Efficacy of trebananib (AMG 386) in treating epithelial ovarian cancer

INTRODUCTION

Epithelial ovarian cancer (EOC) is the leading cause of death among gynecologic cancers. The majority of women are diagnosed with advanced stage disease. It is considered a chemosensitive cancer with a high initial response rate to first-line platinum and taxane-based chemotherapy. However, most patients with advanced EOC will relapse with subsequent resistance to conventional chemotherapy and ultimately succumb to their disease. Therefore, new therapeutic agents and strategies are desperately needed to improve the outcomes in patients with advanced EOC.

AREAS COVERED

This review focuses on the use of Trebananib (a non-VEGF-dependent angiogenesis pathway inhibitor) in EOC. Angiogenesis has been recognized as an important process promoting EOC growth and metastasis. Targeting angiogenesis in EOC have been developed and studied with demonstrated clinical efficacy. Bevacizumab, a humanized monoclonal antibody, that targets vascular endothelial growth factor A (VEGF-A), has been the most well evaluated molecular targeted therapy in the treatment of advanced and recurrent EOC with proven clinical efficacy. However, VEGF-dependent angiogenesis pathway inhibitors are often associated with serious toxicities and drug resistance ultimately develops. Hence, new therapeutic approach targeting the angiopoietin-Tie-2 complex pathway (a non-VEGF-dependent angiogenesis pathway) has gained interest over the past few years as an alternative strategy to overcome VEGF-dependent anti-angiogenesis-related toxicity and resistance.

EXPERT OPINION

Targeting angiopoietin-Tie-2 pathway represents a promising alternative approach to tumor anti-angiogenesis with a distinct toxicity profile from the VEGF-dependent pathway inhibitors. However, there are still many questions to be answered regarding the optimal treatment schedules, maintenance regimens, duration of maintenance therapy, and the best combination strategy. Currently there is no reliable surrogate molecular, cellular, or genetic marker that would definitively predict response to anti-angiogenic therapy. Identification of certain relevant and predictive biomarkers in the future may optimize treatment's efficacy by distinguishing the subset group of patients with EOC that would derive the most benefit from existing antiangiogenic treatment regimens.

Emerging therapies: angiogenesis inhibitors for ovarian cancer

INTRODUCTION

Patients with epithelial ovarian cancer (EOC) have a high rate of recurrence, and overall survival remains at ∼ 25%. There is a need for new treatments that can increase progression free survival and quality of life. Recent clinical trials focus on angiogenesis, VEGFs, and tyrosine kinase inhibitors that play a role in recurrence, metastasis, and ascites in EOC.

AREAS COVERED

This review summarizes clinical rationale, mechanisms of action, and clinical data for angiogenesis inhibitors under evaluation in Phase II and III trials for EOC. Anti-angiogenesis agents reviewed in this paper include aflibercept, bevacizumab, cediranib, fosbretabulin, imatinib, nintedanib, pazopanib, saracatinib, sorafenib, sunitinib, and trebananib.

EXPERT OPINION

These agents have particular rationale for potential use in EOC due to the molecular changes associated with EOC tumorigenesis, namely a significant increase in angiogenic activity. Due to the costs and toxicities associated with anti-angiogenics, biomarker or molecular signature selection strategy for patients who will most benefit would be ideal but no such strategy has been validated to date.

Anti-vascular therapies in ovarian cancer: moving beyond anti-VEGF approaches

Resistance to chemotherapy is among the most important issues in the management of ovarian cancer. Unlike cancer cells, which are heterogeneous as a result of remarkable genetic instability, stromal cells are considered relatively homogeneous. Thus, targeting the tumor microenvironment is an attractive approach for cancer therapy. Arguably, anti-vascular endothelial growth factor (anti-VEGF) therapies hold great promise, but their efficacy has been modest, likely owing to redundant and complementary angiogenic pathways. Components of platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), epidermal growth factor (EGF), and other pathways may compensate for VEGF blockade and allow angiogenesis to occur despite anti-VEGF treatment. In addition, hypoxia induced by anti-angiogenesis therapy modifies signaling pathways in tumor and stromal cells, which induces resistance to therapy. Because of tumor cell heterogeneity and angiogenic pathway redundancy, combining cytotoxic and targeted therapies or combining therapies targeting different pathways can potentially overcome resistance. Although targeted therapy is showing promise, much more work is needed to maximize its impact, including the discovery of new targets and identification of individuals most likely to benefit from such therapies.

A multifunctional nanoparticulate theranostic system with simultaneous chemotherapeutic, photothermal therapeutic, and MRI contrast capabilities

Herein, a single-step, scalable approach for preparing a multifunctional, theranostic drug delivery system made out of paclitaxel, iron oxide nanoparticles, gold nanoparticles, and poly(ethylene oxide)-b-poly(ε-caprolactone) is reported.

Angiogenesis inhibitors for patients with ovarian cancer: a meta-analysis of 12 randomized controlled trials

OBJECTIVES

To investigate the effects of angiogenesis inhibitors in the treatment of patients with advanced or recurrent ovarian cancer, a meta-analysis was performed and overall survival (OS), progression-free survival (PFS), and toxicity were assessed.

PATIENTS AND METHODS

The PubMed and Embase databases, and the Cochrane Central Register of Controlled Trials were searched for publications between January 2000 and June 2015. Hazard ratios (HRs) with their 95% confidence intervals (CIs), or data for calculating HRs with 95% CIs were derived.

RESULTS

The 12 trials in this meta-analysis were divided into three groups: four trials with a VEGF inhibitor (the bevacizumab group), six trials with VEGFR inhibitors (the VEGFRIs group), and two trials with an angiopoietin inhibitor (the trebananib group). PFS improvement was seen in all groups (HR = 0.61, 95% CI 0.48 to 0.79, P < 0.001 for bevacizumab; HR = 0.71, 95% CI 0.59 to 0.87, P = 0.001 for VEGFRIs; and HR = 0.67, 95% CI 0.62 to 0.72, P < 0.001 for trebananib). Regarding OS, bevacizumab showed a trend of improvement (HR = 0.90, 95% CI 0.80 to 1.01, P = 0.079), VEGFRIs showed no improvement (HR = 0.92, 95% CI 0.75 to 1.11, P = 0.368), and trebananib demonstrated a significant prolongation (HR = 0.81, 95% CI 0.67 to 0.99, P = 0.036). Bevacizumab was associated with more class-specific adverse events (RR = 4.05, 95% CI 1.99 to 8.27, P < 0.001). Although the toxicity profiles differed, VEGFRIs developed common higher incidences of hypertension, diarrhea, and fatigue. A higher incidence of edema was reported in the trebananib group (RR = 2.60, 95% CI 0.84 to 8.00, P = 0.097).

CONCLUSIONS

Anti-angiogenic therapy showed clear PFS benefit with increased toxicity, but its role in OS was undefined for ovarian cancer which emphasized the need for patient selection.

