Preparation, evaluation and application of MRI detectable sunitinib-loaded calcium alginate/poly(acrylic acid) hydrogel microspheres.

Transcatheter arterial chemoembolization (TACE) is an effective method for the treatment of unresectable hepatocellular carcinoma. Although many embolic agents have been developed in TACE, there are few ideal embolic agents that combine drug loading, imaging properties and vessel embolization. Here, we developed novel magnetic embolic microspheres that could simultaneously load sunitinib malate (SU), be detected by magnetic resonance imaging (MRI) and block blood vessels. Calcium alginate/poly (acrylic acid) hydrogel microspheres (CA/PAA-MDMs) with superparamagnetic iron oxide nanoparticles (SPIONs) modified by citric acid were prepared by a drip and photopolymerization method. The embolization and imaging properties of CA/PAA-MDMs were evaluated through a series of experiments such as morphology, X-ray diffraction and X-ray photoelectron spectroscopy, magnetic responsiveness analysis, elasticity, cytotoxicity, hemolysis test, in vitro MRI evaluation, rabbit ear embolization and histopathology. In addition, the ability of drug loading and drug release of CA/PAA-MDMs were investigated by using sunitinib (SU) as the model drug. In conclusion, CA/PAA-MDMs showed outstanding drug loading capability, excellent imaging property and embolization effect, which would be expected to be used as a potential biodegradable embolic agent in the clinical interventional therapy.

Sunitinib-induced hyperammonemic encephalopathy in metastatic gastrointestinal stromal tumors: A case report.

BACKGROUND: Sunitinib, a multi-targeted tyrosine kinase inhibitor (TKI), has been approved for the salvage treatment of gastrointestinal stromal tumors (GIST). Hyperammonemic encephalopathy is a rare but severe complication of sunitinib use. Here, we present the case of a 66-year-old male with metastatic GIST without underlying liver cirrhosis who developed sunitinib-induced hyperammonemic encephalopathy. CASE SUMMARY: A 66-year-old male with metastatic GIST was admitted because of reduced consciousness. Imatinib was administered as the first-line systemic therapy. He experienced repeated episodes of peritonitis due to tumor perforation, and surgery was performed. Progressive disease was confirmed based on increased liver metastasis, and sunitinib was initiated as a salvage treatment. However, 23 d after the third course of sunitinib, he presented to the emergency room with an episode of altered consciousness and behavioral changes. Based on the patient clinical history and examination findings, sunitinib-induced encephalopathy was suspected. Sunitinib was discontinued, and the patient was treated for hyperammonemia. The patient had a normal level of consciousness four days later, and the serum ammonia level gradually decreased. No further neurological symptoms were reported in subsequent follow-ups. CONCLUSION: TKI-induced hyperammonemic encephalopathy is potentially life-threatening. Patients receiving TKIs experiencing adverse reactions should undergo systemic evaluation and prompt treatment.

Ocular metabolism and distribution of drugs in the rabbit eye: Quantitative assessment after intracameral and intravitreal administrations.

Quantitation of ocular drug metabolism is important, but only sparse data is currently available. Herein, the pharmacokinetics of four drugs, substrates of metabolizing enzymes, was investigated in albino rabbit eyes after intracameral and intravitreal administrations. Acetaminophen, brimonidine, cefuroxime axetil, and sunitinib and their corresponding metabolites were quantitated in the cornea, iris-ciliary body, aqueous humor, lens, vitreous humor, and neural retina with LC-MS/MS analytics. Non-compartmental analysis was employed to estimate the pharmacokinetic parameters of the parent drugs and metabolites. The area under the curve (AUC) values of metabolites were 12-70 times lower than the AUC values of the parent drugs in the tissues with the highest enzymatic activity. The ester prodrug cefuroxime axetil was an exception because it was efficiently and quantitatively converted to cefuroxime in the ocular tissues. In contrast to the liver, sulfotransferases, aldehyde oxidase, and cytochrome P450 3A activities were low in the eye and they had negligible impact on ocular drug clearance. With the exception of esterase substrates, metabolism seems to be a minor player in ocular pharmacokinetics. However, metabolites might contribute to ocular toxicity, and drug metabolism in various eye tissues should be investigated and understood thoroughly.

