Pharmacological management of gastrointestinal stromal tumours: an update on the role of sunitinib

Individualized Dosing Patterns in the Treatment of Older Patients with Gastrointestinal Stromal Tumors: Results of a Registry-Based Observational National Cohort Study Including 871 Patients

BACKGROUND

While the effectiveness of tyrosine kinase inhibitors (TKIs) seems similar in older patients with gastrointestinal stromal tumors (GIST) compared with younger patients, toxicities in older patients treated with TKIs more often lead to discontinuation of treatment.

OBJECTIVE

To better understand the age-related pharmacology and pharmacodynamic differences in patients with GIST treated with TKIs, the primary aim of this study was to evaluate TKI dosing patterns in older patients with GIST, while the secondary aims were to evaluate differences in imatinib trough plasma concentrations between age groups and to compare the overall survival (OS) in patients with and without dose reductions in all treatment lines in a palliative setting.

METHODS

Patients (18 years of age or older) with histologically proven GIST diagnosed between January 2009 and June 2021 and treated with one or more lines of TKIs were selected from the Dutch GIST Registry (DGR) database. Age groups were divided into younger patients (age <70 years) and older patients (age ≥70 years). All imatinib trough plasma concentrations of blood withdrawals taken from initiation of imatinib until a maximum of 1 year of treatment with imatinib were collected. Reasons for first adjustment of treatment were classified as adverse event, dose modification, progressive disease and other reasons. The next treatment steps after first adjustment of treatment were defined as dose escalation, dose reduction, dose interruption, or end of treatment. The association of dose reduction and OS was analyzed using the landmark approach.

RESULTS

Overall, 871 patients were included in this study, including 577 younger patients and 294 older patients. Older patients more often had an adverse event as the reason for first adjustment of treatment with both imatinib (45.6%; p < 0.001) and sunitinib (58.6%; p = 0.224) compared with younger patients (19.5% and 42.7%, respectively). Adjustment of imatinib and sunitinib after starting on a standard dose because of an adverse event most often resulted in dose reduction in both age groups. Median trough plasma concentrations of all samples taken within the first year after initiation of imatinib were higher in older patients (1228 ng/mL, interquartile range [IQR] 959-1687) compared with younger patients (1035 ng/mL [IQR 773-1377]; p < 0.001). No significant differences were seen between OS in patients with or without dose reduction in all treatment lines (imatinib: p = 0.270; sunitinib: p = 0.547; and regorafenib: p = 0.784).

CONCLUSION

Older patients showed higher imatinib trough plasma concentrations compared with younger patients and also had earlier and more often adverse events as the reason for first adjustment of treatment with imatinib followed by dose reduction. However, in a landmark analysis, patients with imatinib dose reductions had no poorer outcomes compared with patients not requiring a dose reduction.

Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review

In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.

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.

Emerging Data on the Safety and Efficacy of Ripretinib for the Treatment of Gastrointestinal Stromal Tumors

In patients with gastrointestinal stromal tumors (GIST), systemic treatment after disease progression on imatinib is challenging. Sunitinib and regorafenib are approved in the second- and third-line setting, respectively, with activity against certain secondary mutations with comparatively much lower response rates and survival increment compared to imatinib. All three of these drugs were serendipitously found to have activity in GIST, starting with imatinib, which was formulated for its ability to inhibit BCR-ABL in chronic myelogenous leukemia. Ripretinib is a drug that was specifically developed as a more potent KIT tyrosine kinase inhibitor (TKI), with broad-spectrum activity against the mutations encountered in GIST. Encouraging responses in early and later lines of treatment in the Phase 1 trial of ripretinib in GIST led to the rapid development of this novel drug. In a Phase 3 randomized clinical trial with cross-over, ripretinib demonstrated superior PFS and overall survival (OS) in 4th-line treatment and beyond compared to placebo. This established 150 mg once daily ripretinib as the standard of care in this setting. Ripretinib is generally well tolerated, with common adverse effects of hair loss, diarrhea, cramps, fatigue and nausea. The favorable safety profile and efficacy of ripretinib prompted its evaluation in a randomized phase 3 trial in the 2nd-line treatment setting. However, it did not result in a longer PFS duration than sunitinib. Although the efficacy of ripretinib in this unselected patient population was not significantly different from that of sunitinib, the tolerability profile was better. This review article aims to review the efficacy and tolerability profile of ripretinib, together with its role in the setting of unresectable or metastatic GIST.

Combined Ibuprofen-Nanoconjugate Micelles with E-Selectin for Effective Sunitinib Anticancer Therapy

Introduction

Sunitinib, a first-line therapy with a certain effect, was utilized in the early stages of renal cell carcinoma treatment. However, its clinical toxicity, side effects, and its limited bioavailability, resulted in inadequate clinical therapeutic efficacy. Building neoteric, simple, and safe drug delivery systems with existing drugs offers new options. Therefore, we aimed to construct a micelle to improve the clinical efficacy of sunitinib by reusing ibuprofen.

