reliable biomarkers of efficacy.

Luminal B breast cancer: molecular characterization, clinical management, and future perspectives

Gene expression profiling has reshaped our understanding of breast cancer by defining and characterizing four main intrinsic molecular subtypes: human epidermal growth factor receptor 2-enriched, basal-like, luminal A, and luminal B subtypes. Luminal B breast cancer has been reported to have lower expression of hormone receptors, higher expression of proliferation markers, and higher histologic grade than luminal A. It also exhibits worse prognosis and has a distinct profile of response to hormone therapy and chemotherapy. Although luminal cancers share similarities, the studies conducted in recent years using next-generation sequencing technology show that luminal A and B breast cancers should be perceived as distinct entities, with specific oncogenic drivers, rather than more proliferative varieties of luminal tumors. This review discusses the definition and molecular characterization of luminal B breast cancer and presents the available clinical evidence for chemotherapy and endocrine therapy patterns of response. It also provides an overview of ongoing research on molecularly targeted agents for this disease.

Cost-effectiveness analysis of everolimus plus exemestane versus exemestane alone for treatment of hormone receptor positive metastatic breast cancer

Everolimus in combination with exemestane significantly improved progression-free survival compared to exemestane alone in patients previously treated with non-steroidal aromatase inhibitors in the BOLERO-2 trial. As a result, this combination has been approved by the food and drug administration to treat postmenopausal women with hormone receptor positive and HER2 negative metastatic breast cancer. A cost-effectiveness analysis was conducted to determine whether everolimus represents good value for money, utilizing data from BOLERO-2. A decision-analytic model was used to estimate the incremental cost-effectiveness ratio between treatment arms of the BOLERO-2 trial. Costs were obtained from the Center for Medicare Services drug payment table and physician fee schedule. Benefits were expressed as quality-adjusted progression-free survival weeks (QAPFW) and quality-adjusted progression-free years (QAPFY), with utilities/disutilities derived from the literature. Deterministic and probabilistic sensitivity analyses were performed. A willingness to pay threshold of 1-3 times the per capita gross domestic product was adopted, as per the definition of the World Health Organization. The U.S. per capita gross domestic product in 2013 was $49,965; thus, a threshold varying between $49,965 and $149,895 was considered. Everolimus/exemestane had an incremental benefit of 11.88 QAPFW (0.22 QAPFY) compared to exemestane and an incremental cost of $60,574. This translated into an ICER of $265,498.5/QAPFY. Univariate sensitivity analyses showed important variations of the ICER, ranging between $189,836.4 and $530,947/QAPFY. A tornado analysis suggested that the key drivers of our model, by order of importance, included health utility value for stable disease, everolimus acquisition costs, and transition probabilities from the stable to the progression states. The Monte-Carlo simulation showed results that were similar to the base-case analysis. This cost-effectiveness analysis showed that everolimus plus exemestane is not cost-effective compared to exemestane alone. Further research is needed to investigate the cost-effectiveness of the drug combination within sub-groups of the population studied in BOLERO-2.

Everolimus in Breast Cancer

Objective: To highlight the potential role of pharmacists in facilitating use of everolimus in breast cancer and increase practitioner knowledge of everolimus therapy to enhance patient outcomes. Data Sources: A PubMed (1966 to May 2013) search included the terms everolimus, breast cancer, adverse events (AEs), pharmacist, and pharmacy. Abstracts presented at the American Society of Clinical Oncology 2012 Annual Meeting were also reviewed. Study Selection and Data Extraction: Articles published in English and directly related to everolimus clinical trials in breast cancer and other cancers were included, as were general pharmacy practice articles. Data Synthesis: Phase 3 clinical trials are currently exploring the efficacy of everolimus in combination therapy for breast cancer and the pharmacotherapeutical implications of the drug’s mechanism of action in relation to the PI3K/Akt pathway. Everolimus treatment–related topics relevant for pharmacists include drug administration, AE profile, potential drug interactions, dose adjustments, and comorbidity management. This comprehensive literature review of all components of everolimus treatment reveals the complexity of this treatment approach and the need for increased pharmacist involvement. Conclusions: Research based on the current treatment landscape and health care delivery system shows that pharmacists can greatly enhance patient care by providing teaching as part of a comprehensive cancer treatment approach. Because of their advanced knowledge of pharmacotherapy, pharmacists can directly support safe and effective use of everolimus while promoting optimal patient outcomes through a multidisciplinary approach that addresses comorbid conditions; they can also provide effective counseling and patient teaching in an ever-changing health care delivery system.

