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1.  Pneumothorax as adverse event in patients with lung metastases of soft tissue sarcoma treated with pazopanib: a single reference centre case series 
Recently, the phase III PALETTE study introduced pazopanib (Votrient®) as treatment for adult patients with locally advanced or metastatic non-liposarcoma soft tissue sarcoma after prior treatment with doxorubicin and/or ifosfamide. Pneumothorax was reported as adverse event in 8 of 246 treated patients (3.3%) in that study. This case series presents the incidence and clinic of this complication in the Leiden University Medical Centre.
Forty-three patients were treated with pazopanib of which six patients (14.0%) developed a pneumothorax. These six patients were treated for malignant peripheral nerve sheath tumour, angiosarcoma, synovial sarcoma, fibromyxomatoid sarcoma, pleomorphic sarcoma and endometrial stromal sarcoma. All six patients had subpleural pulmonary or pleural metastases at the start of pazopanib and the pneumothorax developed during or shortly after treatment with pazopanib and was difficult to treat.
The incidence reported by us is higher than the incidence in the PALETTE study. Trials with pazopanib in renal cell carcinoma, urothelial carcinoma and cervix carcinoma did not report pneumothorax as an adverse event, suggesting pneumothorax as a specific adverse event in soft tissue sarcoma patients treated with pazopanib. This may be related to the fact that there is often pleural metastatic involvement and cystic degeneration due to pazopanib treatment may add to the risk.
The risk of an, often difficult to treat, pneumothorax during pazopanib therapy should be discussed with the patient before initiation of treatment for a pulmonary metastasized sarcoma and physicians should be alert to the occurrence of such an event.
PMCID: PMC4191680  PMID: 25302110
Soft tissue sarcoma; Pazopanib; Pneumothorax; Adverse event; Pleural metastases; Pulmonary metastases
2.  Budget impact analysis of first-line treatment with pazopanib for advanced renal cell carcinoma in Spain 
BMC Cancer  2013;13:399.
Due to economic constraints, cancer therapies are under close scrutiny by clinicians, pharmacists and payers alike. There is no published pharmacoeconomic evidence guiding the choice of first-line therapy for advanced renal cell carcinoma (RCC) in the Spanish setting. We aimed to develop a model describing the natural history of RCC that can be used in healthcare decision-making. We particularly analyzed the budget impact associated with the introduction of pazopanib compared to sunitinib under the Spanish National Healthcare System (NHS) perspective.
We developed a Markov model to estimate the future number of cases of advanced RCC (patients with favorable or intermediate risk) resulting either from initial diagnosis or disease progression after surgery. The model parameters were obtained from the literature. We assumed that patients would receive either pazopanib or sunitinib as first-line therapy until disease progression. Pharmacological costs and costs associated with the management of adverse events (AE) were considered. A univariate sensitivity analysis was undertaken in order to test the robustness of the results.
The model predicted an adult RCC prevalence of 7.5/100,000 (1-year), 20.7/100,000 (3-year) and 32.5/100,000 (5-year). These figures are very close to GLOBOCAN reported RCC prevalence estimates of 7.6/100,000, 20.2/100,000 and 31.1/100,000, respectively. The model predicts 1,591 advanced RCC patients with favorable or intermediate risk in Spain in 2013. Annual per patient pharmacological costs were €32,365 and €39,232 with pazopanib and sunitinib, respectively. Annual costs associated with the management of AE were €662 and €974, respectively. Overall annual per patient costs were €7,179 (18%) lower with pazopanib compared to sunitinib. For every point increase in the percentage of patients treated with pazopanib, the NHS would save €67,236. If all the 1,591 patients predicted were treated with pazopanib, the NHS would save €6,723,622 in 2013. Results were robust according to the sensitivity analysis.
We developed a model that accurately reproduces the natural history of RCC and can be thus used in healthcare decision-making. When applied to the Spanish case, the introduction of pazopanib results in savings for the NHS, as a consequence of both reduced pharmacological costs and lower costs associated with the management of AE compared to sunitinib.
PMCID: PMC3856525  PMID: 24004638
Renal cell carcinoma; Kidney cancer; Pazopanib; Sunitinib; Markov models; Budget impact analysis; Cost analysis
3.  Pharmacotherapy Options in Advanced Renal Cell Carcinoma: What Role for Pazopanib? 
Over the last 6 years, the treatment of metastatic renal cell carcinoma (mRCC) has undergone dramatic changes. A better understanding of the pathogenesis and tumor biology of sporadic renal cell carcinoma has led to the approval of 6 drug regimens: 3 oral multi-targeted tyrosine-kinase inhibitors (sorafenib, sunitinib, and pazopanib), 2 inhibitors of the mammalian target of rapamycin (temsirolimus and everolimus), and 1 monoclonal antibody against the vascular endothelial growth factor (bevacizumab). Pazopanib, a multi-targeted tyrosine kinase inhibitor that targets VEGFR-1, -2, and-3; PDGFR-α and PDGFR-β, and c-Kit, was approved for the treatment of mRCC in October 2009, several years after the other drugs in its class. The efficacy and safety of pazopanib in Phase I, II, and III trials will be examined and its role in mRCC treatment will be described. Future studies that may clarify pazopanib’s role in mRCC will be discussed. Based on pazopanib’s demonstrated efficacy in treatment-naïve and cytokine-refractory patients, along with a seemingly favorable toxicity profile compared with other multi-targeted tyrosine-kinase inhibitors, pazopanib may have a unique niche in the armamentarium of treatment options for mRCC. Results from ongoing studies are awaited to confirm pazopanib’s favorable efficacy-toxicity ratio, especially in comparison with the previous first-line standard-of-care, sunitinib.
