7th Symposium on Targeted Alpha Therapy Palais am Festungsgraben Am Festungsgraben 1, Berlin, Germany July 17-19, 2011

Organizers: Alfred Morgenstern European Commission Joint Research Centre Institute for Transuranium Elements PO Box 2340 76125 Karlsruhe, Germany

Franziska Held Eckert & Ziegler Eurotope GmbH Robert-Rössle-Str. 10 13125 Berlin, Germany

Scientific committee: Barry Allen George Sgouros Christof Seidl

Christos Apostolidis Frank Bruchertseifer Alfred Morgenstern

The symposium is kindly supported by: European Commission, JRC, Institute for Transuranium Elements Eckert & Ziegler Eurotope GmbH Department of Energy - Office of Science NorthStar Medical Radioisotopes, LLC Algeta ASA

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Program of the 7th Symposium on Targeted Alpha Therapy Palais am Festungsgraben Am Festungsgraben 1, Berlin, Germany July 17-19, 2011

Sunday July 17, 2011 19:00 – 21:00

WELCOME RECEPTION AND REGISTRATION Lichtsaal of Palais am Festungsgraben

Monday July 18, 2011 8:30 – 8:45

WELCOME / INTRODUCTION Alfred Morgenstern Thomas Fanghänel Director, JRC, Institute for Transuranium Elements Roger Knopp CEO, Eckert & Ziegler Eurotope

SESSION I

CLINICAL EXPERIENCES Moderators: Markus Essler, Alfred Morgenstern

8:45 – 9:05

Radium-223 chloride, a first-in-class alpha-pharmaceutical with a benign safety profile for patients with castration resistant prostate cancer (CRPC) and bone metastases; Combined analysis of phase I and II clinical trials. S. Nilsson, C. Parker, I. Haugen, A. Lokna, A. K. Aksnes, B. Bolstad, G. O'Bryan-Tear, O. S. Bruland Karolinska University Hospital, Stockholm, Sweden; Royal Marsden Hospital, Surrey, UK; Algeta ASA, Oslo, Norway; University of Oslo Norwegian Radium Hospital

9:05 – 9:25

Alpha-Particle Immunotherapy for Acute Myeloid Leukemia (AML) with Bismuth-213 (213Bi) and Actinium-225 (225Ac) Joseph G. Jurcic, Todd L. Rosenblat, Michael R. McDevitt, Neeta Pandit-Taskar, Jorge Carrasquillo, Chaitanya R. Divgi, George Sgouros, Alfred Morgenstern, Dragan Cicic, Steven M. Larson, David A. Scheinberg Memorial Sloan-Kettering Cancer Center, New York, NY USA; European Joint Commission, Joint Research Center, Institute for Transuranium Elements, Karlsruhe, Germany, and Actinium Pharmaceuticals, Inc., Newark, NJ, USA -2-

9:25 – 9:45

Analysis of Patient Survival in a Phase 1 Trial of Systemic Targeted Alpha Therapy for Metastatic Melanoma Barry J Allen 1,2, Apresh A Singla2, Syed M Abbas Rizvi1, Peter Graham2, Frank Bruchertseifer3, Christos Apostolidis3, Alfred Morgenstern3 1 Centre for Experimental Radiation Oncology, St. George Hospital, Kogarah 2217, Australia 2 Radiation Oncology, St George Hospital, Sydney, Australia 3 Institute for Transuranium Elements, 76125 Karlsruhe, Germany

9:45 – 10:05

Targeted alpha-radionuclide therapy of functionally critically located gliomas with 213Bi-DOTA-[Thi8,Met(O2)11]-substance P: a pilot trial D. Cordier, F. Forrer, F. Bruchertseifer, A. Morgenstern, C. Apostolidis, S. Good, J. Müller-Brand, H. Mäcke, J. C. Reubi and A. Merlo Division of Neurosurgery (D.C., A.Me.), University Hospitals, Basel, Institute of Nuclear Medicine and Radiochemistry Unit (F.F., J.M-B., H.M.), University Hospitals, Basel, Switzerland, European Commission, Joint Research Centre, Institute for Transuranium Elements (F.B., A.Mo. C.A.), Karlsruhe, Germany, Institute of Pathology (J.C.R.), University of Berne, Berne, Switzerland

10:05 – 10:25

Dose escalation study of peptide receptor alpha-therapy with arterially administered 213Bi-DOTATOC in GEP-NET patients refractory to beta-emitters C. Kratochwil1, F. Bruchertseifer2, F. L. Giesel1, C. Apostolidis2, W. Mier1, U. Haberkorn1; A. Morgenstern2 1 University Hospital, Heidelberg, Germany. 2 European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany.

10:25 - 10:40

Multimodal imaging for therapy monitoring of i.a. 213BiDOTATOC treatment in patients with hepatic metastases of neuroendocrine tumors Giesel FL1, Bruchertseifer F2, Morgenstern A2, Wulfert S1, Zechmann C1, Haberkorn U1, Kratochwil C1 1 University Hospital, Heidelberg, Germany., 2 European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany.