Relationship of PIK3CA mutation and pathway activity with antiproliferative response to aromatase inhibition

INTRODUCTION

PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α) somatic mutations are the most common genetic alteration in breast cancer (BC). Their prognostic value and that of the phosphatidylinositol 3-kinase (PI3K) pathway in BC remains only partly defined. The effect of PIK3CA mutations and alterations of the PI3K pathway on the antiproliferative response to aromatase inhibitor treatment was determined.

METHODS

The Sequenom MassARRAY System was used to determine the presence of 20 somatic mutations across the PIK3CA gene in 85 oestrogen receptor-positive (ER+) BC patients treated with 2 weeks of anastrozole before surgery. Whole-genome expression profiles were used to interrogate gene signatures (GSs) associated with the PI3K pathway. Antiproliferative activity was assessed by the change in Ki67 staining between baseline and surgery. Three GSs representing the PI3K pathway were assessed (PIK3CA-GS (Loi), PI3K-GS (Creighton) and PTEN-loss-GS (Saal)).

RESULTS

In our study sample, 29% of tumours presented with either a hotspot (HS, 71%) or a nonhotspot (non-HS, 29%) PIK3CA mutation. Mutations were associated with markers of good prognosis such as progesterone receptor positivity (PgR+) (P=0.006), low grade (P=0.028) and luminal A subtype (P=0.039), with a trend towards significance with degree of ER positivity (P=0.051) and low levels of Ki67 (P=0.051). Non-HS mutations were associated with higher PgR (P=0.014) and ER (P<0.001) expression than both wild-type (WT) and HS-mutated samples, whereas neither biomarker differed significantly between WT and HS mutations or between HS and non-HS mutations. An inverse correlation was found between the Loi signature and both the Creighton and Saal signatures, and a positive correlation was found between the latter signatures. Lower pretreatment Ki67 levels were observed in mutation compared with WT samples (P=0.051), which was confirmed in an independent data set. Mutation status did not predict change in Ki67 in response to 2 weeks of anastrozole treatment; there was no significant difference between HS and non-HS mutations in this regard.

CONCLUSIONS

PIK3CA mutations are associated with classical markers of good prognosis and signatures of PI3K pathway activity. The presence of a PIK3CA mutation does not preclude a response to neoadjuvant anastrozole treatment.

Targeting the mammalian target of rapamycin pathway with everolimus: implications for the management of metastatic breast cancer

The inhibitors of mammalian target of rapamycin (mTOR) have documented antitumor activity via disruption of various signaling pathways leading to impaired cellular growth, proliferation, and survival. In preclinical studies, mTOR inhibitors use in combination with hormonal therapy has shown promising results in overcoming endocrine resistance in breast cancer cells. The role of everolimus in breast cancer was established in the Breast Cancer Trial of Oral Everolimus-2 (BOLERO-2) trial in combination with exemestane for patients with advanced metastatic hormone receptor-positive (HR+) breast cancer, who relapsed after initial hormonal manipulation. The study met its primary endpoint of significant improvement in progression free survival (PFS) with a median time to progression of 6.9 months in the combination group versus 2.8 months in exemestane group. Favorable improvements in PFS were reported across all patient subgroups regardless of age, Eastern Cooperative Oncology Group performance status, number of prior therapies, and presence of visceral metastases. Adverse events were mostly mild to moderate in severity and consistent with the known safety profile of everolimus. Major toxicities reported include stomatitis, non-infectious pneumonitis, and hyperglycemia. The purpose of this review is to discuss the role of everolimus as a valuable component in advanced metastatic breast cancer and delineate current strategies to prevent and manage the most common toxicities associated with this combination regimen.

