Bevacizumab, bleeding, thrombosis, and warfarin

Sclerosing cholangitis in the era of target chemotherapy: a possible anti-VEGF effect

Preoperative systemic chemotherapy is generally applied in patients who undergo hepatic resection for colorectal metastases. Although the tumour response rate has been improved recently with the development of new molecular targeted therapies the related hepatic injury is ill defined. Bevacizumab is a monoclonal antibody to vascular endothelial growth factor. It can achieve high response rates and is accepted as a first line treatment in the metastatic colorectal disease. However, the data about its hepatotoxicity profile is still limited. We describe a case of secondary sclerosing cholangitis in a patient with liver metastases treated by Bevacizumab in the neoadjuvant setting and liver resection. It is possible that Bevacizumab may have induced a hypercoagulative condition that was further precipitated by surgery.

Bevacizumab immune complexes activate platelets and induce thrombosis in FCGR2A transgenic mice

BACKGROUND

Treatment with Bevacizumab has been associated with arterial thromboembolism in colorectal cancer patients. However, the mechanism of this remains poorly understood, and preclinical testing in mice failed to predict thrombosis.

OBJECTIVE

We investigated whether thrombosis might be the result of platelet activation mediated via the FcgammaRIIa (IgG) receptor - which is not present on mouse platelets - and aimed to identify the functional roles of heparin and platelet surface localization in Bev-induced FcgammaRIIa activation.

METHODS AND RESULTS

We found that Bev immune complexes (IC) activate platelets via FcgammaRIIa, and therefore attempted to reproduce this finding in vivo using FcgammaRIIa (hFcR) transgenic mice. Bev IC were shown to be thrombotic in hFcR mice in the presence of heparin. This activity required the heparin-binding domain of Bev's target, vascular endothelial growth factor (VEGF). Heparin promoted Bev IC deposition on to platelets in a mechanism similar to that observed with antibodies from patients with heparin-induced thrombocytopenia. When sub-active amounts of ADP or thrombin were used to prime platelets (simulating hypercoagulability in patients), Bev IC-induced dense granule release was significantly potentiated, and much lower (sub-therapeutic) heparin concentrations were sufficient for Bev IC-induced platelet aggregation.

CONCLUSIONS

The prevailing rationale for thrombosis in Bev therapy is that VEGF blockade leads to vascular inflammation and clotting. However, we conclude that Bev can induce platelet aggregation, degranulation and thrombosis through complex formation with VEGF and activation of the platelet FcgammaRIIa receptor, and that this provides a better explanation for the thrombotic events observed in vivo.

Bevacizumab treatment for cancer patients with cardiovascular disease: a double edged sword?

Recently, bevacizumab, the novel humanized monoclonal antibody directed against vascular endothelial growth factor (VEGF), has shown promising preclinical and clinical anti-cancer activity. However, concerns have been raised regarding a possible increased risk for arterial thrombo-embolic events associated with its administration, especially in patients with pre-existing cardiovascular disease. On the other hand, bevacizumab treatment is associated with an increased bleeding risk that may be augmented by the co-administration of anti-platelet drugs such as aspirin and clopidogrel. In this paper, we present the available data, identify controversies and unresolved issues, and suggest solutions regarding the administration of bevacizumab to cancer patients with cardiovascular disease.

Targeting the VEGF pathway: antiangiogenic strategies in the treatment of non-small cell lung cancer