Sunitinib malate inhibits intestinal tumor development in male ApcMin/+ mice by down-regulating inflammation-related factors with suppressing ß-cateinin/c-Myc pathway and re-balancing Bcl-6 and Caspase-3.

Sunitinib is a tyrosine kinase inhibitor for many tumors. Inflammation is one of the most important factors in the development of intestinal tumors. Many inflammation-related factors are regulated by tyrosine kinase receptors. It is reasonable to hypothesize that sunitinib can regulate the development of intestinal tumors by regulating the expression and/or activity of inflammation-related factors. Here, ApcMin/+ male mouse model was used to investigate the effect and mechanism of sunitinib malate against intestinal cancer. Results show that compared to vehicle, after sunitinib malate treatment, overall survival of ApcMin/+ mice was lengthened up to 25 days, with a gain of body weight, reduction of spleen/body weight index, and RBC, WBC and HGC regulated to normal levels of wild type mice, and a number of polyps no less than 1 mm significantly reduced. Meanwhile, in the intestines, the nuclear ß-Catenin protein and c-Myc mRNA were both down-regulated, and Bcl-6 was significantly reduced with Caspase-3 up regulated. Furthermore, inflammation-related factors including IL-6, TNF-α, IL-1α, IL-1ß and IFN-γ were down-regulated at mRNA levels in the intestines. These results suggest that sunitinib malate can significantly improve the survival status and inhibit intestinal tumor development in male ApcMin/+ mice, through inhibiting inflammation-related factors, while suppressing ß-cateinin/c-Myc pathway and re-balancing protein levels of Bcl-6 and Caspase-3.

Modulating the tumor immune microenvironment with sunitinib malate supports the rationale for combined treatment with immunotherapy.

Small molecule inhibitors have proven useful in the treatment of a variety of tumors, but they are often limited by unsustainable benefits and confer resistance quickly. Immunotherapy can result in durable clinical responses, but activity only occurs in a minority of patients. The unfavorable tumor microenvironment (TME) is an important factor limiting immunotherapy. An appropriate understanding of how small molecule inhibitors modulate the TME may optimize the combination of targeted treatment and immunotherapy in managing tumors. In this study, we found that transient treatment with sunitinib malate inhibited the disorganized extension of tumor vessels, pericytes and collagen IV but increased the relative ratio of pericyte-wrapping blood vessels with alleviated hypoxia in tumors, which resulted from tumor vascular normalization. Sunitinib malate increased infiltration of CD8+ T cells and decreased regulatory T cells (Tregs), accompanied by inhibited expression of TGF-ß1 and IL-10 and increased CCL-28, IFN-γ and IL-12, but no significant inhibition of myeloid-derived suppressor cells (MDSCs) was observed. In addition, sunitinib malate increased the levels of PD-1 and PD-L1 in TME, combined with anti-PD-1 therapy showed a significant reduction in tumor burden compared with either monotherapy, suggesting that anti-PD-1 therapy is reasonable after sunitinib malate treatment.

Pharmacological restoration of visual function in a zebrafish model of von-Hippel Lindau disease.