PMCID: PMC3235998  PMID: 22174596
pazopanib; GW786034; VEGFR; TKI; renal cell carcinoma
4.  Comparative effectiveness of approved first-line anti-angiogenic and molecularly targeted therapeutic agents in the treatment of good and intermediate risk metastatic clear cell renal cell carcinoma 
BMC Cancer  2014;14(1):592.
Based on improved clinical outcomes in randomized controlled clinical trials (RCTs) the FDA and EMA have approved bevacizumab with interferon, sunitinib, and pazopanib in the first-line treatment of low to intermediate risk metastatic clear cell renal cell carcinoma (mRCC). However, there is little comparative data to help in choosing the most effective drug among these agents.
We performed an indirect comparative effectiveness analysis of the pivotal RCTs of bevacizumab with interferon, sunitinib, or pazopanib compared to one another or interferon alone in first-line treatment of metastatic or advanced RCC. Endpoints of interest were overall survival (OS), progression free survival (PFS), and response rate (RR). Adverse events were also examined.
The meta-estimate of the hazard ratio (95% confidence interval) for OS for bevacizumab with interferon vs. interferon alone was 0.86 (0.76-0.97), for sunitinib vs. interferon alone was 0.82 (0.67-1.00), for pazopanib vs. interferon alone was 0.74 (0.57-0.97), for sunitinib vs. bevacizumab with interferon was 0.95 (0.75-1.20), for pazopanib vs. bevacizumab with interferon was 0.86 (0.64-1.16), and for pazopanib vs. sunitinib was 0.91 (0.76-1.08). Similarly, bevacizumab with interferon, sunitinib, or pazopanib had better PFS and RR than interferon alone. Sunitinib and pazopanib had better RR than bevacizumab with interferon and there was suggestive evidence pazopanib may outperform sunitinib in terms of RR.
Bevacizumab with interferon, sunitinib, and pazopanib are adequate first-line options in treatment of mRCC. Interferon alone should not be considered an optimal first-line treatment.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2407-14-592) contains supplementary material, which is available to authorized users.
PMCID: PMC4148555  PMID: 25127891
Renal cell carcinoma; VEGF-targeted therapy; Bevacizumab; Sunitinib; Pazopanib; Interferon
5.  Pazopanib-induced hyperbilirubinemia is associated with Gilbert's syndrome UGT1A1 polymorphism 
British Journal of Cancer  2010;102(9):1371-1377.
Pazopanib has shown clinical activity against multiple tumour types and is generally well tolerated. However, isolated elevations in transaminases and bilirubin have been observed. This study examined polymorphisms in molecules involved in pharmacokinetic and pharmacodynamic pathways of pazopanib and their association with hepatic dysfunction.
Twenty-eight polymorphisms in 11 genes were evaluated in pazopanib-treated renal cell carcinoma patients. An exploratory analysis was conducted in 116 patients from a phase II study; a replication study was conducted in 130 patients from a phase III study.
No polymorphisms were associated with alanine aminotransferase elevation. The Gilbert's uridine-diphosphoglucuronate glucuronosyltransferase 1A1 (UGT1A1) TA-repeat polymorphism was significantly associated with pazopanib-induced hyperbilirubinemia in the phase II study. This association was replicated in the phase III study (P<0.01). Patients with TA6/TA6, TA6/TA7, and TA7/TA7 genotypes experienced median bilirubin increases of 0.31, 0.37, and 0.71 × upper limit of the normal range (ULN), respectively. Of the 38 patients with hyperbilirubinemia (⩾1.5 × ULN), 32 (84%) were either TA7 homozygotes (n=18) or TA7 heterozygotes (n=14). For TA7 homozygotes, the odds ratio (95% CI) for developing hyperbilirubinemia was 13.1 (5.3–32.2) compared with other genotypes.
The UGT1A1 polymorphism is frequently associated with pazopanib-induced hyperbilirubinemia. These data suggest that some instances of isolated hyperbilirubinemia in pazopanib-treated patients are benign manifestations of Gilbert's syndrome, thus supporting continuation of pazopanib monotherapy in this setting.
PMCID: PMC2865761  PMID: 20389299
alanine aminotransferase; bilirubin; pazopanib; pharmacogenetics; renal cell carcinoma; UGT1A1
6.  Fatal atypical reversible posterior leukoencephalopathy syndrome: a case report 
Reversible posterior leukoencephalopathy syndrome – a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures – is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. Complete reversibility of both clinical signs and magnetic resonance imaging lesions is regarded as a defining feature of reversible posterior leukoencephalopathy syndrome. Reversible posterior leukoencephalopathy syndrome is almost exclusively seen in the setting of a predisposing clinical condition, such as pre-eclampsia, systemic infections, sepsis and shock, certain autoimmune diseases, various malignancies and cytotoxic chemotherapy, transplantation and concomitant immunosuppression (especially with calcineurin inhibitors) as well as episodes of abrupt hypertension. We describe for the first time clinical, radiological and histological findings in a case of reversible posterior leukoencephalopathy syndrome with an irreversible and fatal outcome occurring in the absence of any of the known predisposing clinical conditions except for a hypertensive episode.
