VB-111 for cancer

INTRODUCTION: Antibody, small molecule and protein inhibitors of angiogenesis are used in the management of several cancers. These do not specifically target tumor vascularity, and resistance can be problematic. VB-111 is a vascular-targeting agent consisting of a non-replicating adenovirus vector with a pre-proendothelin-1 promoter that encodes an apoptotic receptor. AREAS COVERED: The rationale and design of VB-111, its mechanism of action, and preclinical studies examining antitumor activity, toxicology and pharmacodynamics are reviewed. Phase I and Phase II clinical trials are also reviewed. EXPERT OPINION: VB-111 is a vascular-targeting gene therapeutic that is both tissue- and condition-specific, with effects limited to endothelial cells undergoing angiogenesis. Systemic administration produces selective destruction of tumor vascularity. Synergistic antitumor activity can be observed when combined with chemotherapy. VB-111 has been found to be safe and well tolerated in a Phase I clinical trial in patients with advanced solid tumors. Phase II clinical trials are in progress. VB-111 is novel agent for cancer that may have application as monotherapy and in combination with other therapies.     

Bevacizumab for the treatment of high-grade glioma: an update after Phase III trials

Introduction: Gliomas are highly vascular and rich in VEGF, which promotes angiogenesis. Bevacizumab is a monoclonal antibody against VEGF, inhibiting angiogenesis by preventing receptor activation. Early Phase II clinical trials using bevacizumab in both newly diagnosed and recurrent high-grade gliomas (HGG) showed promising results, but these have not been confirmed in recent Phase III trials. This review is an update including recently reported Phase II and III study results.

Areas covered: This is a review of clinical trials investigating bevacizumab in newly diagnosed and recurrent HGG with a focus on outcome results. A future perspective about the expected future role of bevacizumab is given. Bevacizumab efficacy, safety and tolerability, the combination of radiation and bevacizumab, as well as the use of bevacizumab to treat pseudoprogression are discussed. Further criteria of response evaluation needed to be adjusted in the age of antiangiogenic therapy are also discussed.

Expert opinion: Bevacizumab has been shown to be safe and tolerable in HGG. In the recurrent disease setting, bevacizumab might offer clinical benefits and is currently approved as a single agent for this indication. Although clinical trials demonstrate a prolonged progression-free survival (PFS) in bevacizumab-treated HGG, a benefit on overall survival has not been demonstrated. Research so far shows that bevacizumab appears to prolong PFS in newly diagnosed glioblastoma. Available data do not demonstrate a survival benefit in newly diagnosed patients. In the recurrent setting, there is no adequately powered randomized clinical trial to address whether there is a PFS or survival benefit with bevacizumab. Bevacizumab has also been introduced into other settings in neuro-oncology, including concurrent administration with re-irradiation for recurrent HGG.     

Trastuzumab emtansine: a novel antibody-drug conjugate for HER2-positive breast cancer

Introduction: Trastuzumab emtansine (T-DM1) is an antibody–drug conjugate (ADC) that combines intracellular delivery of the potent cytotoxic agent, DM1 (a derivative of maytansine) with the antitumor activity of trastuzumab. While there are several ADCs in Phase III development, T-DM1 is the only one in which the targeting antibody has antitumor properties. T-DM1 is also the only ADC that is directed toward the human EGFR 2 (HER2). Effective therapies are limited in HER2-positive advanced or metastatic breast cancer (MBC), particularly following progression on available HER2-targeted therapies.

Areas covered: The mechanisms of action, preclinical efficacy and clinical profile of T-DM1 are reported. The latest preclinical and clinical data for T-DM1 are examined.

Expert opinion: T-DM1 has significant antitumor potency in vitro and in vivo, which is maintained in tumors resistant to trastuzumab or lapatinib. In Phase I and II trials, T-DM1 provided objective tumor responses and was well tolerated across various lines of therapy in patients with HER2-positive MBC. In addition, it showed similar efficacy to trastuzumab plus docetaxel in first-line MBC. Ongoing trials (including two Phase III studies) are investigating T-DM1 as single-agent therapy or combined with other chemotherapeutic or biologic agents, and the results should help to define the place of T-DM1 within current treatment algorithms for HER2-positive disease.     