Prediction of anti-angiogenesis escape

Many clinical trials have demonstrated the benefit of anti-angiogenesis therapy in the treatment of gynecologic cancer. However, these benefits have often been in terms of progression-free rather than overall survival and in some cases, the magnitude of benefit demonstrated in the pivotal phase 3 trials has been disappointing when compared with the percentage of patients who responded in earlier phase 2 trials. Two potential explanations for this are the current inability to stratify patients according to chance of benefit and the development of resistance mechanisms within the tumor. In this article, we review the prediction of response and the proposed resistance and escape mechanisms involved in anti-angiogenesis therapy, including the up-regulation of alternative proangiogenic pathways, vascular co-option, and resistance to hypoxia. These insights may offer a personalized strategy for anti-angiogenesis therapy and help us to consider the best selection of other therapies that should be combined with anti-angiogenesis therapy to improve the outcome of patients with gynecologic cancer.

Taxane anticancer agents: a patent perspective

INTRODUCTION

Paclitaxel and docetaxel were two epoch-making anticancer drugs and have been successfully used in chemotherapy for a variety of cancer types. In the year 2010, a new taxane, cabazitaxel, was approved by FDA for use in combination with prednisone for the treatment of metastatic hormone-refractory prostate cancer. Albumin-bound paclitaxel (nab™-paclitaxel; abraxane) nanodroplet formulation was another notable invention (FDA approval 2005 for refractory, metastatic, or relapsed breast cancer). Abraxane in combination with gemcitabine for the treatment of pancreatic cancer was approved by FDA in 2013. Accordingly, there have been a huge number of patent applications dealing with taxane anticancer agents in the last 5 years. Thus, it is a good time to review the progress in this area and find the next wave for new developments.

AREA COVERED

This review covers the patent literature from the year 2010 to early 2015 on various aspects of taxane-based chemotherapies and drug developments.

EXPERT OPINION

Three FDA-approved taxane anticancer drugs will continue to expand their therapeutic applications, especially through drug combinations and new formulations. Inspired by the success of abraxane, new nano-formulations are emerging. Highly potent new-generation taxanes will play a key role in the development of efficacious tumor-targeted drug delivery systems.

Intensive cisplatin/oral etoposide for epithelial ovarian cancer: the Cambridge Gynae-Oncology Centre experience: too toxic for relapse?

Intensive cisplatin and oral etoposide for relapsed epithelial ovarian cancer (EOC), commonly known as the van der Burg (VDB) protocol, has been reported to improve response rates and progression-free survival. We report on all patients with relapsed EOC treated on the VDB protocol at the Cambridge Gynae-Oncology Centre. From the institutional databases, we identified all patients treated since 2001. We extracted demographic, clinical, treatment, and toxicity data and outcomes. We used Cox regression to identify predictors of survival. A total of 35 patients were treated on the VDB protocol. Toxicity was significant, with grade 3/4 fatigue, nausea and vomiting affecting 46, 46 and 29% of patients, respectively. Six patients had grade 3/4 infection and four (11%) deaths occurred on treatment. Efficacy was encouraging, with a radiological response rate of 43%, a median progression-free survival of 5.8 months and a median overall survival of 14.1 months. No significant difference in efficacy was seen between platinum-resistant and sensitive patients. We report significant activity of the VDB protocol in a routine clinical setting. However, the high rates of serious toxicity and treatment-related deaths among patients treated with palliative intent proved unacceptable. The Cambridge Gynae-Oncology Centre no longer uses this regimen in women with relapsed EOC.

Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer

Introduction

In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the non-specific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets.

Methods

We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription.

Results and conclusion

Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies.

Generation of new peptide-Fc fusion proteins that mediate antibody-dependent cellular cytotoxicity against different types of cancer cells

Antibody-dependent cellular cytotoxicity (ADCC), a key effector function for the clinical effectiveness of monoclonal antibodies, is triggered by the engagement of the antibody Fc domain with the Fcγ receptors expressed by innate immune cells such as natural killer (NK) cells and macrophages. Here, we fused cancer cell-binding peptides to the Fc domain of human IgG1 to engineer novel peptide-Fc fusion proteins with ADCC activity. The designed fusion proteins were expressed in human embryonic kidney 293T cells, followed by purification and characterization by western blots. One of the engineered variants (WN-Fc), bound with high affinity to a wide range of solid tumor cell lines (e.g., colon, lung, prostate, skin, ovarian, and mammary tumors). Treatment of cancer cells with the engineered peptide-Fc fusions in the presence of effector NK cells potentially enhanced cytotoxicity, degranulation, and interferon-γ production by NK cells when compared to cells treated with the Fc control. The presence of competing peptides inhibited NK cell activation. Furthermore, a bispecific peptide-Fc fusion protein activated NK cells against HER-1- and/or HER-2-expressing cancer cells. Collectively, the engineered peptide-Fc fusions constitute a new promising strategy to recruit and activate NK cells against tumor cells, a primary goal of cancer immunotherapy.

Beyond Bevacizumab: An Outlook to New Anti-Angiogenics for the Treatment of Ovarian Cancer

In addition to the monoclonal vascular endothelial growth factor (VEGF) antibody bevacizumab, several alternative anti-angiogenic treatment strategies for ovarian cancer patients have been evaluated in clinical trials. Apart from targeting extracellular receptors by the antibody aflibercept or the peptibody trebananib, the multikinase inhibitors pazopanib, nintedanib, cediranib, sunitinib, and sorafenib were developed to interfere with VEGF receptors and multiple additional intracellular pathways. Nintedanib and pazopanib significantly improved progression-free survival in two positive phase III trials for first-line therapy. A reliable effect on overall survival could, however, not be observed for any anti-angiogenic first-line therapies so far. In terms of recurrent disease, two positive phase III trials revealed that trebananib and cediranib are effective anti-angiogenic agents for this indication. Patient selection and biomarker guided prediction of response seems to be a central aspect for future studies. Combining anti-angiogenics with other targeted therapies to possibly spare chemotherapy in certain constellations represents another very interesting future perspective for clinical trials. This short review gives an overview of current clinical trials for anti-angiogenic treatment strategies beyond bevacizumab. In this context, possible future perspectives combining anti-angiogenics with other targeted therapies and the need for specific biomarkers predicting response are elucidated.

Maintenance Therapy in Ovarian Cancer with Targeted Agents Improves PFS and OS: A Systematic Review and Meta-Analysis

Background

Maintenance therapy with targeted agents for prolonging remission for ovarian cancer patients remains controversial. As a result, a meta-analysis was conducted to assess the effectiveness and safety of using maintenance therapy with targeted agents for the treatment of ovarian cancer.

Methods

From inception to January 2015, we searched for randomized, controlled trials (RCTs) using the following databases: PubMed, ScienceDirect, the Cochrane Library, Clinicaltrials.gov and EBSCO. Eligible trials included RCTs that evaluated standard chemotherapy which was either followed or not followed by targeted maintenance in patients with ovarian cancer who had been previously receiving adjunctive treatments, such as cytoreductive surgery and standard chemotherapy. The outcome measures included progression-free survival (PFS), overall survival (OS) and incidence of adverse events.

