Lapa C, Reiter T, Werner RA, Ertl G, Wester HJ, Buck AK, Bauer WR, Herrmann K

14.12.2015 [Original Artikel]

Rischpler C, Nekolla SG, Kossmann H, Dirschinger RJ, Schottelius M, Hyafil F, Wester HJ, Laugwitz KL, Schwaiger M

14.12.2015 [Original Artikel]

Herrmann K, Schottelius M, Lapa C, Osl T, Poschenrieder A, Hänscheid H, Lückerath K, Schreder M, Bluemel C, Knott M, Keller U, Schirbel A, Samnick S, Lassmann M, Kropf S, Buck AK, Einsele H, Wester HJ, Knop S

12.11.2015 [Original Artikel]

Chemokine receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer. Based on promising experiences with a radiolabeled CXCR4 ligand ((68)Ga-pentixafor) for diagnostic receptor targeting, (177)Lu- and (90)Y-pentixather were recently developed as endoradiotherapeutic vectors. Here, we summarize the first-in-human experience in 3 heavily pretreated patients with intramedullary and extensive extramedullary manifestations of multiple myeloma undergoing CXCR4-directed endoradiotherapy. CXCR4 target expression was demonstrated by baseline (68)Ga-pentixafor PET. Each treatment was approved by the clinical ethics committee. Pretherapeutic (177)Lu-pentixather dosimetry was performed before (177)Lu-pentixather or (90)Y-pentixather treatment. Subsequently, patients underwent additional chemotherapy and autologous stem cell transplantation for bone marrow rescue. A remarkable therapeutic effect was visualized in 2 patients, who showed a significant reduction in (18)F-FDG uptake. CXCR4-targeted radiotherapy with pentixather appears to be a promising novel treatment option in combination with cytotoxic chemotherapy and autologous stem cell transplantation, especially for patients with advanced multiple myeloma.

Thackeray JT, Derlin T, Haghikia A, Napp LC, Wang Y, Ross TL, Schäfer A, Tillmanns J, Wester HJ, Wollert KC, Bauersachs J, Bengel FM

11.11.2015 [Original Artikel]

An assay for molecular imaging of myocardial CXCR4 expression was evaluated, in order to obtain mechanistic insights noninvasively based on quantitative positron emission tomography (PET). The chemokine receptor CXCR4 has emerged as a therapeutic target after acute myocardial infarction (AMI), because of its role in inflammatory and progenitor cell recruitment. PET with the specific CXCR4 ligand, gallium-68 ((68)Ga)-pentixafor, was performed in mice (n = 53) and compared with ex vivo autoradiography, immunohistochemistry, and left ventricular flow cytometry. In addition, 12 patients were imaged at 2 to 8 days after AMI. In mice, (68)Ga-pentixafor identified regional CXCR4 upregulation in the infarct region, peaking at 3 days (infarct/remote [I/R] ratio 1.5 ± 0.2 at 3 days vs. 1.2 ± 0.3 at 7 days; p = 0.03), corresponding to a flow cytometry-based peak of CD45+ leukocytes and immunohistochemical detection of CD68+ macrophages and Ly6G+ granulocytes. Blockade with the CXCR4 antagonist AMD3100 abolished the signal. No specific uptake was found in sham-operated or control animals. Long-term treatment with oral enalapril attenuated the CXCR4 signal (I/R 1.2 ± 0.2 at 3 days and 1.0 ± 0.0.1 at 7 days; p = 0.01 vs. untreated). Patients showed variable degrees of CXCR4 upregulation in the infarct region. No single clinical parameter allowed for prediction of CXCR4 signal strength. At multivariate analysis, a combination of infarct size and time after reperfusion predicted the CXCR4 infarct signal (rmultiple = 0.73; p = 0.03). Infarct signal in the myocardium was paralleled by elevated pentixafor uptake in bone marrow (r = 0.61; p = 0.04), which highlighted systemic interactions. Targeted PET imaging with (68)Ga-pentixafor identifies the global and regional CXCR4 expression pattern in myocardium and systemic organs. CXCR4 upregulation after AMI coincides with inflammatory cell infiltration, but shows interindividual variability in patients. This may have implications for the response to CXCR4- or other inflammation-targeted therapy, and for subsequent ventricular remodeling.