10:40 – 11:10

Coffee break

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SESSION IIa

PRECLINICAL STUDIES Moderators: Brenda Sandmeier, Christof Seidl

11:10 – 11:25

Therapeutic efficacy and toxicity of 225Ac labelled tumour-homing peptides in treatment of peritoneal carcinomatosis Markus Essler1, Alfred Morgenstern2, Frank Bruchertseifer2 and Christof Seidl1 1 Department of Nuclear Medicine, Technische Universität München, Munich,Germany 2 Institute for Transuranium Elements, European Commission. JRC, Karlsruhe, Germany

11:25 – 11:40

Fractionated intravesical therapy with 213Bi-anti-EGFR in a mouse model of human bladder cancer prolongs survival without affecting the normal urothelium C. Seidl1, S. Roetzer1, J. Fazel1, A. Frank1, A. Morgenstern2, F. Bruchertseifer2, M. Autenrieth3, M. Schwaiger1, R. SenekowitschSchmidtke1 1. Department of Nuclear Medicine, Technische Universität München, Munich, Germany 2. European Commission, JRC, Institute for Transuranium Elements, Karlsruhe, Germany 3. Department of Urology, Technische Universität München, Munich, Germany

11:40 – 11:55

Targeting the CD138 antigen for the treatment of multiple myeloma with bismuth-213 Chérel* M., Gouard* S., Gaschet* J., Faivre-Chauvet* A., Bruchertseifer** F., Morgenstern** A., Saï-Maurel* C., KraeberBodéré* F., Barbet* J. and Davodeau* F * Cancer Research Center CRCNA, Université de Nantes, INSERM UMR 892, Nantes, France ** European Commission, JRC, Institute for Transuranium Elements, Karlsruhe, Germany

11:55 – 12:10

Human pathogen C. neoformans as a model for radioimmunotherapy of infectious diseases E. Dadachova1, R. A. Bryan1, Z. Jiang1, A. Morgenstern2, F. Bruchertseifer2, A. Casadevall1 1 Albert Einstein College of Medicine, Bronx, NY USA and 2Institute for Transuranium Elements, Karlsruhe, Germany

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12:10 – 12:25

Comparison of therapeutic efficacy and biodistribution of 213Biand 211At-labeled monoclonal antibody MX35 in an ovarian cancer model Anna M. E. Gustafssona, Tom Bäcka, Jörgen Elgqvistb, Lars Jacobssona, Ragnar Hultbornb, Per Albertssonb, Alfred Morgensternc, Frank Bruchertseiferc, Holger Jensend and Sture Lindegrena a Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden b Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden c European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany d PET and Cyclotron Unit, Rigshospitalet, Copenhagen, Denmark

12:25 – 12:40

Avidin-conjugated MX35 and 211At-labelled, biotinylated poly-Llysine for pretargeted intraperitoneal α-radioimmunotherapy Sofia HL Frost, MSc1*, Tom Bäck1, Holger Jensen, PhD2, Ragnar Hultborn, MD, PhD3, Lars Jacobsson, PhD1, and Sture Lindegren, PhD1 1 Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden 2 Cyclotron and PET Unit, KF-3982, Rigshospitalet, Copenhagen, Denmark 3 Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden

12:40 – 13:40

Lunch

SESSION IIb

PRECLINICAL STUDIES Moderators: Brenda Sandmeier, Christof Seidl

13:40 – 13:55

Radioimmunotherapy with astatine-211 (211At)-labeled anti-CD45 monoclonal antibody (mAb) as nonmyeloablative conditioning in dog leukocyte antigen (DLA)-identical bone marrow transplantation Brenda M Sandmaier, MD1,2, Brian T Kornblit, MD, PhD1, Yun Chen, MD1, Hirohisa Nakamae, MD, PhD1, Donald K Hamlin3, Erlinda B Santos1, Rainer Storb, MD1,2, and D Scott Wilbur, PhD3 1 Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA; 2Dept. of Medicine, University of Washington, Seattle, WA; 3 Department of Radiation Oncology, University of Washington, Seattle, WA;

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13:55 – 14:10

Preclinical evaluation of 227Th- and 177Lu-labeled-trastuzumab in mice with HER-2 Positive Ovarian Cancer Xenografts Nasir Abbas*1 · Øyvind S. Bruland2,3 · Ellen Mengshoel Brevik4 · Jostein Dahle1 1 Dept. of Radiation Biology, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 2 Faculty of Medicine, University of Oslo, Box 1074 Blindern, 0316 Oslo, Norway. 3 Dept. of Oncology, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 4 Algeta ASA, Kjelsås, 0411 Oslo, Norway.

14:10 – 14:25

Alpha-emitting effect of radioimmunoconjugate on vascular network of SKOV-3 xenografts in athymic nude mice studied by dynamic contrast-enhanced magnetic resonance imaging Helen Heyerdahl1, Kathrine Røe1, Ellen Mengshoel Brevik2, Jostein Dahle1 1 Dept. of Radiation Biology, Oslo University Hospital, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 2 Algeta ASA, Box 54 Kjelsås, 0411 Oslo, Norway.

14:25 – 14:40

Biodistribution of alpha-emitting bone-seeking radiopharmaceuticals, 223Ra-chloride, 227Th-EDTMP, and 226ThEDTMP. Kohshin Washiyama1*, Kazuma Ogawa1, Seigo Kinuya1, Tomoo Yamamura2, Isamu Satoh2, Toshiaki Mitsugashira3, Naruto Takahashi4, Atsushi Shinohara4, Akihiko Yokoyama5, and Ryohei Amano1 1 Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan. 2 Institute for Materials Research, Tohoku University, Sendai, Japan. 3 International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Japan 4 Graduate School of Science, Osaka University, Osaka, Japan. 5 Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.

SESSION III

RADIOBIOLOGY AND DOSIMETRY Moderators: Barry Allen, George Sgouros

14:40 – 14:55

Alpha radioimmunotherapy of BRCA-1 deficient triple negative breast cancer Hong Song1, Robert Hobbs1, Chunbo Shao2, George Sgouros1 1 Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology and Radiological Science, 2Department of Otolaryngology, Head and Neck Cancer Research Division, Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD.