The management of advanced non-small cell lung cancer (NSCLC) has evolved considerably in recent years, due to a progressive understanding of tumour biology and the identification of promising molecular targets. Several agents have been developed so far inhibiting vascular endothelial growth factor (VEGF) - a key protein in tumour neoangiogenesis, growth and dissemination - or its receptor signalling system. The finding in study E4599 of a survival benefit for carboplatin-paclitaxel plus bevacizumab - a humanised anti-VEGF monoclonal antibody - over chemotherapy (CT) alone led the U.S. Food and Drug Administration (FDA) to approve the novel combination for first-line treatment of patients with unresectable, locally advanced, recurrent or metastatic non-squamous NSCLC. In a randomised phase III trial presented at the American Society of Clinical Oncology (ASCO) 2007 Annual Meeting, patients receiving cisplatin-gemcitabine plus bevacizumab experienced a significantly longer progression-free survival (PFS) compared to the standard arm. Based on these data, the European Medicines Agency (EMEA) has granted marketing authorisation for bevacizumab in addition to any platinum-based CT for first-line treatment of advanced NSCLC other than predominantly squamous histology. Aim of this report is to provide an overview on bevacizumab in NSCLC, with special emphasis on clinical results presented at ASCO last meeting. Multitargeted tyrosine kinase inhibitors (TKIs), sharing a focus on both the angiogenesis process and additional cell-surface receptors, and VEGF Trap, a novel fusion protein with markedly higher affinity for VEGF than bevacizumab, will be briefly discussed as well.

The diagnosis and management of cardiovascular disease in cancer patients

Cardiovascular disease is commonly found in cancer patients. The co-existence of heart disease and cancer in a patient often complicates treatment, because therapy for one disease may negatively affect the outcome of the other disease. In addition, guidelines for the treatment of cardiovascular disease are often based on studies, which exclude patients who have cancer. In this review we will discuss the diagnosis and management of cardiovascular disease in cancer patients. We will focus on cancer-related causes of cardiovascular disease and special treatment options for cardiovascular disease in cancer patients. The cardiac complications of cancer therapy will be discussed according to common syndromes: left ventricular dysfunction, myocardial ischemia, blood pressure changes, thromboembolism, bradyarrhythmias, and prolonged QT interval.

"Spontaneous," delayed colon and rectal anastomotic complications associated with bevacizumab therapy

Bevacizumab, a humanized monoclonal antibody used to treat recurrent and metastatic colorectal cancer, targets the vascular endothelial growth factor (VEGF) molecule. It is hypothesized that bevacizumab works by both depriving tumors of the neovascularity they require to grow, and by improving local delivery of chemotherapy through alterations of tumor vasculature permeability and Starling forces. Complications of bevacizumab treatment include bowel ischemia and perforation, but to date, these complications have only rarely been described as occurring at the site of presumably healed anastomoses following surgery. We report two cases of delayed, "spontaneous" low anterior colorectal anastomotic dehiscence and one right colon anastomotic colocutaneous fistula associated with bevacizumab therapy. After seeing three patients with complications arising from apparently healed low anterior colorectal or right colon anastomoses following initiation of bevacizumab therapy for treatment of metastatic colorectal cancer, we reviewed the experience of The Cancer Institute of New Jersey (CINJ) with use of bevacizumab in approximately 50 patients between April 2004 and December 2006. The three index cases had been treated surgically at CINJ but received chemotherapy elsewhere. None of the 50 patients receiving bevacizumab at CINJ who had previous colon or rectal anastomoses were identified as having this complication. The medical records of the three index cases were reviewed and analyzed. Additionally, a Medline search was performed to identify other reports documenting similar cases. Two reports of related cases were found in the literature. In two of our index cases who underwent low anterior anastomoses, the patients had received preoperative pelvic irradiation before their initial low anterior resection. In one of the two cases, the initial resection was complicated by an anastomotic leak requiring proximal diversion and then subsequent stoma takedown. In both cases, the dehiscence occurred more than 1 year after anastomosis, and became evident 1-10 months following initiation of bevacizumab treatment. In the third index case, a colocutaneous fistula arising from the anastomotic site presented 5 months following right colon resection and 3 months after starting adjuvant systemic therapy with FOLFOX (5-fluorouracil (5-FU), leucovorin, and oxaliplatin) and bevacizumab. Delayed colorectal anastomotic complications may occur in association with bevacizumab therapy. Contributing factors may include anastomotic leak at the time of the original operation and history of anastomotic irradiation. Clinicians treating patients who receive bevacizumab following colectomy for colorectal cancer should be aware of this possible life-threatening complication. These findings may also be relevant to the design of trials of the use of bevacizumab for the postoperative adjuvant treatment of patients with colorectal cancer.

