Traditional anatomic tumor response criteria are based on uni‐ or bidimensional changes in tumor size, and do not take into account changes in tumor metabolism, tumor density, or decrease in the ...number of intratumoral vessels. These changes are, however, all indicative of response to imatinib therapy in patients with gastrointestinal stromal tumor (GIST). In these patients, metabolic responses seen on positron emission tomography (PET) using fluorine‐18‐fluorodeoxyglucose (18FDG) have been shown to be closely related to clinical benefit. Furthermore, these metabolic changes precede by weeks or months significant decrease in tumor size on computed tomography (CT). Conversely, lack of metabolic response on FDG‐PET indicates primary resistance to the drug and may help identify patients who would benefit from another therapy, while re‐emergence of metabolic activity within tumor sites following a period of therapeutic response indicates secondary resistance to the drug. Newly proposed CT criteria using either no growth in tumor size or a combination of tumor density and size criteria have shown a close correlation with the predictive value results of FDG‐PET. Thus, the integration of FDG‐PET and CT, as in the combined hybrid PET/CT scanners now available, will not only optimize the evaluation of patients with GIST treated with molecularly targeted drugs, but may ultimately help shorten clinical trials, and accelerate drug development in this disease and other cancers as well.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary Background Sunitinib, a multitargeted tyrosine-kinase inhibitor, which is approved by both US and European Commission regulatory agencies for clinical use, extends survival of patients with ...metastatic renal-cell carcinoma and gastrointestinal stromal tumours, but concerns have arisen about its cardiac safety. We therefore assessed the cardiovascular risk associated with sunitinib in patients with metastatic gastrointestinal stromal tumours. Methods We retrospectively reviewed all cardiovascular events in 75 patients with imatinib-resistant, metastatic, gastrointestinal stromal tumours who had been enrolled in a phase I/II trial investigating the efficacy of sunitinib. The composite cardiovascular endpoint was cardiac death, myocardial infarction, and congestive heart failure. We also examined sunitinib's effects on left ventricular ejection fraction (LVEF) and blood pressure. We investigated potential mechanisms of sunitinib-associated cardiac effects by studies in isolated rat cardiomyocytes and in mice. Findings Eight of 75 (11%) patients given repeating cycles of sunitinib in the phase I/II trial had a cardiovascular event, with congestive heart failure recorded in six of 75 (8%). Ten of 36 (28%) patients treated at the approved sunitinib dose had absolute LVEF reductions in ejection fraction (EF) of at least 10%, and seven of 36 (19%) had LVEF reductions of 15 EF% or more. Sunitinib induced increases in mean systolic and diastolic blood pressure, and 35 of 75 (47%) individuals developed hypertension (>150/100 mm Hg). Congestive heart failure and left ventricular dysfunction generally responded to sunitinib being withheld and institution of medical management. Sunitinib caused mitochondrial injury and cardiomyocyte apoptosis in mice and in cultured rat cardiomyocytes. Interpretation Left ventricular dysfunction might be due, in part, to direct cardiomyocyte toxicity, exacerbated by hypertension. Patients treated with sunitinib should be closely monitored for hypertension and LVEF reduction, especially those with a history of coronary artery disease or cardiac risk factors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Most gastrointestinal stromal tumors (GIST) have activating mutations of
, or uncommonly
. Fifteen percent of adult and 85% of pediatric GISTs are wild type (WT), commonly having high expression of ...IGF-1R and loss of succinate dehydrogenase (SDH) complex function. We tested the efficacy of linsitinib, an oral TKI IGF-1R inhibitor, in patients with WT GIST.
A multicenter phase II trial of linsitinib was conducted. The primary endpoint was objective response rate. Secondary endpoints were clinical benefit rate: complete response, partial response, and stable disease (SD) ≥ 9 months, and quantitative 218Ffluoro-2-deoxy-D-glucose (FDG) metabolic response (MR) at week 8. Serum levels for glucose, insulin, IGF-1R ligand IGF1, and binding proteins were obtained to explore correlations to patient outcomes and FDG-PET results.
Twenty patients were accrued in a 6-month period. Grade 3-4 toxicities possibly related to linsitinib were uncommon (8.5%). No objective responses were seen. Clinical benefit rate (CBR) at 9 months was 40%. Intense FDG uptake was observed at baseline, with partial MR of 12% and stable metabolic disease of 65% at week 8; these patients had RECIST 1.1 SD as their best response. Progression-free survival (PFS) and overall survival Kaplan-Meier estimates at 9 months were 52% and 80%, respectively. SDHA/B loss determined by IHC was seen in 35% and 88% of cases, respectively.
Linsitinib is well tolerated in patients with WT GIST. Although the 9-month CBR was 40%, and PFS at 9 months was 52%, no objective responses were observed. Rapid accrual to this study demonstrates that clinical trials of experimental agents in selected subtypes of GIST are feasible.