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14:55 – 15:10

High cytotoxicity of 213Bi-immunoconjugates is due to efficient induction of DNA double-strand breaks and is independent of cellular oxygenation C. Seidl1, C. Wulbrand1, K.-P. Gilbertz2, S. Rauser3, A. Feuchtinger3, A. Frank1, F. Gärtner1, A. Morgenstern4, C. Apostolidis4, M. Schwaiger1, R. Senekowitsch-Schmidtke1 1. Department of Nuclear Medicine, Technische Universität München, Munich, Germany 2. Institute of Radiobiology, German Armed Forces, Munich, Germany 3. Institute of Pathology, Helmholtz Zentrum München, Neuherberg, Germany 4. European Commission, JRC, Institute for Transuranium Elements, Karlsruhe, Germany

15:10 – 15:25

Differential gene expression of fibroblasts after high- and lowLET irradiation Anna Danielsson1, Kristina Claesson1, Toshima Z. Parris1, Szilárd Nemes1, Khalil Helou1, Kecke Elmroth1, Holger Jensen2 Ragnar Hultborn1 1 Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden 2 Cyclotron and PET Unit, KF-3982, Rigshospitalet, Copenhagen, Denmark

15:25 – 15:45

Coffee break

15:45 – 16:00

Alpha-Particle Emitter Dosimetry: The Fallible Mean George Sgouros, Robert E. Hobbs, Hong Song Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD.

16:00 – 16:15

Microdosimetric analysis of 211At In a thyroid (follicle) model Anders Josefsson, Eva Forssell-Aronsson Department of Radiation Physics; Institute of Clinical Sciences The Sahlgrenska Academy; University of Gothenburg; Sweden

16:15 – 16:30

A trabecular and cellular model of bone marrow dosimetry for targeted 223Ra therapy Robert F Hobbs1, Hong Song1, Christopher J Watchman2, Wesley E Bolch3, Anne-Kirsti Aksnes4, Thomas Ramdahl4, Glenn D Flux5, George Sgouros1. 1 Johns Hopkins University, Baltimore MD, USA 2 University of Arizona, Tuscon AZ, USA 3 University of Florida, Gainsville FL, USA 4 ALGETA ASA, Oslo, Norway 5 Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK

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16:30 – 16:45

Renal toxicity in targeted alpha therapy: advantages of a nephron-based dosimetry model Robert F Hobbs, Hong Song, David Huso, George Sgouros. Johns Hopkins University, Baltimore MD, USA

16:45 – 17:00

A Feasibility Study of Monte Carlo Simulations of AlphaEmissions Derived from Thorium-227 Immunotargeted to Tumor Necrotic Cells Adjacent to Tumor Hypoxic Cells. Michael P. Brown1,3, Scott Penfold2, Fares Al-Ejeh5, and Eva Bezak2,4 1 Cancer Clinical Trials Unit and 2Department of Medical Physics, Royal Adelaide Hospital Cancer Centre, and 3School of Medicine and 4 School of Chemistry & Physics, University of Adelaide, Adelaide, South Australia, and 5Signal Transduction Laboratory, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.

17:00 – 17:15

Monte Carlo dose calculation of targeted alpha therapy in a capillary endothelial cell model Chen-Yu HUANG1,2 Susanna GUATELLI3 Bradley M OBORN3,4 and Barry J ALLEN1,2 1 St. George Clinical School, University of New South Wales, Kogarah, NSW 2217Australia 2 Centre for Experimental Radiation Oncology (CERO), St George Hospital, Kogarah, NSW 2217 Australia 3 Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 Australia 4 Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW 2500 Australia

17:15 – 17:30

Ex vivo measurements of 211At radiolabeled antibody uptake within micrometastases by α-camera imaging and calculations of the dose delivered at the cellular scale. N.Chouin1, T.Bäck1, S.Lindegren1, S.Frost1, H.Kahu2, J.Elgqvist2, S.Palm3, P.Albertsson2, L.Jacobsson1 1 Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden 2 Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden 3 IAEA, Vienna, Austria

17:30

ADJOURN

18:30 – 22:00

SYMPOSIUM DINNER CRUISE Meeting point: Reichstagsufer 18 near train station Friedrichstraße Landing stage shipping company Bruno Winkler

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Tuesday July 19, 2011 SESSION IVa

RADIONUCLIDE PRODUCTION Moderators: Frank Bruchertseifer, tbd

8:30 – 8:45

Alpha emitter production by the US Dept. of Energy Robert W. Atcher, PhD, MBA Director, National Isotope Development Center

8:45 – 9:00

Status of Supply of Alpha Emitting Radioisotopes from Oak Ridge National Laboratory (ORNL) Rose Boll, Karen Murphy, Greg Grover, Matt Gott, Spenser Walsh, David Denton and Saed Mirzadeh Oak Ridge National Laboratory, Oak Ridge, TN 37831

9:00 – 9:15

Alpha-emitters for the oncology disease therapy N. Nerozin, S. Khamyanov SSC RF - IPPE, Obninsk, Russia

9:15 – 9:30

Accelerator production of the therapy isotope 225Ac at 800 MeV J.W. Weidner, H.T. Bach, L.J. Bitteker, M. Cisneros, A. Couture, D. Dry, M.E. Fassbender, M. Gallegos, G.S. Goff, R. Grizo, K.D. John, S.G Mashnik. J.L. Ullmann, W. Taylor, L.E. Wolfsberg, S. Wender, R.S. Baty and F.M. Nortier Los Alamos National Laboratory, Los Alamos, New Mexico, USA

9:30 – 9:45

Alternate Method for Production of 225Ac James Harvey1, Jerry A. Nolen3, John P. Greene3, Thomas Kroc4, Itacil Gomes5, P. Horwitz2, D. McAlister2 1) NorthStar Medical Radioisotopes, LLC, Madison, WI 2) PG Research Foundation, Darien, IL 3) Argonne National Laboratory, Argonne, IL 4) Fermi National Accelerator Laboratory, Batavia, IL 5) I.C. Gomes Consulting, Naperville, IL

