A randomised non-comparative phase II trial of cixutumumab (IMC-A12) or ramucirumab (IMC-1121B) plus mitoxantrone and prednisone in men with metastatic docetaxel-pretreated castration-resistant prostate cancer

Determining the late effect parameter in the Fleming-Harrington test using asymptotic relative efficiency in cancer immunotherapy clinical trials

The delayed treatment effect, which manifests as a separation of survival curves after a change point, has often been observed in immunotherapy clinical trials. A late effect of this kind may violate the proportional hazards assumption, resulting in the non-negligible loss of statistical power of an ordinary log-rank test when comparing survival curves. The Fleming-Harrington (FH) test, a weighted log-rank test, is configured to mitigate the loss of power by incorporating a weight function with two parameters, one each for early and late treatment effects. The two parameters need to be appropriately determined, but no helpful guides have been fully established. Since the late effect is expected in immunotherapy trials, we focus on the late effect parameter in this study. We consider parameterizing the late effect in a readily interpretable fashion and determining the optimal late effect parameter in the FH test to maintain statistical power in reference to the asymptotic relative efficiency (ARE). The optimization is carried out under three lag models (i.e. linear, threshold, and generalized linear lag), where the optimal weights are proportional to the lag functions characterized by the change points. Extensive simulation studies showed that the FH test with the selected late parameter reliably provided sufficient power even when the change points in the lag models were misspecified. This finding suggests that the FH test with the ARE-guided late parameter may be a reasonable and practical choice for the primary analysis in immunotherapy clinical trials.

Insulin-like growth factor family and prostate cancer: new insights and emerging opportunities

Prostate cancer is the second most commonly diagnosed cancer in men. The mammalian insulin-like growth factor (IGF) family is made up of three ligands (IGF-I, IGF-II, and insulin), three receptors (IGF-I receptor (IGF-1R), insulin receptor (IR), and IGF-II receptor (IGF-2R)), and six IGF-binding proteins (IGFBPs). IGF-I and IGF-II were identified as potent mitogens and were previously associated with an increased risk of cancer development including prostate cancer. Several reports showed controversy about the expression of the IGF family and their connection to prostate cancer risk due to the high degree of heterogeneity among prostate tumors, sampling bias, and evaluation techniques. Despite that, it is clear that several IGF family members play a role in prostate cancer development, metastasis, and androgen-independent progression. In this review, we aim to expand our understanding of prostate tumorigenesis and regulation through the IGF system. Further understanding of the role of IGF signaling in PCa shows promise and needs to be considered in the context of a comprehensive treatment strategy.

Enzalutamide and olaparib synergistically suppress castration-resistant prostate cancer progression by promoting apoptosis through inhibiting nonhomologous end joining pathway

Recent studies revealed the relationship among homologous recombination repair (HRR), androgen receptor (AR), and poly(adenosine diphosphate-ribose) polymerase (PARP); however, the synergy between anti-androgen enzalutamide (ENZ) and PARP inhibitor olaparib (OLA) remains unclear. Here, we showed that the synergistic effect of ENZ and OLA significantly reduced proliferation and induced apoptosis in AR-positive prostate cancer cell lines. Next-generation sequencing followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed the significant effects of ENZ plus OLA on nonhomologous end joining (NHEJ) and apoptosis pathways. ENZ combined with OLA synergistically inhibited the NHEJ pathway by repressing DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and X-ray repair cross complementing 4 (XRCC4). Moreover, our data showed that ENZ could enhance the response of prostate cancer cells to the combination therapy by reversing the anti-apoptotic effect of OLA through the downregulation of anti-apoptotic gene insulin-like growth factor 1 receptor ( IGF1R ) and the upregulation of pro-apoptotic gene death-associated protein kinase 1 ( DAPK1 ). Collectively, our results suggested that ENZ combined with OLA can promote prostate cancer cell apoptosis by multiple pathways other than inducing HRR defects, providing evidence for the combined use of ENZ and OLA in prostate cancer regardless of HRR gene mutation status.