Everolimus in postmenopausal, hormone receptor-positive advanced breast cancer: summary and results of an austrian expert panel discussion

In patients with hormone receptor-positive advanced breast cancer, response to endocrine therapy is frequently limited by endocrine resistance. One important mechanism of resistance is related to mammalian target of rapamycin (mTOR), a molecule involved in the activation of alternative signaling pathways. Preclinically, resensitization of endocrine resistance can be achieved by the addition of the mTOR inhibitor everolimus to endocrine therapy. Recent results of clinical trials confirmed the clinical activity of combining everolimus and endocrine therapy in neoadjuvant and advanced breast cancer. The BOLERO-2 trial demonstrated significant progression-free survival benefits for the addition of everolimus to exemestane. These data were the basis for the recent approval of everolimus in combination with exemestane for the treatment of advanced hormone r eceptor-positive breast cancer. In clinical practice, the following 3 patient groups are particularly suitable for this treatment: those with progression on aromatase inhibitor therapy, those who respond well to chemotherapy and might benefit from subsequent endocrine therapy, and those with non-aggressive tumor biology. Everolimus treatment requires careful clinical monitoring due to the potentially serious side effects, e.g. stomatitis and pneumonitis. It is also important to educate patients and physicians in order to increase their awareness of side effects. At present, everolimus is investigated in clinical trials.

Endocrine resistance in breast cancer: focus on the phosphatidylinositol 3-kinase/akt/mammalian target of rapamycin signaling pathway

Breast cancer is the most common cancer among women. Up to 75% of breast cancers express the estrogen receptor (ER)α and/or the progesterone receptor (PR). Patients with hormone receptor-positive metastatic breast cancer are typically treated with endocrine therapy. Yet, not all patients with metastatic breast cancer respond to endocrine treatments and are considered to have primary (de novo) resistance. Furthermore, all patients who initially respond to endocrine treatment will eventually develop acquired resistance. Several mechanisms have been linked to the development of endocrine resistance, including reduced expression of ERα, altered regulation of the ER pathway, and activation of various growth factor signaling pathways, among them the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway. This pathway is involved in critical processes including cell survival, proliferation, and angiogenesis, and plays a central role in breast cancer development. Recent laboratory and clinical data implicate this pathway as mediating endocrine resistance, and agents directed against critical components of this pathway are either already approved for clinical use in breast cancer patients or are currently being tested in clinical trials. In this review, we describe the interaction between the PI3K/Akt/mTOR pathway and the ER cascade, its role in mediating endocrine resistance, and the clinical implications of this interaction.

Newer therapies for the treatment of metastatic breast cancer: a clinical update

Breast cancer is the foremost common malignancy among the female population around the world. Female breast cancer incidence rates have increased since 1980, slowed in 1990, the rate of increase have leveled off since 2001. In spite of the advances in the early detection, treatment, surgery and radiation support, almost 70% of the patients develop metastasis and die of the disease. Around 10% of the patients when diagnosed with breast cancer have metastases. Survival among the breast cancer patients have increased due to the introduction of novel single agent, combination of chemotherapeutic agents and targeted biologic agents, which is breast cancer specific. The staging of tumor-node-metastasis is significant for the prognosis and treatment. Predominantly the combination of chemotherapeutic regimen is given to improve the rate of clinical benefit and the overall survival rate. Novel mono-therapeutic options are being used often in metastatic setting as they will not be able to endure the toxicity of the combination regimen. Usually, endocrine therapy is recommended for hormone-responsive breast cancer due to efficacy and favorable side effect profile but chemotherapy becomes an option when endocrine therapy fails. This review summarizes the newer therapeutic options for early breast cancer and advanced breast cancer that are pretreated heavily on other chemotherapeutic agents. Further it provides monotherapies and other emerging novel combination regime which can be opted for first line or second line setting.

Pneumonitis and pulmonary fibrosis associated with breast cancer treatments

To review the available published data regarding the incidence, mechanisms of pathogenesis, clinical presentations and management of pneumonitis caused by anti-cancer treatments (radiotherapy (RT) and systemic agents) that are included in the guidelines of the treatment of breast cancer (BC) and address the issues on the current grading classification of pneumonitis. A literature search was performed between July and October 2013 using PubMed for papers published from January 1989 to October 2013. Any clinical trial, case report, case series, meta-analysis or systematic review that reported on pulmonary toxicity of any BC therapeutic modality was included (only papers published in English). Most of anticancer treatments currently used in the management of BC may induce some degree of pneumonitis that is estimated to have an incidence of 1-3 %. There is an obvious distinction between chemotherapy- and targeted treatment-related lung toxicity. Moreover, the current classification of pneumonitis needs to be modified as there is a clear diversity in grade 2. As pneumonitis is relatively common and reported as side effect of new anticancer agents, physicians need to be aware of the clinical and radiological manifestations of drug- and RT-induced toxicities in patients with BC. A key recommendation is the subdivision of grade 2 cases to two subgroups. We provide an algorithm, along with real life cases as managed in the breast Unit of Royal Marsden Hospital, with the aim to guide physicians in managing all possible eventualities that may come across in clinical practise.