Results

A total of 13 RCTs, which were published between 2006 and 2014, were found to be in accordance with our inclusion criteria. The primary meta-analysis indicated that both PFS and OS were statistically and significantly improved in the targeted maintenance therapy group as compared to the control group (PFS: HR = 0.84, 95%CI: 0.75 to 0.95, p = 0.001; OS: HR = 0.91, 95%CI: 0.84 to 0.98, p = 0.02). When taking safety into consideration, the use of targeted agents was significantly correlated with increased risks of fatigue, diarrhea, nausea, vomiting, and hypertension. However, no significant differences were found in incidence rates of abdominal pain, constipation or joint pain.

Conclusions

Our results indicate that targeted maintenance therapy clearly improves the survival of ovarian cancer patients but may also increase the incidence of adverse events. Additional randomized, double-blind, placebo-controlled, multicenter investigations will be required on a larger cohort of patients to verify our findings.

Photoacoustic Tomography Detects Early Vessel Regression and Normalization During Ovarian Tumor Response to the Antiangiogenic Therapy Trebananib

The primary aim of this study was to assess the potential of in vivo photoacoustic tomography for direct functional measurement of ovarian tumor response to antiangiogenic therapy.

METHODS

In vivo studies were performed with institutional animal care and use committee approval. We used an orthotopic mouse model of ovarian cancer treated with trebananib (n = 9) or vehicle (n = 9). Tumor-bearing mice were randomized into trebananib or vehicle groups at day 10 and dosed on days 12, 15, and 18 after implantation. Photoacoustic tomography and blood draws were performed at day 10 and then 24 h after each drug dose. Tumors were excised for histopathology after the final studies on day 19. Data analysis to test for statistical significance was performed blinded.

RESULTS

Blockade of angiopoietin signaling using trebananib resulted in reduced total hemoglobin-weighted photoacoustic signal (n = 9, P = 0.01) and increased oxyhemoglobin-weighted photoacoustic signal (n = 9, P < 0.01). The latter observation indicated normalization of the residual tumor vessels, which was also implied by low levels of angiopoietin 1 in serum biomarker profiling (0.76 ± 0.12 ng/mL). These noninvasive measures reflected a 30% reduction in microvessel density and increased vessel maturation in ex vivo sections.

CONCLUSION

Photoacoustic tomography is able to evaluate both vessel regression and normalization in response to trebananib. Noninvasive imaging data were supported by modulation of serum markers in vitro and ex vivo histopathology.

A phase 1b, open-label study of trebananib plus bevacizumab or motesanib in patients with solid tumours

BACKGROUND

To examine the angiopoietin pathway inhibitor trebananib IV plus the anti-VEGF agents bevacizumab or motesanib in advanced solid tumours.

METHODS

In this open-label phase 1b study, patients received IV trebananib 3 mg kg-1 QW plus bevacizumab 15 mg kg-1 Q3W (cohort 1) or motesanib orally 75 mg (cohort 2); or trebananib 10 mg kg-1 plus bevacizumab 15 mg kg-1 (cohort 3) or motesanib 125 mg (cohort 4). If <33% of patients had dose-limiting toxicities (DLTs), dose escalation occurred. Endpoints were treatment-related adverse events (AEs) incidence and pharmacokinetics (primary); anti-trebananib antibodies, biomarkers, and tumour response (secondary).

RESULTS

Thirty-six patients received ≥ 1 dose of trebananib (cohorts 1, 2, 3, 4; n = 6, 8, 19, 3). DLT of G3 intestinal perforation and G3 tumor haemorrhage occurred in cohorts 2 and 3, respectively (both n = 1). Across both trebananib plus bevacizumab cohorts, the most common AEs included fatigue (n = 8), diarrhoea (n =4), constipation (n = 3), nausea (n = 3), and epistaxis (n = 3). Three patients across those cohorts had grade ≥ 3 AEs. Across the trebananib plus motesanib cohorts, the most common AEs included hypertension (n = 4), diarrhoea (n = 4), nausea (n = 3), fatigue (n = 3), vomiting (n = 2), and decreased appetite (n = 2). Two patients had grade ≥ 3 AEs. Trebananib did not markedly affect motesanib pharmacokinetics. Across the trebananib plus bevacizumab cohorts, two patients had a partial response; 11 patients had stable disease lasting >6 months. Across the trebananib plus motesanib cohorts, one patient had a partial response; five patients had stable disease lasting >6 months.

CONCLUSION

Trebananib IV 3 mg kg-1 or 10 mg kg-1 plus bevacizumab or motesanib in advanced solid tumours may be associated with less severe toxicities relative to those emerging when combining two anti-VEGF agents.

Trebananib (AMG 386) in Combination With Sunitinib in Patients With Metastatic Renal Cell Cancer: An Open-Label, Multicenter, Phase II Study

PURPOSE

Trebananib, an investigational recombinant peptide-Fc fusion protein, neutralizes the receptor-ligand interaction between Tie2 and angiopoietin-1/2. This phase II study was conducted to evaluate trebananib plus sunitinib, a vascular endothelial growth factor receptor inhibitor, in patients with metastatic clear cell renal cell carcinoma.

PATIENTS AND METHODS

Adults with metastatic renal cell carcinoma were enrolled sequentially onto two cohorts that received sunitinib 50 mg once per day for 4 weeks on and 2 weeks off and intravenous trebananib once per week at a dose of 10 mg/kg in cohort A or 15 mg/kg in cohort B. The primary end points were incidences of adverse events (AEs) and dose interruptions of sunitinib during the first 12 weeks of treatment. Secondary end points included objective response rate and progression-free survival.

RESULTS

Eighty-five patients were enrolled: 43 in cohort A, and 42 in cohort B. During the first 12 weeks of treatment, 58% and 57% of patients in cohorts A and B, respectively, had sunitinib dose interruptions (dose decrease, withholding, or withdrawal). The most frequent AEs were diarrhea (cohort A, 74%; cohort B, 67%), mucosal inflammation (cohort A, 49%; cohort B, 60%), and hypertension (cohort A, 52%; cohort B, 45%). AEs of grade 3 or greater occurred in 58% of patients in cohort A and in 69% of patients in cohort B. The objective response rate was 58% and 63% in cohorts A and B, respectively. The median progression-free survival time was 13.9 months (95% CI, 10.4 to 19.2) and 16.3 months (95% CI, 13.1 to 21.4) in cohorts A and B, respectively. The median overall survival time was 36 months (95% CI, 25.2 to not estimable) in cohort A and was not estimable (median follow-up, 25 months) in cohort B.

CONCLUSION

Trebananib plus sunitinib seemed to increase toxicity at the tested doses. Efficacy results suggest a potential benefit for the addition of trebananib to sunitinib.

The prognostic significance of anti-angiogenesis therapy in ovarian cancer: a meta-analysis

Objective

The prognostic value of anti-angiogenesis therapy in ovarian cancer patients is currently under debate. In this study, we assessed the effects of anti-angiogenesis therapy on the progression free survival (PFS) and overall survival (OS) of ovarian cancer patients.

Materials and methods

PubMed was searched to identify relevant studies that evaluated the therapeutic value of anti-angiogenic agents in ovarian cancer (the final search was current to Dec. 13th 2014). Reviews of each study were conducted, and the data were extracted. The primary outcomes that were analysed were progression free survival (PFS) and overall survival (OS). The pooled hazard ratio (HR) and 95 % confidence intervals (CIs) were calculated using the random and fixed-effects models, and subgroup and sensitivity analyses were subsequently performed.