9:45 – 10:00

Automated Radioisotope Separation and Application to Shortlived Radioisotopes Used in Nuclear Medicine James T. Harvey and Glenn H. Isensee NorthStar Medical Radioisotopes, Madison, WI Philip Horwitz and Daniel McAlister PG Research Foundation, Darien, IL

10:00 – 10:15

High-purity Radiochemical Separation of Radium-223 and Thorium-227 from Actinium-227 Chuck Soderquist, Bruce McNamara, and Darrell R. Fisher Isotope Sciences Program, Pacific Northwest National Laboratory Richland, Washington 99352 USA

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10:15 – 10:45

Coffee break

SESSION IVb

RADIONUCLIDE PRODUCTION Moderators: Holger Jensen, Michael Zalutsky

10:45 – 11:00

Production of 211At at the Copenhagen University Hospital, Denmark. Holger J. Jensen PET and Cyclotron Unit, Copenhagen University Hospital, DK-2100, Copenhagen, Denmark.

11:00 – 11:15

211

At production on the Warsaw Cyclotron J. Choiński, A. Jakubowski, J. Jastrzębski, B. Paprzycki, A. Pietrzak, R. Tańczyk, A. Stolarz, D. Szczepaniak, A. Trzcińska Heavy Ion Laboratory University of Warsaw, PL J.Chudyka, K. Tworek, W. Zipper Department of Nuclear Physic and its Applications, Silesian University, Katowice, PL B. Petelenz, B. Wąs Niewodniczanski Institute of Nuclear Physic, Krakow, PL A. Bilewicz, M. Łyczko Institute of Nuclear Chemistry and Technology, Warsaw, PL

11:15 – 11:30

Overview of Alpha emitter radioisotopes production at the JRCCyclotron K. Abbas, F. Simonelli, U. Holzwarth, I. Cydzik and A. Bulgheroni Institute for Health and Consumer Protection, Joint Research Centre, European Commission, I-21020 Ispra (VA), Italy C. Apostolidis, F. Bruchertseifer and A. Morgenstern Institute for Transuranium Elements, Joint Research Centre, European Commission, P.O. Box 2340, 76125 Karlsruhe, Germany

SESSION Va

LABELING APPROACHES Moderators: Holger Jensen, Michael Zalutsky

11:30 – 11:45

Progress in optimization and semi-automation of the “wet chemistry” approach to astatine-211 isolation D. Scott Wilbur, Donald K. Hamlin, Ming-Kuan Chyan, Sujit Pal and Damir Dadachov Department of Radiation Oncology, University of Washington, Seattle, WA, USA

11:45 – 12:00

Rhodium complexes with organic bifunctional ligands labelled with 131I and 211At as precursors for therapeutic radiopharmaceuticals Monika Lyczko, Krzysztof Lyczko, Marek Pruszynski, Aleksander Bilewicz Institute of Nuclear Chemistry and Technology, Warsaw, Poland - 10 -

12:00 – 12:15

Stabilised hypervalent astatine-211 for the radiolabelling of proteins Guérard, François1; Rajerison, Holisoa1; Faivre-Chauvet, Alain1;Barbet, Jacques1; Meyer, Geerd J.2; Haddad, Ferrid3; Gestin, Jean-François1 1 CRCNA, Inserm U892, Nantes, France. 2 Klinik für Nuklearmedizin, Medizinische Hochschule Hannover, Hannover, Germany. 3 SUBATECH, IN2P3/CNRS/EMN, Université de Nantes, France

12:15 – 13:15

Lunch

SESSION Vb

LABELING APPROACHES Moderators: Stavroula Sofou, Saed Mirzadeh

13:15 – 13:30

Antivascular alpha-particle therapy by targeted liposomes loaded with Ac-225 Stavroula Sofou, Ph.D. Departments of Biomedical Engineering and Chemical and Biochemical Engineering, Rutgers University, Piscataway, NJ 08854

13:30 – 13:45

Polymersomes as nano-carriers for alpha radionuclide therapy G. Wang1, L. Thijssen1, D. R. Schaart 1, D. DeVries1, A. Morgenstern2, F. Brucherseifer2, A.G. Denkova1 1 Radiation, Radionuclides & Reactors, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands 2 European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe, Germany

13:45– 14:00

Non-toxic Thorium-227 Nanoparticle Constructs for Radioimmunotherapy of Cancer Darrell R. Fisher, Hong Wu, and Yuehe Lin Isotope Sciences Program Pacific Northwest National Laboratory Richland, Washington 99352 USA

14:00 – 14:15

Nanozeolites as carriers for radium radionuclides Agata Kasperek, Aleksander Bilewicz Institute of Nuclear Chemistry and Technology, Warsaw, Poland

14:15 – 14:30

Retention in vivo of daughter radioisotopes of Ac-225 sequestered in LaPO4 nanoparticles Stephen J. Kennel1, Jonathan Woodward2, Robert Standaert2, Alan Stuckey1, Jonathan Wall1 and Saed Mirzadeh2 1 Graduate School of Medicine, University of TN, Knoxville, TN 37920 and 2Oak Ridge National Laboratory, Oak Ridge, TN 37831

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14:30 – 14:45

Synthesis, Characterization, Surface Functionalization, and In Vivo Analysis of Au/GdPO4/{La0.5Gd0.5}(225Ac)PO4 nanoparticles with MAb 201B Mark F. McLaughlin1,2, Jonathan Woodward2, Molly Dunne2, Adam J. Rondinone,2 Robert F. Standaert2, Rose A. Boll,2 Karen Murphy,2 J. David Robertson1, Saed Mirzadeh2 and Stephen J. Kennel3 1 Department of Chemistry and University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211 2 Oak Ridge National Laboratory, Oak Ridge, TN 37831 3 Graduate School of Medicine, University of TN, Knoxville, TN 37920