Gene therapy for peripheral arterial disease

Introduction: Gene therapy has emerged as a novel therapy to promote angiogenesis in patients with critical limb ischemia (CLI) caused by peripheral artery disease. Researchers working in this area have focused on pro-angiogenic factors, such as VEGF, fibroblast growth factor (FGF) and hepatocyte growth factor (HGF). Based on the elaborate studies and favorable results of basic research using naked plasmid DNA (pDNA) encoding these growth factors, some clinical Phase I and Phase II trials have been performed. The results of these studies demonstrate the safety of these approaches and their potential for symptomatic improvement in CLI patients. However, the Phase III clinical trials have so far been limited to HGF gene therapy. Because one pitfall of the Phase III trials has been the limited transgene expression achieved using naked pDNA alone, the development of more efficient gene transfer systems, such as ultrasound microbubbles and the needleless injector, as well as the addition of other genes will make these novel therapies more effective and ease the symptoms of CLI.

Areas covered: This study reviews the previously published basic research and clinical trials that have studied VEGF, FGF and HGF gene therapies for the treatment of CLI. Adjunctive therapies, such as the addition of prostacyclin synthase genes and the development of more efficient gene transfer techniques for pDNA, are also reviewed.

Expert opinion: To date, clinical studies have demonstrated the safety of gene therapy in limb ischemia but the effectiveness of this treatment has not been determined. Larger clinical studies, as well as the development of more effective gene therapy, are needed to achieve and confirm beneficial effects.     

Flavopiridol, a novel cyclin-dependent kinase inhibitor, in clinical development

OBJECTIVE: To review preclinical and clinical information on flavopiridol, an inhibitor of cyclin-dependent kinases (CDKs), tested as an antitumor agent. DATA SOURCES: Primary and review articles were identified by MEDLINE search (1990-June 2001). Abstracts from recent meetings were also used as source materials. DATA EXTRACTION: Flavopiridol was reviewed with regard to its mechanisms, preclinical and clinical results, pharmacokinetics, and metabolism. DATA SYNTHESIS: Flavopiridol is an inhibitor of several CDKs and displays unique anticancer properties. In addition to direct CDK inhibition, flavopiridol also exhibited other features such as inducing apoptosis in many cancer cell lines, decreasing cyclin D1 concentration, and inhibiting angiogenesis. Preclinical xenograft models showed significant antitumor activity for flavopiridol. The regimen using 72-hour continuous infusion every 2 weeks has been most extensively applied in clinical trials, with a 1-hour infusion currently being explored to achieve higher peak concentrations. Several Phase I and II trials have been reported, with some evidence of antitumor activity noted. Further Phase I and II trials using flavopiridol as a single agent and in combination with standard chemotherapeutic regimens and various tumor types are ongoing. CONCLUSIONS: Flavopiridol is the first CDK inhibitor to enter clinical trials. Several Phase I and Phase II clinical trials with different regimens (72-h or 1-h infusion) have been completed. Initial clinical trials have been intriguing, but many questions remain: What is the best regimen (< or =72-h infusion)? Does optimal future development of this drug depend on the combination with other chemotherapy? What is the best combination of flavopiridol with other chemotherapy?     

Monoclonal antibodies currently in Phase II and III trials for multiple myeloma

Introduction: Despite the introduction of novel agents, such as thalidomide, lenalidomide and bortezomib, multiple myeloma (MM) remains an incurable disease and new therapies are needed. mAbs are a new promising anticancer treatment option.

Areas covered: This review will focus on mAbs that are currently under evaluation in Phase II and III clinical trials, as single agent and in combination with established treatment options.

Expert opinion: mAbs are a new strategy against MM, and they have demonstrated encouraging results in preclinical models. mAbs have a relatively benign side-effect profile and work synergistically with traditional chemotherapies and with immunomodulatory drugs and proteasome inhibitors.     

Farletuzumab in epithelial ovarian carcinoma

Importance of the field: Ovarian cancer is the leading cause of death from a gynecologic malignancy. Recurrence is both common and lethal, necessitating the development of novel targeted therapies. Farletuzumab (MORAb-003) is a humanized mAb with high affinity for folate receptor α (FRα), a 38 kDa GPI-anchored protein that is overexpressed in 90% of epithelial ovarian cancers.

Areas covered in this review: Preclinical and clinical trials, published or presented at national meetings from 2006 to the present, are presented in this review.

What the reader will gain: Preclinical studies have demonstrated robust antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro, inhibition of tumor growth in ovarian tumor xenografts and a safe toxicology profile in non-human primates. Phase I and II studies have demonstrated single agent and combination therapy efficacy with minimal drug-specific toxicity. The Phase III development plan in ovarian cancer patients includes combination chemotherapy studies in both platinum-sensitive (recently launched) and platinum-resistant (planned) recurrent disease.

Take home message: FRα is overexpressed in ovarian cancers but largely absent from normal tissue, making it an attractive therapeutic target. Farletuzumab is a novel inhibitor of FRα and has shown clinical efficacy in early phase trials.     

