Bevacizumab in the treatment of colorectal cancer

Intravitreal Therapy for Diabetic Macular Edema: An Update

Diabetic macular edema (DME) represents a prevalent and disabling eye condition. Despite that DME represents a sight-threatening condition, it is also among the most accessible to treatment. Many different treatment options including photocoagulation, intravitreal medical treatment (either vascular endothelial growth factor inhibitors or corticosteroids therapies), and surgical removal are currently available. Although laser has been considered as the gold standard for many years, over the past several years vascular endothelial growth factor inhibitors (anti-VEGFs) have become first-line therapy. However, many patients do not adequately respond to them. With the development of sustained-release corticosteroid devices, steroids have gained a presence in the management of the DME. We review and update the role of anti-VEGF and intravitreal sustained-release corticosteroid management of DME. According to the currently available scientific evidence, the choice of one anti-VEGF over another critically depends on the baseline best-corrected visual acuity (BCVA). While aflibercept may be the drug of choice in low baseline BCVA, the three anti-VEGFs (bevacizumab, ranibizumab, and aflibercept) provided similar functional outcomes when the baseline BCVA was higher. DEX implants are a valuable option for treating DME, although they are usually seen as a second choice, particularly in those eyes that have an insufficient response to anti-VEGF. The new evidence suggested that, in eyes that did not adequately respond to anti-VEGF, switching to a DEX implant at the time to 3 monthly anti-VEGF injections provided better functional outcomes.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

Guidelines for the management of neovascular age-related macular degeneration by the European Society of Retina Specialists (EURETINA)

Age-related macular degeneration (AMD) is still referred to as the leading cause of severe and irreversible visual loss world-wide. The disease has a profound effect on quality of life of affected individuals and represents a major socioeconomic challenge for societies due to the exponential increase in life expectancy and environmental risks. Advances in medical research have identified vascular endothelial growth factor (VEGF) as an important pathophysiological player in neovascular AMD and intraocular inhibition of VEGF as one of the most efficient therapies in medicine. The wide introduction of anti-VEGF therapy has led to an overwhelming improvement in the prognosis of patients affected by neovascular AMD, allowing recovery and maintenance of visual function in the vast majority of patients. However, the therapeutic benefit is accompanied by significant economic investments, unresolved medicolegal debates about the use of off-label substances and overwhelming problems in large population management. The burden of disease has turned into a burden of care with a dissociation of scientific advances and real-world clinical performance. Simultaneously, ground-breaking innovations in diagnostic technologies, such as optical coherence tomography, allows unprecedented high-resolution visualisation of disease morphology and provides a promising horizon for early disease detection and efficient therapeutic follow-up. However, definite conclusions from morphologic parameters are still lacking, and valid biomarkers have yet to be identified to provide a practical base for disease management. The European Society of Retina Specialists offers expert guidance for diagnostic and therapeutic management of neovascular AMD supporting healthcare givers and doctors in providing the best state-of-the-art care to their patients.

TRIAL REGISTRATION NUMBER

NCT01318941.

Anti-VEGF therapy for the treatment of glaucoma: a focus on ranibizumab and bevacizumab

INTRODUCTION

Anti-VEGF therapy has been widely used in the treatment of ocular neovascular diseases. Because of their anti-angiogenic and anti-fibrotic properties, anti-VEGF antibodies such as bevacizumab and ranibizumab have emerged as an adjunctive treatment modality in glaucoma to improve success of conventional treatments.

AREAS COVERED

Ranibizumab is an anti-VEGF-A antigen binding fragment currently indicated in neovascular age-related macular degeneration as well as macular edema following retinal vein occlusion. Several off-label uses include the treatment of neovascular glaucoma to regress/suppress iris and iridocorneal angle neovascularization and the modulation of wound healing after glaucoma filtration surgery. Bevacizumab is a full-length anti-VEGF antibody, which is also being used in aforementioned eye conditions off-label. An overview of these anti-VEGF antibodies and the results of preclinical and clinical studies regarding their use in the treatment of glaucoma are presented.