Von Hippel-Lindau (VHL) syndrome is a rare, autosomal dominant disorder, characterised by hypervascularised tumour formation in multiple organ systems. Vision loss associated with retinal capillary hemangioblastomas remains one of the earliest complications of VHL disease. The mortality of Vhl-/- mice in utero restricted modelling of VHL disease in this mammalian model. Zebrafish harbouring a recessive germline mutation in the vhl gene represent a viable, alternative vertebrate model to investigate associated ocular loss-of-function phenotypes. Previous studies reported neovascularisation of the brain, eye and trunk together with oedema in the vhl-/- zebrafish eye. In this study, we demonstrate vhl-/- zebrafish almost entirely lack visual function. Furthermore, hyaloid vasculature networks in the vhl-/- eye are improperly formed and this phenotype is concomitant with development of an ectopic intraretinal vasculature. Sunitinib malate, a multi tyrosine kinase inhibitor, market authorised for cancer, reversed the ocular behavioural and morphological phenotypes observed in vhl-/- zebrafish. We conclude that the zebrafish vhl gene contributes to an endogenous molecular barrier that prevents development of intraretinal vasculature, and that pharmacological intervention with sunitinib can improve visual function and hyaloid vessel patterning while reducing abnormally formed ectopic intraretinal vessels in vhl-/- zebrafish.

Anticancer Efficacy of Self-Nanoemulsifying Drug Delivery System of Sunitinib Malate.

Sunitinib malate (SM) is reported as a weakly soluble drug in water due to its poor dissolution rate and oral bioavailability. Hence, in the current study, various "self-nanoemulsifying drug delivery systems (SNEDDS)" of SM were prepared, characterized and evaluated for the enhancement of its in vitro dissolution rate and anticancer efficacy. On the basis of solubilization potential of SM in various excipients, "Lauroglycol-90 (oil), Triton-X100 (surfactant) and Transcutol-P (cosurfactant)" were selected for the preparation of SM SNEDDS. SM-loaded SNEDDS were developed by spontaneous emulsification method, characterized and evaluated for "thermodynamic stability, self-nanoemulsification efficiency, droplet size, polydispersity index (PDI), zeta potential (ZP), surface morphology, refractive index (RI), the percent of transmittance (% T) and drug release profile." In vitro dissolution rate of SM was significantly enhanced from an optimized SNEDDS in comparison with SM suspension. The optimized SNEDDS of SM with droplet size of 42.3 nm, PDI value of 0.174, ZP value of -36.4 mV, RI value of 1.339, % T value of 97.3%, and drug release profile of 95.4% (after 24 h via dialysis membrane) was selected for in vitro anticancer efficacy in human colon cancer cells (HT-29) by MTT assay. MTT assay indicated significant anticancer efficacy of optimized SM SNEDDS against HT-29 cells in comparison with free SM. The results of this study showed the great potential of SNEDDS in the enhancement of in vitro dissolution rate and anticancer efficacy of poorly soluble drug such as SM.

A case of successful conversion from everolimus to surgical resection of a giant pancreatic neuroendocrine tumor.

BACKGROUND: Although pancreatic neuroendocrine tumors generally have a far better prognosis relative to pancreatic cancer, the varied manifestations lead to treatment-related challenges. Everolimus therapy is generally recommended for patients with advanced pancreatic neuroendocrine tumors; however, its efficacy in a neoadjuvant setting remains unclear. Here we present a case of a giant pancreatic neuroendocrine tumor with a portal tumor thrombus that became resectable after everolimus therapy. CASE PRESENTATION: A 62-year-old woman was admitted to our hospital for surgical resection of a giant pancreatic neuroendocrine tumor in the left upper abdomen. Unfortunately, she was ineligible for surgery because the tumor had extended near the hepatic hilus in the portal vein, and she was administered everolimus (10 mg/day). After 2 years of this therapy, the extent of portal vein involvement had decreased, despite the lack of significant changes in the tumor size, and the hepatic hilus became free of disease. She was subsequently referred to us for resection via distal pancreatectomy with portal vein reconstruction because the tumor had begun to grow slowly. Pathological review identified a grade 2 neuroendocrine tumor with no lymph node metastasis. The patient's postoperative course was uneventful, and she has remained recurrence-free for 27 months, despite a lack of additional treatment. CONCLUSIONS: Our experience suggests that everolimus could be useful for neoadjuvant therapy in cases of locally advanced pancreatic neuroendocrine tumor.