Review: side effects of approved molecular targeted therapies in solid cancers

Major advances have been achieved in the field of biologically based therapies for cancer in the last few years, and some of the recently approved molecular-targeted therapies are now being used in daily clinical practice. These molecular targets are also expressed in normal cells, which explains the different grades of toxicity, resulting from the disruption of normal cellular function. In general, targeted molecular therapies have good toxicity profiles, but some patients are exquisitely sensitive to these drugs and can develop particular and severe toxicities. In this article, we review the toxicity and safety of various small molecules and monoclonal antibodies used in solid tumors, with discussion of the pathophysiology, correlation with response, and strategies for prevention and management.

Evaluation of Early and Late Toxicities in Chemoradiation Trials

Combined chemoradiotherapy is increasingly becoming a standard of care for the nonoperative management of a variety of solid malignancies. A string of randomized controlled phase III trials have shown statistically significant and clinically relevant improvements in outcome, ostensibly without any apparent increase in late toxicity. However, the reliability and the sensitivity of toxicity reporting in most trials are questionable. Audits and phase IV studies suggest that the chemoradiotherapy success comes at a price in terms of late toxicity. This review presents some of the challenges in recording, analyzing, and reporting toxicity data. Methods for summarizing toxicity are reviewed, and a new investigational metric, the TAME reporting system, is discussed. The need for special vigilance in the era of molecular-targeted agents is emphasized because of the possibility that unexpected serious adverse events with a low incidence may occur. Finally, we discuss how progress in molecular pathology and radiation biology may provide novel opportunities for stratifying patients according to risk of adverse effects, interventional targets for reducing or treating adverse effects, and surrogate markers of normal-tissue injury.

Blood Flow Indices by Doppler Ultrasonography Vary with Neoadjuvant Chemotherapy but Are Not Related to Plasma VEGF Levels in Locally Advanced Breast Cancer

OBJECTIVE

The aim of our study was to assess the quantity of blood flow to malignant tissue by color Doppler ultrasonography, its correlation with plasma vascular endothelial growth factor (VEGF) levels and response to neoadjuvant chemotherapy of patients with locally advanced and inflammatory breast carcinoma.

METHODS

We measured blood velocity at peak systole (PSV), end-diastolic velocity and resistivity index [RI = (PSV - end-diastolic velocity)/PSV] by Doppler ultrasonography in primary tumors and/or axillary lymph nodes of patients before and after 2-4 cycles of anthracycline-containing neoadjuvant chemotherapy and basal plasma VEGF levels.

RESULTS

Of 21 patients with a median age of 42 years (range 26-68), 16 (76.2%) were premenopausal. Median basal RI was 0.70 (interquartile range 0.68-0.78) and PSV was 24.2 cm/s (interquartile range 18.7-56.6). The median measured VEGF level was 231.5 pg/ml (interquartile range 187.5-345.5). After 2-4 cycles of chemotherapy, 13 patients (61.9%) had partial remission and 8 (38.1%) were stable. Median basal RI (0.70, interquartile range 0.68-0.78) significantly decreased to 0.66 (interquartile range 0.59-073) after chemotherapy (p = 0.043). There was a trend that the greater the shrinkage of the tumor with chemotherapy, the lower the RI (r = 0.70, p = 0.078).

CONCLUSION

The decrease in RI with chemotherapy, which means increased blood flow at diastole of the cardiac cycle into the tumoral tissue, may be related to decreased intratumoral pressure secondary to tumor shrinkage and may reflect a new type of response, that is vascular response.