14:45 – 15:00

Surface Functionalization and In Vivo Analysis of Au{La0.5Gd0.5}PO4 Nanoparticles with Murine Synaptophysin and GFAP Antibodies Mark F. McLaughlin1,2, Ariel Gross3, Nicholas Sobol3, Gang Li1, Jonathan Woodward2, Douglas C. Miller3, Paul H. Pevsner,3 J. David Robertson1, Saed Mirzadeh2, and Stephen J. Kennel4 1 Department of Chemistry and University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211 2 Oak Ridge National Laboratory, Oak Ridge, TN 37831 3 Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, University of Missouri, Columbia, MO 65211 4 Graduate School of Medicine, University of TN, Knoxville, TN 37920

15:00 – 15:30

Coffee break

15:30 – 15:45

WRAP UP Benchmarks for targeted alpha therapy for cancer Barry J Allen PhD DSc Centre for Experimental Radiation Oncology St George Hospital Kogarah 2217 NSW Australia

15:45 – 16:30

OPEN DISCUSSION & SYMPOSIUM CLOSURE

16:30

VISIT OF ECKERT & ZIEGLER EUROTOPE

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SESSION I CLINICAL EXPERIENCES

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Radium-223 chloride, a first-in-class alpha-pharmaceutical with a benign safety profile for patients with castration resistant prostate cancer (CRPC) and bone metastases; Combined analysis of phase I and II clinical trials. S. Nilsson, C. Parker, I. Haugen, A. Lokna, A. K. Aksnes, B. Bolstad, G. O'Bryan-Tear, O. S. Bruland Karolinska University Hospital, Stockholm, Sweden; Royal Marsden Hospital, Surrey, UK; Algeta ASA, Oslo, Norway; University of Oslo Norwegian Radium Hospital

Background: Radium-223 chloride (Alpharadin) is a first-in-class alpha-pharmaceutical which has a potent and highly targeted antitumor effect on bone metastases. Efficacy, safety and tolerability of this agent were evaluated in a combined analysis of Phase I/II trials. Methods: Two open-label Phase I trials (37 pts) and three double-blind phase II trials (255 pts) were performed in mainly CRPC pts with bone metastases. Doses of radium-223 varied from 5 to 250 kBq/kg b.w. The trials included assessments of safety (haematology and AEs), efficacy (survival, PSA, b-ALP, pain) and dosimetry. Results: Radium-223 was rapidly eliminated from blood with uptake into bone metastases and excretion into the small intestine with no hepatobiliary excretion, and minimal activity in kidneys, liver or other internal organs. Among 292 pts 33% were seen in 6 of 10 evaluable patients at 4 weeks, including 2 patients with < 5% blasts. Conclusions: This is the first study to show that therapy with a targeted α-particle generator is feasible in humans. 225Ac-lintuzumab is tolerable at doses < 148 kBq/kg and has antileukemic activity.

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Analysis of Patient Survival in a Phase 1 Trial of Systemic Targeted Alpha Therapy for Metastatic Melanoma Barry J Allen 12, Apresh A Singla2, Syed M Abbas Rizvi1, Peter Graham2, Frank Bruchertseifer3, Christos Apostolidis3, Alfred Morgenstern3 1

Centre for Experimental Radiation Oncology, St. George Hospital, Kogarah 2217, Australia 2 Radiation Oncology, St George Hospital, Sydney, Australia 3 Institute for Transuranium Elements, 76125 Karlsruhe, Germany

Survival results are analysed from a Phase 1 study of Systemic Targeted Alpha Therapy for patients with metastatic melanoma. The effect of key parameters such as melanoma inhibitory activity protein, age, sex, injected dose, lactate dehydrogenase (LDH), metastatic disease stage and treatment dose are examined. Following intravenous administration of the alpha immunoconjugate, 213Bi-cDTPA-9.2.27, patients were monitored for response and toxicity over subsequent days, weeks and months. Responses were measured by physical examination, computed tomography scan and blood sampling, including MIA and LDH. Responses were assessed using CT at 8 weeks. In addition to the above tools, toxicity was monitored by blood pathology, urine analysis and glomerular filtration rate and human anti-mouse antibody response. Thirty eight patients with stage IV melanoma or in transit metastasis were treated with activities in the range 55-925 MBq. No adverse events of any type or level were observed, so the maximum tolerance dose was not achieved. An objective partial response rate of 10% was observed, with 40% stable disease at 8 weeks and a median survival of 8.9 months. Survival analysis showed MIA, disease stage, LDH and treatment effect to be significant prognostic indicators for survival. The favourable clinical characteristic identified in this study will be important in stratification, based on positive prognostic survival, for future clinical trials of metastatic melanoma patients. The lack of significant effect of dose on survival suggests a confounding factor, namely the variable tumour capillary permeability that alters the delivery and efficacy of the radio-immunoconjugate to the melanoma cells in the perivascular space.