Case presentation
A 58-year-old Caucasian woman presented with a two-week history of subacute and progressive occipital headache, blurred vision and imbalance of gait and with no evidence for raised arterial blood pressure during the two weeks previous to admission. Her past medical history was unremarkable except for controlled arterial hypertension. Cerebral magnetic resonance imaging demonstrated cortical and subcortical lesions with combined vasogenic and cytotoxic edema atypical for both venous congestion and arterial infarction. Routine laboratory and cerebrospinal fluid parameters were normal. The diagnosis of reversible posterior leukoencephalopathy syndrome was established.
Within hours after admission the patient showed a rapidly decreasing level of consciousness, extension and flexion synergisms, bilaterally extensor plantar responses and rapid cardiopulmonary decompensation requiring ventilatory and cardiocirculatory support. Follow-up cerebral imaging demonstrated widespread and confluent cytotoxic edematous lesions in different arterial territories, global cerebral swelling, and subsequent upper and lower brainstem herniation. Four days after admission, the patient was declared dead because of brain death.
This case demonstrates that fulminant and fatal reversible posterior leukoencephalopathy syndrome may occur spontaneously, that is, in the absence of any of the known predisposing systemic conditions.
PMCID: PMC3562210  PMID: 23305457
Blood pressure; Cerebral autoregulation; Generalized cerebral edema; Reversible posterior leukoencephalopathy syndrome
7.  Are All Multi-targeted Tyrosine Kinase Inhibitors Created Equal? An In Vitro Study of Sunitinib and Pazopanib in Renal Cell Carcinoma Cell Lines 
The Canadian journal of urology  2011;18(4):5819-5825.
We examined the in vitro cellular effects of the multi-targeted receptor tyrosine kinase inhibitors (TKIs) sunitinib and pazopanib on a series of human renal cell carcinoma (RCC) cell lines.
The human RCC cell lines 769-P, 786-O, HRC-24, HRC-31, HRC-45, HRC-78, RCC-26B, and SK-45 were treated with varying concentrations of sunitinib and pazopanib. Cellular proliferation and cellular death were assessed using the CellTiter-Blue Cell Viability Assay and the TUNEL assay, respectively. Effective doses (ED) for inhibition of cellular proliferation or induction of apoptosis were calculated for sunitinib and pazopanib in each RCC cell line.
Both sunitinib and pazopanib exhibited anti-proliferative activity to varying degree against all human RCC cell lines; however, sunitinib’s effects were achieved at significantly lower concentrations. Moreover, sunitinib had a direct pro-apoptotic effect on all tested cell lines, while pazopanib failed to induce apoptosis in any of the examined human RCC cell lines even at maximal concentrations.
Although sunitinib and pazopanib are often used interchangeably in the clinical setting, our results suggest that in-vitro biological activity of the two agents differs. Sunitinib exhibits a cytotoxic effect on RCC cell lines, while pazopanib’s activity is solely cytostatic. These data may be clinically relevant given the current lack of comparative in-vivo studies between the two agents.
PMCID: PMC3182114  PMID: 21854714
advanced kidney cancer; tyrosine kinase inhibitors; pazopanib; sunitinib
8.  Antiangiogenic effects of pazopanib in xenograft hepatocellular carcinoma models: evaluation by quantitative contrast-enhanced ultrasonography 
BMC Cancer  2011;11:28.
Antiangiogenesis is a promising therapy for advanced hepatocellular carcinoma (HCC), but the effects are difficult to be evaluated. Pazopanib (GW786034B) is a pan-vascular endothelial growth factor receptor inhibitor, the antitumor effects or antiangiogenic effects haven't been investigated in HCC.
In vitro direct effects of pazopanib on human HCC cell lines and endothelial cells were evaluated. In vivo antitumor effects were evaluated in three xenograft nude mice models. In the subcutaneous HCCLM3 model, intratumoral blood perfusion was detected by contrast-enhanced ultrasonography (CEUS), and serial quantitative parameters were profiled from the time-intensity curves of ultrasonograms.
In vitro proliferation of various HCC cell lines were not inhibited by pazopanib. Pazopanib inhibited migration and invasion and induced apoptosis significantly in two HCC cell lines, HCCLM3 and PLC/PRF/5. Proliferation, migration, and tubule formation of human umbilical vein endothelial cells were inhibited by pazopanib in a dose-dependent manner. In vivo tumor growth was significantly inhibited by pazopanib in HCCLM3, HepG2, and PLC/PRF/5 xenograft models. Various intratumoral perfusion parameters changed over time, and the signal intensity was significantly impaired in the treated tumors before the treatment efficacy on tumor size could be observed. Mean transit time of the contrast media in hotspot areas of the tumors was reversely correlated with intratumoral microvessel density.
Antitumor effects of pazopanib in HCC xenografts may owe to its antiangiogenic effects, and the in vivo antiangiogenic effects could be evaluated by quantitative CEUS.
PMCID: PMC3033852  PMID: 21251271
9.  The prospects of pazopanib in advanced renal cell carcinoma 
Therapeutic Advances in Urology  2013;5(5):223-232.
The landscape of treatment for advanced/metastatic renal cell carcinoma (mRCC) has advanced significantly in the last decade and continues to evolve with the approval of new drugs targeting the vascular endothelial growth factor (VEGF) and its receptors and mammalian target of rapamycin (mTOR). Currently available oral VEGF tyrosine kinase inhibitors (TKIs) approved for treatment of mRCC include sorafenib, sunitinib, pazopanib, and axitinib. This review focuses on pazopanib, a multikinase VEGF TKI indicated for patients with treatment-naïve and cytokine-refractory mRCC. This article describes the preclinical and clinical evolution of pazopanib, with an emphasis on its development and role in mRCC. Pivotal trials are discussed that demonstrate the efficacy and safety of pazopanib and its important role in the treatment of patients with mRCC in comparison to other available treatment options. The clinical path of pazopanib continues to develop further, with several ongoing studies exploring its role in neoadjuvant and adjuvant RCC. Furthermore, its potential role in sequential and combination studies with other VEGFR and non-VEGFR targeted agents is discussed. Overall, pazopanib is a unique VEGF TKI, with a different and more favorable safety profile compared with other members of the VEGF TKI family and represents an attractive alternative for patients with mRCC.