EXPERT OPINION

Early studies on the utility of both bevacizumab and ranibizumab in neovascular glaucoma and filtration surgery reported promising results. However, a large-scale randomized clinical trial as well as comparative studies between the two anti-VEGF antibodies are currently lacking. A single dose of ranibizumab costs approximately 40 times as much as a single dose of bevacizumab. Clinicians should take this into account, in addition to their differences in the efficacy and safety, when treating patients.

Immune microenvironmental shift along human colorectal adenoma-carcinoma sequence: is it relevant to tumor development, biomarkers and biotherapeutic targets?

Human colorectal carcinoma (CRC) is one of the leading cancers. Every year, the WHO estimates a total of 945,000 new CRC cases, with 492,000 deaths worldwide. Most CRCs arise from the main premalignant lesion, colorectal adenomas, and the progression of colorectal adenoma to CRCs may take a long-term time course. The development of human CRCs is not only determined by the adenomatous cells, but also by the interaction between adenomatous cells and host immune environment. In response to tumor initiation or invasion, many inflammatory cells and components will be inevitably activated and form an inflammatory microenvironment surrounding the CRC tumors. Accumulative evidence has revealed that inflammatory response plays a key role in the development of human CRCs by implicating in many aspects including in determining the microenvironmental immune function shift from immunosurveillance to immunosuppression and significantly influences the progression of precancerous lesions to cancers. In this review, the functional changes of immune microenvironment from precancerous stage (adenoma) to cancer stage are summarized, and their potential as predictive biomarkers and biotherapeutic significance in preventing the development of CRCs are discussed.

Colorectal cancer: response to sunitinib in a heavily pretreated colorectal cancer patient

A 64-year-old man was admitted to the emergency room in May 2000 due to pelvic pain, functional disability of the lower limb, and bleeding from a rectal fistula. The patient was diagnosed with a rectum-sigma adenocarcinoma (pT1N0M0 stage). After surgery by left hemicolectomy, the patient received adjuvant chemotherapy with tegafur for 6 months. Due to the development of subsequent recurrences (infravesical relapse, bone and lung progression) associated with CEA progression and pain worsening, the patient received treatment by every available agent for the metastatic colorectal cancer, including oxaliplatin and radiotherapy; irinotecan; FOLFOX schema; oral capecitabine; raltitrexed; irinotecan and cetuximab; cetuximab as a single agent; always in combination with zolendronic acid-based treatment for pain control. Once the patient had progressed to all the approved drugs available in the market, sunitinib (50mg/day given for 4 weeks followed by 2 weeks of rest) was proposed as compassionate use. The patient received sunitinib for a total of 6 months (four cycles). On account of the nonmeasurable disease nature of the metastatic presentation in the present case, the clinical benefit was measured in terms of reduction of painkiller intake, improvement in performance status of the patient, and CEA serum levels. In addition to all of these clinical and biological data, CT images showed an increase in necrotic area of the bone lesion without any decrease in tumor size by classical RECIST criteria. The patient is still under sunitinib treatment and has recovered his normal daily activity.

Future perspectives for the treatment of pulmonary arterial hypertension

Over the past 2 decades, pulmonary arterial hypertension has evolved from a uniformly fatal condition to a chronic, manageable disease in many cases, the result of unparalleled development of new therapies and advances in early diagnosis. However, none of the currently available therapies is curative, so the search for new treatment strategies continues. With a deeper understanding of the genetics and the molecular mechanisms of pulmonary vascular disorders, we are now at the threshold of entering a new therapeutic era. Our working group addressed what can be expected in the near future. The topics span the understanding of genetic variations, novel antiproliferative treatments, the role of stem cells, the right ventricle as a therapeutic target, and strategies and challenges for the translation of novel experimental findings into clinical practice.

