Entity

Time filter

Source Type

Exton, PA, United States

Thomas A.,U.S. National Institutes of Health | Maltzman J.,Morphotek | Hassan R.,U.S. National Institutes of Health
Lung Cancer | Year: 2013

Folate is essential for proliferating cells and folate transport pathways and folate-dependent metabolic processes show promise as targets for anti-neoplastic therapy. Folate receptor α (FOLR1), a folate transporter, is an attractive target for anti-neoplastic therapy due to its high affinity for folate, restricted range of expression in normal tissue and differential over-expression in malignant tissue. FOLR1 is expressed in non-small cell lung cancer, with a higher expression in adenocarcinoma compared with squamous cell carcinoma. Farletuzumab is a monoclonal antibody targeting FOLR1 which in pre-clinical studies led to cytotoxicity of FOLR1-expressing cells, inhibited tumor growth in animal models and showed limited reactivity with normal tissue. In phase I/II trials, farletuzumab was well tolerated as a single-agent and in combination, without additive toxicity with chemotherapy. An ongoing phase II, double blind, placebo-controlled study is evaluating farletuzumab in patients with FOLR1 expressing metastatic adenocarcinoma of lung. © 2013. Source


Lindenberg L.,U.S. National Institutes of Health | Thomas A.,U.S. National Institutes of Health | Adler S.,SAIC | Mena E.,Johns Hopkins University | And 8 more authors.
Oncotarget | Year: 2015

Amatuximab is a chimeric high-affinity monoclonal IgG1/k antibody targeting mesothelin that is being developed for treatment of mesothelin-expressing cancers. Considering the ongoing clinical development of amatuximab in these cancers, our objective was to characterize the biodistribution, and dosimetry of 111Indium (111In) radiolabelled amatuximab in mesothelin-expressing cancers. Between October 2011 and February 2013, six patients including four with malignant mesothelioma and two with pancreatic adenocarcinoma underwent Single Photon Emission Computed Tomography-Computed Tomography (SPECT/CT) imaging following administration of 111In amatuximab. SPECT/CT images were obtained at 2-4 hours, 24-48 hours and 96-168 hours after radiotracer injection. In all patients, tumor to background ratios (TBR) consistently met or exceeded an uptake of 1.2 (range 1.2-62.0) which is considered the minimum TBR that can be visualized. TBRs were higher in tumors of patients with mesothelioma than pancreatic adenocarcinoma. 111In-amatuximab uptake was noted in both primary tumors and metastatic sites. The radiotracer dose was generally well-tolerated and demonstrated physiologic uptake in the heart, liver, kidneys and spleen. This is the first study to show tumor localization of an antimesothelin antibody in humans. Our results show that 111In-amatuximab was well tolerated with a favorable dosimetry profile. It localizes to mesothelin expressing cancers with a higher uptake in mesothelioma than pancreatic cancer. Source


Geiger X.J.,Laboratory Medicine | Kalari K.R.,Mayo Medical School | Sun Z.,Mayo Medical School | O'Shannessy D.J.,Morphotek | And 5 more authors.
PLoS ONE | Year: 2015

Folate receptor alpha (FOLR1) has been identified as a potential prognostic and therapeutic target in a number of cancers. A correlation has been shown between intense overexpression of FOLR1 in breast tumors and poor prognosis, yet there is limited examination of the distribution of FOLR1 across clinically relevant breast cancer subtypes. To explore this further, we used RNA-seq data from multiple patient cohorts to analyze the distribution of FOLR1 mRNA across breast cancer subtypes comprised of estrogen receptor positive (ER+), human epidermal growth factor receptor positive (HER2+), and triple negative (TNBC) tumors. FOLR1 expression varied within breast tumor subtypes; triple negative/basal tumors were significantly associated with increased expression of FOLR1 mRNA, compared to ER+ and HER2+ tumors. However, subsets of high level FOLR1 expressing tumors were observed in all clinical subtypes. These observations were supported by immunohistochemical analysis of tissue microarrays, with the largest number of 3+ positive tumors and highest H-scores of any subtype represented by triple negatives, and lowest by ER+ tumors. FOLR1 expression did not correlate to common clinicopathological parameters such as tumor stage and nodal status. To delineate the importance of FOLR1 overexpression in triple negative cancers, RNA-interference was used to deplete FOLR1 in overexpressing triple negative cell breast lines. Loss of FOLR1 resulted in growth inhibition, whereas FOLR1 overexpression promoted folate uptake and growth advantage in low folate conditions. Taken together, our data suggests patients with triple negative cancers expressing high FOLR1 expression represent an important population of patients that may benefit from targeted anti-FOLR1 therapy. This may prove particularly helpful for a large number of patients who would typically be classified as triple negative and who to this point have been left without any targeted treatment options. © 2015 Necela et al. Source