PMCID: PMC3763778  PMID: 24082917
kidney cancer; pazopanib; renal cell carcinoma; targeted therapy; tyrosine kinase inhibitors; vascular endothelial growth factor
10.  New advancements and developments in treatment of renal cell carcinoma: focus on pazopanib 
OncoTargets and therapy  2010;3:147-155.
With the recent approval of pazopanib, an oral multitargeted tyrosine kinase inhibitor which potently targets vascular endothelial growth factor receptors 1–3, platelet-derived growth factor, and c-kit, six agents are now available for use in the management of metastatic renal cell carcinoma (RCC). Pazopanib has shown improved progression-free survival compared with placebo in treatment-naïve or cytokine-treated patients with metastatic RCC in large Phase II and Phase III clinical trials. Pazopanib has demonstrated a tolerable side effect profile and is currently being compared with sunitinib in a Phase III noninferiority trial. In this review, the outcomes of the clinical testing of pazopanib are discussed, as well as a perspective on the placement of pazopanib among other approved agents.
PMCID: PMC2962303  PMID: 21049083
renal cell carcinoma; targeted agents; vascular endothelial growth factor inhibitors; pazopanib
11.  Critical appraisal of pazopanib as treatment for patients with advanced metastatic renal cell carcinoma 
The management of renal cell carcinoma (RCC) has undergone significant changes during the past 10 years, with the treatment of metastatic RCC undergoing the most radical changes. These developments reflect an enhanced understanding of this tumor’s underlying biology, which was then translated into the development of a new treatment paradigm. Current therapeutic approaches for the management of patients with metastatic RCC utilize knowledge of histology, molecular abnormalities, clinical prognostic factors, the natural history of this malignancy, and the treatment efficacy and toxicity of available agents. The treatment options available for patients with metastatic RCC have changed dramatically over the past 6 years. Interferon-α and interleukin-2 were the previous mainstays of therapy, but since December 2005, six new agents have been approved in the US for the treatment of advanced RCC. Three are multi-targeted tyrosine kinase inhibitors (TKI) including sunitinib, sorafenib, and pazopanib, two target the mammalian target of rapamycin (temsirolimus and everolimus), and one is a humanized monoclonal antibody (bevacizumab in combination with interferon-α). The current review focuses on the newest TKI available to treat patients with metastatic RCC, pazopanib. The development of this agent both preclinically and clinically is reviewed. The efficacy and safety data from the pivotal clinical trials are discussed, and the potential role of pazopanib in the treatment of patients with metastatic RCC in comparison to other treatment alternatives is critically appraised. This agent has a favorable overall risk benefit, and the available data demonstrate efficacy in patients with metastatic RCC who are either treatment-naïve or cytokine refractory. It therefore represents another alternative for treatment of metastatic RCC patients.
PMCID: PMC3173017  PMID: 21931501
renal cell carcinoma; metastatic; pazopanib
12.  Reversible posterior leukoencephalopathy syndrome during sunitinib therapy for metastatic renal cell carcinoma 
Oncology Letters  2012;3(6):1293-1296.
Sunitinib is an oral receptor tyrosine kinase inhibitor with potent antiangiogenic and antitumor activity that is approved for the treatment of advanced renal cell carcinoma (RCC), malignant gastrointestinal stromal tumors and pancreatic neuroendocrine tumors. Well-known side effects of sunitinib include hypertension, fatigue, thyroid dysfunction, cardiotoxicity, gastrointestinal toxicity and skin toxicity. In this study, we report the case of a 61-year-old male with papillary metastatic RCC who responded to sunitinib but developed generalized tonic-clonic seizures during the third cycle. Magnetic resonance imaging (MRI) was compatible with reversible posterior leukoencephalopathy syndrome (RPLS). After the administration of anti-epileptic drugs and the withdrawal of sunitinib there was rapid clinical improvement. Notably, radiological characteristics of RPLS persisted during second-line therapy with the mammalian target of rapamycin (mTOR) inhibitor everolimus and only resolved when everolimus was terminated due to disease progression. Although sunitinib-induced RPLS has been reported previously, our case is the first to additionally suggest that everolimus may sustain and therefore potentially contribute to the occurrence of RPLS.
PMCID: PMC3392579  PMID: 22783436
renal cell cancer; sunitinib; reversible posterior leukoencephalopathy syndrome
13.  Pazopanib Enhances Paclitaxel-Induced Mitotic Catastrophe in Anaplastic Thyroid Cancer 
Science translational medicine  2013;5(166):166ra3.