A dilemma in geriatric oncology: malignant bowel obstruction in an 81-year-old man

An 81-year-old male presenting with bowel obstruction was found upon examination to have bilobar liver metastases. In light of the patient's advanced age, bowel resection was foregone in favor of stent deployment, which led to rapid resolution of symptoms. The multidisciplinary team assembled to coordinate further care advised the use of chemotherapy with irinotecan, oxaliplatin, and 5-FU, which was well tolerated and led to an objective response. The special considerations relevant to the patient's advanced age, including the choice of stent deployment rather than resection and the decision to employ 5-FU-based chemotherapy in spite of limited trial data with this approach in patients of advanced age, are explained in detail.

Vascular endothelial growth factor polymorphisms -1154 G/A and -460 C/T are not associated with VEGF mRNA expression and susceptibility to sporadic colon cancer

Vascular endothelial growth factor (VEGF) is important mediator of angiogenesis, and its expression in colorectal tumors is related to tumor progression. VEGF expression has been detected in normal mucosa, primary colon cancers, and metastatic tumors, and patients with low VEGF expression have a better survival rate. In addition, anti-VEGF monoclonal antibody improves overall survival when used in combination with existing metastatic colorectal cancer therapy. Therefore, prediction of VEGF production based on individual genetic background might be important for predicting the course of the disease and the efficacy of anticancer treatment. The number of studies evaluating the influence of VEGF polymorphisms on cancer susceptibility is growing; however, their results are often conflicting. In addition, these studies are rarely accompanied with the expression analysis examining the influence of these polymorphisms on mRNA expression in tumor tissue. In this study, we have examined the influence of VEGF polymorphisms -1154 G/A and -460 C/T on VEGF mRNA expression and susceptibility to sporadic colon cancer by real-time PCR-SNP and mRNA expression analysis. The study included population control group consisting of 160 unrelated volunteers and a group of 160 patients with sporadic colon cancer. According to our results, -1154 G/A and -460 C/T do not influence VEGF mRNA expression in colorectal tumors and susceptibility to sporadic colon cancer, although the role of other polymorphisms cannot be excluded.

Use of antibodies and immunoconjugates for the therapy of more accessible cancers

There are currently 6 unconjugated antibodies and 3 immunoconjugates approved for use in the United States in a variety of cancers, with a considerable number of new agents in clinical testing and preclinical development. Unconjugated antibodies alone can be effective, but more often, antibodies need to be combined with chemotherapy, which enhances the efficacy of the standard treatment. Immunoconjugates tend to be more effective than their unconjugated counterparts, but their increased toxicity often restricts when and how they are used. In order to improve efficacy, a number of immunoconjugates are being examined in settings where the disease is more easily accessible, such as leukemias, or within compartments that allow easier and more direct access to the tumor, such as in the peritoneal cavity or brain, or both locally and systemically, in adjuvant situations, where the disease burden has been reduced by some other means, and with the main goal of these treatments being to kill residual disease.

BIBF 1120: triple angiokinase inhibitor with sustained receptor blockade and good antitumor efficacy

Inhibition of tumor angiogenesis through blockade of the vascular endothelial growth factor (VEGF) signaling pathway is a novel treatment modality in oncology. Preclinical findings suggest that long-term clinical outcomes may improve with blockade of additional proangiogenic receptor tyrosine kinases: platelet-derived growth factor receptors (PDGFR) and fibroblast growth factor receptors (FGFR). BIBF 1120 is an indolinone derivative potently blocking VEGF receptor (VEGFR), PDGFR and FGFR kinase activity in enzymatic assays (IC(50), 20-100 nmol/L). BIBF 1120 inhibits mitogen-activated protein kinase and Akt signaling pathways in three cell types contributing to angiogenesis, endothelial cells, pericytes, and smooth muscle cells, resulting in inhibition of cell proliferation (EC(50), 10-80 nmol/L) and apoptosis. In all tumor models tested thus far, including human tumor xenografts growing in nude mice and a syngeneic rat tumor model, BIBF 1120 is highly active at well-tolerated doses (25-100 mg/kg daily p.o.), as measured by magnetic resonance imaging of tumor perfusion after 3 days, reducing vessel density and vessel integrity after 5 days, and inducing profound growth inhibition. A distinct pharmacodynamic feature of BIBF 1120 in cell culture is sustained pathway inhibition (up to 32 hours after 1-hour treatment), suggesting slow receptor off-kinetics. Although BIBF 1120 is rapidly metabolized in vivo by methylester cleavage, resulting in a short mean residence time, once daily oral dosing is fully efficacious in xenograft models. These distinctive pharmacokinetic and pharmacodynamic properties may help explain clinical observations with BIBF 1120, currently entering phase III clinical development.