Inhibition of immune checkpoints, including cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and its ligand PD-L1, has demonstrated exciting and durable remissions across a ...spectrum of malignancies. Combinatorial regimens blocking complementary immune checkpoints further enhance the therapeutic benefit. The activity of these agents for patients with glioblastoma, a generally lethal primary brain tumor associated with significant systemic and microenvironmental immunosuppression, is not known. We therefore systematically evaluated the antitumor efficacy of murine antibodies targeting a broad panel of immune checkpoint molecules, including CTLA-4, PD-1, PD-L1, and PD-L2 when administered as single-agent therapy and in combinatorial regimens against an orthotopic, immunocompetent murine glioblastoma model. In these experiments, we observed long-term tumor-free survival following single-agent anti-PD-1, anti-PD-L1, or anti-CTLA-4 therapy in 50%, 20%, and 15% of treated animals, respectively. Combination therapy of anti-CTLA-4 plus anti-PD-1 cured 75% of the animals, even against advanced, later-stage tumors. In long-term survivors, tumor growth was not seen upon intracranial tumor rechallenge, suggesting that tumor-specific immune memory responses were generated. Inhibitory immune checkpoint blockade quantitatively increased activated CD8(+) and natural killer cells and decreased suppressive immune cells in the tumor microenvironment and draining cervical lymph nodes. Our results support prioritizing the clinical evaluation of PD-1, PD-L1, and CTLA-4 single-agent targeted therapy as well as combination therapy of CTLA-4 plus PD-1 blockade for patients with glioblastoma.
Metastatic GI stromal tumor (GIST) is a life-threatening disease with no therapy of proven efficacy after failure of imatinib and sunitinib. Regorafenib is a structurally unique inhibitor of multiple ...cancer-associated kinases, including KIT and platelet-derived growth factor receptor (PDGFR), with broad-spectrum anticancer activity in preclinical and early-phase trials. Because KIT and PDGFR-α remain drivers of GIST after resistance to imatinib and sunitinib, we performed a multicenter single-stage phase II trial of regorafenib in patients with advanced GIST after failure of at least imatinib and sunitinib.
Patients received regorafenib orally, 160 mg daily, on days 1 to 21 of a 28-day cycle. Disease assessment was performed every two cycles per RECIST 1.1. Primary end point was clinical benefit rate (CBR), defined as objective responses (ie, complete or partial response PR as well as stable disease SD ≥ 16 weeks). Serial tumor biopsies were obtained from consenting patients whenever possible.
From February to December 2010, 34 patients were enrolled at four US centers. As of July 28, 2011, 33 patients had received at least two cycles of regorafenib (range, two to 17 cycles). CBR was 79% (95% CI, 61% to 91%). Four patients achieved PR, and 22 exhibited SD ≥ 16 weeks. Median progression-free survival was 10.0 months. The most common grade 3 toxicities were hypertension and hand-foot-skin reaction.
Regorafenib has significant activity in patients with advanced GIST after failure of both imatinib and sunitinib. A phase III trial of regorafenib versus placebo is ongoing to define more fully the safety and efficacy of regorafenib in this setting.
The objectives of this article are to review the new Response Evaluation Criteria in Solid Tumors (RECIST) guideline, version 1.1, highlighting the major changes in the new version compared with the ...original RECIST guideline (version 1.0), and to present case examples with representative imaging.
Familiarity with the revised RECIST is essential in day-to-day oncologic imaging practice to provide up-to-date service to oncologists and their patients. Some of the changes in the revised RECIST affect how radiologists select, measure, and report target lesions.
Oncology clinical trials have become increasingly dependent upon image-based surrogate endpoints for determining patient eligibility and treatment efficacy. As therapeutics have evolved and ...multiplied in number, the tumor metrics criteria used to characterize therapeutic response have become progressively more varied and complex. The growing intricacies of image-based response evaluation, together with rising expectations for rapid and consistent results reporting, make it difficult for site radiologists to adequately address local and multicenter imaging demands. These challenges demonstrate the need for advanced cancer imaging informatics tools that can help ensure protocol-compliant image evaluation while simultaneously promoting reviewer efficiency. LesionTracker is a quantitative imaging package optimized for oncology clinical trial workflows. The goal of the project is to create an open source zero-footprint viewer for image analysis that is designed to be extensible as well as capable of being integrated into third-party systems for advanced imaging tools and clinical trials informatics platforms.
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Combined with computed tomography as a hybrid imaging device, PET/CT has replaced stand-alone PET. Since first introduced in the 1970s 2, ring-configured PET scanners have gone through progressive ...technological enhancements that have included the removal of septa to allow 3-D imaging 3, improvements in the scintillation detector materials 4, and implementation of time-of-flight capability 5. ...with a state-of-the-art digital PET/CT the Biograph Vision 600 (Siemens Healthineers), itself a scanner with a substantially higher performance than most of the globally-installed PET/CT base, the ultra-extended FOV of the Quadra scanner yielded an 8–10-fold increment in signal-to-noise ratio (SNR) depending on the radionuclide used 15. Where good-manufacturing procedures are required for PET tracers, the ability to affray quality-assurance compliance testing costs across a larger number of patients per production batch provides efficiencies that could further improve cost-effectiveness. In a thematic series on total-body PET-CT, we have invited the developers and early adopters of this technology to provide insights into how they are using the unique capabilities of these scanners in research and their routine clinical practice, perspectives on the impact that they will have on radiopharmaceutical development and salutary warnings on the challenges that must be met in processing and analyzing the huge data files generated.
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