Targeted drug delivery of Sunitinib Malate to tumor blood vessels by cRGD-chiotosan-gold nanoparticles.

The unique characteristics of tumor vasculature represent an attractive strategy for targeted delivery of antitumor and antiangiogenic agents to the tumor. The purpose of this study was to prepare c(RGDfK) labeled chitosan capped gold nanoparticles [cRGD(CS-Au) NPs] as a carrier for selective intracellular delivery of Sunitinib Malate (STB) to the tumor vasculature. cRGD(CS-Au) NPs was formed by electrostatic interaction between cationic CS and anionic AuNPs. cRGD modified CS-Au NPs had a spherical shape with a narrow size distribution. The entrapment efficiency of sunitinib molecule was found to be 45.2%±2.05. Confocal microscopy showed enhanced and selective uptake of cRGD(CS-Au) NPs into MCF-7 and HUVEC cells compared with non-targeted CS-Au NPs. Our results suggest that it may be possible to use cRGD(CS-Au) NPs as a carrier for delivery of anticancer drugs, genes and biomolecules for inhibiting tumor vasculature.

Development and validation of a HPTLC method for analysis of Sunitinib malate

ABSTRACT A simple high performance thin layer chromatography (HPTLC) has been developed and validated for determination of sunitinib malate and possible impurities. The samples were applied in forms of bands on an aluminum TLC plate pre-coated with silica gel and were separated using dichloromethane: methanol: toluene: ammonia solution as the mobile phase. Sunitinib malate was thoroughly separated from impurities including E-isomer, sunitinib N-oxide and impurity B with a retention factor (RF) of 0.35±0.02. Quantitative analysis of sunitinib was carried out using a mobile phase consisting of dichloromethane:methanol:ammonia solution, RF value was 0.53±0.02 for Z isomer. Detection was performed densitometrically in absorbance mode at 430 nm. This method was found to produce sharp, symmetrical, and well resolved peaks. Linear relationship with the coefficients of determination > 0.99 was achieved over the concentration range of 27.34 to 437.5 ng/spot. This method provides robust, replicable and accurate results with acceptable sensitivity.

Preclinical Evidence for the Use of Sunitinib Malate in the Treatment of Plexiform Neurofibromas.

PURPOSE: Plexiform neurofibromas (pNF) are pathognomonic nerve and soft tissue tumors of neurofibromatosis type I (NF1), which are highly resistant to conventional chemotherapy and associated with significant morbidity/mortality. Disruption of aberrant SCF/c-Kit signaling emanating from the pNF microenvironment induced the first ever objective therapeutic responses in a recent phase 2 trial. Sunitinib malate is a potent, highly selective RTK inhibitor with activity against c-Kit, PDGFR, and VEGFR, which have also been implicated in the pathogenesis of these lesions. Here, we evaluate the efficacy of sunitinib malate in a preclinical Krox20;Nf1(flox/-) pNF murine model. EXPERIMENTAL DESIGN: Proliferation, ß-hexosaminidase release (degranulation), and Erk1/2 phosphorylation were assessed in sunitinib treated Nf1(+/-) mast cells and fibroblasts, respectively. Krox20;Nf1(flox/-) mice with established pNF were treated sunitinib or PBS-vehicle control for a duration of 12 weeks. pNF metabolic activity was monitored by serial [(18)F]DG-PET/CT imaging. RESULTS: Sunitinib suppressed multiple in vitro gain-in-functions of Nf1(+/-) mast cells and fibroblasts and attenuated Erk1/2 phosphorylation. Sunitinib treated Krox20;Nf1(flox/-) mice exhibited significant reductions in pNF size, tumor number, and FDG uptake compared to control mice. Histopathology revealed reduced tumor cellularity and infiltrating mast cells, markedly diminished collagen deposition, and increased cellular apoptosis in sunitinib treated pNF. CONCLUSIONS: Collectively, these results demonstrate the efficacy of sunitinib in reducing tumor burden in Krox20;Nf1(flox/-) mice. These preclinical findings demonstrate the utility of inhibiting multiple RTKs in pNF and provide insights into the design of future clinical trials.