Kalari K.R.,Mayo Medical School | Sun Z.,Mayo Medical School | O'Shannessy D.J.,Morphotek | Maltzman J.D.,Morphotek | And 4 more authors.
PLoS ONE | Year: 2015

Folate receptor alpha (FOLR1) has been identified as a potential prognostic and therapeutic target in a number of cancers. A correlation has been shown between intense overexpression of FOLR1 in breast tumors and poor prognosis, yet there is limited examination of the distribution of FOLR1 across clinically relevant breast cancer subtypes. To explore this further, we used RNA-seq data from multiple patient cohorts to analyze the distribution of FOLR1 mRNA across breast cancer subtypes comprised of estrogen receptor positive (ER+), human epidermal growth factor receptor positive (HER2+), and triple negative (TNBC) tumors. FOLR1 expression varied within breast tumor subtypes; triple negative/basal tumors were significantly associated with increased expression of FOLR1 mRNA, compared to ER+ and HER2+ tumors. However, subsets of high level FOLR1 expressing tumors were observed in all clinical subtypes. These observations were supported by immunohistochemical analysis of tissue microarrays, with the largest number of 3+ positive tumors and highest H-scores of any subtype represented by triple negatives, and lowest by ER+ tumors. FOLR1 expression did not correlate to common clinicopathological parameters such as tumor stage and nodal status. To delineate the importance of FOLR1 overexpression in triple negative cancers, RNA-interference was used to deplete FOLR1 in overexpressing triple negative cell breast lines. Loss of FOLR1 resulted in growth inhibition, whereas FOLR1 overexpression promoted folate uptake and growth advantage in low folate conditions. Taken together, our data suggests patients with triple negative cancers expressing high FOLR1 expression represent an important population of patients that may benefit from targeted anti-FOLR1 therapy. This may prove particularly helpful for a large number of patients who would typically be classified as triple negative and who to this point have been left without any targeted treatment options. Source


Chacko A.-M.,University of Pennsylvania | Li C.,University of Pennsylvania | Hu J.,University of Pennsylvania | Grasso L.,University of Pennsylvania | And 3 more authors.
Journal of Nuclear Medicine | Year: 2014

Tumor endothelialmarker 1 (TEM1/endosialin) is a tumor vascular marker highly overexpressed in multiple human cancers with minimal expression in normal adult tissue. In this study, we report the preparation and evaluation of 124I-MORAb-004, a humanized monoclonal antibody targeting an extracellular epitope of human TEM1 (hTEM1), for its ability to specifically and sensitively detect vascular cells expressing hTEM1 in vivo. Methods: MORAb-004 was directly iodinated with 125I and 124I, and in vitro binding and internalization parameters were characterized. The in vivo behavior of radioiodinated MORAb-004 was characterized in mice bearing subcutaneous ID8 tumors enriched with mouse endothelial cells expressing hTEM1 and by biodistribution and small-animal immuno-PET studies. Results: MORAb-004 was radiolabeled with high efficiency and isolated in high purity. In vitro studies demonstrated specific and sensitive binding of MORAb-004 to MS1 mouse endothelial cells expressing hTEM1, with no binding to control MS1 cells. 125IMORAb- 004 and 124I-MORAb-004 both had an immunoreactivity of approximately 90%. In vivo biodistribution experiments revealed rapid, highly specific and sensitive uptake of MORAb-004 in MS1-TEM1 tumors at 4 h (153.2 ± 22.2 percentage injected dose per gram [%ID/ g]), 24 h (127.1 ± 42.9 %ID/g), 48 h (130.3 ± 32.4 %ID/g), 72 h (160.9 ± 32.1 %ID/g), and 6 d (10.7 ± 1.8%ID/g). Excellent image contrast was observed with 124I-immuno-PET. MORAb-004 uptake was statistically higher in TEM1-positive tumors than in control tumors. Binding specificity was confirmed by blocking studies using excess nonlabeled MORAb-004. Conclusion: In our preclinical model, with hTEM1 exclusively expressed on engineered murine endothelial cells that integrate into the tumor vasculature, 124I-MORAb-004 displays high tumor-to-background tissue contrast for detection of hTEM1 in easily accessible tumor vascular compartments. These studies strongly suggest the clinical utility of 124I-MORAb-004 immuno-PET in assessing TEM1 tumor-status. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc. Source

Discover hidden collaborations