Results

A total of 12 studies were included in the meta-analysis. The overall analysis revealed that the incorporation of anti-angiogenesis therapy was significantly associated with a longer PFS (HR, 0.66; 95 % CI, 0.58-0.75; P < 0.01) and a longer OS (HR, 0.89; 95 % CI, 0.82-0.97; P = 0.01) in the total population, and these findings were confirmed by one-way sensitivity analyses. Further subgroup analyses demonstrated that the administrations of each of the agents were associated with improved PFSs. The prognostic value of anti-angiogenesis therapy for the OS was significant in the trebananib subgroup (HR, 0.81; 95 % CI, 0.67-0.99; P = 0.04). The bevacizumab subgroup exhibited a similar trend that did not reach statistical significance (HR, 0.90; 95 % CI, 0.80-1.01; P = 0.08).

Conclusions

The present meta-analysis indicated that anti-angiogenesis therapy in ovarian cancer patients was associated with a better clinical outcome. Further studies are warranted to identify the specific subgroup of patients who are most likely to benefit from anti-angiogenesis therapy.

Antiangiogenic agents in gynecological cancer: State of art and perspectives of clinical research

Vascular endothelial growth factor [VEGF] pathway, which plays a key role in angiogenesis, may be blocked by either extracellular interference with VEGF itself (bevacizumab [BEV] or aflibercept), or intracytoplasmic inhibition of VEGF receptor (pazopanib, nintedanib, cediranid, sunitinib and sorafenib). An alternative approach is represented by trebananib, a fusion protein that prevents the interaction of angiopoietin [Ang]-1 and Ang-2 with Tie2 receptor on vascular endothelium. The combination of antiangiogenic agents, especially BEV, and chemotherapy is a rational therapeutic option for primary or recurrent ovarian carcinoma. However, it will be difficult to accept that it represents the new standard treatment, until biological characterization of ovarian carcinoma has not identified subsets of tumors with different responsiveness to BEV. Anti-angiogenesis is an interesting target also for recurrent cervical or endometrial cancer, but nowadays the use of anti-angiogenic agents in these malignancies should be reserved to patients enrolled in clinical trials.

First-line and maintenance therapy for ovarian cancer: current status and future directions

Paclitaxel and carboplatin combination chemotherapy has remained the standard of care in the frontline therapy of advanced epithelial ovarian carcinoma during the last decade. Maintenance chemotherapy or immunotherapy has not been proven to impact on overall survival and only one clinical trial that explored the administration of monthly paclitaxel for 1 year showed a benefit in terms of progression-free survival (PFS), but at the cost of maintained alopecia and increased peripheral neuropathy. This scenario may be changing with the incorporation of targeted therapy to the frontline therapy of ovarian cancer. In particular, anti-angiogenic therapy has been identified as the most promising targeted therapy, and the addition of bevacizumab to first-line chemotherapy followed by a maintenance period of bevacizumab in monotherapy has shown to prolong PFS. This was considered the proof of concept of the value of anti-angiogenic therapy in the frontline of ovarian cancer, and the results of two additional clinical trials with anti-angiogenic tyrosine-kinase inhibitors have shown results in the same direction.

Pharmacokinetic drug-drug interaction study of the angiopoietin-1/angiopoietin-2-inhibiting peptibody trebananib (AMG 386) and paclitaxel in patients with advanced solid tumors

BACKGROUND

Trebananib is an anti-angiogenic peptibody under investigation in patients with advanced cancer. This study evaluated the pharmacokinetic (PK) drug-drug interaction of paclitaxel and trebananib.

PATIENTS AND METHODS

Patients with advanced solid tumors received weekly 80 mg/m(2) intravenous (IV) paclitaxel (3 weeks on/1 week off) with weekly 15 mg/kg IV trebananib starting at Week 2. Blood samples for PK analysis were collected at Week 1 (paclitaxel alone), Week 6 (paclitaxel and trebananib), and Week 8 (trebananib alone). An absence of interaction was to be concluded if the 90 % confidence intervals (CI) for the differences in paclitaxel exposure fell within the 0.80-1.25 interval.

RESULTS

The primary study was conducted between 7/2012 and 10/2013. Thirty-five patients were enrolled and 34 received both treatments. Most patients were white (91 %) and female (59 %); mean age was 61 years. The most common tumor types were ovarian (32 %) and bladder (27 %), 71 % of patients had stage IV disease, and all had Eastern Cooperative Oncology Group (ECOG) scores of 0 or 1. PK parameter analysis was done on patients with evaluable PK data at both assessments (with and without concomitant therapy; n = 28). The geometric least squares mean (GLSM) ratio (90 % CI) of paclitaxel AUCinf with and without trebananib was 1.17 (1.10, 1.25). The GLSM ratio (90 % CI) of trebananib AUCtau,ss with and without paclitaxel was 0.92 (0.87, 0.97). The most common adverse events were fatigue, local edema, peripheral edema, and nausea.

CONCLUSIONS

This study showed no evidence of clinically meaningful PK interaction between paclitaxel and trebananib.

Trebananib (AMG 386) plus weekly paclitaxel with or without bevacizumab as first-line therapy for HER2-negative locally recurrent or metastatic breast cancer: A phase 2 randomized study

INTRODUCTION

This phase 2 randomized study evaluated trebananib (AMG 386), a peptide-Fc fusion protein that inhibits angiogenesis by neutralizing the interaction of angiopoietin-1 and -2 with Tie2, in combination with paclitaxel with or without bevacizumab in previously untreated patients with HER2-negative locally recurrent/metastatic breast cancer.

METHODS

Patients received paclitaxel 90 mg/m(2) once weekly (3-weeks-on/1-week-off) and were randomly assigned 1:1:1:1 to also receive blinded bevacizumab 10 mg/kg once every 2 weeks plus either trebananib 10 mg/kg once weekly (Arm A) or 3 mg/kg once weekly (Arm B), or placebo (Arm C); or open-label trebananib 10 mg/kg once a week (Arm D). Progression-free survival was the primary endpoint.

RESULTS

In total, 228 patients were randomized. Median estimated progression-free survival for Arms A, B, C, and D was 11.3, 9.2, 12.2, and 10 months, respectively. Hazard ratios (95% CI) for Arms A, B, and D versus Arm C were 0.98 (0.61-1.59), 1.12 (0.70-1.80), and 1.28 (0.79-2.09), respectively. The objective response rate was 71% in Arm A, 51% in Arm B, 60% in Arm C, and 46% in Arm D. The incidence of grade 3/4/5 adverse events was 71/9/4%, 61/14/5%, 62/16/3%, and 52/4/7% in Arms A/B/C/D. In Arm D, median progression-free survival was 12.8 and 7.4 months for those with high and low trebananib exposure (AUCss ≥ 8.4 versus < 8.4 mg·h/mL), respectively.

CONCLUSIONS

There was no apparent prolongation of estimated progression-free survival with the addition of trebananib to paclitaxel and bevacizumab at the doses tested. Toxicity was manageable. Exposure-response analyses support evaluation of combinations incorporating trebananib at doses > 10 mg/kg in this setting.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00511459.