Teplizumab therapy for type 1 diabetes

Importance of the field: Type 1 diabetes mellitus (T1D) is a T-cell mediated autoimmune disease with selective destruction of β cells. Immunological interventions are directed at arresting the loss of β-cell function with the promise that this will make it easier for patients to control their glucose levels.

Areas covered in this review: This review provides a summary of the preclinical and clinical research published between 1992 and 2009 using teplizumab and other anti-CD3 antibodies to arrest the loss of β-cell function in new onset T1D. Data from animal and human studies on the probable mechanism of action of teplizumab are also reviewed.

What the reader will gain: A broad perspective on the use of teplizumab in inducing disease specific tolerance.

Take home message: In Phase I/II randomized control trials, in patients with new onset T1D, teplizumab slowed the rate of loss of β-cell function over 2 years of follow-up. Treated patients had better glycemic control and lower insulin requirements. Adverse events so far are mild and of limited duration. Phase III clinical trials are underway to confirm these results and to determine if two courses of drug have greater efficacy in arresting loss of β-cell function.     

Velimogene aliplasmid

Importance of the field: Immunotherapy for cancer has been investigated for several decades, achieving limited success. The development of effective new immunotherapeutic agents has reignited interest in the filed. Intralesional injection of plasmids in order to transfect genes capable of stimulating or augmenting immune recognition and destruction of tumors is a relatively new approach.

Areas covered in this review: Our objective is to discuss the role velimogene aliplasmid (Allovectin-7^®, Vical Incorporated), a plasmid–lipid complex containing the DNA sequences encoding HLA-B7 and β2 microglobulin, as an immunotherapeutic agent.

What the reader will gain: Intralesional velimogene aliplasmid induces anti-tumor responses in a proportion of melanoma patients with locoregional and limited distant metastases. Preclinical data and the results of Phase I, II and III clinical trials with this drug are reviewed. The limited data in other malignancies is also reviewed. Velimogene aliplasmid in humans appears safe, with minimal drug-related adverse events.

Take home message: Velimogene aliplasmid has activity in melanoma with local and limited distant disease associated with an excellent safety profile. The activity of this approach is also being investigated in other malignancies.     

AE37: a novel T-cell-eliciting vaccine for breast cancer

Introduction: Immunotherapy, including vaccines targeting the human EGFR2 (HER-2/neu) protein, is an active area of investigation in combatting breast cancer. Several vaccines are currently undergoing clinical trials, most of which are CD8⁺ T-cell-eliciting vaccines. AE37 is a promising primarily CD4⁺ T-cell-eliciting HER-2/neu breast cancer vaccine currently in clinical trials.

Areas covered: This article reviews preclinical investigations as well as findings from completed and ongoing Phase I and Phase II clinical trials of the AE37 vaccine.

Expert opinion: Clinical trials have shown the AE37 vaccine to be safe and capable of generating peptide-specific, durable immune responses. This has been shown in patients with any level of HER-2/neu expression. Early clinical findings suggest there may be benefit to AE37 vaccination in preventing breast cancer recurrence.     

The role of talactoferrin alfa in the treatment of non-small cell lung cancer

Importance of the field: Immunotherapeutic approaches to treating NSCLC via either adoptive transfer of immunity or stimulation of the endogenous immune system have shown increasing promise in recent years.

Areas covered in this review: Talactoferrin alfa is an oral immunomodulatory agent currently in late-stage clinical trials that acts through dendritic cell recruitment and activation in the gut-associated lymphoid tissue.

What the reader will gain: Talactoferrin is a recombinant human lactoferrin that is a member of the transferrin family of iron-binding glycoproteins. Lactoferrins have multiple known biological activities including cancer protection, cellular growth and differentiation and antimicrobial and anti-inflammatory properties. This review discusses the proposed mechanism of action of talactoferrin-alfa and outlines the pre-clinical, Phase I and II data in NSCLC. The ongoing Phase III trials are discussed.

Take home message: The current role of Talactoferrin alpha in the treatment of NSCLC is described and we explore potential future roles for this drug in both early stage and advanced stage disease.     

The coming of ramucirumab in the landscape of anti-angiogenic drugs: potential clinical and translational perspectives

Introduction: Angiogenesis plays a pivotal role in the development and progression of tumors and it represents a crucial target for therapeutic strategies. Until now, regulatory agencies approved antiangiogenic agents targeting the VEGF and multi-target agents carrying antiangiogenic and anti-proliferative effects. They often provide only a modest survival benefit and their role in clinical practice is debated. The limited efficacy may be partially explained by the complexity of the molecular background of angiogenic processes, composed of several pathways interacting with both tumor cells and the microenvironment.