Anastrozole and everolimus in advanced gynecologic and breast malignancies: activity and molecular alterations in the PI3K/AKT/mTOR pathway

BACKGROUND

Since PI3K/AKT/mTOR pathway activation diminishes the effects of hormone therapy, combining aromatase inhibitors (anatrozole) with mTOR inhibitors (everolimus) was investigated.

PATIENTS AND METHODS

We evaluated anastrozole and everolimus in 55 patients with metastatic estrogen (ER) and/or progesterone receptor (PR)-positive breast and gynecologic tumors. Endpoints were safety, antitumor activity and molecular correlates.

RESULTS

Full doses of anastrozole (1 mg PO daily) and everolimus (10 mg PO daily) were well tolerated. Twelve of 50 evaluable patients (24%) (median = 3 prior therapies) achieved stable disease (SD) ≥ 6 months/partial response (PR)/complete response (CR) (n = 5 (10%) with PR/CR): 9 of 32 (28%) with breast cancer (n=5 (16%) with PR/CR); 2 of 10 (20%), ovarian cancer; and 1 of 6 (17%), endometrial cancer. Six of 22 patients (27%) with molecular alterations in the PI3K/AKT/mTOR pathway achieved SD ≥ 6 months/PR/CR. Six of 8 patients (75%) with SD ≥ 6 months/PR/CR with molecular testing demonstrated at least one alteration in the PI3K/AKT/mTOR pathway: mutations in PIK3CA (n=3) and AKT1 (n=1) or PTEN loss (n=3). All three responders (CR (n = 1); PR (n=2)) who had next generation sequencing demonstrated additional alterations: amplifications in CCNE1, IRS2, MCL1, CCND1, FGFR1 and MYC and a rearrangement in PRKDC.

CONCLUSIONS

Combination anastrozole and everolimus is well tolerated at full approved doses, and is active in heavily-pretreated patients with ER and/or PR-positive breast, ovarian and endometrial cancers. Responses were observed in patients with multiple molecular aberrations. CLINICAL TRAILS INCLUDED: NCT01197170.

[Exemestane-everolimus in HER2-negative, hormonal receptor-positive, post-menopausal metastatic breast cancer with resistance to non-steroidal aromatase inhibitor: a new option]

Phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is commonly deregulated in breast cancer and has been involved in resistance to endocrine therapy. In the BOLERO-2 study, the addition of everolimus, a selective inhibitor of mTOR protein, to exemestane was associated with a significant improvement in progression-free survival, compared to exemestane plus placebo, in patients with hormone receptor-positive, HER2-negative metastatic breast cancer, and resistant to non-steroidal aromatase inhibitor therapy. However, adverse events and treatment stops were more often observed with the combination therapy, suggesting the need for a careful benefit/risk evaluation before initiating this new combination. This review aims at synthesizing the biological basis of the everolimus-exemestane association, presenting the main validated and ongoing therapeutic trials, interests and limits, as well as the multiple potential therapeutic perspectives.

Contribution of the R-Ras2 GTP-binding protein to primary breast tumorigenesis and late-stage metastatic disease

R-Ras2 is a transforming GTPase that shares downstream effectors with Ras subfamily proteins. However, little information exists about the function of this protein in tumorigenesis and its signalling overlap with classical Ras GTPases. Here we show, by combining loss- and gain-of-function studies in breast cancer cells, mammary epithelial cells and mouse models, that endogenous R-Ras2 has a role in both primary breast tumorigenesis and the late metastatic steps of cancer cells in the lung parenchyma. R-Ras2 drives tumorigenesis in a phosphatidylinostiol-3 kinase (PI3K)-dependent and signalling autonomous manner. By contrast, its prometastatic role requires other priming oncogenic signals and the engagement of several downstream elements. R-Ras2 function is required even in cancer cells exhibiting constitutive activation of classical Ras proteins, indicating that these GTPases are not functionally redundant. Our results also suggest that application of long-term R-Ras2 therapies will result in the development of compensatory mechanisms in breast tumours.

Interleukin-15 gene therapy and the mammalian target of rapamycin inhibitor everolimus inhibit the growth of metastatic breast cancer

BACKGROUND

Novel methods to control and treat metastatic breast cancer are needed. Interleukin (IL)-15 is a promising cytokine for cancer immunotherapy, and everolimus is an orally administered mammalian target of rapamycin (mTOR) inhibitor, which is already approved for cancer treatment. In the present study, we investigated the efficacy of IL-15 gene therapy and explored the possibility of combining IL-15 therapy with everolimus to treat metastatic breast cancer.