Anaplastic thyroid cancer (ATC) has perhaps the worst prognosis of any cancer, with a median survival of only about 5 months regardless of stage. Pazopanib monotherapy has promising clinical activity in differentiated thyroid cancers (generally attributed to vascular endothelial growth factor receptor inhibition), yet has less effective single-agent activity in ATC. We now report that combining pazopanib with microtubule inhibitors such as paclitaxel produced heightened and synergistic antitumor effects in ATC cells and xenografts that were associated with potentiated mitotic catastrophe. We hypothesized that combined effects may reflect enhanced paclitaxel-induced cytotoxicity mediated by cell cycle regulatory kinase inhibition by pazopanib. Indeed, pazopanib potently inhibited aurora A, with pazopanib/paclitaxel synergy recapitulated by aurora A short hairpin RNA knockdown or by specific aurora A pharmacological inhibition. Pazopanib/paclitaxel synergy was reversed by aurora A knockdown. Moreover, aurora A (but not B or C) message and protein levels were significantly increased in patient ATCs, and durable benefit resulted from pilot clinical translation of pazopanib/paclitaxel therapy in a patient with metastatic ATC. Collectively, these results suggest that the pazopanib/paclitaxel combination is a promising candidate therapeutic approach in ATC and that aurora A may represent a potentially viable therapeutic molecular target in ATC.
PMCID: PMC3905331  PMID: 23283368
14.  Pazopanib reveals a role for tumor cell B-Raf in the prevention of HER2+ breast cancer brain metastasis 
Brain metastases of breast cancer contribute significantly to patient morbidity and mortality. We have tested pazopanib, a recently approved anti-angiogenic drug that targets VEGFR1-3, PDGFRβ, PDGFRα and c-kit, for prevention of experimental brain metastases and mechanism of action.
Experimental Design
In vitro assays included B-Raf enzymatic assays, western blots and angiogenesis assays. For in vivo assays, HER2 transfectants of the brain seeking sublines of MDA-MB-231 cells (231-BR-HER2) and MCF7 cells (MCF7-HER2-BR3, derived herein) were injected into the left cardiac ventricle of mice and treated with vehicle or pazopanib beginning on day 3 post-injection. Brain metastases were counted histologically, imaged and immunostained.
Treatment with 100 mg/kg pazopanib resulted in a 73% decline in large 231-BR-HER2 metastases (p<0.0001) and 39% decline in micrometastases (p=0.004). In vitro, pazopanib was directly anti-proliferative to 231-BR-HER2 breast cancer cells and inhibited MEK and ERK activation in vitro despite B-Raf and Ras mutations. Enzymatic assays demonstrated that pazopanib directly inhibited the wild type and exon 11 oncogenic mutant, but not the V600E mutant forms of B-Raf. Activation of the B-Raf targets pERK1/2 and pMEK1/2 was decreased in pazopanib treated brain metastases while blood vessel density was unaltered. In the MCF7-HER2-BR3 experimental brain metastasis model, pazopanib reduced overall brain metastasis volume upon MRI imaging by 55% (p=0.067), without affecting brain metastasis vascular density.
The data identify a new activity for pazopanib directly on tumor cells as a pan-Raf inhibitor, and suggest its potential for prevention of brain metastatic colonization of HER2+ breast cancer.
PMCID: PMC3059742  PMID: 21081656
Brain; metastases; B-Raf; HER2; breast cancer
15.  (Pre-)Clinical Pharmacology and Activity of Pazopanib, a Novel Multikinase Angiogenesis Inhibitor 
The Oncologist  2010;15(6):539-547.
This review summarizes the preclinical and clinical pharmacokinetics and pharmacodynamics of pazopanib, as well as data on clinical activity, that ultimately resulted in its recent approval.
Pazopanib is a recently approved, novel tyrosine kinase inhibitor specifically designed to impair angiogenesis by abrogating vascular endothelial growth factor receptor 2 (VEGFR-2) to exert its function. Pazopanib inhibits VEGF-induced endothelial cell proliferation in vitro and angiogenesis in vivo and demonstrates antitumor activity in mouse models. Furthermore, the pazopanib concentration resulting in maximal inhibition of VEGFR-2 phosphorylation in vivo was in line with the steady-state concentration required to inhibit growth of tumor xenografts, suggesting that pazopanib's mechanism of action is indeed through VEGFR-2 inhibition.
In a phase I trial, a generally well-tolerated dose was identified at which the majority of patients achieved pazopanib plasma concentrations above the concentration required for maximal in vivo inhibition of VEGFR-2 phosphorylation in preclinical models. Administered as monotherapy, evidence of antitumor activity was observed in phase II studies in several tumor types, including soft tissue sarcoma, renal cell cancer (RCC), ovarian cancer, and non-small cell lung cancer. Recently, the U.S. Food and Drug Administration granted approval for treatment with pazopanib in patients with RCC based on the longer progression-free survival time observed with this agent in a placebo-controlled, randomized trial. This review summarizes the preclinical and clinical pharmacokinetics and pharmacodynamics of pazopanib, as well as data on clinical activity, that ultimately resulted in its recent approval.
PMCID: PMC3227994  PMID: 20511320
Pazopanib; Angiogenesis; Tyrosine kinase inhibitor; Renal cell cancer
16.  Factors involved in treatment preference in patients with renal cancer: pazopanib versus sunitinib 
The last decade has seen a surge in the treatment options for metastatic renal cell carcinoma and life expectancies are now approaching 3 years from diagnosis. There is some suggestion that, for now at least, we may have reached a plateau in efficacy. Patients are often stable and on treatment for years rather than months. Attention has therefore shifted to a focus on patient preference rather than reported frequency of toxicities. The standard first-line treatment for metastatic clear-cell renal cancer is either sunitinib or pazopanib. The COMPARZ trial has shown that sunitinib and pazopanib have similar efficacy. The PISCES trial, with its unique design, has evaluated patient preference between pazopanib and sunitinib. This review explores the factors involved in treatment preference in patients with renal cancer and in particular the choice between pazopanib and sunitinib.