Generation of small 32P-labeled peptides as a potential approach to colorectal cancer therapy

Cancers have been revealed to be extremely heterogenous in terms of the frequency and types of mutations present in cells from different malignant tumors. Thus, it is likely that uniform clinical treatment is not optimal for all patients, and that the development of individualized therapeutic regimens may be beneficial. We describe the generation of multiple, unique small peptides nine to thirty-four amino acids in length which, when labeled with the radioisotope (32)P, bind with vastly differing efficiencies to cell lines derived from different colon adenocarcinomas. In addition, the most effective of these peptides permanently transfers the (32)P radioisotope to colorectal cancer cellular proteins within two hours at a rate that is more than 150 times higher than in cell lines derived from other cancers or from the normal tissues tested. Currently, the only two FDA-approved radioimmunotherapeutic agents in use both employ antibodies directed against the B cell marker CD20 for the treatment of non-Hodgkin's lymphoma. By using the method described herein, large numbers of different (32)P-labeled peptides can be readily produced and assayed against a broad spectrum of cancer types. This report proposes the development and use of (32)P-labeled peptides as potential individualized peptide-binding therapies for the treatment of colon adenocarcinoma patients.

The promise and perils of 'targeted therapy' of advanced ovarian cancer

For several reasons, ovarian cancer is an excellent malignancy to consider the use of 'targeted' therapeutic strategies. However, to date, despite considerable effort, there remains limited evidence that such approaches are clinically relevant in the malignancy. The one important exception is the delivery of anti-angiogenic anti-neoplastic agents, which actually appear to be more biologically active as single drugs in ovarian cancer than in other solid tumors where they have been examined. It is anticipated that future trials of 'targeted' therapy in ovarian cancer will focus on molecular targets of documented relevance in the malignancy.

Molecularly targeted therapies in adult soft tissue sarcomas: present approach and future directions

BACKGROUND

Sarcomas are rare neoplasms. Given the overwhelming chemotherapy resistance of the disease, patients with progressive and metastatic soft tissue sarcomas are ideal candidates for trials of investigational new drugs.

OBJECTIVE

The authors review the molecular mechanisms underlying soft tissue sarcomas and discuss molecularly targeted therapies developed to improve the poor outcome of these uncommon tumors.

METHODS

A Medline and American Society of Clinical Oncology abstract search was conducted using the keyword 'soft tissue sarcoma'. Articles and abstracts were reviewed and eligible for inclusion if they used targeted therapies for the treatment of patients with soft tissue sarcomas.

RESULTS/CONCLUSION

Phase II clinical trials for patients with soft tissue sarcomas using novel targets and present recognized targets are ongoing and planned.

Blockade of CD200 in the presence or absence of antibody effector function: implications for anti-CD200 therapy