Emerging Role of IGF-1 in Prostate Cancer: A Promising Biomarker and Therapeutic Target

Prostate cancer (PCa) is a highly heterogeneous disease driven by gene alterations and microenvironmental influences. Not only enhanced serum IGF-1 but also the activation of IGF-1R and its downstream signaling components has been increasingly recognized to have a vital driving role in the development of PCa. A better understanding of IGF-1/IGF-1R activity and regulation has therefore emerged as an important subject of PCa research. IGF-1/IGF-1R signaling affects diverse biological processes in cancer cells, including promoting survival and renewal, inducing migration and spread, and promoting resistance to radiation and castration. Consequently, inhibitory reagents targeting IGF-1/IGF-1R have been developed to limit cancer development. Multiple agents targeting IGF-1/IGF-1R signaling have shown effects against tumor growth in tumor xenograft models, but further verification of their effectiveness in PCa patients in clinical trials is still needed. Combining androgen deprivation therapy or cytotoxic chemotherapeutics with IGF-1R antagonists based on reliable predictive biomarkers and developing and applying novel agents may provide more desirable outcomes. This review will summarize the contribution of IGF-1 signaling to the development of PCa and highlight the relevance of this signaling axis in potential strategies for cancer therapy.

Current Status of Monoclonal Antibodies-Based Therapies in Castration-Resistant Prostate Cancer: A Systematic Review and Meta-Analysis of Clinical Trials

Background Multiple patients with prostate cancer become resistant to castration therapies, which is termed castration-resistant prostate cancer (CRPC). Purpose The purpose of this review is to assess the status of efficacy (≥50% decline in prostate-specific antigen (PSA), progression-free survival (PFS), and overall survival (OS)) and safety (grade 3-4 adverse effects) of monoclonal antibodies in CRPC. Data source We searched databases including PubMed, Embase, Cochrane, Web of Science, and ClinicalTrials.gov. Results Hazard ratios of PFS and OS were 0.77 (95% CI = 0.69-0.87, I2 = 53%) and 0.98 (95% CI = 0.86-1.11, I2 = 40%), respectively, in the favor of monoclonal antibodies as compared to placebo. Risk ratio (RR) of >50% decline in PSA was 1.99 (95% CI = 0.97-4.08, I2 = 53%) in favor of monoclonal antibodies. Pooled incidence of >50% decline in PSA levels was 15% (95% CI = 0.1-0.23, I2 = 83%), 29% (95% CI = 0.14-0.51, I2 = 93%), 63% (95% CI = 0.49-0.76, I2 = 77%), and 88% (95% CI = 0.81-0.93, I2 = 0%) in single, two, three, and four-drug regimens, respectively. Conclusion Monoclonal antibodies are well tolerated and showed better PFS as compared to placebo. However, OS was only improved with ipilimumab. Denosumab delayed skeletal-related adverse events as compared to zoledronic acid. More multicenter double-blind clinical trials may be needed to confirm these results.

Targeting the IGF-1R in prostate and colorectal cancer: reasons behind trial failure and future directions

IGF-1Rs enact a significant part in cancer growth and its progress. IGF-1R inhibitors were encouraged in the early trials, but the patients did not benefit due to the unavailability of predictive biomarkers and IGF-1R system complexity. However, the linkage between IGF-1R and cancer was reported three decades ago. This review will shed light on the IGF-1R system, targeting IGF-1R through monoclonal antibodies, reasons behind IGF-1R trial failure and future directions. This study presented that targeting IGF-1R through monoclonal antibodies is still effective in cancer treatment, and there is a need to look for future directions. Cancer patients may benefit from using mAbs that target existing and new cancer targets, evidenced by promising results. It is also essential that the academician, trial experts and pharmaceutical companies play their role in finding a treatment for this deadly disease.

Risk of hypertension with anti-VEGF monoclonal antibodies in cancer patients: a systematic review and meta-analysis of 105 phase II/III randomized controlled trials

We performed a meta-analysis to fully investigate the hypertension of anti-VEGF mAbs in cancer patients. Databases were searched for randomized controlled trials (RCTs) treated with anti-VEGF mAbs till January 2021. The relevant RCTs in cancer patients treated with anti-VEGF mAbs were retrieved and the systematic evaluation was conducted. One hundred and five RCTs and 65358 patients were included. Our study suggests that anti-VEGF mAbs significantly increased the risks of all-grade (RR, 3.22; 95%CI, 2.83-3.65; p < 0.00001; I²=71%) and high-grade (RR, 6.15; 95%CI, 5.58-6.78; p < 0.00001; I²=48%) hypertension in cancer patients. Those risks may be dependent on drug type. Icrucumab did not association with an increased risk of hypertension. The RR of hypertension did not vary significantly according to the type of cancer, line of therapy, and treatment duration. The available data suggested that the use of anti-VEGF mAbs were associated with a significantly increased risk of hypertension.

Randomized Phase II Trial of Capecitabine and Lapatinib with or without IMC-A12 (Cituxumumab) in Patients with HER2-Positive Advanced Breast Cancer Previously Treated with Trastuzumab and Chemotherapy: NCCTG N0733 (Alliance)

PURPOSE

To compare efficacy and safety of capecitabine and lapatinib with or without IMC-A12 (cituxumumab) in patients with HER2-positive metastatic breast cancer (MBC) previously treated with trastuzumab.