Methods

We synthesized the sialic acid-poly (ethylene glycol)-ibuprofen (SA-PEG-IBU) amphipathic conjugate in two-step reaction. The SA-PEG-IBU amphiphilic conjugates can form into stable SPI nanomicelles in aqueous solution, which can be further loaded sunitinib (SU) to obtain the SPI/SU system. Following nanomicelle creation, sialic acid exposed to the nanomicelle surface can recognize the overexpressed E-selectin receptor on the membrane of cancer cells to enhance cellular uptake. The properties of morphology, stability, and drug release about the SPI/SU nanomicelles were investigated. Confocal microscopy and flow cytometry were used to assess the cellular uptake efficiency of nanomicelles in vitro. Finally, a xenograft tumor model in nude mice was constructed to investigate the body distribution and tumor suppression of SPI/SU in vivo.

Results

The result showed that SPI nanomicelles exhibited excellent tumor targeting performance and inhibited the migration and invasion of tumor cell in vitro. The SPI nanomicelles can improve the accumulation of drugs in the tumor site that showed effective tumor inhibition in vivo. In addition, H&E staining and immunohistochemical analysis demonstrated that the SPI/SU nanomicelles had a superior therapeutic effect and lower biotoxicity.

Conclusion

The SPI/SU nanomicelles displayed excellent anti-tumor ability, and can suppress the metastasis of tumor cell by decreasing the expression of Cyclooxygenase-2 due to the ibuprofen, providing an optimistic clinical application potential by developing a simple but safe drug delivery system.

Continuous sunitinib schedule in advanced platinum refractory thymic epithelial neoplasms: A retrospective analysis from the ThYmic MalignanciEs (TYME) Italian collaborative group

BACKGROUND

Thymic epithelial tumors (TETs) are rare diseases, with diverse clinical behaviour and prognosis. Intermittent dosing sunitinib represents the gold-standard systemic treatment following platinum-based chemotherapy. To ensure more homogeneous drug exposure, continuous daily dosing (CDD) sunitinib is utilised in other malignancies; however, no data exist in patients with TETs.

METHODS

We retrospectively examined data from patients with platinum-resistant TETs receiving CDD sunitinib 37.5 mg between 1 May 2017 and 31 May 2022 within the Italian collaborative group for ThYmic MalignanciEs. Primary end-points were median progression-free survival, overall response rate (ORR), median duration of response and major treatment-related adverse events.

RESULTS

A total of 20 consecutive patients (12 thymic carcinoma [TC], 6 B3, and 2 B2 thymoma) were evaluated. Among the 19 patients evaluable for response, ORR was 31.6% (95% CI, 12.5%-56.5%). Among patients with TC, one complete response, four partial responses, and four stable diseases were observed (ORR 41%).The overall median progression-free survival was 7.3 months (95% CI, 4.5-10.3): 7.3 months (95% CI, 4.4-NA) within patients with thymoma and 6.8 months (95% CI, 2.8-10.3) in patients with TC; median duration of response was 10.3 months (95% CI, 2.8-NA). CDD was associated with a manageable toxicity profile. Six patients (30%) experienced >G2 toxicity, nine required dose reduction and three discontinued treatment due to adverse events.

CONCLUSIONS

CDD sunitinib showed a relevant antitumor activity and confirmed a good toxicity profile. Similar effectiveness and a better toxicity profile as compared with intermittent dosing historical data suggest that this schedule should be considered.

Safety of Imatinib Mesylate in a Multicenter Expanded Access Program in Adult Patients with Gastrointestinal Stromal Tumors in the Adjuvant Setting

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors most often caused by activating mutations of the KIT gene. KIT tyrosine kinase inhibitors provide targeted therapy for the underlying genetic mutation, and adjuvant therapy is indicated for patients who are at significant risk of relapse following GIST resection. This is a report of the safety of imatinib in patients with GIST in the adjuvant setting in an expanded access program.

METHODS

In this multicenter, open-label, single-arm trial, safety was assessed based on the frequency of adverse events (AEs).

RESULTS

Three hundred patients were treated and analyzed; 40 patients discontinued treatment. Median overall exposure during the program was 181 days (range 9-420); most patients (260/300 treated) completed the study. Six patients had disease recurrence, 4 of whom discontinued. In line with previously published reports, the most frequent AEs were nausea, diarrhea, and periorbital edema. The AEs were mild to moderate in most cases (76%).

CONCLUSIONS

These findings are in agreement with the known safety profile of imatinib and confirm the safety of imatinib at 400 mg/day in the adjuvant setting. The incidence of severe AEs was low.