Advances in anti-angiogenic agents for ovarian cancer treatment: The role of trebananib (AMG 386)

Ovarian cancer is a multifaceted and genomically complex disease and has emerged as leading cause of death among gynecological malignancies. Gold-standard treatment consisted of cytoreductive surgery and paclitaxel-carboplatin chemotherapy. Recently, promising results of randomized trials have definitively confirmed the importance of angiogenesis in oncogenesis and ovarian cancer behavior, by showing a significant prolongation of progression-free survival with the addiction of an angiogenesis inhibitor to standard treatment in the first and second line setting. Research over the years has sequentially provided a rapidly broadening signaling landscape and many drugs targeting different signaling pathways of angiogenesis have been developed and investigated. Recently accumulating scientific evidence has started to shed light on the efficacy of AMG 386, a new peptibody reported to neutralize the interaction between angiopoietins (Ang1/2) and their Tie2 receptors, thus representing a promising alternative, both in terms of efficacy and toxicity profile and is considerably under investigation. The aim of this review is to summarize the recent researches and clinical progresses of AMG 386 as a novel target agent in ovarian cancer.

New ways to successfully target tumor vasculature in ovarian cancer

PURPOSE OF REVIEW

The aim of this article was to review the recent literature on potential therapeutic strategies for overcoming resistance to antivascular endothelial growth factor drugs in ovarian cancer.

RECENT FINDINGS

Although clinical benefits of antivascular endothelial growth factor therapy were observed in ovarian cancer treatment trials, this use yielded only modest improvement in progression-free survival and, with the exception of cediranib, no effect on overall survival. Adaptive resistance and escape from antiangiogenesis therapy is likely a multifactorial process, including induction of hypoxia, vascular modulators, and immune response. New drugs targeting the tumor vasculature or other components of the surrounding microenvironment have shown promising results.

SUMMARY

When to start and end antiangiogenesis therapy and the choice of optimal treatment combinations remain controversial. Further evaluation of personalized novel angiogenesis-based therapy is warranted. Defining the critical interaction of these agents and pathways and the appropriate predictive markers will become an increasingly important objective for effective treatment.

Paclitaxel resistance increases oncolytic adenovirus efficacy via upregulated CAR expression and dysfunctional cell cycle control

Resistance to paclitaxel chemotherapy frequently develops in ovarian cancer. Oncolytic adenoviruses are a novel therapy for human malignancies that are being evaluated in early phase trials. However, there are no reliable predictive biomarkers for oncolytic adenovirus activity in ovarian cancer. We investigated the link between paclitaxel resistance and oncolytic adenovirus activity using established ovarian cancer cell line models, xenografts with de novo paclitaxel resistance and tumour samples from two separate trials. The activity of multiple Ad5 vectors, including dl922-947 (E1A CR2-deleted), dl1520 (E1B-55K deleted) and Ad5 WT, was significantly increased in paclitaxel resistant ovarian cancer in vitro and in vivo. This was associated with greater infectivity resulting from increased expression of the primary receptor for Ad5, CAR (coxsackie adenovirus receptor). This, in turn, resulted from increased CAR transcription secondary to histone modification in resistant cells. There was increased CAR expression in intraperitoneal tumours with de novo paclitaxel resistance and in tumours from patients with clinical resistance to paclitaxel. Increased CAR expression did not cause paclitaxel resistance, but did increase inflammatory cytokine expression. Finally, we identified dysregulated cell cycle control as a second mechanism of increased adenovirus efficacy in paclitaxel-resistant ovarian cancer. Ad11 and Ad35, both group B adenoviruses that utilise non-CAR receptors to infect cells, are also significantly more effective in paclitaxel-resistant ovarian cell models. Inhibition of CDK4/6 using PD-0332991 was able both to reverse paclitaxel resistance and reduce adenovirus efficacy. Thus, paclitaxel resistance increases oncolytic adenovirus efficacy via at least two separate mechanisms - if validated further, this information could have future clinical utility to aid patient selection for clinical trials.

The development of anti-angiogenic heparan sulfate oligosaccharides

Angiogenesis has emerged as a novel target for anti-cancer therapies through randomized clinical trials that tested the benefit of adding vascular endothelial growth factor (VEGF) inhibitors to conventional cytotoxic therapies. However, despite improvements in the progression-free survival, the benefit in overall survival is modest. Tumour angiogenesis is regulated by a number of angiogenic cytokines. Thus innate or acquired resistance to VEGF inhibitors can be caused, at least in part, through expression of other angiogenic cytokines, including fibroblast growth factor 2 (FGF2), interleukin 8 (IL-8) and stromal-cell-derived factor 1α (SDF-1α), which make tumours insensitive to VEGF signalling pathway inhibition. The majority of angiogenic cytokines, including VEGF-A, FGF2, IL-8 and SDF-1α, manifest an obligate dependence on heparan sulfate (HS) for their biological activity. This mandatory requirement of angiogenic cytokines for HS identifies HS as a potential target for novel anti-angiogenic therapy. Targeting multiple angiogenic cytokines with HS mimetics may represent an opportunity to inhibit tumour angiogenesis more efficiently. Our published studies and unpublished work have demonstrated the feasibility of generating synthetic HS fragments of defined structure with biological activity against a number of angiogenic cytokines.

Antagonism of Ang-Tie2 and Dll4-Notch signaling has opposing effects on tumor endothelial cell proliferation, evidenced by a new flow cytometry method

Sustained angiogenesis is essential for tumor growth as it provides the tumor with a network of blood vessels that supply both oxygen and essential nutrients. Limiting tumor-associated angiogenesis is a proven strategy for the treatment of human cancer. To date, the rapid detection and quantitation of tumor-associated endothelial cell (TAEC) proliferation has been challenging, largely due to the low frequency of endothelial cells (ECs) within the tumor microenvironment. In this report, we address this problem using a new multiparametric flow cytometry method capable of rapid and precise quantitation of proliferation by measuring bromodeoxyuridine (BrdUrd) uptake in mouse TAECs from established human tumor xenografts. We determined the basal proliferation labeling index of TAECs in two human tumor xenografts representing two distinct histologies, COLO 205 (colorectal cancer) and U-87 (glioblastoma). We then investigated the effects of two large-molecule antiangiogenic agents targeting different biochemical pathways. Blocking angiopoietin-Tie2 signaling with the peptide-Fc fusion protein, trebananib (AMG 386), inhibited proliferation of TAECs, whereas blocking Dll4-Notch signaling with an anti-Dll4-specific antibody induced hyperproliferation of TAECs. These pharmacodynamic studies highlight the sensitivity and utility of this flow cytometry-based method and demonstrate the value of this assay to rapidly assess the in vivo proliferative effects of angiogenesis-targeted agents on both the tumor and the associated vasculature.

Ovarian cancer

Epithelial ovarian cancer is the commonest cause of gynaecological cancer-associated death. The disease typically presents in postmenopausal women, with a few months of abdominal pain and distension. Most women have advanced disease (International Federation of Gynecology and Obstetrics [FIGO] stage III), for which the standard of care remains surgery and platinum-based cytotoxic chemotherapy. Although this treatment can be curative for most patients with early stage disease, most women with advanced disease will develop many episodes of recurrent disease with progressively shorter disease-free intervals. These episodes culminate in chemoresistance and ultimately bowel obstruction, the most frequent cause of death. For women whose disease continues to respond to platinum-based drugs, the disease can often be controlled for 5 years or more. Targeted treatments such as antiangiogenic drugs or poly (ADP-ribose) polymerase inhibitors offer potential for improved survival. The efficacy of screening, designed to detect the disease at an earlier and curable stage remains unproven, with key results expected in 2015.