Areas covered: Ramucirumab is a fully human monoclonal antibody selectively binding and inhibiting the VEGF receptor 2 (VEGFR-2), a crucial molecule involved in angiogenesis. A series of Phase I–II trials conducted in a wide spectrum of malignancies reported promising antitumor activity. In 2014, data from large Phase III clinical trials in gastrointestinal, lung and breast malignancies were released.

Expert opinion: Considering the evidences of efficacy emerging from the available Phase III trials, the antiangiogenic approach emerged as a promising strategy particularly for the treatment of gastric cancer. Nevertheless, the identification and validation of potentially predictive biomarkers are necessary to improve the selection of patients and the globally awaited clinical benefit.     

Oral salmon calcitonin – pharmacology in osteoporosis

Importance of the field: Osteoporosis is a slow progressive disease which develops over decades, and where intervention is needed for an extended number of years. This highlights the need for safe intervention possibilities, which have sustained beneficial effects post-treatment.

Areas covered in this review: Articles on salmon calcitonin appearing on Pubmed from 1960 until today, with focus on a newly developed oral formulation showing increased exposure and efficacy compared with nasal formulation is reviewed. The second half focuses on long-term phenomena, such as bone quality and resolution effects. The final part discusses potential additional benefits of salmon calcitonin.

What the reader will gain: Insight into the clinical development of an orally formulated peptide, as well as a detailed understanding of why this approach could revive salmon calcitonin as a treatment for osteoporosis.

Take home message: The oral formulation of salmon calcitonin provides additional benefits and increased efficacy on bone based on Phase I and II clinical trials data, as compared with the nasal formulation. Hence, the results on the ongoing Phase III fracture trial are awaited with great interest.     

Immunotherapy for metastatic prostate cancer: where are we at with sipuleucel-T?

Importance of the field: Prostate cancer is the leading malignancy in North American men and despite improvements in treatments 20 – 30% of patients will relapse. Immunotherapy using activated mononuclear cells is a way to harness the body's adaptive immune response to fight metastatic prostate cancer.

Areas covered in this review: In 2005, at least 10 therapeutic cancer vaccines, designed to confer active, specific immunotherapy against tumor-associated antigens, were in clinical trials. These covered potential fields of immunological strategy to overcome castration-resistant prostate cancer.

What the reader will gain: A literature review was performed using the search terms sipuleucel-T, Provenge and APC8015 or APC-8015, and restricted to English language articles from 2000 to 2010. The immunological design and development of sipuleucel-T are summarized. The efficacy and safety of sipuleucel-T are discussed based on current data from clinical trials. Ongoing clinical trials involving sipuleucel-T are summarized.

Take home message: Efficacy and safety with sipuleucel-T has been demonstrated in Phase I/II trials. The latest data from a Phase III trial shows that sipuleucel-T has met the primary endpoint of survival benefit. Further work is needed to understand the mechanisms behind cancer vaccine failure and elucidate the population for whom this vaccine will be suitable.     

Convection-enhanced delivery of 131I-chTNT-1/B mAB for treatment of high-grade adult gliomas

Introduction: Despite treatment advances for malignant gliomas in adults, prognosis remains poor, largely due to the infiltrative and heterogeneous biology of these tumors. Response to adjuvant therapy is not always uniform and the blood–brain barrier prevents the majority of chemotherapeutics from adequately reaching primary tumor sites. These obstacles necessitate development of novel delivery methods and agents.

Areas covered: ¹³¹I-chTNT-1/B mAB (Cotara) is a genetically engineered chimeric monoclonal antibody that binds to the DNA–histone H1 complex. It carries ¹³¹I, which delivers sufficient energy to kill adjacent tumor cells. Through convection-enhanced delivery (CED) it provides radioimmunotherapy directly to the resection cavity. We review the pharmacology and clinical experience with ¹³¹I-chTNT-1/B mAB, detailing results of completed Phase I and II trials.

Expert opinion: Novel agents and therapeutic modalities, such as ¹³¹I-chTNT-1/B mAB, are of interest for treatment of malignant glioma, for which the prognosis continues to be dismal. ¹³¹I-chTNT-1/B mAB targets tumor cells and radioisotope labeling allows radiation delivery to the tumor with sharp fall-off. Data from Phase I and II trials of CED delivery of ¹³¹I-chTNT-1/B mAB shows it is well tolerated. Phase II trial data suggests it could be promising therapeutically, though conclusions about efficacy require further trials and clinical experience. The compound is currently in a Phase II trial for dose confirmation in patients with malignant gliomas.     