CD200 is an immunosuppressive molecule overexpressed in multiple hematologic malignancies such as B cell chronic lymphocytic leukemia, multiple myeloma, and acute myeloid leukemia. We previously demonstrated that up-regulation of CD200 on tumor cells suppresses antitumor immune responses and that antagonistic anti-human CD200 mAbs enabled human PBMC-mediated tumor growth inhibition in xenograft NOD/SCID human (hu)-mouse models. Ab variants with effector function (IgG1 constant region (G1)) or without effector function (IgG2/G4 fusion constant region (G2G4)) exhibited high antitumor activity in a human tumor xenograft model in which CD200 was expressed. In this report, we seek to select the best candidate to move forward into the clinic and begin to decipher the mechanisms of tumor cell killing by comparing anti-CD200-G1 vs anti-CD200-G2G4 in two related animal models. In a CD200-expressing xenograft NOD/SCID hu-mouse model where CD200 ligand/receptor interactions are already established before initiating treatment, we find that anti-CD200-G1 is a less effective Ab compared with anti-CD200-G2G4. Separately, in a model that evaluates the effect of the Abs on the immune cell component of the xenograft NOD/SCID hu-mouse model distinctly from the effects of binding to CD200 on tumor cells, we find that the administration of anti-CD200-G1 Abs completely abolished human PBMC-mediated tumor growth inhibition. Along with supporting in vitro studies, our data indicate that anti-CD200-G1 Abs efficiently mediate Ab-dependent cellular cytotoxicity of activated T cells, critical cells involved in immune-mediated killing. These studies suggest important implications regarding the selection of the constant region in anti-CD200 immunotherapy of cancer patients.

Distributions of angiogenesis and lymphangiogenesis in gastrointestinal intramucosal tumors

BACKGROUND

Although angiogenesis and lymphangiogenesis in gastrointestinal cancers has been investigated in many studies, their distribution characteristics in gastrointestinal intramucosal tumors have not been well addressed.

METHODS

We evaluated the blood microvessel density (BMVD) and lymphatic microvessel density (LMVD) by immunostaining with monoclonal antibodies of CD34 and D2-40 in 37 patients with stomach intramucosal carcinoma and 28 patients with colorectal intramucosal neoplasia. Microvessels with endothelial cells labeled by CD34 but not by D2-40 were recognized as blood microvessels; and microvessels with endothelial cells labeled by both CD34 and D2-40 were recognized as lymphatic vessels. Furthermore, the relationships between expression of vascular endothelial growth factor (VEGF), VEGF-C, and BMVD, LMVD were investigated as well.

RESULTS

The LMVD was significantly higher in peritumoral tissues than in corresponding normal tissues in gastrointestinal intramucosal tumors (20.87 versus 14.56, P = 0.003). However, there was no significant difference in the BMVD between peritumoral tissues and corresponding normal tissues (P = 0.166). The BMVD in peritumoral tissues was higher in patients with lymph node metastases than in patients without lymph nodes metastases (P = 0.047). Our results did not show significant association between VEGF, VEGF-C and BMVD, LMVD.

CONCLUSIONS

Our results suggested that the increase of lymphangiogenesis seems superior to the increase of angiogenesis in gastrointestinal intramucosal tumors.

Pulsed high-intensity focused ultrasound enhances uptake of radiolabeled monoclonal antibody to human epidermoid tumor in nude mice

The aim of this study was to determine if pulsed high-intensity focused ultrasound (HIFU) exposures could enhance tumor uptake of (111)In-MX-B3, a murine IgG1kappa monoclonal antibody directed against the Le(y) antigen.

METHODS

MX-B3 was labeled with (111)In, purified, and confirmed for its binding to the antigen-positive A431 cell line. Groups of nude mice were inoculated subcutaneously with A431 tumor cells on both hind flanks. A tumor on one flank was treated with pulsed-HIFU; the other tumor was used as an untreated control. Within 10 min after the HIFU exposure, the mice received intravenous (111)In-MX-B3 for imaging and biodistribution studies. Mice were euthanized at 1, 24, 48, and 120 h after injection for biodistribution studies.

RESULTS

The HIFU exposure shortened the peak tumor uptake time (24 vs. 48 h for the control) and increased the peak tumor uptake value (38 vs. 25 %ID/g [percentage injected dose per gram] for the control). The HIFU effect on enhancing tumor uptake was greater at earlier times up to 24 h, but the effect was gradually diminished thereafter. The HIFU effect on enhancing tumor uptake was substantiated by nuclear imaging studies. HIFU also increased the uptake of the antibody in surrounding tissues, but the net increase was marginal compared with the increase in tumor uptake.