METHODS

A plasmid encoding IL-15 and everolimus were given to mice inoculated with 4 T1 mouse breast cancer cells. Tumor size and metastasis were monitored to assess the effect of different treatment regimens. Immunohistochemistry was used to detect CD4⁺, CD8⁺ and NKG2D⁺ cells and also the expression of Ki-67 in tumor tissue; these analyses helped establish the immunization status and tumor proliferation rate of different treatment groups. Terminal deoxynucleotidyl transferase dUTP nick end labeling assays were performed to assess cellular apoptosis in tumor tissues.

RESULTS

Both IL-15 and everolimus significantly decreased tumor size. IL-15 gene therapy increased the proportion of CD4⁺ T and natural killer (NK) cells but had no effect on CD8⁺ T cells. By contrast, everolimus decreased the number of CD8⁺ T cells but had no effect on CD4⁺ T and NK cells compared to the control group. Both IL-15 and everolimus decreased expression of Ki-67 and increased rates of apoptosis. Although effective on their own, no synergistic effect was observed with a combined treatment of everolimus and IL-15 gene therapy.

CONCLUSIONS

IL-15 gene therapy was potentially useful for the treatment of metastatic breast cancer. The possibility of combining immunotherapy with everolimus requires further study.

Treatment-related mortality with everolimus in cancer patients

INTRODUCTION

The overall incidence and odds of fatal adverse events (FAEs) after exposure to everolimus are not well defined. We performed a comprehensive meta-analysis of published randomized controlled trials (RCTs) to determine the role of everolimus in treatment-related mortality in patients with cancer.

METHODS

PubMed databases and abstracts from the proceedings of the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium were searched for RCTs of everolimus either alone or in combination with another agent compared with the control arm without everolimus and that reported deaths from an adverse event from January 1966 to July 2013. The primary objective was to determine the difference of FAEs between everolimus-treated patients and control group patients.

RESULTS

In total, 2,997 patients with multiple solid tumors from nine RCTs were included. The overall incidence of FAEs in cancer patients treated with everolimus was 0.7% (95% CI 0.3%-1.1%) compared with 0.4% (95% CI 0.0%-0.7%) in cancer patients who did not receive everolimus. The odds ratio of FAEs was greater in everolimus-treated patients (Peto odds ratio = 3.80, 95% CI 1.59-9.07, p = .003). In subgroup analyses, no significant difference was found in the incidence or odds of FAEs by everolimus administration (alone or in combination) or tumor type (breast cancer vs. nonbreast cancer; p = .63).

CONCLUSION

In patients with cancer, everolimus is associated with a small but significant increase in the odds of a treatment-related fatal events.

Predicting targeted drug combinations based on Pareto optimal patterns of coexpression network connectivity

Background

Molecularly targeted drugs promise a safer and more effective treatment modality than conventional chemotherapy for cancer patients. However, tumors are dynamic systems that readily adapt to these agents activating alternative survival pathways as they evolve resistant phenotypes. Combination therapies can overcome resistance but finding the optimal combinations efficiently presents a formidable challenge. Here we introduce a new paradigm for the design of combination therapy treatment strategies that exploits the tumor adaptive process to identify context-dependent essential genes as druggable targets.

Methods

We have developed a framework to mine high-throughput transcriptomic data, based on differential coexpression and Pareto optimization, to investigate drug-induced tumor adaptation. We use this approach to identify tumor-essential genes as druggable candidates. We apply our method to a set of ER⁺ breast tumor samples, collected before (n = 58) and after (n = 60) neoadjuvant treatment with the aromatase inhibitor letrozole, to prioritize genes as targets for combination therapy with letrozole treatment. We validate letrozole-induced tumor adaptation through coexpression and pathway analyses in an independent data set (n = 18).

Results

We find pervasive differential coexpression between the untreated and letrozole-treated tumor samples as evidence of letrozole-induced tumor adaptation. Based on patterns of coexpression, we identify ten genes as potential candidates for combination therapy with letrozole including EPCAM, a letrozole-induced essential gene and a target to which drugs have already been developed as cancer therapeutics. Through replication, we validate six letrozole-induced coexpression relationships and confirm the epithelial-to-mesenchymal transition as a process that is upregulated in the residual tumor samples following letrozole treatment.