Oncolytic vaccinia virus for the treatment of cancer

Introduction: Gene therapy offers promising approaches for the development of anticancer agents with new modes of action. Among gene therapy vectors, vaccinia virus has emerged as an attractive agent especially when used as an oncolytic virus.

Areas covered: This review describes the use of vaccinia virus in cancer therapy as a gene therapy vector, as an oncolytic virus and in the generation of oncolysates. The main achievements of each field are summarized with a special emphasis on vaccinia as an oncolytic vector and its combination therapies. The virus that has advanced furthest in clinical trials, GM-CSF expressing JX-594, is described in detail and its preclinical and clinical data are reviewed.

Expert opinion: Vaccinia virus has great potential in cancer gene therapy, especially when used as an oncolytic virus. In particular, JX-594 has shown promising preclinical and clinical data, and a multi-continental randomized Phase III trial in hepatocellular carcinoma is expected to start soon.     

Bapineuzumab

Importance of the field: Alzheimer's disease is the leading cause of dementia in the elderly, and there is no disease-modifying therapy yet available. Immunotherapy directed against the β-amyloid peptide may be capable of slowing the rate of disease progression. Bapineuzumab, an anti-β-amyloid monoclonal antibody, will be the first such agent to emerge from Phase III clinical trials.

Areas covered in this review: The primary literature on bapineuzumab from 2009 and 2010 is reviewed in its entirety, along with the literature on AN1792, a first-generation anti-β-amyloid vaccine, from 2003 to 2009. Other Alzheimer's disease immunotherapeutics currently in development, according to www.clinicaltrials.gov, are also discussed.

What the reader will gain: In addition to a critical appraisal of the Phase II trial results for bapineuzumab, this review considers the broader field of immunotherapy for Alzheimer's disease as a whole, including the challenges ahead.

Take home message: Bapineuzumab appears capable of reducing the cerebral β-amyloid peptide burden in patients with Alzheimer's disease. However, particularly in APOE ?4 carriers, its ability to slow disease progression remains uncertain, and vasogenic edema – a dose-limiting and potentially severe adverse reaction – may limit its clinical applicability.     

Naptumomab estafenatox: a new immunoconjugate

Importance of the field: New agents that specifically engage the immune system are being tested in a variety of malignancies. This review provides an overview of naptumomab, an immunotoxin, with encouraging clinical activity in Phase I trials.

Areas covered in this review: This review examines the preclinical and the published clinical data with regards to naptumomab.

What the reader will gain: This review provides the reader with an understanding of the mechanism of action, immunology, pharmacokinetics and clinical activity of this agent.

Take home message: Naptumomab has a unique mechanism of action and appears to be an active agent in the treatment of refractory solid tumors such as renal cell carcinoma.     

Solanezumab for Alzheimer's disease

Introduction: Alzheimer's disease (AD) is a debilitating neurodegenerative illness affecting over 35 million people worldwide. Solanezumab is a monoclonal antibody that binds to β-amyloid (Aβ), a protein that plays a key role in the pathogenesis of AD. The drug is currently being investigated in Phase III trials as a disease-modifying treatment for AD.

Areas covered: This paper reviews literature on solanezumab that is available in PubMed from 2008 to 2010, other treatment trials in clinicaltrials.gov and published abstracts from conferences. The article also provides a discussion of the early trials of AN1792 and an overview of the immunotherapies currently in development. The authors provide the reader with a critical appraisal of the to-date clinical trial data on solanezumab and its implications for the broader field of immunotherapies for AD.

Expert opinion: Solanezumab can neutralize soluble Aβ peptides, which may represent the more neurotoxic of the Aβ species. Phase II findings support the compound's safety, which has been a concern for some Aβ immunotherapies. Cerebrospinal and plasma biomarker changes with solanezumab treatment are encouraging. Results of the ongoing Phase III trials will be instrumental in determining the drug's clinical significance.     

Conatumumab: a novel monoclonal antibody against death receptor 5 for the treatment of advanced malignancies in adults

Introduction: Advanced malignancies that are refractory to standard chemotherapy have few treatment options. Conatumumab is an investigational, fully human monoclonal agonist antibody directed at human death receptor DR5, which is expressed in multiple advanced cancers.

Areas covered: The rationale for the use of conatumumab based on in vitro, in vivo, Phase I, and Phase II data will be discussed.

Expert opinion: Conatumumab, at a dose of 20 mg/kg every 2 weeks, has demonstrated acceptable safety and tolerability in patients with advanced tumors based on available and published data. Further clinical trials are underway evaluating the use of conatumumab in combination with chemotherapeutic and targeted agents.