CONCLUSION

This study demonstrates that pulsed-HIFU significantly enhances the delivery of (111)In-MX-B3 in human epidermoid tumors xenografted in nude mice. The results of this pilot study warrant further evaluation of other treatment regimens, such as repeated HIFU exposures for greater delivery enhancement of antibodies labeled with cytotoxic radioisotopes or pulsed-HIFU exposure in addition to a combined therapy of (90)Y-B3 and taxol to enhance the synergistic effect.

Novel decapeptides that bind avidly and deliver radioisotope to colon cancer cells

BACKGROUND

The rapidly growing field of targeted tumor therapy often utilizes an antibody, sometimes tagged with a tumor-ablating material such as radioisotope, directed against a specific molecule.

METHODOLOGY/PRINCIPAL FINDINGS

This report describes the discovery of nine novel decapeptides which can be radioactively labeled, bind to, and deliver (32)P to colon cancer cells. The decapeptides vary from one another by one to three amino acids and demonstrate vastly different binding abilities. The most avidly binding decapeptide can permanently deliver very high levels of radioisotope to the adenocarcinoma cancer cell lines at an efficiency 35 to 150 times greater than to a variety of other cell types, including cell lines derived from other types of cancer or from normal tissue.

CONCLUSIONS/SIGNIFICANCE

This experimental approach represents a new example of a strategy, termed peptide binding therapy, for the potential treatment of colorectal and other adenocarcinomas.

Efficacy and safety of bevacizumab in combination with oxaliplatin, irinotecan and fluoropyrimidine-based therapy in advanced colorectal cancer

Background: Bevacizumab is an anti-VEGF, humanized mAb that is the most advanced agent of its class in clinical development. Several studies have examined bevacizumab in combination with chemotherapy in the first- and second-line settings in patients with metastatic CRC. Despite of that, there is lack of information concerning the extent to which bevacizumab can be used to treat metastatic CRC. We still need more evidence related to efficacy and safety of bevacizumab in different settings, or sequential treatments. The aim of this study was to investigate efficacy and safety of bevacizumab added to different chemotherapy in patients with metastatic CRC. Methods: This was a controlled, prospective, multicentre, cohort study. Thirty patients with advanced colorectal cancer were enrolled into this study. Bevacizumab was applied with oxaliplatin-, irinotecan-, 5FU- or capecitabine -based chemotherapy in the first-, second- or third-therapy lines. Totally 261 cycles were applied. The median number of applied cycles per patient was 8 (range 2-16). Results: Objective tumor response (RR) was seen in 11 patients 37% (95%CI 19-69%) calculated on an intention-to-treat basis. The median duration of response was 12 months. Three of 11 patients (27%) with PR had secondary surgery. RR was seen in 9 of 16 patients (56%) who received bevacizumab in the first-line treatment and in 2 of 14 patients (14%) who received therapy in the second+ lines (p=0.02). Clinical benefit (PR+SD) was seen in 22 (74%) patients. 75% of patients achieved clinical benefit in the first-line and 74% in the second+ chemotherapy lines. The median time to progression (TTP) of the patients is was 9 + months (95%CI 7 - + ?) at the moment of this analysis. The median TTP of patients who received bevacizumab in the first line was 11 months (95%CI 8 - + ?). The median TTP of patients who received bevacizumab in the second+ lines was 5.5 months (95%CI 4 - + ?) (p=0.015). The median survival time (OS) for all patients was 9 + months (95%CI 7 - + ?). The median OS at the moment of analysis was 11 months (95%CI 9 - + ?) for patients receiving bevacizumab in the first line, and 7 months for patients receiving the drug in the second+ lines (95%CI 6 - + ?) (p=0.024). The incidence of any toxicity grade 3-4 was less than 10%. Bevacizumab associated incidence of grade 3-4 side effects did not exceed 5%. Hypertension 5% and thromboembolism 5% were the most frequent events. Gastrointestinal perforation did not occur. There was one toxic death due to sepsis and not directly associated with bevacizumab toxicity. Conclusion: Bevacizumab can safely be added to different chemotherapeutic regimens in first- and second+ line. The conferred benefit in overall survival, TTP and response rate obviously requires randomized trials.