Patient-reported outcome measures in a pharmacokinetic study with sunitinib, a prospective cohort study

PURPOSE

During treatment with tyrosine kinase inhibitors, such as sunitinib, patients experience treatment and/or disease-related symptoms. Although application of patient-reported outcome measures (PROMs) enhances early recognition of symptoms, early clinical trials are focused on symptom severity objectified by the Common Terminology Criteria for Adverse Events (CTCAE) in order to evaluate drug safety and to determine a personalized and/or safe dosage range. To gain insight into patient-reported symptoms in addition to healthcare professional-reported adverse events (AEs), a substudy was conducted in an ongoing pharmacokinetic-guided sunitinib dosing study.

METHODS

In patients for whom sunitinib was considered standard therapy or patients with advanced/metastatic tumors for whom no standard therapy was available, patient-reported symptoms and well-being besides healthcare professional-reported AEs were assessed.

RESULTS

Twenty-nine patients were included for analysis. Over 50% of them experienced a decreased well-being, caused by symptoms of mild and moderate intensity. Compared to healthcare professionals, all measured symptoms, with the exception of fatigue and vomiting, were reported statistically significantly more often by patients.

CONCLUSIONS

Application of PROMs in early clinical trials on personalized or individualized oral targeted anticancer agents is feasible and enhances early recognition of symptom burden due to multiple CTCAE grade 1-2 AEs, just as pro-active symptom management and effect evaluation of interventions performed. Application of PROMs in these trials might be clinically relevant in obtaining dose-limiting toxicities.

[Gastrointestinal Stromal Tumors "GIST": status and news through our experience on 54 cases and review of literature]

Les Tumeurs Stromales Gastro-intestinales « GIST » sont une forme très rare de cancers du tube digestif appartenant à la famille des sarcomes. Le but de ce travail est d'établir le profil épidémiologique et évolutif ainsi que les difficultés diagnostique et thérapeutique de cette pathologie maligne prise en charge dans un pays en développement. Une Etude rétrospective étalée sur 8 ans de Janvier 2002 à Mars 2010, a été mené au Service de Radiothérapie et d'Oncologie du CHU de Casablanca (Maroc) ayant colligée 54 cas de tumeurs stromales gastro-intestinales. L'âge moyen de nos patients était de 55 ans. Le délai moyen d'évolution était de 11 mois (0-72 mois). La biopsie a permis de confirmer le diagnostic dans 14 cas et la chirurgie dans 40 cas. La principale forme histologique était fusiforme (92,6%). Les GIST dans notre série avaient une taille tumorale moyenne de 12,5 cm avec un C-Kit positif dans 52 cas. Le risque évolutif a pu être établi dans 47 cas dont 39 avaient un risque élevé. La chirurgie était le principal traitement des patients de notre sérieAprès un recul moyen de 31 mois, la moitié des patients évaluables de notre série (n=19) est en rémission complète maintenue, le tiers (n=13) est décédé alors que le quart (n=8) présente une récidive locale et /ou métastatique. Quoique les recommandations soient éditées pour la prise en charge de ces tumeurs, ces dernières soulèvent encore de nombreux problèmes aussi bien diagnostiques que thérapeutiques dans notre contexte.

A Rare Case of Sunitinib-Induced Hyperammonemic Encephalopathy and Hypothyroidism in Metastatic Renal Cell Carcinoma

Sunitinib has become a standard treatment agent for metastatic renal cell carcinoma (RCC) for several years. However, various adverse events have been reported. We present a rare adverse effect of hyperammonemic encephalopathy induced by sunitinib. A 66-year-old woman with metastatic RCC referred to the emergency department with confusion that developed 14 days after the initiation of 50 mg/d of sunitinib. Her serum ammonia and thyroid-stimulating hormone levels were markedly elevated (146 μg/dL and 27.27 μIU/mL, respectively). Sunitinib was discontinued, and an enema with lactulose and L-thyroxine were administered. Her mental status and neurologic symptoms were normalized 7 days after the treatment. Serum ammonia level decreased to 61 μg/dL and thyroid stimulating hormone level decreased 22.34 μIU/mL. The incidence of sunitinib-induced hyperammonemia is rarely reported. The relationship between sunitinib and the development of hyperammonemia is not well understood, and the mechanism is unclear. Sunitinib-induced hyperammonemia is very rare, and to the best of our knowledge, this is fourth case hyperammonemia and first case hyperammonemic encephalopathy with hypothyroidism as an adverse effect. Therefore, it is important for clinicians to be aware of hyperammonemia that can occur in several days after the initiation of sunitinib treatment in metastatic RCC.