PMCID: PMC4003261  PMID: 24790418
PISCES; patient preference; sunitinib; pazopanib
17.  A Phase I study of pazopanib in combination with gemcitabine in patients with advanced solid tumors 
Pazopanib plus gemcitabine combination therapy was explored in patients with advanced solid tumors.
In a modified 3 + 3 enrollment scheme, oral once-daily pazopanib was administered with intravenous gemcitabine (Days 1 and 8, 21-day cycles). Three protocol-specified dose levels were tested: pazopanib 400 mg plus gemcitabine 1,000 mg/m2, pazopanib 800 mg plus gemcitabine 1,000 mg/m2, and pazopanib 800 mg plus gemcitabine 1,250 mg/m2. Maximum-tolerated dose was based on dose-limiting toxicities during treatment Cycle 1. In the expansion phase, six additional patients were enrolled at the highest tolerable dose level.
Twenty-two patients were enrolled. At the highest dose level tested (pazopanib 800 plus gemcitabine 1,250), patients received >80 % of their planned dose and the regimen was deemed safe and tolerable. The most common treatment-related adverse events included fatigue, neutropenia, nausea, and decreased appetite. Neutropenia and thrombocytopenia were the most common events leading to dose modifications. Pharmacokinetic interaction between pazopanib and gemcitabine was not observed. One objective partial response at the highest dose was observed in a patient with metastatic melanoma. Prolonged disease stabilization (>12 cycles) was reported in three patients (metastatic melanoma, cholangiocarcinoma, and colorectal carcinoma).
Combination pazopanib plus gemcitabine therapy is tolerable, with an adverse event profile reflective of that associated with the individual agents. There was no apparent pharmacokinetic interaction with pazopanib plus gemcitabine co-administration, although patient numbers were limited. Further investigation of combined pazopanib plus gemcitabine is warranted.
PMCID: PMC3535414  PMID: 23064954
Anti-angiogenesis; Combination therapy; Gemcitabine; Melanoma; Pazopanib; Pharmacokinetics; Phase I; Solid tumors
18.  Topical Pazopanib Blocks VEGF-Induced Vascular Leakage and Neovascularization in the Mouse Retina but Is Ineffective in the Rabbit 
To test the effect of pazopanib, a tyrosine kinase inhibitor that blocks VEGF and platelet-derived growth factor (PDGF) receptors and c-Kit, on vascular leakage and neovascularization (NV) in the retina.
Pazopanib was tested to determine its effect on VEGF-induced vascular permeability via measurement of [3H]mannitol retina to lung (RLLR) and retina to renal leakage ratios (RRLR) and in rho/VEGF mice with subretinal NV. In rabbits, the effect of intravitreal, topical, and systemic pazopanib on VEGF-induced leakage was tested by vitreous fluorophotometry.
In mice, oral pazopanib (40 mg/kg twice a day [bid]) reduced RLLR (0.84 to 0.58, P = 0.0014) and RRLR (0.55 to 0.30, P = 0.0018) in VEGF-injected eyes. After intraocular injection of VEGF into both eyes, topical pazopanib (10 mg/mL three times a day [tid] for 14 days) reduced RLLR (0.85 vs. 0.56, P = 0.001), RRLR (0.44 vs. 0.28, P = 0.0075), and immunoreactive albumin in the retina compared to values in fellow eye controls. Treatment of one eye of rho/VEGF mice with 10 mg/mL, but not 5 mg/mL, pazopanib tid reduced the mean area of subretinal NV compared to that in fellow eyes (0.0055 vs. 0.0025 mm2, P = 0.020). In rabbits, intravitreal pazopanib suppressed VEGF-induced fluorescein leakage, but topical (10 mg/mL four times a day [qid] or 12 mg/mL bid) had no significant effect. Systemic administration of pazopanib by osmotic pump with or without 10 mg/mL drops tid also failed to suppress VEGF-induced leakage.
Administration of pazopanib topically or systemically suppressed retinal vascular leakage in mice, but not rabbits. These data suggest differences in the blood–retinal barrier (BRB) of mice and rabbits and indicate that penetration through the outer BRB may be needed for topically administered drugs to exert effects in the retina.
Topical delivery to treat retinal disease is controversial. It is possible in rodents, and we previously found good agreement between results in mice and rabbits, but we now report that this is not the case for pazopanib. This suggests testing topical treatments for retinal disease in more than one species.
PMCID: PMC3558990  PMID: 23169884
19.  Posterior leukoencephalopathy syndrome 
Postgraduate Medical Journal  2001;77(903):24-28.
Posterior leukoencephalopathy syndrome is a newly recognised brain disorder that predominantly affects the cerebral white matter. Oedematous lesions particularly involve the posterior parietal and occipital lobes, and may spread to basal ganglia, brain stem, and cerebellum. This rapidly evolving neurological condition is clinically characterised by headache, nausea and vomiting, seizures, visual disturbances, altered sensorium, and occasionally focal neurological deficit. Posterior leukoencephalopathy syndrome is often associated with an abrupt increase in blood pressure and is usually seen in patients with eclampsia, renal disease, and hypertensive encephalopathy. It is also seen in the patients treated with cytotoxic and immunosuppressive drugs such as cyclosporin, tacrolimus, and interferon alfa. The lesions of posterior leukoencephalopathy are best visualised with magnetic resonance (MR) imaging. T2 weighted MR images, at the height of symptoms, characteristically show diffuse hyperintensity selectively involving the parieto-occipital white matter. Occasionally the lesions also involve the grey matter. Computed tomography can also be used satisfactorily to detect hypodense lesions of posterior leukoencephalopathy. Early recognition of this condition is of paramount importance because prompt control of blood pressure or withdrawal of immunosuppressive agents will cause reversal of the syndrome. Delay in the diagnosis and treatment can result in permanent damage to affected brain tissues.