PATIENTS AND METHODS

Following an initial safety run-in cohort, patients were randomized 1:2 to Arm A (capecitabine and lapatinib) or to Arm B (capecitabine, lapatinib, and cituxumumab). Given the frequency of non-hematologic grade ≥ 3 adverse events in those receiving the three-drug combination in the safety cohort, lapatinib and capecitabine doses were reduced in Arm B only. The primary objective was to determine if the addition of cituxumumab to capecitabine and lapatinib improved progression-free survival (PFS) compared with capecitabine and lapatinib. Secondary objectives included a comparison between arms of other clinical endpoints, safety, change in overall quality of life (QOL) and self-assessed fatigue, rash, diarrhea, and hand-foot syndrome.

RESULTS

From July 2008 to March 2012, 68 patients (out of 142 planned) were enrolled and 63 were evaluable, including 8 for the safety run-in and 55 for the randomized cohort. Study enrollment was stopped early due to slow accrual. The addition of cituxumumab to capecitabine and lapatinib did not improve PFS (HR 0.93, 95% CI: 0.52-1.64). Furthermore, no difference in objective response rate or overall survival (OS) was observed. No difference between arms was observed in grade ≥ 3 adverse events, overall QOL change from baseline after 4 cycles of treatment.

CONCLUSION

The addition of cituxumumab to lapatinib and capecitabine did not improve PFS or OS compared with lapatinib and capecitabine in patients with HER2-positive MBC.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov Identifier: NCT00684983.

Design for immuno-oncology clinical trials enrolling both responders and nonresponders

A typical challenge facing the design and analysis of immuno-oncology (IO) trials is the prevalence of nonproportional hazards (NPH) patterns manifested in Kaplan-Meier curves under time-to-event endpoints. The NPH patterns would violate the proportional hazards assumption, and yet conventional design and analysis strategies often ignore such a violation, resulting in underpowered or even falsely negative IO studies. In this article, we show, both empirically and analytically, that treating nonresponders in IO studies of inadequate size would give rise to a variety of NPH patterns; we then present a novel design and analysis strategy, P%-responder information embedded (PRIME), to properly incorporate the dichotomized response incurred from treating nonresponders. Empirical studies demonstrate that the proposed strategy can achieve desirable power, whereas the conventional alternative leads to a severe power loss. The PRIME strategy allows us to quantify the impact of treating nonresponders on study efficiency, thereby enabling a proper design of IO trials with an adequate power. More importantly, it pinpoints a solution to enhance the study efficiency and alleviates the NPH patterns by enrolling more prospective responders. An R package (Immunotherapy.Design) is developed for implementation.

The Influence of Radical Prostatectomy on the Expression of Cell-Free MiRNA

MiRNAs of blood and urine have been shown to represent a convenient source of biomarkers for prostate cancer (PCa) diagnosis and assessment of the therapy effectiveness due to their high stability and representation and the low invasiveness of sample collection. Here, we studied the influence of radical prostatectomy (RP) on the expression of 12 cell-free miRNAs previously shown as potential markers of PCa (i.e., miR-19b, miR-22, miR-92a, miR-378, miR-425, miR-30e, miR-31, miR-125b, miR-200b, miR-205, miR-375 and miR-660). The relative expression of the miRNAs combined into 31 paired ratios was evaluated in the urine extracellular vesicles (EVs), clarified urine (CU) and blood plasma of healthy donors, pre- and post-RP samples of PCa patients. Nineteen miRNA ratios based on combinations of ten of the miRNAs (miR-19b, miR-30e, miR-31, miR-125b, miR-200b, miR-205, miR-375, miR-378, miR-425, and miR-660) were altered by RP. The comparative expression analysis of the cell-free miRNA ratios between healthy donors and PCa patients revealed miR-125b/miR-30e and miR-375/miR-30e as potential markers for evaluating therapeutic efficacy. MiR-378/miR-19b, miR-425/miR-19b, miR-200/miR-30e, miR-660/miR-30e, and miR-205/miR-30e had minor prognostic value but could be used to increase the steadiness of the diagnostic system. The urine EVs had the highest potential as a source of markers.

The role of insulin-like growth factors in the development of prostate cancer

INTRODUCTION

Preclinical, clinical, and population studies have provided robust evidence for an important role for the insulin-like growth factor (IGF) system in the development of prostate cancer.

