Phase II multicenter, uncontrolled trial of sorafenib in patients with metastatic breast cancer

A single-arm phase II clinical trial of anlotinib combined with chemotherapy for the treatment of metastatic triple-negative breast cancer

Background

Anlotinib is a novel oral small-molecule tyrosine kinase inhibitor (TKI), which can inhibit angiogenesis. The purpose of this study was to evaluate the efficacy and safety of anlotinib combined with chemotherapy in patients with metastatic triple-negative breast cancer (TNBC).

Methods

This phase II clinical trial included 40 patients with metastatic TNBC who had previously received anthracycline and/or taxane treatment. All patients received anlotinib combined with chemotherapy. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR), disease control rate (DCR) and safety.

Results

During May 1, 2019 and April 30, 2022, there were 40 patients enrolled in this study. The median PFS and median OS were 8.8 months (95% confidence interval [CI] 6.5-11.1 months) and 19.0 months (95% CI, 12.1-25.9 months), respectively. The ORR, CBR and DCR were 40.0% (16/40), 85.0% (34/40) and 95.0% (38/40), respectively. Cox univariate and multivariate analyses demonstrated that having more than 3 metastatic sites (p = 0.001; p = 0.020) was an independent and meaningful unfavorable prognostic factor for PFS. 37.5% of patients had grade 3 to 4 treatment-related adverse events (TRAEs). The grade 3 to 4 TRAEs included neutropenia (22.5%), leukopenia (20.0%), secondary hypertension (10.0%), hand-foot syndrome (5.0%), vomiting (5.0%), proteinuria (5.0%) and thrombocytopenia (2.5%). None of the patients withdrew from the study or died due to TRAEs.

Conclusion

In this single-arm study, the treatment of metastatic TNBC with anlotinib combined with chemotherapy showed certain efficacy, and its toxicity was acceptable.

Efficacy and safety of apatinib monotherapy for patients with advanced breast cancer: a systematic review and meta-analysis

Background

Patients with advanced breast cancer usually have poor prognosis. Apatinib is a small-molecule tyrosine kinase inhibitor, and the reports regarding the efficacy and safety of apatinib monotherapy for advanced breast cancer in the current literature are controversial. Therefore, we performed a systematic review and meta-analysis to collect and pool efficacy and safety data of apatinib monotherapy for advanced breast cancer with the aim of providing up-to-date evidence to aid clinical practice.

Methods

This study was registered at PROSPERO (CRD42020190049). Three literature databases, including PubMed, EMBASE, and Cochrane Library, were searched. For evaluating efficacy, the objective response rate and disease control rate were extracted or calculated. Safety was evaluated in terms of the proportions of patients with grade 3 or 4 treatment-related adverse events. The pooled proportions of the outcomes and their 95% confidence interval were shown. The Kaplan–Meier curves of overall survival and progression-free survival were pooled from the extracted data of the included studies. Furthermore, pooled medians for overall survival and progression-free survival were calculated. A p-value of < 0.05 was considered statistically significant.

Results

Six studies were included and deemed eligible for further quality evaluation and analysis. The pooled objective response rate and disease control rate were 20.4% and 71.6%, respectively. The pooled proportions of four hematologic adverse events ranged from 2.6% to 6.9%. The pooled proportions of hypertension, hand-foot syndrome, transaminase increased, and proteinuria ranged from 4.1% to 24.3%, and other non-hematologic adverse events were <1%. The pooled median progression-free survival and overall survival were 4.00 and 10.43 months, respectively, in cases of advanced breast cancer treated with apatinib.

Conclusions

This study confirms the reliable efficacy of apatinib monotherapy for advanced breast cancer. However, non-hematologic grade 3–4 adverse events, especially hypertension, are more frequently observed during apatinib treatment than during treatment with other tyrosine kinase inhibitors, such as sunitinib or sorafenib.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42020190049.

Anti-vascular endothelial growth factor therapy in breast cancer: Molecular pathway, potential targets, and current treatment strategies

As the highest incidence of female malignancy, breast cancer is likewise the leading cause of cancer-related deaths. The development of cancer relies on neo-vascularization, which provides sufficient nutrition and oxygen, and supplies a pathway for distant metastasis. Angiogenesis represents the formation of new blood vessels, and is a principal pathogenetic action in breast cancer. Vascular endothelial growth factor (VEGF) is a major angiogenesis regulator that modulates the maintenance and function of mature vascular networks. Therefore, the VEGF pathway is a promising oncotherapeutic target. This review elaborates an update on the prognostic value of VEGF in breast cancer, summarizes clinical experience and lessons of anti-VEGF therapeutics, meanwhile, provides an overview of biomarkers that predict the effectiveness of anti-angiogenic treatment.

Significant response to apatinib monotherapy in heavily pretreated advanced HER2-positive breast cancer: a case report and literature review

Although HER2-targeted therapy has been shown to prolong the survival of patients with HER2-positive breast cancer, most patients eventually progress due to drug resistance. Novel treatment options are urgently needed to overcome resistance to HER2-targeted therapy. The VEGF/VEGFR (Vascular endothelial growth factor and its receptors) pathway is essential in tumor angiogenesis, which may be a promising target in HER2-positive breast cancer providing a rationale for the use of tyrosine kinase inhibitors (TKIs) targeting VEGFR. Here, we present a case of a heavily pretreated advanced breast cancer patient who did not respond to HER2-targeted therapy and developed resistance to multiple lines of HER2-targeted treatment. The patient was treated with apatinib at a dose of 500 mg daily, and obtained partial remission (PR) with a progression-free-stage (PFS) of 6 months. Our case indicates that apatinib might have anti-tumor activity in patients with HER2-positive breast cancer with HER2-targeted resistance. This case is of value which may provide new insights into strategies for HER2-targeted therapy resistance options in the clinic.

Apatinib combined with chemotherapy in patients with previously treated advanced breast cancer: An observational study

Locally advanced or metastatic disease accounts for the majority of breast cancer-associated cases of mortality. Treatment options for patients with locally advanced or metastatic disease are limited. The current study aimed to explore the efficacy and safety of apatinib combined with chemotherapy in patients with previously treated advanced breast cancer in real-world clinical practice. A total of 85 patients with advanced breast cancer, who had previously been exposed to anthracyclines or taxanes, received combined treatment. Tumor response was evaluated by a computed tomography scan based on the Response Evaluation Criteria in Solid Tumors. Adverse events were graded based on the Common Terminology Criteria for Adverse Events. The Kaplan-Meier method and a log-rank test were used to analyze the univariate discrimination of progression-free survival (PFS) and overall survival (OS) by demographic data, baseline clinical information and toxicities. The combined effects of these variables were analyzed by a Cox proportional hazards regression model. At a median follow-up time of 9.7 months, 73 patients exhibited disease progression and 48 had succumbed to the disease. During the follow-up, 19 patients demonstrated a partial response (PR) and 53 patients achieved stable disease (SD), with an objective response rate of 23.2%. Additionally, 39 patients demonstrated a PR or SD for ≥24 weeks, with a clinical benefit rate of 47.6%. The median PFS was 4.4 months [95% confidence interval (CI)=2.8-6.0] and the median OS was 11.3 months (95% CI=8.9-13.8). No treatment-associated mortalities occurred. The most common adverse events of all grades included myelosuppression (49.4%), gastrointestinal reaction (45.9%) and fatigue (43.5%). Proteinuria was an independent predictive factor for PFS and OS. Apatinib combined with chemotherapy appeared to be efficacious for pretreated advanced breast cancer, with acceptable toxicity for real-world clinical practice.