Sunitinib malate (SU-11248) reduces tumour burden and lung metastasis in an intratibial human xenograft osteosarcoma mouse model.

Osteosarcoma is a rare type of cancer that commonly occurs as a primary bone tumour in children and adolescents and is associated with a poor clinical outcome. Despite complex treatment protocols, including chemotherapy combined with surgical resection, the prognosis for patients with osteosarcoma and metastases remains poor and more effective therapies are required. In this study, we evaluated the therapeutic efficacy of sunitinib malate, a wide-spectrum tyrosine kinase inhibitor, in a preclinical mouse model of osteosarcoma. Sunitinib significantly inhibited proliferation, provoked apoptosis and induced G2/M cell cycle arrest in the human osteosarcoma cell lines SaOS-2 and 143B in vitro. Importantly, sunitinib treatment significantly reduced tumour burden, microvessel density and suppressed pulmonary metastasis in a 143B cell-derived intratibial osteosarcoma model in SCID mice. Sunitinib significantly decreased primary tumor tissue proliferation and reduced tumor vasculature. Our study indicates that sunitinib has potential for effective treatment of metastasizing osteosarcoma and provides the framework for future clinical trials with sunitinib alone or in combination with conventional and other novel therapeutics aiming at increased treatment efficacy and improved patient outcome.

Long term experience of patients with unresectable or metastatic KIT positive gastrointestinal stromal tumours.

A retrospective analysis of consecutive patients (183 in total, of which 105 were males and 78 females) with gastrointestinal stromal tumour (GIST) was performed. The mean age was 61 years, median age 64 years. The most frequent localization of the tumour was stomach in 74 patients (40.4 %) and the small intestine in 46 patients (25.1 %). Two or more different synchronous or metachronous cancers occurred in 34 (18.6 %) patients with histologically confirmed GIST. Ninety-six patients were treated with imatinib mesylate in palliative setting during the course of their disease. The therapy was finished in 60 patients and 36 patients have been treated so far. The median progression-free survival reached 32.9 months in the group of 96 patients treated with imatinib. The median overall survival in the group of 96 patients treated for metastatic disease reached 77 months. Two-year and 5-year survival was 85.2 % and 63.1 %, respectively. The second-line therapy with sunitinib malate was administered in 37 patients, of which 31 finished and 6 continued in the therapy. The median progression free survival and median survival since the sunitinib therapy initiation reached 8.4 and 22.1 months, respectively (Tab. 2, Fig. 2, Ref. 16).

Sunitinib microspheres based on [PDLLA-PEG-PDLLA]-b-PLLA multi-block copolymers for ocular drug delivery.

Sunitinib is a multi-targeted receptor tyrosine kinase (RTK) inhibitor that blocks several angiogenesis related pathways. The aim of this study was to develop sunitinib-loaded polymeric microspheres that can be used as intravitreal formulation for the treatment of ocular diseases. A series of novel multi-block copolymers composed of amorphous blocks of poly-(D,L-lactide) (PDLLA) and polyethylene glycol (PEG) and of semi-crystalline poly-(L-lactide) (PLLA) blocks were synthesized. Sunitinib-loaded microspheres were prepared by a single emulsion method using dichloromethane as volatile solvent and DMSO as co-solvent. SEM images showed that the prepared microspheres (∼ 30 µm) were spherical with a non-porous surface. Sunitinib-loaded microspheres were studied for their degradation and in-vitro release behavior. It was found that increasing the percentage of amorphous soft blocks from 10% to 30% accelerated the degradation of the multi-block copolymers. Sunitinib microspheres released their cargo for a period of at least 210 days by a combination of diffusion and polymer erosion. The initial burst (release in 24h) and release rate could be tailored by controlling the PEG-content of the multi-block copolymers. Sunitinib-loaded microspheres suppressed angiogenesis in a chicken chorioallantoic membrane (CAM) assay. These microspheres therefore hold promise for long-term suppression of ocular neovascularization.