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Targeted alpha-radionuclide therapy of functionally critically located gliomas with 213Bi-DOTA-[Thi8,Met(O2)11]-substance P: a pilot trial D. Cordier, F. Forrer, F. Bruchertseifer, A. Morgenstern, C. Apostolidis, S. Good, J. MüllerBrand, H. Mäcke, J. C. Reubi and A. Merlo Division of Neurosurgery (D.C., A.Me.), University Hospitals, Basel, Institute of Nuclear Medicine and Radiochemistry Unit (F.F., J.M-B., H.M.), University Hospitals, Basel, Switzerland, European Commission, Joint Research Centre, Institute for Transuranium Elements (F.B., A.Mo. C.A.), Karlsruhe, Germany, Institute of Pathology (J.C.R.), University of Berne, Berne, Switzerland Purpose: Functionally critically located gliomas represent a challenging subgroup of intrinsic brain neoplasms. Standard therapeutic recommendations often cannot be applied, because radical treatment and preservation of neurological function are contrary goals. The successful targeting of gliomas with locally injected beta radiation emitting 90YDOTAGA-substance P has been shown previously. However, in critically located tumours, the mean tissue range of 5 mm of 90Y may seriously damage adjacent brain areas. In contrast, the alpha radiationemitting radionuclide 213Bi with a mean tissue range of 81 µm may have a more favourable toxicity profile. Therefore, we evaluated locally injected 213Bi-DOTA-substance P in patients with critically located gliomas as the primary therapeutic modality. Methods: In a pilot study, we included five patients with critically located gliomas (WHO grades II–IV). After diagnosis by biopsy, 213Bi-DOTA-substance P was locally injected, followed by serial SPECT/CT and MR imaging and blood sampling. Besides feasibility and toxicity, the functional outcome was evaluated. Results: Targeted radiopeptide therapy using 213Bi-DOTAsubstance P was feasible and tolerated without additional neurological deficit. No local or systemic toxicity was observed. 213 Bi-DOTA-substance P showed high retention at the target site. MR imaging was suggestive of radiationinduced necrosis and demarcation of the tumours, which was validated by subsequent resection. Conclusion: This study provides proof of concept that targeted local radiotherapy using 213BiDOTA-substance P is feasible and may represent an innovative and effective treatment for critically located gliomas. Primarily nonoperable gliomas may become resectable with this treatment, thereby possibly improving the prognosis.

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Dose escalation study of peptide receptor alpha-therapy with arterially administered 213Bi-DOTATOC in GEP-NET patients refractory to beta-emitters C. Kratochwil1, F. Bruchertseifer2, F. L. Giesel1, C. Apostolidis2, W. Mier1, U. Haberkorn1; A. Morgenstern2 1

2

University Hospital, Heidelberg, Germany European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany

Aim: Beta-emitter labelled 90Y- or 177Lu-DOTATOC is a therapeutic option in gastroenteropancreatic neuroendocrine tumor (GEP-NET). However, some patients become refractory to that treatment. The alpha emitter 213Bi demonstrated the capability to break radioresistance to beta-radiation in vitro; however, its relatively short half-life of 46 min requires rapid tumor targeting. Recently, we demonstrated an accelerated tumor uptake of DOTATOC by regional arterial administration, thus promoting the use of 213Bi-DOTATOC. This is a dose escalation study of 213Bi-DOTATOC to assess the toxicity and efficacy for this kind of peptide receptor alpha-therapy. Methods: Twelve patients with unresectable neuroendocrine primary tumor or liver metastases, refractory to a previous treatment with 90Y-/177Lu-DOTATOC, were enrolled. The cumulative activity administered was up to 17 GBq 213Bi per patient. The activity administered during a single treatment cycle was escalated from 1- 10.5 GBq and was injected in fractions of 0.5 -1.5 GBq into an arterial catheter placed in the tumor feeding vessel. Response was assessed with contrast enhanced sonography, MRI, DSA, 68Ga-DOTATOCPET/CT and tumor markers. Hematologic, kidney and endocrine toxicity was assessed according to CTCAE criteria initially, interim and following the final treatment. Results: Given highly selective into the feeding vessel of a single lesion, we observed partial remission (>30% tumor shrinkage) with a minimal activity of 1 GBq 213Bi-DOTATOC. Higher activities are required for whole liver treatment. No acute kidney, endocrine or hematologic toxicity higher than grade 0/I were observed in the first escalation steps (≤10 GBq cumulative activity, ≤7.5 GBq per cycle). Short term follow up demonstrated reduced tumor-perfusion (increase of TTP >25%) in 8/12 patients. While morphologic long term response is still pending, tumor shrinkage (as assessed by MRI) has already been observed in some patients. Conclusion: This pilot study indicates that peptide receptor alpha-therapy with 213BiDOTATOC can be a new treatment option customised for patients refractory to beta-emitters. No severe toxicity was observed with the activities administered until now. Moreover, the maximum tolerable dose was not reached so far and dose escalation continues.

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Multimodal imaging for therapy monitoring of i.a. 213Bi-DOTATOC treatment in patients with hepatic metastases of neuroendocrine tumors 1

Giesel FL, 2Bruchertseifer F, 2Morgenstern A, 1Wulfert S, 1Zechmann C, 1Haberkorn U, 1 Kratochwil C 1

2

University Hospital, Heidelberg, Germany European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany

Purpose: Radiolabeled somatostatin analogs play an emerging role in the therapy of patients with neuroendocrine cancers. The first-in-human peptid receptor alpha-therapy with 213BiDOTATOC was assessed with multimodal imaging (MRI, PET/CT and US) for initial therapy monitoring and surveillance of possible local side effects of this new approach. Material and Methods: In 12 patients the recently introduced alpha-particle-emitting 213BiDOTATOC was administered loco-regional via arterial catheter in the hepatic artery. Morphological and functional imaging of liver metastases was assessed using MRI with standard sequences and dynamic contrast-enhanced (DCE-MRI) as well as diffusion-weighted imaging (DW-MRI) before and 4-6 weeks after therapy. This modality delivers the lesion diameter (LD), Apparent Diffusion Coefficient (ADC) as a surrogate of tumor integrity, and contrast enhancement in arterial and venous phase as a surrogate of tumor perfusion. In addition, contrast-enhanced ultrasound (CEUS) was accomplished as an on site imaging modality to assess tumor microvascularisation. CEUS benefits from high temporal resolution for the assessment of time-to-intensity curves and the derivation of analyze time-to-peak (TTP), maximum intensity and intensity ratios between metastases and normal liver. Results: In the early MR analysis, most metastases demonstrated only a moderate decrease in LD whereas median tumor ADC as a representative of tumor integrity increased from 1,21x10-3mm2/sec to 1,47x10-3mm2/sec 4-6 weeks after last loco-regional intervention. The pronounced hyper-arterialisation of liver metastases, as visually assessed with DCE-MRI, declined. Prior to therapeutic intervention CEUS presented a pronounced enhancement in the liver metastases compared to the adjacent liver parenchyma (median TTP metastasis = 26.6 sec; median TTP liver parenchyma = 53.6sec). 2 months after intervention the i.a. 213Bitreated patients showed a decline in contrast enhancement in 56%. Conclusions: In many tumor identities it has been shown, that functional changes in tumorintegrity and tumor perfusion precedes morphological tumor shrinkage. In this ongoing study CEUS, diffusion-weighted and perfusion MRI were able to demonstrate such tumor changes also early after treatment with 213Bi-DOTATOC. However, some lesions already demonstrated a moderate decline in diameter. Therefore this functional tumor imaging assessment seems to be a reliable bio-surrogate of treatment response and might predict in an early stage lesion responses. Nevertheless, the long term follow-up results of gold standard imaging methods are still pending.

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SESSION II PRECLINICAL STUDIES

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Therapeutic efficacy and toxicity of 225Ac labelled tumour-homing peptides in treatment of peritoneal carcinomatosis Markus Essler1, Alfred Morgenstern2, Frank Bruchertseifer2 and Christof Seidl1 1 2

Department of Nuclear Medicine, Technische Universität München, Munich,Germany Institute for Transuranium Elements, European Commission. JRC, Karlsruhe, Germany

Aims: F3 is a vascular tumour-homing peptide binding to nucleolin on the surface of tumourand tumour endothelial cells. Upon binding to nucleolin F3 is internalized into the nucleus. We generated stable conjugates of the vascular tumour-homing peptide F3 with 225Ac to accomplish targeted delivery of this isotope into tumour cells. The aim of our study was to determine the therapeutic window of both 225Ac-DOTA-F3 and to compare it with 213BiDTPA-F3. Methods: 213Bi-DTPA-F3 and 225Ac-DOTA-F3 were tested in-vitro using clonogenic assays. Activities with equivalent anti-tumour effects in vitro were then used for treatment of mice with intra-peritoneal MDA-MB-435 xenograft tumours in vivo. Survival of animals was analyzed. Therapy monitoring was performed by optical imaging and histological analysis. To study nephrotoxicity mice were injected with different activities of 213Bi-DTPA-F3 or 225AcDOTA-F3 as indicated. After 6 month mice were sacrificed and kidneys were examined by histology. Results: We found that in vitro the ID50 of 213Bi-DTPA-F3 or 225Ac-DOTA-F3 is 1,4 µCi/ml and 1,8 nCi/ml, respectively. In vivo, we compared therapy with 6 x 50 nCi 225Ac-DOTA-F3 or 6 x 50 µCi 213Bi-DTPA-F3 or 6 x 100 µl PBS. Median survival in the PBS group was 60 days. Median survival in the group treated with 225Ac-DOTA-F3 was 95 days and 97 days in the group treated with 213Bi-DTPA-F3. 213Bi-DTPA-F3 and 225Ac-DOTA-F3 had different effects on tumour growth as determined by optical imaging. 213Bi-DTPA-F3 reduces the tumour mass at early time points until 30 days after treatment whereas 225Ac-DOTA-F3 has a prolonged anti-tumour effect leading to a reduction of tumour mass until the death of animals. 213 Bi-DTPA-F3 was more effective in reducing the number of metastases but no obvious difference concerning the necrosis fraction between the therapy groups was found (225AcDOTA-F3: 43 %; 213Bi-DTPA-F3 36%; PBS: 5%). The fraction of apoptotic cells was lower than 1% in all groups. We analyzed the renal pathology upon treatment with the two constructs. HE stainings of the kidney samples of the 225Ac-DOTA-F3-group presented acute tubule necrosis in 30% of the cortex tubuli. Tubular edema was present in 30% of tubuli. Neither HE nor PAS staining revealed protein casts (2%), indicating a minor damage of the kidney. No fibrosis (scar formation) was seen in EvG stain. In the 213Bi-DTPA-F3 treated group acute tubule necrosis and edema was found in 10%-20% of the cortex tubuli. Tubular damage was present in 5% of tubuli. Neither HE nor PAS staining revealed protein casts (2%), indicating only minor nephrotoxicity. We also studied long term effects of treatment with 213Bi-DTPA-F3 or 225Ac-DOTA-F3: Both isotopes induced renal fibrosis which was less pronounced after treatment with 225Ac-DOTA-F3. Conclusions 225Ac-DOTA-F3 is capable of controlling tumour growth and to increase survival of mice with peritoneal carcinomatosis. The time course of anti-tumor activity is different as 213Bi-DTPA-F3 is active at earlier time points. Short term renal toxicity of both constructs is only mild whereas long term effect of both constructs is partial renal fibrosis which is less pronounced after treatment with 225Ac-DOTA-F3.