Combinatorial inhibition of PTPN12-regulated receptors leads to a broadly effective therapeutic strategy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer diagnosed in more than 200,000 women each year and is recalcitrant to targeted therapies. Although TNBCs harbor multiple hyperactive receptor tyrosine kinases (RTKs), RTK inhibitors have been largely ineffective in TNBC patients thus far. We developed a broadly effective therapeutic strategy for TNBC that is based on combined inhibition of receptors that share the negative regulator PTPN12. Previously, we and others identified the tyrosine phosphatase PTPN12 as a tumor suppressor that is frequently inactivated in TNBC. PTPN12 restrains several RTKs, suggesting that PTPN12 deficiency leads to aberrant activation of multiple RTKs and a co-dependency on these receptors. This in turn leads to the therapeutic hypothesis that PTPN12-deficient TNBCs may be responsive to combined RTK inhibition. However, the repertoire of RTKs that are restrained by PTPN12 in human cells has not been systematically explored. By methodically identifying the suite of RTK substrates (MET, PDGFRβ, EGFR, and others) inhibited by PTPN12, we rationalized a combination RTK-inhibitor therapy that induced potent tumor regression across heterogeneous models of TNBC. Orthogonal approaches revealed that PTPN12 was recruited to and inhibited these receptors after ligand stimulation, thereby serving as a feedback mechanism to limit receptor signaling. Cancer-associated mutation of PTPN12 or reduced PTPN12 protein levels diminished this feedback mechanism, leading to aberrant activity of these receptors. Restoring PTPN12 protein levels restrained signaling from RTKs, including PDGFRβ and MET, and impaired TNBC survival. In contrast with single agents, combined inhibitors targeting the PDGFRβ and MET receptors induced the apoptosis in TNBC cells in vitro and in vivo. This therapeutic strategy resulted in tumor regressions in chemo-refractory patient-derived TNBC models. Notably, response correlated with PTPN12 deficiency, suggesting that impaired receptor feedback may establish a combined addiction to these proto-oncogenic receptors. Taken together, our data provide a rationale for combining RTK inhibitors in TNBC and other malignancies that lack receptor-activating mutations.

RESILIENCE: Phase III Randomized, Double-Blind Trial Comparing Sorafenib With Capecitabine Versus Placebo With Capecitabine in Locally Advanced or Metastatic HER2-Negative Breast Cancer

INTRODUCTION

Sorafenib is a multikinase inhibitor with antiangiogenic/antiproliferative activity. In this randomized, double-blind, placebo-controlled phase III trial, we assessed first- or second-line capecitabine with sorafenib or placebo in patients with locally advanced/metastatic HER2-negative breast cancer resistant to a taxane and anthracycline and with known estrogen/progesterone receptor status.

PATIENTS AND METHODS

A total of 537 patients were randomized to capecitabine 1000 mg/m2 orally twice per day for days 1 to 14 every 21 days with oral sorafenib 600 mg/d or placebo. The primary end point was progression-free survival (PFS). Patients were stratified according to hormone receptor status, previous chemotherapies for metastatic breast cancer, and geographic region.

RESULTS

Treatment with sorafenib with capecitabine, compared with capecitabine with placebo, did not prolong median PFS (5.5 vs. 5.4 months; hazard ratio [HR], 0.973; 95% confidence interval [CI], 0.779-1.217; P = .811) or overall survival (OS; 18.9 vs. 20.3 months; HR, 1.195; 95% CI, 0.943-1.513; P = .140); or enhance overall response rate (ORR; 13.5% vs. 15.5%; P = .515). Any grade toxicities (sorafenib vs. placebo) included palmar-plantar erythrodysesthesia syndrome (PPES; 79.2% vs. 59.6%), diarrhea (47.3% vs. 37.8%), mucosal inflammation (15.4% vs. 6.7%), and hypertension (26.2% vs. 5.6%). Grade 3/4 toxicities included PPES (15.4% vs. 7.1%), diarrhea (4.2% vs. 6.4%), and vomiting (3.5% vs. 0.7%).

CONCLUSION

The combination of sorafenib with capecitabine did not improve PFS, OS, or ORR in patients with HER2-negative advanced breast cancer. Rates of Grade 3 toxicities were higher in the sorafenib arm.

Apatinib for metastatic breast cancer in non-clinical trial setting: Satisfying efficacy regardless of previous anti-angiogenic treatment

Apatinib is a novel tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2. This study aimed to evaluate the efficacy and safety of apatinib in metastatic breast cancer (MBC) under non-clinical trial setting, and to study the impact of previous antiangiogenic treatment to the efficacy of apatinib. 52 MBC patients treated with apatinib under non-clinical trial setting in Fudan University Shanghai Cancer Center between January 1st 2015 and October 1st 2016 were included. All patients were included in time-to-treatment failure (TTF) analysis, while 45 patients were enrolled for progression-free survival (PFS) and overall survival (OS) analysis because 7 of the patients with treatment discontinuation due to intolerable toxicities had too short time for efficacy assessment. Impact of previous exposure to antiangiogenic treatment and other factors to patients' survival were analyzed by Log-rank analysis and Cox multivariate analysis. The median PFS, median OS, and median TTF were 4.90 (95% confidence interval [CI] 3.44 - 6.36), 10.3 (unable to calculate 95% CI), and 3.93 (95% CI 1.96 - 5.90) months, respectively. Previous treatment of bevacizumab did not affect the efficacy of apatinib. Previous exposure to anthracycline, age of 60 years or older and palmar-plantar erythrodysesthesia syndrome were independent predictors for prolonged PFS. Discontinuation of treatment was more common in age group of 60 years or older than that in younger group, although the difference was not significant. Although toxicities were generally managable, a previously unrecorded grade 3~4 adverse event of dyspnea has been observed. This study confirmed the encouraging efficacy and manageable safety of apatinib on pretreated MBC patients in non-clinical trial setting. For the first time to our knowledge, this study found that previous treatment of bevacizumab did not affect the efficacy of apatinib, and reported an undocumented severe adverse effect of dyspnea.

Sorafenib for the treatment of breast cancer

INTRODUCTION

Breast cancer treatment includes many options depending on the tumor clinicopathological profile, which groups breast cancer into various subtypes. Bevacizumab is currently the only drug capable of targeting angiogenesis in breast cancer. Sorafenib has also been studied in combination with other agents. Areas covered: Pharmacological aspects of sorafenib, including results from preclinical studies on breast cancer cells; findings about clinical efficacy and safety in both single-arm and randomized clinical trials; ongoing trials. Expert opinion: Since sorafenib as a single agent has shown limited efficacy in breast cancer, its combination with other drugs is under investigation. Dose reduction is the main challenge when sorafenib is combined with chemotherapy or endocrine therapy. Although randomized phase-II trials on sorafenib plus chemotherapy versus chemotherapy alone have shown potential benefits in progression-free survival, preliminary results from a phase-III study in combination with capecitabine are negative. The definitive results of this trial and results from other ongoing phase-II trials will determine further developments of sorafenib in breast cancer. Although these additional data could help determine the most appropriate dose, drug combination and patient settings, a confirmation of the preliminary negative results reported in the phase-III trial are likely to discourage further use of sorafenib in breast cancer, given its non-negligible toxicity, lack of predicting markers, and the number of more promising drugs for breast cancer.

Inefficiencies and Patient Burdens in the Development of the Targeted Cancer Drug Sorafenib: A Systematic Review

Failure in cancer drug development exacts heavy burdens on patients and research systems. To investigate inefficiencies and burdens in targeted drug development in cancer, we conducted a systematic review of all prelicensure trials for the anticancer drug, sorafenib (Bayer/Onyx Pharmaceuticals). We searched Embase and MEDLINE databases on October 14, 2014, for prelicensure clinical trials testing sorafenib against cancers. We measured risk by serious adverse event rates, benefit by objective response rates and survival, and trial success by prespecified primary endpoint attainment with acceptable toxicity. The first two clinically useful applications of sorafenib were discovered in the first 2 efficacy trials, after five drug-related deaths (4.6% of 108 total) and 93 total patient-years of involvement (2.4% of 3,928 total). Thereafter, sorafenib was tested in 26 indications and 67 drug combinations, leading to one additional licensure. Drug developers tested 5 indications in over 5 trials each, comprising 56 drug-related deaths (51.8% of 108 total) and 1,155 patient-years (29.4% of 3,928 total) of burden in unsuccessful attempts to discover utility against these malignancies. Overall, 32 Phase II trials (26% of Phase II activity) were duplicative, lacked appropriate follow-up, or were uninformative because of accrual failure, constituting 1,773 patients (15.6% of 11,355 total) participating in prelicensure sorafenib trials. The clinical utility of sorafenib was established early in development, with low burden on patients and resources. However, these early successes were followed by rapid and exhaustive testing against various malignancies and combination regimens, leading to excess patient burden. Our evaluation of sorafenib development suggests many opportunities for reducing costs and unnecessary patient burden in cancer drug development.