FGF2 Prevents Sunitinib-Induced Cardiotoxicity in Zebrafish and Cardiomyoblast H9c2 Cells

Sunitinib is used extensively in the treatment of metastatic renal cell carcinoma and imatinib-resistant gastrointestinal stromal tumors. However, the undesirable cardiotoxic effects of sunitinib, such as congestive heart failure and hypertension, limit its use in the clinical setting. As multiple receptor tyrosine kinases are inhibited by sunitinib, it raises a question as to which target mediates sunitinib-induced cardiotoxicity. Here, we reported that the injection of fibroblast growth factor 2 (FGF2) mRNA into one- to two-cell stage embryos protected against sunitinib-induced cardiotoxicity in zebrafish. In addition, FGF2 significantly prevented sunitinib-induced cardiotoxicity in cardiomyoblast H9c2 cells, possibly via activating the PLC-γ/c-Raf/CREB pathway. Importantly, FGF2 did not compromise the antitumor activity of sunitinib in Caki-1 and OS-RC-2 renal cell carcinoma cells. Molecular docking simulations further revealed an interaction between the tyrosine kinase domain of FGF receptor 1 (FGFR1) and sunitinib. Taken together, our results clearly demonstrated that FGF2 inhibition plays an important role in sunitinib-induced cardiotoxicity both in vitro and in vivo. This study also provided a basis for further research on sunitinib-induced cardiotoxicity and may allow rational design of new sunitinib derivatives with fewer or weak cardiotoxic effects.

Oral Platelet-Derived Growth Factor and Vascular Endothelial Growth Factor Inhibitor Sunitinib Prevents Chronic Allograft Injury in Experimental Kidney Transplantation Model

BACKGROUND

Expression of both platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) is increased during the development of chronic rejection which remains the major reason for late allograft loss in clinical kidney transplantation. Sunitinib is a tyrosine kinase inhibitor which inhibits both VEGF and PDGF receptors. Here we investigated its effect on the development of chronic rejection.

METHODS

Rat aortic denudation model was used to define sunitinib dose. In vitro studies were done to investigate the effect of sunitinib on smooth muscle cell proliferation and migration. Kidney transplantations were performed from dark agouti rat strain (DA) to Wistar furth rat strain rats and syngenic DA-DA grafts were used as controls. Allografts were immunosuppressed either with cyclosporine or with cyclosporine and sunitinib. Grafts were harvested at 5 and 90 days for histology and immunohistochemistry. Serum creatinine levels were measured weekly to monitor graft function.

RESULTS

Sunitinib decreased neointimal formation and smooth muscle cell proliferation and migration in a dose-dependent manner. Sunitinib was well tolerated and almost completely prevented chronic rejection changes and preserved significantly better renal graft function after transplantation. Sunitinib also inhibited chronic PDGF-A and -B and VEGF-A and -B expressions.

CONCLUSIONS

These results demonstrate that combined inhibition of PGDF and VEGF with sunitinib prevents chronic rejection changes in experimental kidney transplantation which indicates that sunitinib could be a potential intervention also in clinical kidney transplantation.

Gaining power and precision by using model-based weights in the analysis of late stage cancer trials with substantial treatment switching

In randomised controlled trials of treatments for late-stage cancer, it is common for control arm patients to receive the experimental treatment around the point of disease progression. This treatment switching can dilute the estimated treatment effect on overall survival and impact the assessment of a treatment's benefit on health economic evaluations. The rank-preserving structural failure time model of Robins and Tsiatis (Comm. Stat., 20:2609-2631) offers a potential solution to this problem and is typically implemented using the logrank test. However, in the presence of substantial switching, this test can have low power because the hazard ratio is not constant over time. Schoenfeld (Biometrika, 68:316-319) showed that when the hazard ratio is not constant, weighted versions of the logrank test become optimal. We present a weighted logrank test statistic for the late stage cancer trial context given the treatment switching pattern and working assumptions about the underlying hazard function in the population. Simulations suggest that the weighted approach can lead to large efficiency gains in either an intention-to-treat or a causal rank-preserving structural failure time model analysis compared with the unweighted approach. Furthermore, violation of the working assumptions used in the derivation of the weights only affects the efficiency of the estimates and does not induce bias or inflate the type I error rate. The weighted logrank test statistic should therefore be considered for use as part of a careful secondary, exploratory analysis of trial data affected by substantial treatment switching.

Lack of Correlation Between Liver Tests Abnormalities and Trabectedin Efficacy in the Treatment of Soft Tissue Sarcoma: a Retrospective Study

Elevation in liver transaminases is common in patients treated with the marine antitumor agent trabectedin. However, the impact of trabectedin-related transaminase elevations on treatment outcomes is unclear. This retrospective study investigated the correlation between liver tests abnormalities and treatment outcomes in patients with unresectable advanced or metastatic soft tissue sarcomas (STS) treated with trabectedin 1.5 mg/m² once every 3 weeks at three reference centers in Italy. The effect of grade 3/4 elevations in alanine aminotransferase (ALT) or aspartate aminotransferase (AST) during the first two cycles and at any time during trabectedin treatment on progression-free survival (PFS) and overall survival (OS) were analyzed. Liver tests abnormalities during the first two cycles of chemotherapy or at any time during trabectedin treatment did not significantly affect PFS or OS. Nor were survival outcomes significantly different in the subgroups of patients with or without ALT/AST increases or with ALT/AST elevations ≥15 × the upper limit of normal (ULN) versus those with ALT/AST elevation <15 × ULN. Although liver tests abnormalities are common in patients treated with trabectedin, elevations in ALT and AST are usually transient, occur during the first two cycles of treatment, and do not appear to affect survival.