AREAS COVERED

An overview of the IGF system is provided. The evidence implicating the IGF system in the development of prostate cancer is summarized. The compelling evidence culminated in a number of clinical trials of agents targeting the system; the reasons for the failure of these trials are discussed.

EXPERT OPINION

Clinical trials of agents targeting the IGF system in prostate cancer were terminated due to limited objective clinical responses and are unlikely to be resumed unless a convincing predictive biomarker is identified that would enable the selection of likely responders. The aging population and increased screening will lead to greater diagnosis of prostate cancer. Although the vast majority will be indolent disease, the epidemics of obesity and diabetes will increase the proportion that progress to clinical disease. The increased population of worried men will result in more trials aimed to reduce the risk of disease progression; actual clinical endpoints will be challenging and the IGFs remain the best intermediate biomarkers to indicate a response that could alter the course of disease.

Treating non-responders: pitfalls and implications for cancer immunotherapy trial design

BACKGROUND

Conventional trial design and analysis strategies fail to address the typical challenge of immune-oncology (IO) studies: only a limited percentage of treated patients respond to the experimental treatment. Treating non-responders, we hypothesize, would in part drive non-proportional hazards (NPH) patterns in Kaplan-Meier curves that violates the proportional hazards (PH) assumption required by conventional strategies. Ignoring such violation incurred from treating non-responders in the design and analysis strategy may result in underpowered or even falsely negative studies. Hence, designing innovative IO trials to address such pitfall becomes essential.

METHODS

We empirically tested the hypothesis that treating non-responders in studies of inadequate size is sufficient to cause NPH patterns and thereby proposed a novel strategy, p-embedded, to incorporate the dichotomized response incurred from treating non-responders, as measured by the baseline proportion of responders among treated patients p%, into the design and analysis procedures, aiming to ensure an adequate study power when the PH assumption is violated.

RESULTS

Empirical studies confirmed the hypothetical cause contributes to the manifestation of NPH patterns. Further evaluations revealed a significant quantitative impact of p% on study efficiency. The p-embedded strategy incorporating the properly pre-specified p% ensures an adequate study power whereas the conventional design ignoring it leads to a severe power loss.

CONCLUSION

The p-embedded strategy allows us to quantify the impact of treating non-responders on study efficiency. Implicit in such strategy is the solution to mitigate the occurrence of NPH patterns and enhance the study efficiency for IO trials via enrolling more prospective responders.

AZD3463, an IGF-1R inhibitor, suppresses breast cancer metastasis to bone via modulation of the PI3K-Akt pathway

Background

The bone-derived insulin-like growth factor I (IGF-1) and its receptor IGF-1R play a crucial role in promoting the survival and proliferation of cancer cells, and have thus been considered as prime targets for the development of novel antitumor therapeutics.

Methods

By using the MDA-MB-231BO cell line, which is the osteotropic metastatic variant of the human breast adenocarcinoma cell line MDA-MB-231, and an in vivo model of breast cancer metastasis to bone, the current study evaluated the effect of AZD3463, an IGF-1R inhibitor, used alone or in combination with zoledronic acid (ZA), on the regulation of IGF-1R associated signal pathway and treatment of bone metastases (BM). Cell proliferation and invasion were measured by methyl thiazolyl tetrazolium (MTT) and Transwell assay respectively. Apoptotic cell number was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL).

Results

AZD3463 was shown to alleviate IGF-1R phosphorylation promoted by IGF-1 treatment in MDA-MB-231BO cells in a dose-dependent manner. In both the cells and the mouse model, 5 nM of AZD3463 stimulated cell apoptosis and suppressed proliferation on a level similar to that of 100 µM of ZA. Remarkably, the combined use of AZD3463 and ZA exhibited a synergistic effect and greater antitumor activity compared to when they were employed individually. Mechanistic investigations indicated that the apoptosis-inducing activity of AZD3463 could be associated to its role in the activation of the phosphoinositide 3-kinase (PI3K)-Akt signaling pathway.

Conclusions

These findings suggested that AZD3463 could serve as a promising therapeutic molecule for treating BM in breast cancer patients, particularly when applied in conjunction with ZA or other antitumor agents.