Phase I/II Trial of Sorafenib in Combination with Vinorelbine as First-Line Chemotherapy for Metastatic Breast Cancer

Background

Preclinical models have reported a synergistic interaction between sorafenib and vinorelbine. We investigated the toxicity, efficacy, and pharmacokinetics interaction of this combination as first-line treatment for patients with metastatic breast cancer.

Methods

Patients were HER2-negative and treated with vinorelbine 30 mg/m² IV days 1,8 every 21 plus daily oral sorafenib. In the phase I portion (3+3 design) patients received sorafenib 200 mg BID (cohort 1) or 400 mg BID (cohort 2). In the phase II expansion, 21 more evaluable patients were planned to receive the maximum tolerated dose (MTD). Pharmacokinetic analysis was performed in 6 patients: blood concentrations were compared for each drug in the presence or absence of the other drug.

Results

In cohort 1, one patient experienced a dose-limiting toxicity (DLT) (grade 3 pancreatitis), requiring the expansion of this cohort to 6 patients, without further documented DLTs. In cohort 2, one patient of six experienced a grade 4 DLT (asymptomatic rise in amylase not requiring drug discontinuation), establishing this dose level as the MTD (sorafenib 400 mg BID). After expansion at the MTD, a total of 27 patients (median age 57) were treated for a median of 8 cycles. One grade 5 febrile neutropenia occurred. With repeated cycles, 52% of patients required at least 1 dose reduction of either drug. One patient experienced a sustained grade 3 fatigue resulting in treatment discontinuation. The response rate was 30%. Median PFS was 5.7 months (95% CI 4.4–7.6), and clinical benefit (absence of disease progression at 6 months) was 48%. PK analysis showed a significant interaction between the two drugs, resulting in a higher Cmax of vinorelbine in the presence of sorafenib.

Conclusion

The combination of sorafenib and vinorelbine at full doses is feasible but not devoid of toxicity, likely also due to a significant PK interaction.

Trial Registration

ClinicalTrials.gov NCT00764972

Design and Reporting of Targeted Anticancer Preclinical Studies: A Meta-Analysis of Animal Studies Investigating Sorafenib Antitumor Efficacy

The validity of preclinical studies of candidate therapeutic agents has been questioned given their limited ability to predict their fate in clinical development, including due to design flaws and reporting bias. In this study, we examined this issue in depth by conducting a meta-analysis of animal studies investigating the efficacy of the clinically approved kinase inhibitor, sorafenib. MEDLINE, Embase, and BIOSIS databases were searched for all animal experiments testing tumor volume response to sorafenib monotherapy in any cancer published until April 20, 2012. We estimated effect sizes from experiments assessing changes in tumor volume and conducted subgroup analyses based on prespecified experimental design elements associated with internal, construct, and external validity. The meta-analysis included 97 experiments involving 1,761 animals. We excluded 94 experiments due to inadequate reporting of data. Design elements aimed at reducing internal validity threats were implemented only sporadically, with 66% reporting animal attrition and none reporting blinded outcome assessment or concealed allocation. Anticancer activity against various malignancies was typically tested in only a small number of model systems. Effect sizes were significantly smaller when sorafenib was tested against either a different active agent or combination arm. Trim and fill suggested a 37% overestimation of effect sizes across all malignancies due to publication bias. We detected a moderate dose-response in one clinically approved indication, hepatocellular carcinoma, but not in another approved malignancy, renal cell carcinoma, or when data were pooled across all malignancies tested. In support of other reports, we found that few preclinical cancer studies addressed important internal, construct, and external validity threats, limiting their clinical generalizability. Our findings reinforce the need to improve guidelines for the design and reporting of preclinical cancer studies. Cancer Res; 76(16); 4627-36. ©2016 AACR.

Sorafenib: 10 years after the first pivotal trial

Sorafenib is an oral multikinase inhibitor with anticancer activity against a wide spectrum of cancers. It is currently approved for the treatment of patients with hepatocellular carcinoma, advanced renal cell carcinoma or progressive, locally advanced or metastatic differentiated thyroid carcinoma. In this review, we present a number of studies that investigated the efficacy and safety of sorafenib in these settings. We also discuss the perspectives on the use of this molecule, including the role of sorafenib as comparator for the development of new drugs, the combination of sorafenib with additional therapies (such as transarterial chemoembolization for hepatocellular carcinoma) and the use of this treatment in several other advanced refractory solid tumors.

Resistance to Targeted Therapies in Breast Cancer

Seventy five percent of all breast cancer (BC) patients express estrogen receptor (ER) but a quarter to half of patients with ER positive BC relapse on ET (endocrine therapy), tamoxifen, aromatase inhibitors (AIs), surgical castration, amongst other treatment strategies. ER positive BC at relapse loses ER expression in 20 % of cases and reduces quantitative ER expression most of the time. ER is not the only survival pathway driving ER positive BC and escape pathways intrinsic or acquired are activated during ET. This overview gives an account of ligand-independent ER activation, namely by receptor networks cross talk, and by the various genomic factors and mechanisms leading to ET response failure. Also the mechanisms of Her1 and Her2 inhibition resistance are dealt within this overview, along with the therapeutic indications and limitations of tyrosine kinase inhibitors, PARP inhibitors, PI3K/AKT/mTOR inhibitors, RAS/RAF/MEK/ERK/MAPK inhibitors, and antiangiogenic drugs. In spite of the many advances in controlling the division of BC cells and the progression of BC tumors these still remain the main cause of death among women in age range of 20-50 years requiring even more efforts in new therapeutic approaches besides the drugs within the scope of the overview.

Sorafenib: a brief review with emphasis on its possible role in breast cancer

SUMMARY 

The treatment of metastatic breast cancer is palliative and usually requires hormone treatment, and/or chemotherapy and trastuzumab for HER2-positive disease. Randomized studies only demonstrate marginal survival benefit with combination chemotherapy, as opposed to sequential single agents or nontaxane versus taxane-containing regimens. Metastatic breast cancer remains an unmet medical need. Sorafenib is an oral multikinase inhibitor that exhibits antiangiogenic activity by targeting numerous proangiogenic pathways. Sorafenib has marketing authorization for the treatment of patients with advanced renal cell, hepatocellular and thyroid carcinomas. Recent studies have explored the usage of sorafenib as a single agent and in combination with chemotherapy. An overview of sorafenib is presented in this article with the current data and potential future usage in patients with metastatic breast cancer.

Correlation of perfusion MRI and 18F-FDG PET imaging biomarkers for monitoring regorafenib therapy in experimental colon carcinomas with immunohistochemical validation

Objectives

To investigate a multimodal, multiparametric perfusion MRI / ¹⁸F-fluoro-deoxyglucose-(¹⁸F-FDG)-PET imaging protocol for monitoring regorafenib therapy effects on experimental colorectal adenocarcinomas in rats with immunohistochemical validation.

Materials and Methods

Human colorectal adenocarcinoma xenografts (HT-29) were implanted subcutaneously in n = 17 (n = 10 therapy group; n = 7 control group) female athymic nude rats (Hsd:RH-Foxn1^rnu). Animals were imaged at baseline and after a one-week daily treatment protocol with regorafenib (10 mg/kg bodyweight) using a multimodal, multiparametric perfusion MRI/¹⁸F-FDG-PET imaging protocol. In perfusion MRI, quantitative parameters of plasma flow (PF, mL/100 mL/min), plasma volume (PV, %) and endothelial permeability-surface area product (PS, mL/100 mL/min) were calculated. In ¹⁸F-FDG-PET, tumor-to-background-ratio (TTB) was calculated. Perfusion MRI parameters were correlated with TTB and immunohistochemical assessments of tumor microvascular density (CD-31) and cell proliferation (Ki-67).