Profile of trebananib (AMG386) and its potential in the treatment of ovarian cancer

Angiogenesis has been implicated in ovarian cancer pathogenesis. Bevacizumab, an anti-vascular endothelial growth factor monoclonal antibody, has recently been incorporated in ovarian cancer treatment in combination with chemotherapy both in a frontline setting and in disease recurrence. However, resistance eventually develops and treatment with bevacizumab is associated with increased risk for toxicities such as thromboembolic and hemorrhagic events, gastrointestinal perforation, and impaired wound healing, suggesting the need for new therapeutic approaches. Targeting of the angiopoietins/Tie2 pathway has gained accumulating interest during the last few years as a strategy to overcome bevacizumab resistance and toxicities. Trebananib is a first-in-class peptibody that inhibits angiopoietin 1 and 2 interaction with their receptor Tie2. The molecular profile of this agent, the preclinical data, and clinical studies demonstrating its efficacy in ovarian cancer are discussed in this review.

The role of bevacizumab in recurrent, platinum-sensitive ovarian cancer

The majority of women with ovarian cancer will experience a recurrence of their disease despite aggressive primary cytoreduction and adjuvant cytotoxic chemotherapy. Notwithstanding the high rate of recurrence, targeted and biologic agents have helped to decrease the dependence on cytotoxic chemotherapy. Bevacizumab, a vascular endothelial growth factor inhibitor, has been shown to cause regression in tumor vasculature, inhibition of angiogenesis and prevention of progenitor cell recruitment. Phase III clinical trials of bevacizumab in patients with primary epithelial ovarian cancer and in patients with platinum-sensitive ovarian cancer have shown an improvement in progression free survival without an appreciable difference in overall survival. The addition of bevacizumab to standard cytotoxic chemotherapy regimens has demonstrated improved response rates, and improved progression free survival. These results have stimulated research in additional angiogenesis inhibitors and trials to further incorporate bevacizumab into the treatment schema for patients with recurrent ovarian cancer.

The combination of circulating Ang1 and Tie2 levels predicts progression-free survival advantage in bevacizumab-treated patients with ovarian cancer

PURPOSE

Randomized ovarian cancer trials, including ICON7, have reported improved progression-free survival (PFS) when bevacizumab was added to conventional cytotoxic therapy. The improvement was modest prompting the search for predictive biomarkers for bevacizumab.

EXPERIMENTAL DESIGN

Pretreatment training (n=91) and validation (n=114) blood samples were provided by ICON7 patients. Plasma concentrations of 15 angio-associated factors were determined using validated multiplex ELISAs. Our statistical approach adopted PFS as the primary outcome measure and involved (i) searching for biomarkers with prognostic relevance or which related to between-individual variation in bevacizumab effect; (ii) unbiased determination of cutoffs for putative biomarker values; (iii) investigation of biologically meaningfully predictive combinations of putative biomarkers; and (iv) replicating the analysis on candidate biomarkers in the validation dataset.

RESULTS

The combined values of circulating Ang1 (angiopoietin 1) and Tie2 (Tunica internal endothelial cell kinase 2) concentrations predicted improved PFS in bevacizumab-treated patients in the training set. Using median concentrations as cutoffs, high Ang1/low Tie2 values were associated with significantly improved PFS for bevacizumab-treated patients in both datasets (median, 23.0 months vs. 16.2; P=0.003) for the interaction of Ang1-Tie2 treatment in Cox regression analysis. The prognostic indices derived from the training set also distinguished high and low probability for progression in the validation set (P=0.008), generating similar values for HR (0.21 vs. 0.27) between treatment and control arms for patients with high Ang1 and low Tie2 values.

CONCLUSIONS

The combined values of Ang1 and Tie2 are predictive biomarkers for improved PFS in bevacizumab-treated patients with ovarian cancer. These findings need to be validated in larger trials due to the limitation of sample size in this study.

The combination of circulating Ang1 and Tie2 levels predicts progression-free survival advantage in bevacizumab-treated patients with ovarian cancer

PURPOSE

Randomized ovarian cancer trials, including ICON7, have reported improved progression-free survival (PFS) when bevacizumab was added to conventional cytotoxic therapy. The improvement was modest prompting the search for predictive biomarkers for bevacizumab.

EXPERIMENTAL DESIGN

Pretreatment training (n=91) and validation (n=114) blood samples were provided by ICON7 patients. Plasma concentrations of 15 angio-associated factors were determined using validated multiplex ELISAs. Our statistical approach adopted PFS as the primary outcome measure and involved (i) searching for biomarkers with prognostic relevance or which related to between-individual variation in bevacizumab effect; (ii) unbiased determination of cutoffs for putative biomarker values; (iii) investigation of biologically meaningfully predictive combinations of putative biomarkers; and (iv) replicating the analysis on candidate biomarkers in the validation dataset.

RESULTS

The combined values of circulating Ang1 (angiopoietin 1) and Tie2 (Tunica internal endothelial cell kinase 2) concentrations predicted improved PFS in bevacizumab-treated patients in the training set. Using median concentrations as cutoffs, high Ang1/low Tie2 values were associated with significantly improved PFS for bevacizumab-treated patients in both datasets (median, 23.0 months vs. 16.2; P=0.003) for the interaction of Ang1-Tie2 treatment in Cox regression analysis. The prognostic indices derived from the training set also distinguished high and low probability for progression in the validation set (P=0.008), generating similar values for HR (0.21 vs. 0.27) between treatment and control arms for patients with high Ang1 and low Tie2 values.

CONCLUSIONS

The combined values of Ang1 and Tie2 are predictive biomarkers for improved PFS in bevacizumab-treated patients with ovarian cancer. These findings need to be validated in larger trials due to the limitation of sample size in this study.

The search for biomarkers to direct antiangiogenic treatment in epithelial ovarian cancer

Antiangiogenic agents have demonstrated improved progression-free survival in women with primary and recurrent epithelial ovarian cancer (EOC). Biomarkers that predict outcomes in patients treated with antiangiogenic agents are being investigated to rationally direct therapy for women most likely to benefit from these agents. Among the most promising plasma-based biomarkers are vascular endothelial growth factor (VEGF)-A, fibroblast growth factor, platelet-derived growth factor, angiopoietin-2, and VEGF receptor-2. While these biomarkers have been correlated with prognosis, they have not been shown to predict benefit, specifically from anti-VEGF therapy, highlighting the need for alternative biomarkers, including molecular and clinical factors, which may be predictive of outcome in women with ovarian cancer treated with antiangiogenic agents. Biomarkers are currently being investigated as secondary outcomes in several ongoing phase II and phase III clinical trials of antiangiogenic agents in patients with EOC. Molecular techniques, such as microarray analyses, and imaging techniques, such as dynamic contrast-enhanced magnetic resonance imaging, positron emission tomography, and single photon emission computed tomography, are also being explored in this field. In this review, we provide a comprehensive overview of current biomarker research, with an emphasis on angiogenic biomarkers associated with EOC.