Keywords: leukoencephalopathy; eclampsia; hypertensive encephalopathy; occipital lobe seizures
PMCID: PMC1741870  PMID: 11123390
20.  The PACOVAR-trial: A phase I/II study of pazopanib (GW786034) and cyclophosphamide in patients with platinum-resistant recurrent, pre-treated ovarian cancer 
BMC Cancer  2011;11:453.
The prognosis of patients with recurrent, platinum-resistant epithelial ovarian cancer (EOC) is poor. There is no standard treatment available. Emerging evidence suggests a major role for antiangiogenic treatment modalities in EOC, in particular in combination with the metronomic application of low dose chemotherapy. The novel, investigational oral antiangiogenic agent pazopanib targeting vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and c-kit is currently being studied in different tumour types and is already used as first line therapy in recurrent renal cell carcinoma. A combined therapy consisting of pazopanib and metronomic oral cyclophosphamide may offer a well-tolerable treatment option to patients with recurrent, pretreated EOC.
This study is designed as a multicenter phase I/II trial evaluating the optimal dose for pazopanib (phase I) as well as activity and tolerability of a combination regimen consisting of pazopanib and metronomic cyclophosphamide in the palliative treatment of patients with recurrent, platinum-resistant, pre-treated ovarian cancer (phase II). The patient population includes patients with histologically or cytologically confirmed diagnosis of EOC, cancer of the fallopian tube or peritoneal cancer which is platinumresistant or -refractory. Patients must have measurable disease according to RECIST criteria and must have failed available standard chemotherapy. Primary objectives are determination of the optimal doses for pazopanib (phase I) and the overall response rate according to RECIST criteria (phase II). Secondary objectives are time to progression, overall survival, safety and tolerability. The treatment duration is until disease progression or intolerability of study drug regimen (with a maximum of 13 cycles up to 52 weeks per subject).
The current phase I/II trial shall clarify the potential of the multitargeting antiangiogenic tyrosinkinaseinhibitor GW 786034 (pazopanib) in combination with oral cyclophosphamide as salvage treatment in patients with recurrent, pretreated ovarian cancer.
Trial registration NCT01238770
PMCID: PMC3224456  PMID: 22014006
21.  A multicenter phase II study of pazopanib in patients with advanced gastrointestinal stromal tumors (GIST) following failure of at least imatinib and sunitinib 
Annals of Oncology  2014;25(1):236-240.
We conducted a phase II study evaluating the efficacy and toxicity of pazopanib, a broad spectrum TKI inhibiting KIT, VEGFRs (-1, -2, and -3), and PDGFR (-α and-β) in patients with advanced GIST following failure of at least imatinib and sunitinib. Pazopanib as a single agent has marginal activity in unselected heavily pretreated patients with advanced GIST.
Advanced GISTs are incurable, but often treatable for years with tyrosine kinase inhibitors (TKIs). The majority of GISTs harbor an oncogenic activating mutation in KIT or PDGFRA. Inhibition of this activating mutation with TKIs most often leads to durable disease control for many patients. However, almost all patients develop resistance to these TKIs, typically due to the development of secondary mutations, heralding the need for new therapeutic options. We conducted a phase II study evaluating the efficacy and toxicity of pazopanib, a broad spectrum TKI inhibiting KIT, VEGFRs (−1, −2, and −3), and PDGFR (-α and-β) in patients with advanced GIST following failure of at least imatinib and sunitinib.
Patients received pazopanib 800 mg orally once daily. All patients were assessed for efficacy with CT scans every 8 weeks (two cycles). Patients continued pazopanib until progression or unacceptable toxicity. The primary end point was the 24-week nonprogression [complete response+partial response+stable disease (SD)] rate (NPR) per RECIST 1.1. Secondary end points included PFS, OS, and toxicity.
Between August 2011 and September 2012, a total of 25 patients were treated at two institutions. Median number of prior therapy was 3 (range 2–7). A total of 90 cycles of pazopanib were administered, with a median of two cycles (range 1 to 17+) per patient. Best response of SD at any time was observed in 12 (48%) patients. The NPR was 17% [95% confidence interval (CI) 4.5–37]. All but one patient discontinued protocol either due to PD (n = 19) or intolerance (n = 4). One patient with succinate dehydrogenase (SDH)-deficient GIST exhibited continuing disease control after 17 cycles. The median PFS for the entire cohort was 1.9 months (95% CI 1.6–5.2), and the median OS was 10.7 months (95% CI 3.9–NR).
Pazopanib was reasonably well tolerated with no unexpected toxicities. Pazopanib as a single agent has marginal activity in unselected heavily pretreated patients with advanced GIST.