Results

Regorafenib significantly (p<0.01) suppressed PF (81.1±7.5 to 50.6±16.0 mL/100mL/min), PV (12.1±3.6 to 7.5±1.6%) and PS (13.6±3.2 to 7.9±2.3 mL/100mL/min) as well as TTB (3.4±0.6 to 1.9±1.1) between baseline and day 7. Immunohistochemistry revealed significantly (p<0.03) lower tumor microvascular density (CD-31, 7.0±2.4 vs. 16.1±5.9) and tumor cell proliferation (Ki-67, 434.0 ± 62.9 vs. 663.0 ± 98.3) in the therapy group. Perfusion MRI parameters ΔPF, ΔPV and ΔPS showed strong and significant (r = 0.67-0.78; p<0.01) correlations to the PET parameter ΔTTB and significant correlations (r = 0.57-0.67; p<0.03) to immunohistochemical Ki-67 as well as to CD-31-stainings (r = 0.49-0.55; p<0.05).

Conclusions

A multimodal, multiparametric perfusion MRI/PET imaging protocol allowed for non-invasive monitoring of regorafenib therapy effects on experimental colorectal adenocarcinomas in vivo with significant correlations between perfusion MRI parameters and ¹⁸F-FDG-PET validated by immunohistochemistry.

Incidence and risk of xerosis with targeted anticancer therapies

BACKGROUND

Many targeted therapies used in the treatment of cancer can lead to the development of xerosis, but the incidence and relative risk of xerosis have not been ascertained.

OBJECTIVE

We conducted a systematic review and metaanalysis of clinical trials, to ascertain the incidence and risk of developing xerosis after taking anticancer drugs.

METHODS

The PubMed (1966-October 2013), Web of Science (January 1998-October 2013), and American Society of Clinical Oncology abstracts (2004-2013) databases were searched for clinical trials of 58 targeted agents. Results were calculated using random or fixed effects models.

RESULTS

The incidences of all- and high-grade xerosis were 17.9% (95% confidence interval [CI]: 15.6-20.4%) and 1.0% (95% CI: 0.9-1.5%), respectively. The risk of developing all-grade xerosis was 2.99 (95% CI: 2.0-4.3), and it varied across different drugs (P < .001).

LIMITATIONS

The reporting of xerosis may vary among clinicians and institutions, and the incidence may be affected by age, concomitant medications, comorbidities, and underlying malignancies or skin conditions.

CONCLUSION

Patients receiving targeted therapies have a significant risk of developing xerosis. Patients should be counseled and treated early for this symptom to prevent suboptimal dosing and quality of life impairment.

Novel antiangiogenic drugs for the management of breast cancer: new approaches for an old issue?

Since angiogenesis plays an important role in cancer growth, infiltration and metastasis, many agents targeting this pathway have been developed over the last decade. Antiangiogenic drugs interfere with this process and may inhibit neoplastic growth or induce tumor dormancy by blocking the expanding network of newly formed capillaries. Despite the initial promise, targeting angiogenesis in breast cancer has not reached major breakthroughs. Nevertheless, the immunologic role of VEGF deserves to be further explored. We aim to describe the biological mechanisms which underlie the role of angiogenesis in breast cancer carcinogenesis, to depict its contribution to the metastatic process and to review the most important clinical trials testing angiogenic inhibitors in breast cancer, including monoclonal antibodies and novel small molecules.

Impact of adding the multikinase inhibitor sorafenib to endocrine therapy in metastatic estrogen receptor-positive breast cancer

BACKGROUND

Targeting growth factor and survival pathways may delay endocrine-resistance in estrogen receptor-positive breast cancer.

MATERIALS & METHODS

A pilot Phase II study adding sorafenib to endocrine therapy in 11 patients with metastatic estrogen receptor-positive breast cancer was conducted. Primary end point was response by RECIST after 3 months of sorafenib. Secondary end points included safety, time to progression and biomarker modulation. The study closed early owing to slow accrual.

RESULTS

Eight out of 11 patients had progressive disease on study entry and three had stable disease. Of the ten evaluable patients, seven experienced stable disease (70%) and three experienced progressive diseas (30%), with a median time to progression of 6.1 months (8.4 months in the seven patients on tamoxifen). The serum samples demonstrated a significant reduction in VEGF receptor 2 and PDGF receptor-α. Microarray analysis identified 32 suppressed genes, no induced genes and 29 enriched Kyoto Encyclopedia of Genes and Genomes pathways.

CONCLUSION

The strategy of adding a targeted agent to endocrine therapy upon resistance may be worthwhile testing in larger studies.

Multicenter phase II study of apatinib in non-triple-negative metastatic breast cancer

Background

Apatinib is a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2(VEGFR-2). This study was conducted to assess the efficacy and safety of apatinib in patients with non-triple-negative metastatic breast cancer who had received prior chemotherapy for their metastatic disease.

Methods

This multicenter, open-label, single arm study enrolled patients with non-triple-negative breast cancer, pretreated with anthracycline, taxanes and capecitabine, and who failed in the metastatic setting at least 1 and at most 4 prior chemotherapy regimens and at least one endocrine drug for hormone receptor-positive patients as well as at least one anti-Her2 drug for Her2-positive patients. The primary end point of this study was progression free survival (PFS). Secondary end points included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and toxicity. Apatinib was administered as 500 mg daily on days 1 through 28 of each 4-week cycle.

Results

38 patients were enrolled with a median age of 49 years (range, 35 to 62 years) and received apatinib for a median of 4 cycles (range from 0 to 10 cycles). 18 (47.4%) patients experienced dose reduction during treatment. The median relative dose intensity (relative to assigned dose for each cycle) was 82% (range, 45.0% to 100.0%). Median follow-up time was 10.1 months. Median PFS of all 38 patients was 4.0 months (95% confidence interval (CI), 2.8 m – 5.2 m). 36 patients were eligible for efficacy analysis. ORR was 16.7% (6/36). DCR was 66.7% (24/36). Median OS was 10.3 months (95% CI, 9.1 m – 11.6 m). The most common grade 3/4 treatment-related AEs were hypertension (20.5%), hand-foot syndrome (10.3%), and proteinuria (5.1%). Of three possibly drug-related SAEs recorded in the study, 2 (3.4%) deaths occurred within 28 days of last treatment and were both considered to be the result of disease progression. The other one was grade 2 diarrhea needing hospitalization.

Conclusions

Apatinib exhibited objective efficacy in heavily pretreated, metastatic non-triple-negative breast cancer with manageable toxicity, and it might be better to be tested in breast cancer with high angiogenesis dependency.

Trial registration

ClinicalTrials.gov: NCT01653561.

Sorafenib in the Treatment of Early Breast Cancer: Results of the Neoadjuvant Phase II Study - SOFIA

BACKGROUND

Sorafenib was tested for neoadjuvant treatment with an anthracycline/taxane-based chemotherapy in the open-label, multicentre, single-arm phase II study, 'SOFIA'.

PATIENTS AND METHODS

INCLUSION CRITERIA WERE: HER2 negative, cT3, cT4 or cT2 cN+, M0 primary breast cancer. Patients received 4 × epirubicin 90 mg/m(2) and cyclophosphamide 600 mg/m(2) (EC) intravenously (i.v.) in 3-weekly cycles followed or preceded by 12 weeks of paclitaxel (Pw) 80 mg/m(2). In cohort 1, sorafenib started at 800 mg daily with chemotherapy. An initial daily sorafenib dose of 200 mg was escalated, based on individual toxicities, every 3 weeks in cohort 2 (starting with EC) and every 2 weeks in cohort 3 (starting with Pw). The primary objective was to identify the most feasible regimen; secondary objectives were safety, pathological complete response (pCR) at surgery and pharmacokinetics.