Philipp-Abbrederis K, Herrmann K, Knop S, Schottelius M, Eiber M, Lückerath K, Pietschmann E, Habringer S, Gerngroß C, Franke K, Rudelius M, Schirbel A, Lapa C, Schwamborn K, Steidle S, Hartmann E, Rosenwald A, Kropf S, Beer AJ, Peschel C, Einsele H, Buck AK, Schwaiger M, Götze K, Wester HJ, Keller U

03.03.2015 [Original Artikel]

CXCR4 is a G-protein-coupled receptor that mediates recruitment of blood cells toward its ligand SDF-1. In cancer, high CXCR4 expression is frequently associated with tumor dissemination and poor prognosis. We evaluated the novel CXCR4 probe [(68)Ga]Pentixafor for in vivo mapping of CXCR4 expression density in mice xenografted with human CXCR4-positive MM cell lines and patients with advanced MM by means of positron emission tomography (PET). [(68)Ga]Pentixafor PET provided images with excellent specificity and contrast. In 10 of 14 patients with advanced MM [(68)Ga]Pentixafor PET/CT scans revealed MM manifestations, whereas only nine of 14 standard [(18)F]fluorodeoxyglucose PET/CT scans were rated visually positive. Assessment of blood counts and standard CD34(+) flow cytometry did not reveal significant blood count changes associated with tracer application. Based on these highly encouraging data on clinical PET imaging of CXCR4 expression in a cohort of MM patients, we conclude that [(68)Ga]Pentixafor PET opens a broad field for clinical investigations on CXCR4 expression and for CXCR4-directed therapeutic approaches in MM and other diseases.

Wester HJ, Keller U, Schottelius M, Beer A, Philipp-Abbrederis K, Hoffmann F, Šimeček J, Gerngross C, Lassmann M, Herrmann K, Pellegata N, Rudelius M, Kessler H, Schwaiger M

01.03.2015 [Original Artikel]

Chemokine ligand-receptor interactions play a pivotal role in cell attraction and cellular trafficking, both in normal tissue homeostasis and in disease. In cancer, chemokine receptor-4 (CXCR4) expression is an adverse prognostic factor. Early clinical studies suggest that targeting CXCR4 with suitable high-affinity antagonists might be a novel means for therapy. In addition to the preclinical evaluation of [(68)Ga]Pentixafor in mice bearing human lymphoma xenografts as an exemplary CXCR4-expressing tumor entity, we report on the first clinical applications of [(68)Ga]Pentixafor-Positron Emission Tomography as a powerful method for CXCR4 imaging in cancer patients. [(68)Ga]Pentixafor binds with high affinity and selectivity to human CXCR4 and exhibits a favorable dosimetry. [(68)Ga]Pentixafor-PET provides images with excellent specificity and contrast. This non-invasive imaging technology for quantitative assessment of CXCR4 expression allows to further elucidate the role of CXCR4/CXCL12 ligand interaction in the pathogenesis and treatment of cancer, cardiovascular diseases and autoimmune and inflammatory disorders.

Herrmann K, Lapa C, Wester HJ, Schottelius M, Schiepers C, Eberlein U, Bluemel C, Keller U, Knop S, Kropf S, Schirbel A, Buck AK, Lassmann MM

19.02.2015 [Original Artikel]

(68)Ga-pentixafor is a promising PET tracer for imaging the expression of the human chemokine receptor 4 (CXCR4) in vivo. The whole-body distribution and radiation dosimetry of (68)Ga-pentixafor were evaluated. Five multiple-myeloma patients were injected intravenously with 90-158 MBq of (68)Ga-pentixafor (mean ± SD, 134 ± 25 MBq), and a series of 3 rapid multiple-bed-position whole-body scans were acquired immediately afterward. Subsequently, 4 static whole-body scans followed at 30 min, 1 h, 2 h, and 4 h after administration of the radiopharmaceutical. Venous blood samples were obtained. Time-integrated activity coefficients were determined from multiexponential regression of organ region-of-interest data normalized to the administered activity, for example, the time-dependent percentages of the injected activity per organ. Mean organ-absorbed doses and effective doses were calculated using OLINDA/EXM. The effective dose based on 150 MBq of (68)Ga-pentixafor was 2.3 mSv. The highest organ-absorbed doses (for 150 MBq injected) were found in the urinary bladder wall (12.2 mGy), spleen (8.1 mGy), kidneys (5.3 mGy), and heart wall (4.0 mGy). Other organ mean absorbed doses were as follows: 2.7 mGy, liver; 2.1 mGy, red marrow; 1.7 mGy, testes; and 1.9 mGy, ovaries.  (68)Ga-pentixafor exhibits a favorable dosimetry, delivering absorbed doses to organs that are lower than those delivered by (18)F-FDG- or (68)Ga-labeled somatostatin receptor ligands.