Current management of patients with gastrointestinal stromal tumor receiving the multitargeted tyrosine kinase inhibitor sunitinib

BACKGROUND

Gastrointestinal stromal tumor (GIST), a form of soft tissue sarcoma, is often detected incidentally or at an advanced stage. The tyrosine kinase inhibitor sunitinib malate (Sutent * ) is established as second-line treatment for the management of GIST after disease progression on, or intolerance to, first-line imatinib treatment. Several published reviews give guidance on management of side effects in patients with advanced renal cell carcinoma treated with sunitinib, but fewer publications cover side-effect management in patients with GIST.

SCOPE

Using published articles and abstracts, prescribing information, and personal experience in managing patients with GIST at a specialized center of excellence for cancer care, I review side-effect management recommendations for patients with GIST treated with sunitinib and provide an overview of GIST.

FINDINGS

Sunitinib has a well described side-effect profile: most side effects occurring in patients with GIST can be easily managed by standard medical intervention and/or dose modification.

CONCLUSION

Care of patients with GIST can be enhanced through communication, support, knowledge, and education, with the goal of providing effective therapy and optimal symptom control.

Downregulation of CIC does not associate with overexpression of ETV1 or MAP kinase pathway activation in gastrointestinal stromal tumors

ETV1 is a key factor in gastrointestinal stromal tumors (GIST), and is promoted by CIC downregulation in melanoma. We investigated CIC, ETV1, and the MAPK pathway in GIST. Downregulation of CIC protein levels as assessed by immunostaining was seen in 17/144 GIST, but was not associated with ETV1 or pMEK1/2 expression, KIT and PDGFRA mutations, copy number variations (CNV) of 19q13, and clinical factors. However, the data indicate that the incidence of CIC downregulation may differ for GISTs in different locations in the gastrointestinal tract, and that CNV of 19q13 is associated with shorter disease-free survival.

Symptoms from treatment with sunitinib or sorafenib: a multicenter explorative cohort study to explore the influence of patient-reported outcomes on therapy decisions

PURPOSE

Optimal long-lasting treatment with sunitinib and sorafenib is limited by dose modifications (DMs) due to adverse events (AEs). These AEs may be underrecognized and their influence on health-related quality of life (HRQL) underestimated. Improved insight into the relationship between AEs and therapy decisions is needed. To improve decision making around managing symptoms and reduce DMs, this study was set up to explore the influence of patient-reported symptoms on therapy decisions.

METHODS

In this multicenter cohort study, patient characteristics, reasons for and different forms of used dose modifications, and AEs were prospectively obtained from cancer patients on sunitinib/sorafenib treatment. Used instruments to get insight into AEs were the patient-scored Utrecht Symptom Diary (USD) and the professional-scored Common Terminology Criteria for AEs version 3.0.

RESULTS

Median total treatment duration in 42 patients was 16 weeks. Median time till dose modification was 10 weeks. DMs occurred mostly due to multiple mild AEs. By using the USD, a higher prevalence of most AEs was found compared to the literature. Sixty percent of the patients experienced a decreased HRQL due to multiple AEs.

CONCLUSIONS

Because severe AEs due to sunitinib/sorafenib treatment seldom occur, it is more important to focus on treating and preventing multiple mild AEs with higher impact on HRQL, when trying to avoid dose modifications. Using patient self-reported measurement methods helps to early recognize symptoms and to differentiate among symptom intensities. This systematic approach might help to achieve the optimal dosing, which might improve PFS and OS.

Systematic review of the side effects associated with tyrosine kinase inhibitors used in the treatment of gastrointestinal stromal tumours on behalf of the EORTC Quality of Life Group

Tyrosine kinase inhibitors (TKIs) have revolutionised the treatment of advanced gastrointestinal stromal tumours (GISTs). Imatinib is approved as first line therapy and sunitinib is used in cases of imatinib resistance or intolerance. Compared with conventional treatments, TKIs are delivered over longer periods of time and are more specific in their targets (i.e., molecularly targeted), thus presenting different side effect profiles. We review the safety profiles of imatinib and sunitinib, documenting a total of 95 side effects including patient based as well as medically defined outcomes. Gastrointestinal complaints, particularly diarrhoea and nausea, oedema, fatigue and haematological disorders, notably anaemia, are amongst the most prevalent side effects. While there is overlap between the side effect profiles of imatinib and sunitinib, important differences emerge in the frequencies of oedema, hypertension, thyroid functioning, muscle and joint pains, as well as skin and oral conditions. Awareness of potential side effects is informative to both clinician and patient in terms of treatment decision making and can have important implications for treatment adherence and clinical outcome.