Investigational IGF1R inhibitors in early stage clinical trials for cancer therapy

Introduction: The insulin-like growth factors (IGFs) are a family of secreted peptide hormones with important roles in different cellular and organism functions. The biological activities of the IGFs are mediated by the IGF1 receptor (IGF1R), a cell surface, tyrosine kinase-containing heterotetramer that is linked to numerous cytoplasmic signaling cascades. The IGF1R displays potent antiapoptotic, pro-survival capacities and plays a key role in malignant transformation. Research has identified the IGF1R as a candidate therapeutic target in cancer.Areas covered: We offer a synopsis of ongoing efforts to target the IGF axis for therapeutic purposes. Our review includes a digest of early experimental work that led to the identification of IGF1R as a candidate therapeutic target in oncology.Expert opinion: Targeting of the IGF axis has yielded disappointing results in phase III trials, but it is important to learn from this to improve future trials in a rational manner. The potential of anti-IGF1R antibodies and small molecular weight inhibitors, alone or in combination with chemotherapy or other biological agents, should be investigated further in randomized studies. Moreover, the implementation of predictive biomarkers for patient selection will improve the outcome of future trials. Emerging personalized medicine could have a major impact on IGF1R targeting.

Carnosine exerts antitumor activity against bladder cancers in vitro and in vivo via suppression of angiogenesis

Carnosine, a naturally occurring dipeptide, was recently reported to exhibit anticancer activity; however, the molecular mechanisms and regulators underlying its activity against tumor-associated angiogenesis remain unidentified. In this study, we evaluated the in vitro and in vivo antitumor effects of carnosine in EJ bladder cancer cells and EJ-xenografted BALB/c nude mice, respectively. In addition, in vitro capillary tube formation of HUVECs, ex vivo aortic ring and in vivo Matrigel plug assays were employed to examine the antiangiogenic potential of carnosine. Carnosine significantly inhibited EJ cell proliferation. Flow cytometric and immunoblot analyses indicated that carnosine modulated regulators of the G1 cell cycle phase, including cyclin D1, CDK4 and p21WAF1. The mitogen-activated protein kinases, ERK and p38, but not JNK or AKT, responded to carnosine. Carnosine inhibited the migratory and invasive potential of EJ cells by inhibiting MMP-9 activity, which was associated with suppression of binding activity of NF-κB, SP-1 and AP-1. In xenograft tumors, carnosine exhibited antitumor activity equivalent to cisplatin, but no weight loss occurred in carnosine-treated mice. In HUVECs, carnosine inhibited VEGF-mediated proliferation, colony tube formation, migration and invasion. The antiangiogenic activity of carnosine was partially due to the suppression of VEGFR-2-mediated ERK/AKT/eNOS signaling and MMP-2. Furthermore, using aortic ring and Matrigel plug assays, we confirmed the antiangiogenic activity of carnosine. Given that targeting tumor-associated angiogenesis is a proven effective therapeutic strategy, our results may provide valuable information for the development of preventive or therapeutic agents for bladder cancer patients.

Immuno-PET imaging of VEGFR-2 expression in prostate cancer with 89Zr-labeled ramucirumab

The detection and monitoring of prostate cancer (PrCa) malignancies using most of the conventional strategies is challenging. As an over-expressed biomarker of PrCa, the vascular endothelial growth factor receptor 2 (VEGFR-2) can be delineated by non-invasive imaging to address such issue. Herein, we report the positron emission tomography (PET) of VEGFR-2 expression in a PrCa mice models by composing a novel tracer, [⁸⁹Zr]zirconium-labeled clinical VEGFR-2 antibody (Ramucirumab), i.e. ⁸⁹Zr-Df-R. The VEGFR-2 expression levels among three different PrCa cell lines (PC-3, LNCAP and LAPC-4) were confirmed by flow cytometry. The immuno-PET imaging and bio-distribution (Bio-D) study were conducted in subcutaneous PrCa mice models via the ⁸⁹Zr-Df-R. The regions of interest (ROI) data showed that the uptake of ⁸⁹Zr-Df-R in the positive PC-3 (9.5±3 %ID/g) tumors are obviously higher than those ones in the negative LNCAP (6.0±1.7 %ID/g) or LAPC-4 (4.3±0.7 %ID/g) tumors at 120 hours post-injection, while the accumulation of ⁸⁹Zr-Df-R in PC-3 tumors (4.3±1.2 %ID/g)) could be significantly reduced by the blockade of unlabeled Ramucirumab. These quantitative data coincide with the Bio-D data and proves the specificity. Additionally, the immuno-fluorescent staining results confirmed the expression pattern of VEGFR-2 among various PrCa tumors. Finally, the flow cytometry of PC-3 tumor tissue further proved that the binding of ⁸⁹Zr-Df-R to VEGFR-2 primarily occurs on the PC-3 tumor cells. In summary, the description of the VEGFR-2 expression in PrCa by in-vivo PET with ⁸⁹Zr-Df-R is feasible and it may shed light on the early detection of foci and dynamic monitoring of anti-VEGFR-2 therapy in PrCa.