RESULTS

Of the 36 recruited patients, 7/12 patients completed the study in cohort 1 and 24/24 patients in cohorts 2 and 3. The median cumulative sorafenib dose per patient was 37%, 65% and 46% in cohorts 1, 2 and 3, respectively. The main grade 3-4 toxicities were neutropenia and hand-foot syndrome. The pCR (ypT0/is) rate was 27.7%. No pharmacokinetic interaction was observed between sorafenib and epirubicin.

CONCLUSION

Sorafenib EC-Pw is feasible if the starting dose is 200 mg, escalated every 3 weeks based on the patients' individual toxicities.

A phase II trial of BAY 43-9006 (sorafenib) (NSC-724772) in patients with relapsing and resistant multiple myeloma: SWOG S0434

The authors assessed the overall response rate, including confirmed complete response (CR) and partial response, in patients with relapsed/refractory multiple myeloma treated with sorafenib. Qualitative and quantitative toxicities associated with this regimen were evaluated. Patients were eligible if they had a confirmed diagnosis of refractory or relapsed (RR) multiple myeloma (MM) with measurable monoclonal protein. Patients had to have adequate renal, hepatic, hematologic, and cardiac function with a Zubrod performance status of 0–2. Patients were given 400 mg sorafenib by mouth twice daily for 28-day treatment cycles. These patients were followed up for a maximum of 3 years to assess responses and adverse events. Twenty-three patients were enrolled. Of these, five were found to be ineligible for the following reasons: four had insufficient documentation of the baseline disease and one patient did not have measurable disease. All eighteen eligible patients were evaluable for toxicities. Three patients experienced grade 4 toxicities: one with thrombocytopenia, one with anemia, and one with renal failure. Four of the eighteen eligible patients were not assessable for response due to removal from protocol treatment prior to adequate disease assessment. Specifically, three were removed for either grade 4 toxicity or progression of disease and one was removed per patient choice (due to reasons unrelated to treatment). Of the 18 patients who were assessed for toxicities, 5 (27.8%) received at least one fully dosed cycle, 2 (11.1%) of whom had all cycles fully dosed. No responses were observed on this study of the 14 patients who were assessable for response. All patients have discontinued protocol treatment as of August 2008. Overall survival at 12 months was 50% (95% CI 27–73%) and median progression-free survival was 1.2 months (95% CI 1.0–5.4). The trial did not exhibit activity by the International Uniform Response Criteria for MM. Further research should focus on combination therapy of sorafenib with standard treatments in selected patients with RR MM.

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.

Efficacy and Safety Profile of Combining Sorafenib with Chemotherapy in Patients with HER2-Negative Advanced Breast Cancer: A Meta-analysis

Purpose

The aim of the study was to evaluate the efficacy and safety of combining sorafenib with chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer.

Methods

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, American Society for Clinical Oncology abstracts, and European Society for Medical Oncology abstracts were searched. Randomized clinical trials that compared the efficacy and safety of sorafenib plus chemotherapy in patients with HER2-negative advanced breast cancer with placebo plus chemotherapy were eligible. The endpoints were progression-free survival (PFS), overall survival (OS), time to progression (TTP), duration of response (DOR), overall response rate (ORR), clinical benefits, and adverse effects. The meta-analysis was performed using Review Manager 5.2.6 (The Nordic Cochrane Centre), and the fixed-effect model weighted by the Mantel-Haenszel method was used. When considerable heterogeneity was found (p<0.1), further analysis (subgroup analysis, sensitivity analysis, or random-effect model) was performed to identify the potential cause. The results are expressed as hazard ratios or risk ratios, with their corresponding 95% confidence intervals.

Results

The final analysis included four trials comprising 844 patients. The results revealed longer PFS and TTP, and higher ORR and clinical benefit rates in patients receiving sorafenib combined with chemotherapy compared to those receiving chemotherapy and placebo. OS and DOR were similar in the two groups. Meanwhile, the incidence of some adverse effects, including hand-foot skin reaction/hand-foot syndrome, diarrhea, rash, and hypertension, were significantly higher in the sorafenib arm.

Conclusion

Sorafenib combined with chemotherapy may prolong PFS and TTP. This treatment was associated with manageable toxicities, but frequent dose interruptions and reductions were required.

Multicenter phase II study of apatinib, a novel VEGFR inhibitor in heavily pretreated patients with metastatic triple-negative breast cancer

Apatinib is an oral, highly potent tyrosine-kinase inhibitor targeting VEGFR2. Phase I study showed the recommended dose of 750 mg/day with substantial antitumor activity. This phase II study aims to evaluate the optimum dose level for the efficacy and safety of apatinib monotherapy in heavily pretreated patients with metastatic triple negative breast cancer (mTNBC) in China. Phase IIa was first performed among 25 patients previously treated with anthracycline and/or taxane. All patients received apatinib 750 mg/day p.o. in a 4-week cycle. Subsequently, a phase IIb study of 59 patients was activated, with the endpoint progression-free survival (PFS). The dosage of drug for the Phase IIb was determined according to safety, tolerability and efficacy from the phase IIa study. As a result of toxicity associated with the 750 mg dose in phase IIa, the recommended initial dose of apatinib in the phase IIb was 500 mg/day. In phase IIb, grade 3/4 hematologic toxicities were thrombocytopenia (13.6%), leukopenia (6.8%), neutropenia (3.4%) and anemia (1.7%). The most frequent grade 3/4 nonhematologic toxicities were hand-foot syndrome, proteinuria, hypertension, and increased ALT. In the 56 evaluable patients, overall response rate and clinical benefit rate (CBR) were 10.7 and 25.0%, respectively. Median PFS and overall survival were 3.3 (95% CI 1.7-5.0) and 10.6 (95% CI 5.6-15.7) months, respectively. Our results indicate that apatinib dose of 500 mg rather than 750 mg is the recommended starting dose for the heavily pretreated mTNBC patients with measurable rate of partial response and PFS.

Sorafenib-based therapy in HER2-negative advanced breast cancer: Results from a retrospective pooled analysis of randomized controlled trials

A standard systemic therapy for patients with human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC) is yet to be identified. Sorafenib has been developed for the treatment of solid tumors, including breast cancer, as an oral multikinase inhibitor with antiangiogenic and antiproliferative activity. The aim of the present study was to assess the efficacy and safety of sorafenib in patients with HER2-negative ABC by performing a meta-analysis. A literature search was applied to databases, including PubMed, EMBASE, the Cochrane Library Databases, American Society of Clinical Oncology and the European Society for Medical Oncology, with the search terms ‘advanced breast cancer’ and ‘sorafenib’ and relevant studies were selected for analysis. The data extracted from the selected studies included progression-free survival (PFS), time to progression (TTP), overall survival (OS) and overall response rate (ORR). Major adverse events (AEs) were also analyzed. A total of four randomized controlled trials containing 844 cases were identified. Combined results revealed that when compared with chemotherapy (or with anti-hormone receptor therapy) alone, sorafenib-based therapy significantly increased the PFS [hazard ratio (HR), 0.78; 95% confidence interval (CI), 0.54–1.02] and TTP (HR, 0.74; 95% CI, 0.50–0.97), but not the OS (HR, 0.95; 95% CI, 0.75–1.15) and ORR (relative risk, 1.19; 95% CI, 1.01–1.39). In addition, the incidence of grade 3/4 AEs, including hand-foot skin syndrome, anemia, fatigue, rash and stomatitis, were significantly increased in patients that received sorafenib-based therapy. Therefore, the results from the current meta-analysis indicated that sorafenib-based therapy improved the PFS and TTP in patients with HER2-negative ABC, but not the OS and ORR. In addition, combination treatment was associated with increased toxicities and frequently required dose reductions.