PMCID: PMC4271129  PMID: 24356634
GIST; KIT; pazopanib; tyrosine kinase inhibitors
22.  Optimal first-line and second-line treatments for metastatic renal cell carcinoma: current evidence 
Since 2005, an abundance of targeted agents has been approved for the treatment of metastatic renal cell carcinoma (mRCC), without any specification as to what may be the most optimal first-line and second-line sequence. Hence, our objective was to critically examine the evidence supporting the use of first-line and second-line agents in the management of mRCC. Our review suggests that in first line, sunitinib and pazopanib represent treatment options for patients with favorable or intermediate-risk features and clear cell histology. Unfortunately, the Phase III trial cannot conclusively prove the noninferiority of pazopanib relative to sunitinib. Hence, the use of sunitinib as first-line standard of care remains justified. Pazopanib represents an option for specific patients in whom sunitinib might not be tolerated. In patients with poor-risk features, temsirolimus represents the only option supported with level 1 evidence. Less optimal alternatives include sunitinib and bevacizumab combined with interferon, based on the minimal inclusion of poor-risk patients in pivotal Phase III studies of these two molecules. In patients with non-clear cell mRCC, the use of temsirolimus is supported by Phase III data, unlike for any other molecule. In second line, the options consist of everolimus and axitinib. However, the axitinib data are substantially more robust given the inclusion of more patients considered as true second-line, and validly justify the choice of axitinib over everolimus. Nonetheless, the Phase III trial of everolimus may be considered as level 1 evidence for use as third-line or subsequent lines of therapy.
PMCID: PMC4219683  PMID: 25378943
targeted therapy; metastatic; renal cell carcinoma; clear cell; sequential therapy
23.  Stearoyl-CoA desaturase 1 is a novel molecular therapeutic target for clear cell renal cell carcinoma 
We set out to identify SCD1 as a novel molecular target in clear cell renal cell carcinoma (ccRCC) and examine its role in tumor cell growth and viability in vitro and in vivo independently as well as in combination with current FDA approved regimens.
Experimental Design
Patient normal and ccRCC tissue samples and cell lines were examined for SCD1 expression. Genetic knockdown models and targeted inhibition of SCD1 through use of a small molecule inhibitor, A939572, were analyzed for growth, apoptosis, and alterations in gene expression using gene array analysis. Therapeutic models of synergy were evaluated utilizing pharmacologic inhibition of SCD1 with the tyrosine kinase inhibitors (TKI) sunitinib and pazopanib, and the mTOR inhibitor temsirolimus.
Our studies identify increased SCD1 expression in all stages of ccRCC. Both genetic knockdown and pharmacologic inhibition of SCD1 decreased tumor cell proliferation and induced apoptosis in vitro and in vivo. Upon gene array, quantitative real-time PCR, and protein analysis of A939572 treated or SCD1 lentiviral knockdown samples, induction of endoplasmic reticulum (ER) stress response signaling was observed, providing mechanistic insight for SCD1 activity in ccRCC. Furthermore, combinatorial application of A939572 with temsirolimus synergistically inhibited tumor growth in vitro and in vivo.
Increased SCD1 expression supports ccRCC viability and therefore we propose it as a novel molecular target for therapy either independently or in combination with an mTOR inhibitor for patients whose disease cannot be remedied with surgical intervention, such as in cases of advanced or metastatic disease.
PMCID: PMC3644999  PMID: 23633458
Stearoyl-CoA desaturase 1; clear cell renal cell carcinoma; metabolism; mTOR; antitumor synergy
24.  Successful use of pazopanib for treatment of refractory metastatic hemangiopericytoma 
Hemangiopericytoma is a rare disease entity of soft-tissue sarcoma (STS) that can be cured with surgical resection. In cases of inoperable recurrence or metastasis, palliative chemotherapy is indicated, though there is currently no approved chemotherapy regimen. Therefore new treatment regimens are needed.
We describe three cases of metastatic hemangiopericytoma. In the first case, five lines of chemotherapeutic agents were used unsuccessfully in a patient with a 12-year history of metastatic hemangiopericytoma. After one cycle of pazopanib therapy, however, chest radiography showed a decrease in tumor volume of more than 30%. A marked decrease in FDG uptake on PET CT was also noted, and the patient is now on her 5th month of pazopanib therapy. The second case is a patient with a brain hemangiopericytoma with multiple liver, lung, and bone metastases. Pazopanib induced radiologic stabilization of metastatic disease over the course of 8 months. The third case is a patient with a retroperitoneal hemangiopericytoma with pleural and peri-renal metastases. For more than 8 months, he has exhibited stable disease with pazopanib treatment.
Pazopanib may be useful for treatment of metastatic hemangiopericytoma, though further studies are needed to confirm the efficacy of this medication and to investigate its molecular mechanism of action.
PMCID: PMC4179434  PMID: 25276340
Hemangiopericytoma; Pazopanib; Anti-angiogenic agent
25.  Advances in renal cell carcinoma treatment 
The treatment of advanced renal cell carcinoma has been completely changed by the development of new therapeutic modalities during the past 3 years. In this time period six targeted agents have been approved for the treatment of advanced or metastatic disease. Phase 3 data support the use of sunitinib, bevacizumab plus interferon-α and pazopanib for patients with low and intermediate risk of clear-cell renal cell carcinoma. In the pivotal study of temsirolimus a significant longer overall survival compared with interferon-α in high-risk disease including non-clear-cell histology was observed. Patients pretreated with cytokines will benefit from sorafenib and pazopanib while everolimus has been shown to increase significantly progression-free survival after previous anti-angiogenesis therapy. In addition to these phase 3 data-based recommendations, several other factors have to be considered for treatment selection, for example, side effect profile and patients’ comorbidities. Currently, the sequential use of the available targeted drugs and adjuvant treatment are the subject of ongoing clinical trials. However, medical treatment of renal cell carcinoma remains palliative and surgery remains the only curative approach in patients with localized, locally advanced and limited metastatic disease.
PMCID: PMC3126067  PMID: 21789079
targeted therapy; renal cell carcinoma; side effects; sequential therapy; adjuvant therapy

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