Conclusions

To derive the greatest benefit from molecularly targeted drugs it is critical to design combination treatment strategies rationally. Incorporating knowledge of the tumor adaptation process into the design provides an opportunity to match targeted drugs to the evolving tumor phenotype and surmount resistance.

Targeting translation initiation in breast cancer

Over the past 20 years, a better understanding of cancer biology, screening for early detection, improved adjuvant treatment, and targeted therapies have decreased the rate of breast cancer deaths. However, resistance to treatment is common, and new approaches are needed. Deregulation of translation initiation is associated with the commencement and progression of cancer. Often, translation initiation factors are overexpressed and the related signaling pathways activated in human tumors. Recently, a significant number of inhibitors that target translation factors and pathways have become available. These inhibitors are being tested alone or in combination with chemotherapeutic agents in clinical trials. The results are varied, and it is not yet clear which drug treatments most effectively inhibit tumor growth. This review highlights the pathways and downstream effects of the activation of translation and discusses targeting the control of translation initiation as a therapeutic approach in cancer, focusing on breast cancer clinical trials.

Advances in the approach to novel drug clinical development for breast cancer

INTRODUCTION

In the post-genomic era clinical development of new agents to treat breast cancer (BC) can be a real challenge. Different from chemotherapy agents, with a broad but not specific spectrum of activity, novel drugs are being developed as 'targeted' agents, potentially benefiting a subgroup of patients. In BC, different clinically identifiable subtypes are now separately addressed in specific clinical trials.

AREAS COVERED

In this review, the authors discuss the clinical development of targeted drugs that have become part of the current treatment of BC. They also highlight the challenges that in other cases determined the failure of promising compounds. Furthermore, the article reports on how combinations of targeted agents have emerged as valid strategies to overcome acquired resistance. It also provides discussion of how 'old' therapies can be retargeted to certain patient populations or 'reinvented' as safer and more effective with the creation of drug conjugates. They also discuss how novel clinical trial designs are emerging to accelerate the successful matching of targeted drugs to the right patient population.

EXPERT OPINION

It is important not to forget that the development of BC therapeutics is a 'moving target', as its biology evolves in time under the pressure of ongoing treatments. There are currently a finite number of resources available for the development of new therapeutics, which means that resources need to be carefully allocated. There is also a need to prioritize clinical trials that can reduce the number of patients who are candidates for expensive treatments.

Use of mTOR inhibitors in the treatment of breast cancer: an evaluation of factors that influence patient outcomes

Many systemic treatment options are available for advanced breast cancer, including endocrine therapy, chemotherapy, anti-human epidermal growth factor receptor 2 (HER2) therapy, and other targeted agents. Recently, everolimus, a mammalian target of rapamycin (mTOR) inhibitor, combined with exemestane, an aromatase inhibitor, has been approved in Europe and the USA for patients suffering from estrogen receptor-positive, HER2-negative advanced breast cancer previously treated by a nonsteroidal aromatase inhibitor, based on the results of BOLERO-2 (Breast cancer trials of OraL EveROlimus). This study showed a statistically significant and clinically meaningful improvement in median progression-free survival. Results concerning the impact on overall survival are expected in the near future. This clinically oriented review focuses on the use of mTOR inhibitors in breast cancer. Results reported with first-generation mTOR inhibitors (ridaforolimus, temsirolimus, everolimus) are discussed. The current and potential role of mTOR inhibitors is reported according to breast cancer subtype (estrogen receptor-positive HER2-negative, triple-negative, and HER2-positive ER-positive/negative disease). Everolimus is currently being evaluated in the adjuvant setting in high-risk estrogen receptor-positive, HER2-negative early breast cancer. Continuing mTOR inhibition or alternatively administering other drugs targeting the phosphatidylinositol-3-kinase/protein kinase B-mTOR pathway after progression on treatments including an mTOR inhibitor is under evaluation. Potential biomarkers to select patients showing a more pronounced benefit are reviewed, but we are not currently using these biomarkers in routine practice. Subgroup analysis of BOLERO 2 has shown that the benefit is consistent in all subgroups and that it is impossible to select patients not benefiting from addition of everolimus to exemestane. Side effects and impact on quality of life are other important issues discussed in this review. Second-generation mTOR inhibitors and dual mTOR-phosphatidylinositol-3-kinase inhibitors are currently being evaluated in clinical trials.