A phase 1b, open-label study of trebananib in combination with paclitaxel and carboplatin in patients with ovarian cancer receiving interval or primary debulking surgery

AIM

To evaluate the tolerability, pharmacokinetics and tumour response of first-line trebananib plus paclitaxel and carboplatin followed by trebananib maintenance in high-risk or advanced ovarian cancer.

METHODS

In this open-label phase 1b study, patients received intravenous (IV) trebananib 15 mg/kg administered weekly (QW) plus paclitaxel 175 mg/m(2) once every 3 weeks (Q3W) and carboplatin 6 mg/mL · min Q3W followed by trebananib 15 mg/kg QW monotherapy for 18 months. End-points were dose-limiting toxicities (DLTs; primary); treatment-emergent adverse events (AEs), anti-trebananib antibodies, pharmacokinetics and tumour response (secondary).

RESULTS

Twenty seven patients (interval debulking surgery [IDS], n=13) were enrolled. No DLTs occurred. During the combination therapy phase, AEs (>50%) in patients with IDS were nausea, diarrhoea, fatigue, decreased appetite and thrombocytopenia. In patients with primary debulking surgery (PDS), they were nausea, diarrhoea, fatigue and localised oedema. Grade 4 AEs were neutropenia (IDS, PDS; all n=3) and thrombocytopenia (IDS, PDS; all n=1). No deaths occurred. Toxicity results pertaining to trebananib maintenance were immature. The treatment combination did not markedly affect the pharmacokinetics across agents. In patients with IDS (n=14 after one patient was reassigned from PDS to IDS), 12 patients had a partial response (PR), two patients had stable disease. In patients with PDS (n=4), three patients had a complete response, one patient had a PR.

CONCLUSIONS

In women with ovarian cancer receiving IDS or PDS, IV trebananib 15 mg/kg QW plus paclitaxel and carboplatin appears tolerable. Results suggest that the treatment combination followed by trebananib 15 mg/kg monotherapy is associated with antitumour activity.

A phase 1b study of trebananib in combination with pegylated liposomal doxorubicin or topotecan in women with recurrent platinum-resistant or partially platinum-sensitive ovarian cancer

OBJECTIVE

To examine the tolerability and antitumor activity of trebananib plus pegylated liposomal doxorubicin (PLD) or topotecan in recurrent platinum-resistant or partially platinum-sensitive ovarian cancer.

METHODS

In this open-label phase 1b study, patients received trebananib 10 mg/kg or 15 mg/kg IV QW plus PLD 50 mg/m(2) (cohorts A1 and A3, respectively) or topotecan 4 mg/m(2) (cohorts B1 and B3, respectively). Endpoints were dose-limiting toxicity (DLT; primary); treatment-emergent adverse events (AEs), overall response rate, anti-trebananib antibodies, and pharmacokinetics (secondary).

RESULTS

103 patients were enrolled. One patient in A1 and B1 had DLTs. Across all cohorts, the most common AEs were nausea, fatigue, and peripheral edema. Across both trebananib plus PLD cohorts (A1/A3), grade 4 AEs were pulmonary embolism, disease progression, and anemia. Two patients had grade 5 intestinal perforation (n=1) and sudden death (n=1). Across both trebananib plus topotecan cohorts (B1/B3), grade 4 AEs were neutropenia, hypokalemia, decreased granulocyte count, chest pain, dyspnea, decreased neutrophil count, and pulmonary embolism. Two patients had grade 5 disease progression. One patient had grade 5 pleural effusion associated with progressive disease. Confirmed objective response rates were 36.0% (A1), 34.8% (A3), 16.7% (B1), and 0.0% (B3). Median progression-free survival duration (months) was 7.4 (A1), 7.1 (A3), 3.5 (B1), and 3.1 (B3), respectively. No drug-drug interactions were apparent.

CONCLUSIONS

Trebananib 10mg/kg and 15 mg/kg IV QW plus PLD or topotecan appear to have acceptable toxicity profiles in recurrent platinum-resistant or partially platinum-sensitive ovarian cancer. Antitumor activity was evident across all cohorts.

New developments in the treatment of ovarian cancer--future perspectives

Over the past 40 years, the treatment of ovarian cancer has undoubtedly improved as a result of better multi-modality care and platinum-based chemotherapy. More recently, the introduction of anti-angiogenic therapy, PARP inhibitors and a weekly regimen for paclitaxel indicate that results are likely to improve further. However, major challenges remain and these will be reviewed in this article. We assess key issues in anti-angiogenic treatment including potential ways for addressing resistance; we review the current studies of PARP inhibitor treatment, which shows most promise in patients with germline BRCA mutations; we describe the potential for folate-receptor-directed therapy, given the high level of FR expression in ovarian cancer and we highlight the potential for molecular targeted therapy, focusing on specific subgroups of the disease with targets such as the PI3 K/AKT and RAS/RAF/MEK pathways and the ErbB family of oncogenes. We anticipate that progress will accelerate with a better understanding of the molecular pathogenesis of the various subtypes of ovarian cancer, leading to an increasingly personalized approach to treating women with this disease.

Anti-angiopoietin therapy with trebananib for recurrent ovarian cancer (TRINOVA-1): a randomised, multicentre, double-blind, placebo-controlled phase 3 trial

BACKGROUND

Angiogenesis is a valid target in the treatment of epithelial ovarian cancer. Trebananib inhibits the binding of angiopoietins 1 and 2 to the Tie2 receptor, and thereby inhibits angiogenesis. We aimed to assess whether the addition of trebananib to single-agent weekly paclitaxel in patients with recurrent epithelial ovarian cancer improved progression-free survival.

METHODS

For this randomised, double-blind phase 3 study undertaken between Nov 10, 2010, and Nov 19, 2012, we enrolled women with recurrent epithelial ovarian cancer from 32 countries. Patient eligibility criteria included having been treated with three or fewer previous regimens, and a platinum-free interval of less than 12 months. We enrolled patients with a computerised interactive voice response system, and patients were randomly assigned using a permuted block method (block size of four) in a 1:1 ratio to receive weekly intravenous paclitaxel (80 mg/m(2)) plus either weekly masked intravenous placebo or trebananib (15 mg/kg). Patients were stratified on the basis of platinum-free interval (≥0 and ≤6 months vs >6 and ≤12 months), presence or absence of measurable disease, and region (North America, western Europe and Australia, or rest of world). The sponsor, investigators, site staff, and patients were masked to the treatment assignment. The primary endpoint was progression-free survival assessed in the intention-to-treat population. The trial is registered with ClinicalTrials.gov, NCT01204749, and is no longer accruing patients.