Primary gastrointestinal stromal tumors: Current advances in diagnostic biomarkers, prognostic factors and management of its duodenal location

Gastrointestinal stromal tumors (GIST) constitute 1-3% of all gastrointestinal malignancies and is the most common mesenchymal tumor of the gastrointestinal tract. Although GIST were first described in the literature in the year 1941, important advances of kit mutation and tyrosine kinase inhibitors were not made to understand and manage GIST until the last decade. Here current advances in research of possible cellular origin, diagnostic biomarkers and prognostic factors of primary GIST are reviewed, and the management of primary duodenal GIST is focused on due to its specific location. It is possible that personalized assessment and therapy will turn out to be another milestone for primary GIST.

Development of a Nephrotic Syndrome in a Patient with Gastrointestinal Stromal Tumor during a Long-Time Treatment with Sunitinib

A patient with advanced gastrointestinal stromal tumor (GIST) receiving second-line treatment with sunitinib developed edema, increase of the serum creatinine, weight gain, nephrotic syndrome with proteinuria of 12 g/24 h, dyslipidemia, hypoalbuminemia and also presented with hypertension. A kidney biopsy showed an immunocomplex glomerulonephritis. Steroid treatment was started, but the clinical conditions and laboratory values did not improve. So in the hypothesis that the nephrotic syndrome was induced by sunitinib, sunitinib was temporarily discontinued with a subsequent reduction of proteinuria and improvement in blood pressure control. In the last years, the introduction of sunitinib has modified the natural history of advanced GIST. However, due to chronic and prolonged intake of this drug, there is increasingly frequent detection of late and unknown toxicities in clinical practice. In particular, the late renal toxicity from sunitinib may be the primary clinical problem with this drug in the case of prolonged treatment. Monitoring of kidney function and blood pressure should be performed for early detection of side effects such as hypertension and kidney dysfunction in advanced GIST patients receiving long-term treatment with sunitinib. A clinical collaboration between oncologists and nephrologists could be useful with the objective to optimize the management of sunitinib.

Genetics and molecular pathology of gastric malignancy: Development of targeted therapies in the era of personalized medicine

Gastric malignancy constitutes a major cause of cancer deaths worldwide. Despite recent advances in surgical techniques combined with neoadjuvant chemotherapy and radiotherapy approaches, patients with advanced disease still have poor outcomes. An emerging understanding of the molecular pathways that characterize cell growth, cell cycle, apoptosis, angiogenesis, invasion and metastasis has provided novel targets in gastric cancer therapy. In this review, recent advances in the understanding of molecular tumorigenesis for common gastric malignancies are discussed. We also briefly review the current targeted therapies in the treatment of gastric malignancies. Practical insights are highlighted including HER2 testing and target therapy in gastric adenocarcinoma, morphologic features and molecular signatures of imatinib-resistance GISTs, and recent investigations aimed at tumor-specific therapy for neuroendocrine tumors.

Gastrointestinal stromal tumors: Molecular pathogenesis and targeted therapy

The autophosphorylation of KIT protein, resulting from gain-of-function mutations of the c-kit or PDGFR gene, is the most important molecular mechanism involved in the pathogenesis of gastrointestinal stromal tumors (GISTs). Imatinib is a small molecule tyrosine kinase inhibitor and is effective in the treatment of GISTs. KIT is a convenient target in GISTs, and inhibition of this receptor with imatinib (Gleevec, STI571) in GISTs has shown dramatic efficacy. Unfortunately, resistance to imatinib is a significant clinical problem. Further understanding of the molecular pathogenesis of GISTs is therefore important and may lead to the identification of novel drug targets. This review will focus on recent advances in the understanding of molecular mechanisms involved in the pathogenesis of all types of GISTs. The molecular biological characteristics of each type of GISTs will also be discussed.

The outcome and predictive factors of sunitinib therapy in advanced gastrointestinal stromal tumors (GIST) after imatinib failure - one institution study

BACKGROUND

Gastrointestinal stromal tumors (GIST) mutational status is recognized factor related to the results of tyrosine kinase inhibitors therapy such as imatinib (IM) or sunitinib (SU). Arterial hypertension (AH) is common adverse event related to SU, reported as predictive factor in renal cell carcinoma. The aim of the study was to analyze the outcomes and factors predicting results of SU therapy in inoperable/metastatic CD117(+) GIST patients after IM failure.

METHODS

We identified 137 consecutive patients with advanced inoperable/metastatic GIST treated in one center with SU (2nd line treatment). Median follow-up time was 23 months. Additionally, in 39 patients there were analyzed selected constitutive single nucleotide polymorphisms (SNPs) of VEGFA and VEGFR2 genes.