Acute acalculous cholecystitis in a patient with metastatic renal cell carcinoma treated with sunitinib.

A 55-year old man was treated with sunitinib 50 mg/day for 4 weeks on and 2 weeks off, as a first-line therapy for metastatic renal cell carcinoma. During the fourth week of the first cycle, he was admitted to the Emergency Department with abdominal pain and vomiting. Acute acalculous cholecystitis was diagnosed. Sunitnib-associated cholecystitis is a rare adverse event previously reported in few cases. The mechanism behind this complication is not fully understood, although vascular endothelial dysfunction may play a role. The use of this drug is expanding in clinical oncology, and physicians should be aware of this life-threating adverse event.

Flumatinib, a selective inhibitor of BCR-ABL/PDGFR/KIT, effectively overcomes drug resistance of certain KIT mutants.

Activating mutations in KIT have been associated with gastrointestinal stromal tumors (GISTs). The tyrosine kinase inhibitor imatinib mesylate has revolutionized the treatment of GISTs. Unfortunately, primary or acquired resistance to imatinib does occur in GISTs and forms a major problem. Although sunitinib malate, a multi-kinase inhibitor, has shown effectiveness against imatinib-resistant GISTs, recent studies have indicated that some imatinib-resistant GISTs harboring secondary mutations in the KIT activation loop were also resistant to sunitinib. Therefore, new drugs capable of overcoming the dual drug resistance of GISTs probably have potential clinical utility. In this study, we investigated the efficacy of flumatinib, an inhibitor of BCR-ABL/PDGFR/KIT, against 32D cells transformed by various KIT mutants and evaluated its potency to overcome the drug resistance of certain mutants. Interestingly, our in vitro study revealed that flumatinib effectively overcame the drug resistance of certain KIT mutants with activation loop mutations (i.e., D820G, N822K, Y823D, and A829P). Our in vivo study consistently suggested that flumatinib had superior efficacy compared with imatinib or sunitinib against 32D cells with the secondary mutation Y823D. Molecular modeling of flumatinib docked to the KIT kinase domain suggested a special mechanism underlying the capability of flumatinib to overcome the drug-resistance conferred by activation loop mutations. These findings suggest that flumatinib could be a promising therapeutic agent against GISTs resistant to both imatinib and sunitinib because of secondary mutations in the activation loop.

Neem leaf glycoprotein is superior than cisplatin and sunitinib malate in restricting melanoma growth by normalization of tumor microenvironment.

We have observed earlier that therapeutic treatment with neem leaf glycoprotein (NLGP) inhibits murine B16-melanoma growth in vivo and improves survivability of treated mice. Anti-tumor effect of NLGP is directly associated with enhanced CD8(+) T cell activity and downregulation of suppressive cellular functions. Objective of this present study is to know the efficacy of NLGP in comparison to two popular drugs, Cisplatin and Sunitinib malate (Sutent) in relation to the modulation of tumor microenvironment (TME). Analysis of cytokine milieu within TME revealed IL-10, TGFß, IL-6 rich type 2 characters was significantly switched to type 1 microenvironment with dominance of IFNγ and IL-2 within NLGP-TME, which was not found in other cases; however Cisplatin-TME appeared better in type 2 to type 1 conversion than Sutent-TME as evidenced by RT-PCR, ELISA and immunohistochemical analysis. NLGP-TME educated CD8(+) T cells exhibited greater cytotoxicity to B16 Melanoma cells in vitro and these cells showed comparatively higher expression of cytotoxicity related molecules, perforin and granzyme B than Cisplatin-TME and Sutent-TME educated T cells. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of melanoma in vivo. Such tumor growth inhibition was in significantly lower extent when therapeutic CD8(+) T cells were exposed to either Cisplatin-TME or Sutent-TME or control-TME. Accumulated evidences strongly suggest that non toxic NLGP normalized TME allows T cells to perform optimally than other TMEs under study to inhibit the melanoma growth.