Sorafenib: targeting multiple tyrosine kinases in cancer

Sorafenib (BAY 43-9006, Nexavar®) is an oral multiple tyrosine kinase inhibitor. Main targets are receptor tyrosine kinase pathways frequently deregulated in cancer such as the Raf-Ras pathway, vascular endothelial growth factor (VEGF) pathway, and FMS-like tyrosine kinase 3 (FLT3). Sorafenib was approved by the FDA in fast track for advanced renal cell cancer and hepatocellular cancer and shows good clinical activity in thyroid cancer. Multiple clinical trials are undertaken to further investigate the role of sorafenib alone or in combination for the treatment of various tumor entities.

Phosphorylated VEGFR2 and hypertension: potential biomarkers to indicate VEGF-dependency of advanced breast cancer in anti-angiogenic therapy

The efficacy of anti-VEGF agents probably lies on VEGF-dependency. Apatinib, a specific tyrosine kinase inhibitor that targets VEGF receptor 2, was assessed in patients with advanced breast cancer (ABC) (ClinicalTrials.gov NCT01176669 and NCT01653561). This substudy was to explore the potential biomarkers for VEGF-dependency in apatinib-treated breast cancer. Eighty pretreated patients received apatinib 750 or 500 mg/day orally in 4-week cycles. Circulating biomarkers were measured using a multiplex assay, and tissue biomarkers were identified with immunostaining. Baseline characteristics and adverse events (AEs) were included in the analysis. Statistical confirmation of independent predictive factors for anti-tumor efficacy was performed using Cox and Logistic regression models. Median progression-free survival (PFS) was 3.8 months, and overall survival (OS) was 10.6 months, with 17.5 % of objective response rate. Prominent AEs (≥60 %) were hypertension, hand-foot skin reaction (HFSR), and proteinuria. Higher tumor phosphorylated VEGFR2 (p-VEGFR2) expressions (P = 0.001), higher baseline serum soluble VEGFR2 (P = 0.031), hypertension (P = 0.011), and HFSR (P = 0.018) were significantly related to longer PFS, whereas hypertension (P = 0.002) and HFSR (P = 0.001) were also related to OS. Based on multivariate analysis, only p-VEGFR2 (adjusted HR, 0.40; P = 0.013) and hypertension (adjusted HR, 0.58; P = 0.038) were independent predictive factors for both PFS and clinical benefit rate. Apatinib had substantial antitumor activity in ABC and manageable toxicity. p-VEGFR2 and hypertension may be surrogate predictors of VEGF-dependency of breast cancer, which may identify an anti-angiogenesis sensitive population.

Phase I/II trial of vinorelbine and sorafenib in metastatic breast cancer

PURPOSE

We investigated the efficacy and toxicity of sorafenib, a multikinase inhibitor of vascular endothelial growth factor receptor tyrosine kinase, in combination with vinorelbine therapy in a phase I/II trial in patients with metastatic breast cancer.

PATIENTS AND METHODS

We enrolled 11 patients in the phase I portion to determine the maximum tolerated dose (MTD) of the combination, followed by 35 extra patients treated at the MTD in phase II. The median age of patients was 54 years old (range, 31-72 years old). Tumors were estrogen receptor and progesterone receptor (ER/PR) positive in 54% (22/54) of patients, and triple negative (ER(-), PR(-), HER2(-)) in 41% (17/54) of patients. Of all patients, 22% received sorafenib and vinorelbine as first-line therapy, 37% as second-line therapy, and 41% as third-line therapy.

RESULTS

In total, 41 patients were treated at the MTD (6 during phase I; 35 in phase II). The observed 44% 4-month progression-free survival rate was similar to the estimated historical rate of 43% with vinorelbine treatment. The combination was tolerated with expected toxicities. Patients treated at the MTD who had received prior bevacizumab treatment received a median of 1.5 cycles (range, 1-10 cycles) compared with a median of 5 cycles (range, 2-12 cycles) for patients without prior bevacizumab treatment.

CONCLUSION

Further evaluation of vinorelbine and sorafenib in bevacizumab-naive patients may be of interest if specific biomarkers guiding patient selection can be identified.

Pruritus in patients treated with targeted cancer therapies: systematic review and meta-analysis

BACKGROUND

Pruritus has been anecdotally described in association with targeted cancer therapies. The risk of pruritus has not been systematically ascertained.

OBJECTIVE

A systematic review and meta-analysis of the literature was conducted for axitinib, cetuximab, dasatinib, erlotinib, everolimus, gefitinib, imatinib, ipilimumab, lapatinib, nilotinib, panitumumab, pazopanib, rituximab, sorafenib, temsirolimus, tositumomab, vandetanib, and vemurafenib.

METHODS

Databases from PubMed, Web of Science (January 1998 through July 2012), and American Society of Clinical Oncology abstracts (2004 through 2012) were searched. Incidence and relative risk of pruritus were calculated using random- or fixed-effects model.

RESULTS

The incidences of all-grade and high-grade pruritus were 17.4% (95% confidence interval 16.0%-19.0%) and 1.4% (95% confidence interval 1.2%-1.6%), respectively. There was an increased risk of all-grade pruritus (relative risk 2.90 [95% confidence interval 1.76-4.77, P < .001]) and variation among different drugs (P < .001).

LIMITATIONS

The reporting of pruritus may vary, resulting from concomitant medications, comorbidities, and underlying malignancies. We found a higher incidence of pruritus in patients with solid tumors, concordant with those targeted therapies with the highest pruritus incidences.

CONCLUSION

There is a significant risk of developing pruritus in patients receiving targeted therapies. To prevent suboptimal dosing and decreased quality of life, patients should be counseled and treated against this untoward symptom.

[Triple-negative breast cancer: histoclinical and molecular features, therapeutic management and perspectives]

Triple-negative breast cancer (TNBC), as defined by the absence of estrogen and progesterone receptor expression, as well as the lack of HER2 overexpression/amplification, corresponds to 15% of breast cancer and represents an aggressive form of the disease. TNBC are frequently confounded with basal subtype in the molecular classification of breast cancer and also share some similarities with BRCA1-mutated tumors. Epidemiological and clinical characteristics are distinct from other subtypes, including a younger age at diagnosis, a higher risk of relapse in spite of increased chemosensitivity, and a higher incidence of lung and brain metastatic relapses. Conventional cytotoxics remain the mainstay of current systemic management but recent evaluation of more targeted therapeutics, including specific cytotoxics (such as the use of platinum salts), PARP and EGFR inhibition, and antiangiogenics have been performed, providing contrasted but rather disappointing results. Recent data indicate that TNBC represent a heterogeneous entity composed of multiple and distinct molecular subtypes, which should deserve specific targeted therapeutics.

A phase 3 tRial comparing capecitabinE in combination with SorafenIb or pLacebo for treatment of locally advanced or metastatIc HER2-Negative breast CancEr (the RESILIENCE study): study protocol for a randomized controlled trial

BACKGROUND

Sorafenib is an oral multikinase inhibitor with antiangiogenic/antiproliferative activity. A randomized phase 2b screening trial in human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer demonstrated a significant improvement in progression-free survival (PFS) when sorafenib was added to capecitabine versus placebo (median 6.4 versus 4.1 months; hazard ratio = 0.58; P = 0.001). Most drug-related adverse events were Grade 1/2 in severity with the exception of Grade 3 hand-foot skin reaction/syndrome (44% versus 14%, respectively). These results suggest a role for the combination of sorafenib and capecitabine in breast cancer and supported a phase 3 confirmatory trial. Here we describe RESILIENCE - a multinational, double-blind, randomized, placebo-controlled, phase 3 trial - assessing the addition of sorafenib to first- or second-line capecitabine in advanced HER2-negative breast cancer.