Mechanisms of adverse effects of anti-VEGF therapy for cancer

Advances in understanding the role of vascular endothelial growth factor (VEGF) in normal physiology are giving insight into the basis of adverse effects attributed to the use of VEGF inhibitors in clinical oncology. These effects are typically downstream consequences of suppression of cellular signalling pathways important in the regulation and maintenance of the microvasculature. Downregulation of these pathways in normal organs can lead to vascular disturbances and even regression of blood vessels, which could be intensified by concurrent pathological conditions. These changes are generally manageable and pose less risk than the tumours being treated, but they highlight the properties shared by tumour vessels and the vasculature of normal organs.

Possible molecular mechanisms involved in the toxicity of angiogenesis inhibition

Contrary to initial expectations, angiogenesis inhibitors can cause toxicities in patients with cancer. The toxicity profiles of these inhibitors reflect the disturbance of growth factor signalling pathways that are important for maintaining homeostasis. Experiences with angiogenesis inhibitors in clinical trials indicate that short-term toxicities are mostly manageable. However, these agents will also be given in prolonged treatment strategies, so we need to anticipate possible long-term toxicities. In addition, understanding the molecular mechanisms involved in the toxicity of angiogenesis inhibition should allow more specific and more potent inhibitors to be developed.

Bronchoscopy for bevacizumab-related hemoptysis

Bevacizumab is the first anti-angiogenic agent inhibiting vascular endothelial growth factor (VEGF) for treatment of patients suffering from cancer. Life-threatening hemoptysis is the most serious adverse effect of bevacizumab. The inhibition of VEGF is a possible mechanism involved in the destruction of normal lung tissue and subsequent hemoptysis. We report a case of bevacizumab-related hemoptysis and associated bronchoscopic findings that were successfully treated with rigid bronchoscopy and laser photocoagulation.

Double Hazard of Thrombophilia and Bleeding in Leukemia

The association between thrombosis and cancer has been extensively studied since first pointed out by Trousseau in 1895. It is, however, not commonly appreciated that the incidence of thrombosis in malignant hematologic disorders is as high or even higher than in solid tumors. Thrombotic complications in acute leukemia are often overlooked because bleeding complications generally dominate the clinical picture. Yet, the patient is at risk for both. While there are many thrombogenic factors shared by both solid tumors and leukemia, many additional prothrombotic features are present in leukemia. The prothrombotic factors include hyperleukocytosis, increased expression of tissue factor and its activation in leukemic cells, and the prothrombotic adverse effects of therapeutic agents and vascular access catheters. In addition, comorbid conditions including hereditary thrombophilia, infection, endothelial cell activation by cytokines, antiphospholipid syndrome and acquired activated protein C resistance are major contributory factors. Factors that increase the bleeding risk include thrombocytopenia, disseminated intravascular coagulation, and excessive fibrinolysis, which is enhanced by increased expression of Annexin II by leukemic cells. Therapeutic approaches to both bleeding and thrombotic conditions require special considerations of these factors.

Lack of evidence for increased operative morbidity after hepatectomy with perioperative use of bevacizumab: a matched case-control study

BACKGROUND

Bevacizumab (bev) is a humanized monoclonal antibody that targets vascular endothelial growth factor (VEGF). Perioperative bev is now commonly used in patients undergoing hepatic resection. Little is known, however, about the safety of perioperative bev use in the setting of hepatic resection.

METHODS

Computerized pharmacy records were used to identify all patients who received bev between January 2004 and June 2005. Patients who underwent hepatectomy for colorectal metastases and received bev within 12 weeks of surgery were identified and compared with a group of matched historical controls.

RESULTS

Thirty-two patients underwent hepatic resection of colorectal cancer metastases and received bev within the specified perioperative period. Sixteen patients received bev before surgery and 24 received bev after surgery. A subset of eight patients received bev both before and after surgery. The median time between bev administration and surgery was 6.9 weeks before (range, 3-15 weeks) and 7.4 weeks after (range, 5-15 weeks). Perioperative complications occurred in 13 patients (40.6%), two of which were considered major complications. There was no statistically significant difference in perioperative morbidity and severity of complications when compared with a set of matched controls.