Therapeutic potential of sunitinib in the treatment of malignant islet cell tumor / 中华内分泌代谢杂志

Malignant islet cell tumor, a rare type of neuroendocrine carcinoma, biologically behaves in an aggressive way and is difficulty to be treated. Sunitinib malate, a novel tyrosine kinase inhibitor, demonstrates a high efficacy in treating malignant islet cell tumor as shown by promising results in recent trials.

Sunitinib malate for gastrointestinal stromal tumour in imatinib mesylate-resistant patients: recommendations and evidence.

QUESTION: Is sunitinib malate-marketed as Sutent (Pfizer Canada, Kirkland, QC)-superior to placebo or other interventions for primary outcomes of interest in adult patients with gastrointestinal stromal tumour (GIST) who have developed resistance or who exhibit intolerance to imatinib mesylate (IM)? BACKGROUND: In patients with resectable disease, surgery is the mainstay of treatment for GIST; in patients with unresectable or metastatic disease, the tyrosine kinase inhibitor IM is the therapy of choice. However, some patients have primary resistance or intolerance to IM, or they progress after optimal exposure (including an escalated dose). Here, we review the evidence for treating IM-resistant GIST with sunitinib malate. METHODS: Studies of sunitinib malate were identified through MEDLINE, EMBASE, the Cochrane Library databases, and Web sites of guideline organizations. Outcomes of interest included time to progression, progression-free survival, overall survival, and toxicity. RESULTS: One phase III randomized controlled trial, and one abstract and presentation describing that trial, served as the evidentiary base for this clinical practice guideline. Trial data confidently show that both time to progression and progression-free survival are highly statistically significant (p < 0.0001) in favour of sunitinib malate over placebo. Overall survival was improved with sunitinib malate (hazard ratio: 0.49; 95% confidence interval: 0.29 to 0.83; p = 0.007; absolute difference in weeks not reported). The most frequent of all adverse effects (experienced in greater proportion by patients on sunitinib malate) were grades 1 and 2 leucopenia (52% vs. 5% with placebo), neutropenia (43% vs. 4%), and thrombocytopenia (36% vs. 4%). Grade 3 hematologic adverse events were also reported more frequently in the sunitinib malate group, including leucopenia (4% vs. 0%), neutropenia (8% vs. 4%), lymphopenia (9% vs. 2%), and thrombocytopenia (4% vs. 0%). Toxicity comparisons did not include p values. The incidence of grades 1-3 fatigue was greater for the sunitinib malate group (34% vs. 22% with placebo). Other grade 3 nonhematologic treatment-related adverse events that occurred more frequently on sunitinib malate included hand-foot syndrome (4% vs. 0%), diarrhea (3% vs. 0%), and hypertension (3% vs. 0%). No grade 4 adverse events were observed. CONCLUSIONS: In the target population, sunitinib malate is the recommended option for second-line therapy of metastatic GIST.

Gastrointestinal stromal tumors-diagnosis and management: a brief review.

Gastrointestinal stromal tumors (GISTs) are rare but are the most common mesenchymal tumor in the gastrointestinal tract. They arise from a precursor cell in the myenteric plexus, and most tumors express a characteristic CD117 antigen, which is part of a tyrosine kinase receptor. This finding has led to the development of novel chemotherapeutic agents targeted at these receptors and has revolutionized the treatment of these tumors, which had been historically disappointing. Surgery is recommended for tumors >2 cm in size and even has a role in metastatic disease. The approach to tumors <2 cm in size is more controversial, as these lesions tend to be less aggressive, but the true malignant potential of GISTs can only be determined by surgical resection and histologic evaluation.