FINDINGS

919 patients were enrolled, of whom 461 were randomly assigned to the trebananib group and 458 to the placebo group. Median progression-free survival was significantly longer in the trebananib group than in the placebo group (7·2 months [5·8-7·4] vs 5·4 months [95% CI 4·3-5·5], respectively, hazard ratio 0·66, 95% CI 0·57-0·77, p<0·0001). Incidence of grade 3 or higher adverse events was similar between treatment groups (244 [54%] of 452 patients in the placebo group vs 258 [56%] of 461 patients in the trebananib group). Trebananib was associated with more adverse event-related treatment discontinuations than was placebo (77 [17%] patients vs 27 [6%], respectively) and higher incidences of oedema (294 [64%] patients had any-grade oedema in the trebananib group vs 127 [28%] patients in the placebo group). Grade 3 or higher adverse events included ascites (34 [8%] in the placebo group vs 52 [11%] in the trebananib group), neutropenia (40 [9%] vs 26 [6%]), and abdominal pain (21 [5%] vs 22 [5%]). We recorded serious adverse events in 125 (28%) patients in the placebo group and 159 (34%) patients in the trebananib group. There was a difference of 2% or less in class-specific adverse events associated with anti-VEGF therapy (hypertension, proteinuria, wound-healing complications, thrombotic events, gastrointestinal perforations), except bleeding, which was more common in the placebo group than in the trebananib group (75 [17%] vs 46 [10%]).

INTERPRETATION

Inhibition of angiopoietins 1 and 2 with trebananib provided a clinically meaningful prolongation in progression-free survival. This non-VEGF anti-angiogenesis option for women with recurrent epithelial ovarian cancer should be investigated in other settings and in combination with additional agents. Although oedema was increased, typical anti-VEGF associated adverse events were not prominent.

FUNDING

Amgen.

Intravascular immunity as a key to systemic vasculitis: a work in progress, gaining momentum

Vascular inflammation contributes to the defence against invading microbes and to the repair of injured tissues. In most cases it resolves before becoming apparent. Vasculitis comprises heterogeneous clinical entities that are characterized by the persistence of vascular inflammation after it has served its homeostatic function. Most underlying mechanisms have so far remained elusive. Intravascular immunity refers to the surveillance of the vasculature by leucocytes that sense microbial or sterile threats to vessel integrity and initiate protective responses that entail most events that determine the clinical manifestations of vasculitis, such as end-organ ischaemia, neutrophil extracellular traps generation and thrombosis, leucocyte extravasation and degranulation. Understanding how the resolution of vascular inflammation goes awry in patients with systemic vasculitis will facilitate the identification of novel pharmacological targets and bring us a step closer in each patient to the selection of more effective and less toxic treatments.

Dual VEGF/VEGFR inhibition in advanced solid malignancies: clinical effects and pharmacodynamic biomarkers

Our prior phase I study of the combination of vascular endothelial growth factor (VEGF) antibody, bevacizumab, and VEGF receptor (VEGFR) inhibitor, sunitinib, in advanced solid tumors identified an encouraging response evaluation. An expansion phase of this study was thus undertaken to obtain further safety data, response assessment and characterization of pharmacodynamic biomarkers in melanoma, renal, and adrenal carcinoma patients. Patients with metastatic solid tumors received sunitinib (37.5 mg/d, 4 wk on/2 wk off) and bevacizumab (5 mg/kg intravenously every 2 wk). Responses were assessed every 2 cycles. Serum levels of angiogenic molecules were measured using ELISA assays. Twenty-two patients were enrolled, including 11 melanoma, 5 renal cell carcinoma (RCC), 5 adrenal cancer, and 1 angiosarcoma. Grade 3 or higher adverse events were observed in 15 patients, including hypertension (41%), thrombocytopenia (23%), and fatigue (14%). Three RCC patients, and 1 melanoma patient developed thrombotic microangiopathy (TMA). Partial response (PR) occurred in 21% patients, including melanoma (2), adrenal (1), and renal (1) carcinomas. Overall, 6 patients demonstrated some reduction in their tumor burden. Serum VEGF and several other proangiogenic proteins declined over the first 4 wk of treatment whereas the putative VEGF-resistant protein, prokineticin-2, increased over 10-fold. Occurrence of TMA related to dual VEGF/VEGFR inhibition can result from systemic or nephron specific injury even in non-renal malignancies. While the combination of sunitinib and bevacizumab was clinically efficacious in renal cell carcinoma and melanoma, the observance of microangiopathy, even in non-RCC patients, is a significant toxicity that precludes further clinical development.

Bevacizumab in combination with chemotherapy for the treatment of advanced ovarian cancer: a systematic review

As increased angiogenesis has been linked with the progression of ovarian cancer, a number of anti-angiogenic agents have been investigated, or are currently in development, as potential treatment options for patients with advanced disease. Bevacizumab, a recombinant monoclonal antibody against vascular endothelial growth factor, has gained European Medicines Agency approval for the front-line treatment of advanced epithelial ovarian cancer, fallopian tube cancer or primary peritoneal cancer in combination with carboplatin and paclitaxel, and for the treatment of first recurrence of platinum-sensitive ovarian cancer in combination with carboplatin and gemcitabine. We conducted a systematic literature review to identify available efficacy and safety data for bevacizumab in ovarian cancer as well as for newer anti-angiogenic agents in development. We analyzed published data from randomized, controlled phase II/III clinical trials enrolling women with ovarian cancer to receive treatment with bevacizumab. We also reviewed available data for emerging anti-angiogenic agents currently in phase II/III development, including trebananib, aflibercept, nintedanib, cediranib, imatinib, pazopanib, sorafenib and sunitinib. Significant efficacy gains were achieved with the addition of bevacizumab to standard chemotherapy in four randomized, double-blind, phase III trials, both as front-line treatment (GOG-0218 and ICON7) and in patients with recurrent disease (OCEANS and AURELIA). The type and frequency of bevacizumab-related adverse events was as expected in these studies based on published data. Promising efficacy data have been published for a number of emerging anti-angiogenic agents in phase III development for advanced ovarian cancer. Further research is needed to identify predictive or prognostic markers of response to bevacizumab in order to optimize patient selection and treatment benefit. Data from phase III trials of newer anti-angiogenic agents in ovarian cancer are awaited.

The emerging role of anti-angiogenic therapy in ovarian cancer (review)

The introduction of new therapeutic agents into clinical practice of ovarian cancer, in addition to the role of surgery and chemotherapy, has been the subject of numerous studies because this tumor remains worldwide the most lethal gynecological cancer. It is now known that angiogenesis plays a vital role for ovarian physiology, but also in ovarian carcinogenesis and so it has become the main target of ovarian cancer treatment. In this review, the most common molecular pathways of angiogenesis have been investigated leading to the identification of novel targets, including monoclonal antibodies and tyrosine kinase inhibitors. The fundamental targets of anti-angiogenic drugs are vascular endothelial growth factor receptor and its ligand, but also platelet-derived growth factor, fibroblast growth factor and angiopoietin. Moreover, improved knowledge of angiogenic process allowed the discovery of other molecules, such as semaphorins, neuropilins, clusterin, some transcriptional factors, and the identification of features, including stemness, epithelial-mesenchymal transition, downregulation of certain microRNAs, the alteration of immune system, that contribute to angiogenesis and possibly to resistance mechanisms. The following patent and literature review aim to highlight recent findings of approved and novel anti-angiogenic drugs that make the treatment of patients with ovarian cancer a rapidly growing field of oncology.