RESULTS

One year progression-free survival (PFS; calculated from the start of SU) rate was 42% and median PFS was 43 weeks. The estimated overall survival (OS, calculated both from start of SU or IM) was 74 weeks and 51 months, respectively. One-year PFS was 65% (median 74 weeks) in 55 patients with AH vs. 22% (median 17 weeks) in patients without AH. Patients with primary tumors carrying mutations in KIT exon 9 or wild-type had substantially better 1-year PFS (68% and 57%; median 65.5 and 50.5 weeks, respectively) than patients having tumors with KIT exon 11 or PDGFRA mutations (34% and 15%; median 36.8 and 9 weeks, respectively). We identified two independent factors with significant impact on PFS and OS in univariate and multivariate analysis: primary tumor genotype and presence of AH. The most common adverse events during therapy were: fatigue, AH, hypothyroidism, hand and foot syndrome, mucositis, skin reactions, dyspepsia, and diarrhea. Two deaths were assessed as related to tumor rupture caused by reaction to SU therapy. The presence of C-allele in rs833061 and the T-allele in rs3025039 polymorphism of VEGFA were associated with significantly higher risk of hypothyroidism (OR: 10.0 p = 0.041 and OR: 10.5; p = 0.015, respectively).

CONCLUSIONS

We confirmed that many advanced GIST patients benefit from SU therapy with OS > 1.5 year. Primary tumor KIT/PDGFRA genotype and SU-induced AH, as surrogate of its antiangiogenic activity are two independent factors influencing both PFS and OS.

[KIT and KIT: from biology to clinical use]

Scientific knowledge on gastrointestinal stromal tumors (GIST) has highly progressed over the last 10 years. The molecular bases of oncogenic transformation, KIT activating mutations, were identified in 1998 by Hirota et al. The product of KIT proto-oncogene, KIT protein, is a transmembrane receptor with tyrosine kinase activity. Tyrosine kinase inhibitors targeting these mutated activated kinases, namely imatinib and more recently sunitinib, nilotinib, masitinib or sorafenib, have deeply modified GIST prognosis. Molecular biology in GIST is now becoming a routine tool for treatment selection. In patients with advanced GIST, imatinib should be given until progression, and then, other tyrosine kinase inhibitors targeting KIT should be used. In the adjuvant setting, the optimal duration of imatinib treatment remains unknown.

Phase II study of the mammalian target of rapamycin inhibitor ridaforolimus in patients with advanced bone and soft tissue sarcomas

PURPOSE

Ridaforolimus is an inhibitor of mammalian target of rapamycin, an integral component of the phosphatidyl 3-kinase/AKT signaling pathway, with early evidence of activity in sarcomas. This multicenter, open-label, single-arm, phase II trial was conducted to assess the antitumor activity of ridaforolimus in patients with distinct subtypes of advanced sarcomas.

PATIENTS AND METHODS

Patients with metastatic or unresectable soft tissue or bone sarcomas received ridaforolimus 12.5 mg administered as a 30-minute intravenous infusion once daily for 5 days every 2 weeks. The primary end point was clinical benefit response (CBR) rate (complete response or partial response [PR] or stable disease ≥ 16 weeks). Safety, progression-free survival (PFS), overall survival (OS), time to progression, and duration of response were also evaluated.

RESULTS

A total of 212 patients were treated in four separate histologic cohorts. In this heavily pretreated population, 61 patients (28.8%) achieved CBR. Median PFS was 15.3 weeks; median OS was 40 weeks. Response Evaluation Criteria in Solid Tumors (RECIST) confirmed response rate was 1.9%, with four patients achieving confirmed PR (two with osteosarcoma, one with spindle cell sarcoma, and one with malignant fibrous histiocytoma). Archival tumor protein markers analyzed were not correlated with CBR. Related adverse events were generally mild or moderate and consisted primarily of stomatitis, mucosal inflammation, mouth ulceration, rash, and fatigue.

CONCLUSION

Single-agent ridaforolimus in patients with advanced and pretreated sarcomas led to PFS results that compare favorably with historical metrics. A phase III trial based on these data will further define ridaforolimus activity in sarcomas.

Comparison of RECIST and Choi criteria for computed tomographic response evaluation in patients with advanced gastrointestinal stromal tumor treated with sunitinib

BACKGROUND

Controversies exist about computed tomography (CT) response evaluation criteria for patients with gastrointestinal stromal tumor (GIST).

PATIENTS AND METHODS

Fifty-one patients with advanced GIST treated second line with sunitinib were evaluated with contrast-enhanced CT every 3 months. Response was rated according to RECIST and Choi criteria. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier analysis.