METHODS/DESIGN

Eligibility criteria include ≥18 years of age, ≤1 prior chemotherapy regimen for metastatic disease, and resistant to/failed taxane and anthracycline or no indication for further anthracycline. Prior treatment with a vascular endothelial growth factor inhibitor is not allowed. Patients with significant cardiovascular disease or active brain metastases are not eligible. Patients are stratified by hormone-receptor status, geographic region, and prior metastatic chemotherapy status and randomized (1:1) to capecitabine (1000 mg/m2 orally twice daily (BID), days 1 to 14 of 21) in combination with sorafenib (orally BID, days 1 to 21, total dose 600 mg/day) or matching placebo. Capecitabine and sorafenib/placebo doses can be escalated to 1250 mg/m2 BID and 400 mg BID, respectively, as tolerated, or reduced to manage toxicity. Dose re-escalation after a reduction is allowed for sorafenib/placebo but not for capecitabine. This dosing algorithm was designed to mitigate dermatologic and other toxicity, in addition to detailed guidelines for prophylactic and symptomatic treatment. Radiographic assessment is every 6 weeks for 36 weeks, and every 9 weeks thereafter. The primary endpoint is PFS by blinded independent central review (Response Evaluation Criteria in Solid Tumors 1.1 criteria). Secondary endpoints include overall survival, time to progression, overall response rate, duration of response, and safety. Enrollment began in November 2010 with a target of approximately 519 patients.

DISCUSSION

RESILIENCE will provide definitive PFS data for the combination of sorafenib and capecitabine in advanced HER2-negative breast cancer and better characterize the benefit-to-risk profile.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT01234337.

Tyrosine kinase inhibitors (TKIs) in human and pet tumours with special reference to breast cancer: a comparative review

Tyrosine kinase receptors (TKRs) play a key role in tumour cell proliferation and survival since they are involved in endothelial cell activation leading to tumour neoangiogenesis. In particular, vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (c-KitR), and colony-stimulating factor 1 (CSF-1) are overexpressed or constitutively activated in human and pet malignancies. A variety of small molecule inhibitors targeting specific tyrosine kinases (known as tyrosine kinase inhibitors or TKIs) have recently been approved, or are under investigation, for the treatment of human cancer. TKI application in animal cancer is however relatively recent. This review aims to illustrate the major aspects of tyrosine kinase dysfunctions, with special regard to human and animal cancer of the mammary gland, providing an update on the background of the anti-angiogenic and anti-neoplastic properties of TKIs in human and veterinary cancer.

Anti-proliferative actions of N'-desmethylsorafenib in human breast cancer cells

The multi-kinase inhibitor sorafenib is used for the treatment of renal and hepatic carcinomas and is undergoing evaluation for treatment of breast cancer in combination with other agents. Cytochrome P450 (CYP) 3A4 converts sorafenib to multiple metabolites that have been detected in patient plasma. However, recent clinical findings suggest that combination therapy may elicit inhibitory pharmacokinetic interactions involving sorafenib that increase toxicity. While sorafenib N-oxide is an active metabolite, information on the anti-tumor actions of other metabolites is unavailable. The present study evaluated the actions of sorafenib and its five major metabolites in human breast cancer cell lines. All agents, with the exception of N'-hydroxymethylsorafenib N-oxide, decreased ATP formation in four breast cancer cell lines (MDA-MB-231, MDA-MB-468, MCF-7 and T-47D). Prolonged treatment of MDA-MB-231 cells with N'-desmethylsorafenib, N'-desmethylsorafenib N-oxide and sorafenib (10 μM, 72 h) produced small increases in caspase-3 activity to 128-139% of control. Sorafenib and its metabolites, again with the exception of N'-hydroxymethylsorafenib N-oxide, impaired MEK/ERK signaling in MDA-MB-231 cells and modulated the expression of cyclin D1 and myeloid cell leukemia sequence-1, which regulate cell viability. When coadministered with doxorubicin (0.5 or 1 μM), sorafenib and N'-desmethylsorafenib (25 μM) produced greater effects on ATP production than either treatment alone. Thus, it emerges that, by targeting the MEK/ERK pathway, multiple sorafenib metabolites may contribute to the actions of sorafenib in breast cancer. Because N'-desmethylsorafenib is not extensively metabolized and does not inhibit major hepatic CYPs, this metabolite may have a lower propensity to precipitate pharmacokinetic drug interactions than sorafenib.

Targeting the PI3K/AKT/mTOR and Raf/MEK/ERK pathways in the treatment of breast cancer

Alterations of signal transduction pathways leading to uncontrolled cellular proliferation, survival, invasion, and metastases are hallmarks of the carcinogenic process. The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and the Raf/mitogen-activated and extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways are critical for normal human physiology, and also commonly dysregulated in several human cancers, including breast cancer (BC). In vitro and in vivo data suggest that the PI3K/AKT/mTOR and Raf/MEK/ERK cascades are interconnected with multiple points of convergence, cross-talk, and feedback loops. Raf/MEK/ERK and PI3K/AKT/mTOR pathway mutations may co-exist. Inhibition of one pathway can still result in the maintenance of signaling via the other (reciprocal) pathway. The existence of such "escape" mechanisms implies that dual targeting of these pathways may lead to superior efficacy and better clinical outcome in selected patients. Several clinical trials targeting one or both pathways are already underway in BC patients. The toxicity profile of this novel approach of dual pathway inhibition needs to be closely monitored, given the important physiological role of PI3K/AKT/mTOR and Raf/MEK/ERK signaling. In this article, we present a review of the current relevant pre-clinical and clinical data and discuss the rationale for dual inhibition of these pathways in the treatment of BC patients.

Emerging targeted therapies in triple-negative breast cancer

Standard chemotherapy regimens can prove effective for patients with early triple-negative breast cancer (TNBC); however, patients with advanced disease typically respond poorly and rapidly progress, and the outcome is poor. New targeted therapies are therefore an urgent unmet medical need for this patient population. Translational and clinical studies into new TNBC treatments have been facilitated by the increased understanding of the aberrant signal transduction pathways regulating growth and survival and the development of chemoresistance in TNBC. Some of the established targeted agents that have been approved in other indications may prove beneficial to patients with TNBC; however, in the absence of approved targeted agents for the treatment of TNBC, most new agents remain experimental. Increased understanding of molecular profiles of TNBC subtypes is likely to improve therapeutic strategies with targeted agents. Novel strategies have reached clinical evaluation in patients with TNBC, including targeting angiogenesis vascular endothelial growth factor and proliferation signalling (receptor tyrosine kinases and mammalian target of rapamycin). Aggressive TNBCs have been found to associate closely with BRCA1 mutation or dysregulation. The recent development of new investigational agents targeting DNA repair, either directly with poly(adenosine disphosphate-ribose) polymerase inhibitors or indirectly through DNA-binding or DNA-damage potentiation, is a major focus of current clinical studies. These and other targeted therapies represent a new approach to TNBC therapy.

Sorafenib or placebo with either gemcitabine or capecitabine in patients with HER-2-negative advanced breast cancer that progressed during or after bevacizumab

PURPOSE

We assessed adding the multikinase inhibitor sorafenib to gemcitabine or capecitabine in patients with advanced breast cancer whose disease progressed during/after bevacizumab.

EXPERIMENTAL DESIGN

This double-blind, randomized, placebo-controlled phase IIb study (ClinicalTrials.gov NCT00493636) enrolled patients with locally advanced or metastatic human epidermal growth factor receptor 2 (HER2)-negative breast cancer and prior bevacizumab treatment. Patients were randomized to chemotherapy with sorafenib (400 mg, twice daily) or matching placebo. Initially, chemotherapy was gemcitabine (1,000 mg/m(2) i.v., days 1, 8/21), but later, capecitabine (1,000 mg/m(2) orally twice daily, days 1-14/21) was allowed as an alternative. The primary endpoint was progression-free survival (PFS).