Incidence and Risk of Fatal Adverse Events in Cancer Patients Treated With Vascular Endothelial Growth Factor Receptor 2-Targeted Agents: A Meta-Analysis With Trial Sequential Analysis of Randomized Controlled Trials

Background/Aim: Agents targeting vascular endothelial growth factor (VEGF) pathway have dramatically improved the outlook of cancer treatment. Meanwhile, it is well-known that they are associated with increases in the risk of fatal adverse events (FAEs). Vascular endothelial growth factor receptor 2 (VEGFR2)-targeted drugs have been approved for the treatment of several malignancies. However, little is known regarding the FAEs induced by VEGFR2-targeted agents across different tumor types and treatment regimens. Methods: We searched PubMed and Embase database from January 1966 to April 2018 for randomized controlled trials (RCTs) to calculate the incidence and relative risks (RRs) of FAE. Results: Seventeen RCTs involving 6,982 subjects with solid tumors were included in this study. The overall incidence of FAEs associated with VEGFR2-targeted agents was 1.7% (95% CI: 0.9-2.4%). Compared with controls, the administration of VEGFR2-targeted agents did not increase the risk of FAEs (RR, 1.29; 95% CI: 0.90-1.86). No significant association was found between FAE and VEGFR2-targeted agents in subgroup analyses based on tumor type, treatment strategy, clinical phase, masking method, median treatment duration, and approval status. Additionally, FAEs occurred in the major organ systems dispersedly. Trial sequential analysis revealed that our results are solid and further studies are unlikely to change this. Conclusions: VEGFR2-targeted agents were not associated with an increased risk of FAEs.

Protein Tyrosine Signaling and its Potential Therapeutic Implications in Carcinogenesis

Protein tyrosine phosphorylation is a crucial signaling mechanism that plays a role in epithelial carcinogenesis. Protein tyrosine kinases (PTKs) control various cellular processes including growth, differentiation, metabolism, and motility by activating major signaling pathways including STAT3, AKT, and MAPK. Genetic mutation of PTKs and/or prolonged activation of PTKs and their downstream pathways can lead to the development of epithelial cancer. Therefore, PTKs became an attractive target for cancer prevention. PTK inhibitors are continuously being developed, and they are currently used for the treatment of cancers that show a high expression of PTKs. Protein tyrosine phosphatases (PTPs), the homeostatic counterpart of PTKs, negatively regulate the rate and duration of phosphotyrosine signaling. PTPs initially were considered to be only housekeeping enzymes with low specificity. However, recent studies have demonstrated that PTPs can function as either tumor suppressors or tumor promoters, depending on their target substrates. Together, both PTK and PTP signal transduction pathways are potential therapeutic targets for cancer prevention and treatment.

Randomized phase II trial of cixutumumab alone or with cetuximab for refractory recurrent/metastatic head and neck squamous cell carcinoma

OBJECTIVES

Cixutumumab (CIX) and cetuximab (CET) monoclonal antibodies block ligand-binding to insulin-like growth factor-1 receptor (IGF-1R) and epidermal growth factor receptor (EGFR) respectively. The objective of this study was to assess the efficacy of CIX alone or combined with CET in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients.

METHODS

In this open-label phase II trial, 91 R/M HNSCC patients who progressed within 90 days of platinum-based chemotherapy, were randomized to CIX 10 mg/kg alone or with CET 500 mg/m² every 2 weeks. Patients were stratified by prior CET use. The primary endpoint was median progression-free survival (PFS). Exploratory biomarker assessments included relevant markers on archival tumor and serial cytokine/angiogenic-factor profiles in blood.

RESULTS

Forty-seven patients were treated with CIX monotherapy and 44 with combination. The median PFS was 1.9 and 2.0 months and clinical benefit rate (complete or partial responses and stable disease) was 5.9% and 15.3%, respectively. There was no exacerbation of CET toxicity by concurrent CIX exposure. Higher tumor expression of IGF-1 was associated with improved PFS in the CIX + CET arm while increased p-EGFR expression correlated with shorter PFS in patients receiving single agent CIX. Higher serum baseline levels of IGF-1 and IGFBP-3 correlated with improved PFS and overall survival (OS) in the CIX arm. Neither regimen resulted in improved PFS or OS compared to historical data with CET alone.

CONCLUSION

The results of this study do not support the use of cixutumumab alone or with cetuximab in unselected patients with R/M HNSCC.