CONCLUSIONS

Clinical experience thus far does not indicate a statistically significantly increased risk of perioperative complications with the incorporation of bev into pre- and/or postoperative treatment paradigms. Given the long half-life of bev and the potential for anti-VEGF therapy to impede wound healing and/or liver regeneration, we continue to favor a window of 6 to 8 weeks between bev administration and surgery.

Portal thrombosis and steatosis after preoperativechemotherapy with FOLFIRI-bevacizumab for colorectal liver metastases

In order to discuss the role of preoperative chemo-therapy for colorectal liver metastases, which is used frequently before hepatic resection, even in patients with resectable disease at presentation, we herein report the development of two complications, partial portal vein thrombosis and hepatic steatosis with lobular inflammation, during the course of preoperative chemotherapy with FOLFIRI plus bevacizumab for colorectal liver metastases, which recognition led to timely discontinuation of chemotherapy as well as a change in the surgical strategy to resect the tumors and the damaged liver through advanced techniques. We conclude that duration of treatment and drug doses and combinations may impact the development of chemotherapy-induced liver injury. Surgeons and medical oncologists must work together to devise safe, rational, and oncologically appropriate treatments for patients with multiple colorectal liver metastases, and to improve the understanding of the pathogenesis of chemotherapy-induced liver injury.

[(Side) effects of VEGF inhibition]

Vascular endothelial growth factor (VEGF) plays a pivotal role for embryo- and organogenesis. By regulating haemodynamics, (lymphoid) vessel architecture, haematopoiesis and immune system, endocrinology and reparative processes in adults, inhibited VEGF can cause multiple adverse events. Although the intravitreal administration of smaller doses can drastically reduce the systemic exposure, possible local side effects on retinal perfusion and survival of neuronal tissue must be taken into consideration. Before experience has been gained with VEGF inhibitors for longer than several years, individual discussion before the use, extensive informed consent and careful follow-up are necessary. From the ethical point of view, the available drugs should not be used without hesitation despite the clear benefit. First experiences with bevacizumab (Avastin), the first available (off-label) drug in Germany, are reported. In future, direct comparison of the different available drugs has to assess possible differences in the risk-benefit profile.

Bevacizumab: An Angiogenesis Inhibitor with Efficacy in Colorectal and Other Malignancies

OBJECTIVE:

To review the pharmacology, pharmacokinetics, and pivotal clinical trials for bevacizumab, emphasizing its use in colorectal cancer.

DATA SOURCES:

A PubMed/MEDLINE search was conducted (1966—April 2004) using the following terms: bevacizumab, Avastin, anti-VEGF, anti-angiogenesis, and colorectal cancer. Additional data sources included meeting abstracts, bibliographies from identified articles, and information from the manufacturer.

STUDY SELECTION AND DATA EXTRACTION:

Preclinical and clinical trials that used bevacizumab for the treatment of colorectal cancer and other malignancies were selected from the data sources. All published, randomized clinical trials evaluating bevacizumab in colorectal cancer were included in this review.

DATA SYNTHESIS:

Despite advances in chemotherapy, current therapeutic options for metastatic disease provide only temporary benefit for most patients. Bevacizumab is the first anti-cancer agent shown to provide benefit for patients with cancer by inhibiting angiogenesis. Bevacizumab has shown significant activity in the treatment of many cancers, including metastatic colorectal cancer. When used in combination with fluorouracil-based chemotherapy, bevacizumab improves overall response rates, time to progression, and survival in patients with metastatic colorectal cancer. Common toxicities associated with bevacizumab include hypertension, bleeding episodes, and thrombotic events.

CONCLUSIONS:

Although clinical knowledge on the effectiveness of bevacizumab is limited, early data indicate that it is a promising agent, with a novel mechanism of action, for patients with metastatic cancer, including colorectal cancer.