RESULTS

One hundred and sixty patients were randomized. More patients received gemcitabine (82.5%) than capecitabine (17.5%). Sorafenib plus gemcitabine/capecitabine was associated with a statistically significant prolongation in PFS versus placebo plus gemcitabine/capecitabine [3.4 vs. 2.7 months; HR = 0.65; 95% confidence interval (CI): 0.45-0.95; P = 0.02], time to progression was increased (median, 3.6 vs. 2.7 months; HR = 0.64; 95% CI: 0.44-0.93; P = 0.02), and overall response rate was 19.8% versus 12.7% (P = 0.23). Median survival was 13.4 versus 11.4 months for sorafenib versus placebo (HR = 1.01; 95% CI: 0.71-1.44; P = 0.95). Addition of sorafenib versus placebo increased grade 3/4 hand-foot skin reaction (39% vs. 5%), stomatitis (10% vs. 0%), fatigue (18% vs. 9%), and dose reductions that were more frequent (51.9% vs. 7.8%).

CONCLUSION

The addition of sorafenib to gemcitabine/capecitabine provided a clinically small but statistically significant PFS benefit in HER2-negative advanced breast cancer patients whose disease progressed during/after bevacizumab. Combination treatment was associated with manageable toxicities but frequently required dose reductions.

Molecularly targeted therapies for metastatic triple-negative breast cancer

Triple-negative breast cancer (TNBC) refers to a heterogeneous group of tumors that do not express the estrogen/progesterone-receptor (ER/PR), and human epidermal growth factor receptor-2 (HER2). TNBC is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapy regimens. There have been significant improvements in the outcome of other subtypes of breast cancer, including ER-positive/HER2 overexpressed tumors, attributed to the addition of targeted therapy, including hormonal agents and trastuzumab. However, no specific targeted agents are currently available for the treatment of TNBC. This review aims to collate and describe the most recent data on targeted therapies that have demonstrated efficacy in the management of metastatic TNBC. Targeted agents that have been investigated in the treatment of metastatic TNBC include inhibitors of poly(ADP-ribose) polymerase, angiogenesis, mammalian target of rapamycin, epidermal growth factor receptor, HDAC, Jak2, and Src. Several of these agents have shown considerable promise.

North central cancer treatment group (NCCTG) N0537: phase II trial of VEGF-trap in patients with metastatic breast cancer previously treated with an anthracycline and/or a taxane

INTRODUCTION

Angiogenesis is an established target for the treatment of MBC. Aflibercept (VEGF-Trap) is a humanized fusion protein, which binds VEGF-A, VEGF-B, and PIGF-1 and -2.

PATIENTS AND METHODS

A 2-stage phase II study with primary end points of confirmed tumor response and 6-month progression-free survival (PFS). If either end point was promising after the initial 21 patients, an additional 20 patients would be enrolled. Measurable disease, <2 previous chemotherapy treatments, previous anthracycline or taxane therapy, and Eastern Cooperative Oncology Group performance status of 0 or 1 were required. Aflibercept was given at a dose of 4 mg/kg intravenous every 14 days.

RESULTS

Twenty-one patients were enrolled; 71% had visceral disease, 57% were estrogen receptor negative, 19% had HER2(+) disease with previous trastuzumab treatment, and 33% had 2 previous chemotherapy regimens. Partial response rate was 4.8% (95% confidence interval [CI], 0.1%-23.8%) and 6-month PFS was 9.5% (95% CI, 1.2%-30.4%). Neither primary end point met efficacy goals and the study was terminated. A median of 3 cycles was given. Median PFS was 2.4 months. Common grade 3 or 4 adverse events were hypertension (33%), fatigue (19%), dyspnea (14%), and headache (14%). Two cases of severe left ventricular dysfunction were noted.

CONCLUSIONS

Aflibercept did not meet efficacy goals in patients previously treated with MBC. Toxicity was as expected for anti-VEGF therapy.

Combination antiangiogenic therapy in advanced breast cancer: a phase 1 trial of vandetanib, a VEGFR inhibitor, and metronomic chemotherapy, with correlative platelet proteomics

This phase 1 study evaluated the safety and tolerability of antiangiogenic therapy using vandetanib and metronomic cyclophosphamide and methotrexate in metastatic breast cancer. Eligible patients had metastatic breast cancer with 0-4 prior chemotherapy regimens. All received cyclophosphamide 50 mg daily, methotrexate 2.5 mg days 1-2 weekly, and vandetanib daily in 3 dose-escalation cohorts: 100 mg (C1), 200 mg (C2), and 300 mg (C3). The primary endpoint was safety and tolerability; secondary endpoints included response rate and evaluation of platelet-associated proteins. Twenty three patients were treated and evaluable for toxicity. Common mild toxicities included nausea, vomiting, LFTs abnormalities, fatigue, and rash. Three episodes of dose-limiting toxicity occurred in C3. In all cohorts, 1/3 of patients required vandetanib dose reduction, and 22 % ended therapy for toxicity. Of the 20 response-evaluable patients, 10 % demonstrated partial response and 15 % stable disease ≥24 weeks. Proteomic analyses demonstrated changes in platelet content of angiogenesis regulators, including vascular endothelial growth factor and platelet factor 4, with exposure to therapy. This regimen was tolerable at a maximum vandetanib dose of 200 mg; modest clinical activity was observed in this heavily pretreated population. Changes in the platelet proteome may serve as pharmacodynamic markers of angiogenesis inhibition. Metronomic chemotherapy is an attractive partner with biologics and deserves further study in metastatic breast cancer.

A double-blind, randomised, placebo-controlled, phase 2b study evaluating sorafenib in combination with paclitaxel as a first-line therapy in patients with HER2-negative advanced breast cancer

BACKGROUND

We conducted a phase 2b, randomised, double-blind, placebo-controlled screening trial to evaluate the addition of the multikinase inhibitor sorafenib (antiproliferative/antiangiogenic) to first-line paclitaxel for human epidermal growth factor receptor 2 (HER2)-negative locally recurrent/metastatic breast cancer.

METHODS

Patients were randomised to paclitaxel (90mg/m(2), weekly, intravenously, 3 weeks on/1 week off) plus sorafenib (400mg, orally, twice daily) or placebo. The primary endpoint was progression-free survival (PFS). A sample size of 220 patients was planned with relative risk ≤ 0.82 (1-sided α=0.14) after 120 events supporting a treatment effect.

FINDINGS

Patients were randomised in India (n=170), the United States (n=52) and Brazil (n=15). Median PFS was 6.9 months for sorafenib versus 5.6 months for placebo (hazard ratio (HR)=0.788; 95% confidence interval (CI), 0.558-1.112; P=0.1715 [1-sided P=0.0857]). The addition of sorafenib increased time to progression (median, 8.1 versus 5.6 months; HR=0.674; 95% CI 0.465-0.975; P=0.0343) and improved overall response (67% versus 54%; P=0.0468). Overall survival did not statistically differ (median, 16.8 versus 17.4 months; HR=1.022; 95% CI 0.715-1.461; P=0.904). Grade 3/4 toxicities (sorafenib versus placebo) included hand-foot skin reaction (31% versus 3%), neutropenia (13% versus 7%) and anaemia (11% versus 6%). Two treatment-related deaths occurred (malaria and liver dysfunction) in the sorafenib arm.

INTERPRETATION

The addition of sorafenib to paclitaxel improved disease control but did not significantly improve PFS to support a phase 3 trial of similar design. Toxicity of the combination was manageable with dose reductions.

Targeting triple-negative breast cancer: optimising therapeutic outcomes

BACKGROUND

Triple-negative breast cancer (TNBC) is a distinct subset of breast cancer (BC) defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2. It is highly heterogeneous and displays overlapping characteristics with both basal-like and BC susceptibility gene 1 and 2 mutant BCs. This review evaluates the activity of emerging targeted agents in TNBC.

DESIGN

A systematic review of PubMed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with targeted and platinum-based therapies.

RESULTS AND DISCUSSION

Our review identified TNBC studies of agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. Combining targeted agents with chemotherapy in TNBC produced only modest gains in progression-free survival, and had little impact on survival. Six TNBC subgroups have been identified and found to differentially respond to specific targeted agents. The use of biological preselection to guide therapy will improve therapeutic indices in target-bearing populations.

CONCLUSION

Ongoing clinical trials of targeted agents in unselected TNBC populations have yet to produce substantial improvements in outcomes, and advancements will depend on their development in target-selected populations.