A critical review on ramucirumab in the treatment of advanced urothelial cancer

Advanced urothelial cancer (UC) is a lethal disease despite current advances in systemic therapy, including platinum chemotherapy combinations and immune checkpoint inhibition. Tumor angiogenesis is involved in UC growth and metastatic progression. Proangiogenic signaling through the VEGFR is a key process in UC with prognostic significance. Targeting of VEGFR2 with the monoclonal antibody ramucirumab has been tested in various different tumor types. In this review, we discuss the development of the drug in the context of its preclinical and clinical use with a focus on UC. Improvements in our ability to predict responses and resistance are key for maximizing its efficacy and selecting the most appropriate combinations with other active agents.

Efficacy and safety of different interventions in castration resistant prostate cancer progressing after docetaxel-based chemotherapy: Bayesian network analysis of randomized controlled trials

Background: Most patients receiving docetaxel-based chemotherapy for castration resistant prostate cancer (CRPC) will eventually progress, and the optimal interventions for these patients are controversial. The objective of our study is to evaluate the clinical efficacy and safety of pharmacological interventions for CRPC patients progressing after docetaxel-based chemotherapy.

Methods: A systematic review and Bayesian network meta-analysis of the literature was carried out according to standard methods. Major electronic databases including PubMed, Web of Science and Embase were searched until Jan 2017. Hazard ratios (HRs) and odds ratios (ORs) with corresponding 95% credible intervals (CrIs) were used to estimate the association.

Results: 17 Randomized Controlled Trials (RCTs) comprising 14 different interventions with 12347 patients were enrolled. Compared with control arms, Abiraterone Acetate (HR: 0.70, 95%CrI: 0.63-0.79), Cabazitaxel (HR: 0.70, 95%CrI: 0.51-0.95) and Enzalutamide (HR: 0.63, 95%CrI: 0.53-0.75) presented similar benefits in term of OS. Enzalutamide showed superiority over PFS and PSA response with a highest probability to rank 1. Moreover, sensitivity analysis showed that Abiraterone Acetate (HR: 0.71, 95%CrI: 0.63-0.78) exhibited the most efficacious intervention of being rank 1 in term of OS compared with control arms, followed by Cabazitaxel and Cetuximab. On the other hand, Abiraterone Acetate (OR: 0.86, 95%CrI: 0.35-2.03) presented no significant toxicities compared with control arms.

Conclusions: Our results demonstrated that Abiraterone Acetate might be the optimal intervention for CRPC patients after docetaxel failure with acceptable tolerability. Future well-designed RCTs and systematic reviews are needed to validate these findings.

Evolution of ramucirumab in the treatment of cancer - A review of literature

Ramucirumab is a recombinant human monoclonal antibody and is used in the treatment of advanced malignancies. Its mechanism of action is by inhibiting angiogenesis in tumor cells by targeting the vascular endothelial growth factor receptor 2. United States Food and Drug Administration (FDA) approved it initially in 2014 for the treatment of advanced gastric or gastro-esophageal junction adenocarcinoma and metastatic non-small cell lung carcinoma. It was approved by FDA in 2015 for the treatment of advanced colorectal cancer. This manuscript consolidates pre-clinical trials to phase I, II, and III trial data indicating the effects of ramucirumab on different cancer types, which led to its approval. By comparing these clinical trials alongside each other, we can more easily examine the studies that have already been completed, along with currently ongoing studies and potential further areas of interest for this newly approved treatment. This approach makes it convenient to compare dosages, overall survival, adverse events, as well as possible routes for combination therapy with ramucirumab. By compiling results for various oncological malignancies, we can differentiate between treatments that are effective and have the highest incidence of stable disease, and those that do not seem promising. Ramucirumab has been effective in the treatment of various carcinomas and this article outlines other tumors in which this treatment option may be successful.

Antibody therapeutics for treating prostate cancer: where are we now and what comes next?

Progress in the understanding of molecular events of carcinogenesis and cancer evolution as well as the identification of tumor antigens has led to the development of different targeted therapeutic approaches, including the use of monoclonal antibodies (mAbs). Prostate cancer (PC) is highly amenable to mAb targeting given the existence of prostate-specific targets and the natural history and localization of metastatic disease. Areas covered: Several aspects of the PC phenotype, including growth factors, angiogenesis mediators, bone microenvironment signals, and immune evasion pathways, have become areas of ongoing investigation in terms of mAb targeting. These are reviewed. The greatest success so far has been the development of mAbs against prostate-specific tumor antigen (PSMA), which opened an opportunity to improve diagnostic accuracy and simultaneously target metastatic disease. Expert opinion: As mAb use in PC continues to evolve, more accurate imaging of the extent of disease and more effective mAb therapies (naked or conjugated with drugs, toxins or radioactive molecules) are emerging. In addition, the combination of mAbs with other treatment modalities is expected to further improve responses and overall survival. Identification of validated biomarkers is necessary for better recognition of patient subgroups who will derive the greatest benefit from mAb therapy.