RESULTS

According to RECIST, patients were categorized as complete response (CR; n = 0; 0%), partial remission (PR; n = 1; 2.0%), stable disease (SD; n = 37; 72.5%), and progressive disease (PD; n = 13; 25.5%) at 3 months. When Choi criteria were applied responses were CR (n = 0; 0%), PR (n = 16; 31.4%), SD (n = 21; 41.1%), and PD (n = 14; 27.5%). Despite these discrepancies, patients rated as SD with RECIST and PR as well as SD according to Choi criteria displayed similar PFS (41.3, 40.7, and 41.3 weeks, respectively) and OS (100.4, 91.6, and 108.0 weeks, respectively). Patients with PD had significantly shorter PFS (10.1 weeks for both criteria) and OS (29.1 weeks for RECIST; 28.9 weeks for Choi) regardless of the response classification applied.

CONCLUSION

In contrast to absence of progression, discrimination of PR from SD with Choi criteria was of no predictive value.

Molecular basis for primary and secondary tyrosine kinase inhibitor resistance in gastrointestinal stromal tumor

Small molecule kinase inhibitors have irrevocably altered cancer treatment. March 2010 marks the 10th anniversary of using imatinib in gastrointestinal stromal tumors (GIST), a cardinal example of the utility of such targeted therapy in a solid tumor. Before imatinib, metastatic GIST was frustrating to treat due to its resistance to standard cytotoxic chemotherapy. Median survival for patients with metastatic GIST improved from 19 to 60 months with imatinib. In treating patients with GIST, two patterns of tyrosine kinase inhibitor resistance have been observed. In the first, ~9-14% of patients have progression within 3 months of starting imatinib. These patients are classified as having primary or early resistance. Median progression-free survival (PFS) on imatinib is approximately 24 months; patients with later progression are classified as having secondary or acquired resistance. Primary studies and a meta-analysis of studies of imatinib in GIST patients have identified prognostic features that contribute to treatment failure. One of the strongest predictors for success of therapy is KIT or PDGFRA mutational status. Patients with KIT exon 11 mutant GIST have better response rates, PFS, and overall survival compared to other mutations. A great deal has been learned in the last decade about sensitivity and resistance of GIST to imatinib; however, many unanswered questions remain about secondary resistance mechanisms and clinical management in the third- and fourth-line setting. This review will discuss the role of dose effects, and early and late resistance to imatinib and their clinical implications. Patients intolerant to imatinib (5%) and those who progress on imatinib are treated with sunitinib. The mechanism of resistance to sunitinib is unknown at this time but is also appears related to growth of clones with secondary mutations in KIT. Third- and fourth-line treatments of GIST and with future treatment strategies are also discussed.

The clinical relevance of molecular genetics in soft tissue sarcomas

Bone and soft tissue sarcomas are an infrequent and heterogeneous group of mesenchymal tumors including more than a hundred different entities attending to histologic patterns. Research into the molecular aspects of sarcomas has increased greatly in the last few years. This enormous amount of knowledge has allowed, for instance, to refine the classification of sarcomas, improve the diagnosis, and increase the number of therapeutical targets available, most of them under preclinical evaluation. However, other important key issues, such as sarcomagenesis and the cell of origin of sarcomas, remain unresolved. From a molecular point of view, these neoplasias are grouped into 2 main types: (a) sarcomas showing relatively simple karyotypes and translocations, which originate gene fusions (eg, EWS-FLI1 in Ewing sarcoma) or point mutations (eg, c-kit in the gastrointestinal tumors) and (b) sarcomas showing unspecific gene alterations, very complex karyotypes, and no translocations. The discovery of the early mechanisms involved in the genesis of sarcomas, the more relevant signaling pathways, and the development of genetically engineered mouse models could also provide a new individualized therapeutic strategy against these tumors. This review describes the clinical application of some of the molecular alterations found in sarcomas, some advances in the field of sarcomagenesis, and the development of animal models.

Gastrointestinal stromal tumor: a bridge between bench and bedside

Gastrointestinal stromal tumor (GIST) is considered to be driven by a gain-of-function mutation in the KIT or PDGFRA gene. Cure can be obtained only by complete surgical removal of the GIST; however, imatinib, an inhibitor of KIT and PDGFRA, is indicated for advanced, recurrent, and/or metastatic GISTs. Imatinib exhibited remarkable clinical effects on advanced GISTs, with substantial tolerability. Its efficacy greatly depends on the genotype of GIST. The drug, however, met intrinsic or acquired resistance during the treatment, of which the molecular mechanisms were mostly dependent on the genotype of GIST, including primary mutations or secondary mutations in the kinase domains of the corresponding target genes, respectively. Although sunitinib had substantial effects on imatinib-resistant GIST, this drug also encountered primary or secondary resistance depending on the genotype. Thus, advanced GIST may require multidisciplinary treatment. Because resistance mechanisms show some regularity, it is hoped that, in the near future, we may be able to develop a new drug to which resistance does not occur easily, based on scientific evidence.