In silico prediction of B cell epitopes of the extracellular domain of insulin-like growth factor-1 receptor

The insulin-like growth factor-1 receptor (IGF-1R) is a transmembrane receptor with tyrosine kinase activity. The receptor plays a critical role in cancer. Using monoclonal antibodies (MAbs) against the IGF-1R, typically blocks ligand binding and enhances down-regulation of the cell-surface IGF-1R. Some MAbs such as cixutumumab are under clinical trial investigation. Targeting multiple distinct epitopes on IGF-1R, might be an effective strategy to inhibit IGF-1R pathway in cancer. In this study, new linear B cell epitopes for the extracellular domains of IGF-1R were predicted by in silico methods using a combination of linear B cell epitope prediction web servers such as ABCpred, Bepired, BCPREDs, Bcepred and Elliprro. Moreover, Discotope, B- pred and PEPOP web server tools were employed to predict new conformational B cell epitopes. In contrast to previously reported epitopes from extracellular region of the IGF-1R, we predicted new linear P8: (RQPQDGYLYRHNYCSK) and conformational Pc4: (HYYYAGVCVPACPPNTYRFE), Ppc6: (KMCPSTGKRENNESAPDNDT) and Ppc20: (ANILSAESSDSEFMQEPSGFI) epitopes. These epitopes are useful for further study as peptide antigens to actively immune host animals to develop new MAbs. Furthermore, the epitopes can be used in peptide-based cancer vaccines design.

LHD-Modified Mechanism-Based Liposome Coencapsulation of Mitoxantrone and Prednisolone Using Novel Lipid Bilayer Fusion for Tissue-Specific Colocalization and Synergistic Antitumor Effects

Coencapsulation liposomes are of interest to researchers because they maximize the synergistic effect of loaded drugs. A combination regimen of mitoxantrone (MTO) and prednisolone (PLP) has been ideal for tumor therapy. MTO and PLP offer synergistic antitumor effects confirmed by several experiments in this research. The deduced synergistic mechanism is regulation of Akt signaling pathway including the targets of p-Akt, p-GSK-3β, p-s6 ribosomal protein, and p-AMPK by MTO reactivating PLP-induced apoptosis. The liposome fusion method is adopted to create coencapsulation liposomes (PLP-MTO-YM). Low molecular weight heparin-sodium deoxycholate conjugate (LHD) then is used as a targeting ligand to prove target binding and inhibition of angiogenesis. LHD-modified liposomes (PLP-MTO-HM) have a high entrapment efficiency around 95% for both MTO and PLP. DSC results indicate that both drugs interacted with liposomes to prevent drug leak during liposome fusion. DiD-C6-HM dyes colocalize well to tumor tissue, and coadministration of DiD-HM and C6-CM did not achieve dye colocalization until 24 h after administration. In both CT26 and B16F10 mouse model, PLP-MTO-HM shows a significantly higher tumor inhibition rate relative to the coadministration of MTO-HM and PLP-CM (p < 0.05 or p < 0.01). Thus, the coencapsulation system (PLP-MTO-HM) offers ideal antitumor effects relative to coadministration therapy due to enhanced synergistic effect, and this suggests a promising future for the tumor targeting vectors.

Persistent androgen receptor addiction in castration-resistant prostate cancer

It is now understood that persistent activation of the androgen receptor (AR) signaling pathway often underlies the development of castration-resistant prostate cancer (CRPC). This realization led to renewed interest in targeting the AR and ultimately to the development of the potent next-generation AR-directed agents abiraterone and enzalutamide. While these drugs prolong survival in men with CRPC, they are unfortunately not curative. Perhaps not surprisingly, evidence points to persistent AR signaling as one of the key drivers by which resistances to these agents develops. In this context, activation of the AR signaling program can occur through a number of molecular adaptations, including alterations leading to persistent canonical AR signaling (e.g., AR amplification/overexpression, elucidations/concentration of intratumoral androgens), activation of the AR program via feedback pathways (e.g., AKT/mTOR/Pi3K, HER2/Neu), and activation of the AR program via mutation or substitution (e.g., AR ligand binding domain mutation; AR splice variants; glucocorticoid receptor signaling). This review will provide an overview of the more clinical relevant (i.e., druggable) pathways that have been implicated in the emergence of drug resistance in men with CRPC and highlight some of the ongoing efforts towards developing therapeutics to impair these mechanisms.