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Fractionated intravesical therapy with 213Bi-anti-EGFR in a mouse model of human bladder cancer prolongs survival without affecting the normal urothelium C. Seidl1, S. Roetzer1, J. Fazel1, A. Frank1, A. Morgenstern2, F. Bruchertseifer2, M. Autenrieth3, M. Schwaiger1, R. Senekowitsch-Schmidtke1 1. Department of Nuclear Medicine, Technische Universität München, Munich, Germany 2. European Commission, JRC, Institute for Transuranium Elements, Karlsruhe, Germany 3. Department of Urology, Technische Universität München, Munich, Germany Objectives: Among severe malignancies bladder cancer is the most common of the urinary tract with 116.000 new cases in Europe every year. Following transurethral resection of nonmuscle invasive bladder cancer, the recurrence rate is still high due to disseminated tumour cells at the site of surgery. The aim of the present study was to investigate both the efficacy of fractionated intravesical therapy and possible radiation injury of the urothelium using 213Bianti-EGFR immunoconjugates in a nude mouse model of advanced bladder cancer. Methods: Female swiss nu/nu mice were orthotopically instilled with luciferase-transfected EJ28 bladder cancer cells (2x106) after setting small urothelial lesions by electrocautery. Therapy was initiated between days 14 and 36 after cell instillation, as soon as tumour growth could be verified by bioluminescence-imaging. Three groups of mice (n=10) were treated as follows: the first group was intravesically injected three times 0.46 MBq 213Bi-anti-EGFRMAb in a time interval of four days; the second group received the unlabelled anti-EGFRMAb (1 µg) three times; the third group remained untreated. Tumour development was monitored by bioluminescence-imaging and survival was observed up to 300 days. Urothelia of tumour-free animals were histologically examined 300 days after intravesical injection of 213 Bi-anti-EGFR (three times 0.46 MBq). Results: Animals without treatment or after injection with the unlabelled anti-EGFR-MAb showed a mean survival of 44 days. In 60% of the animals treated three times with 213Bi-antiEGFR bioluminescence-imaging signals significantly decreased compared to pretreatment signals. The urothelia of the tumour-free animals that had been intravesically injected with 213 Bi-anti-EGFR according to the therapy group did not show any pathological alterations. Conclusions: Fractionated locoregional radioimmunotherapy in a mouse model of bladder cancer is a promising treatment option also for advanced stages due to efficient reduction of tumour volume and significant prolongation of survival without damaging the normal urothelium.

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Targeting the CD138 antigen for the treatment of multiple myeloma with bismuth-213 Chérel* M., Gouard* S., Gaschet* J., Faivre-Chauvet* A., Bruchertseifer** F., Morgenstern** A., Saï-Maurel* C., Kraeber-Bodéré* F., Barbet* J. and Davodeau* F. * Cancer Research Center CRCNA, Université de Nantes, INSERM UMR 892, Nantes, France ** European Commission, JRC, Institute for Transuranium Elements, Karlsruhe, Germany

Problem: The aim of the study was to evaluate efficacy of syngeneic mouse myeloma model.

213

Bi-anti-CD138 mAb in a

Methods: C57BL/KaLwRij mice were grafted with murine 5T33 cells. Biodistribution, toxicity and RIT efficacy were studied. Results: Median survival time was improved from 45.5 days for control PBS group to 227 days for 7.4 MBq 213Bi-anti-mCD138 treatment group and to more than 300 days for 3.7 MBq 213 Bi-anti-mCD138 treatment group. Analysis of survival curves shows an acute toxicity for injected activities of 213Bi-anti-mCD138 superior or equal to 7.4 MBq. Indeed, until d55, there is no significant difference between a RIT made in an activity injected by 7.4 MBq of antimCD138 and the controls. Finally, an injected activity of 11.1 MBq of 213Bi-anti-mCD138 is extremely toxic and lead to the death of 100% C57BL/KaLwRij mice within 7 days. Conclusion: RIT of MM using alpha emitters seems feasible and effective with CD138 immunotargeting.

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Human pathogen C. neoformans as a model for radioimmunotherapy of infectious diseases E. Dadachova1, R. A. Bryan1, Z. Jiang1, A. Morgenstern2, F. Bruchertseifer2, A. Casadevall1 1

Albert Einstein College of Medicine, Bronx, NY USA and 2European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany

Background. There is an obvious and urgent need for novel approaches to treatment of infectious diseases. The use of monoclonal antibodies (mAbs) in therapy of infectious diseases is now experiencing renaissance. During the last 7 years we have successfully adapted radioimmunotherapy (RIT), a modality previously developed only for cancer treatment, for the treatment of experimental fungal, bacterial and viral infections. Purpose. As our model organism for studying the efficacy, mechanisms, potential toxicity and radioresistance to RIT, as well as for comparison of RIT with the existing anti-microbial therapies we have chosen the encapsulated yeast Cryptococcus neoformans (CN). Methods. MAb 18B7 which binds to CN capsular polysaccharide was radiolabeled with alpha- and beta-emitting radionuclides 213-Bismuth and 188-Rhenium and CN was treated in vitro and in vivo in a systemic mouse model of CN infection. Results/Discussion. RIT of CN was effective in lowering the CFUs in the brains and lungs of treated mice and in prolonging their survival. RIT did not result in generation of radiation resistant cells. Comparison with Amphotericin B treatment of mice infected with melanized or non-melanized CN demonstrated that one injection with radiolabeled mAb was more effective than 2 weeks course of Amphotericin B and the efficacy of RIT was not dependent on the melanization status of the cells. In vitro the radiolabeled mAbs had effect on CN membrane, metabolism and apoptosis while in vivo the treatment was not damaging to the lungs and the brains. Conclusions. The success of RIT approach in laboratory studies provides encouragement for feasibility of therapeutically targeting microbes with radiolabeled mAbs in patients. In addition, the creation of “pan-antibodies” for RIT which would recognize antigens shared by the whole class of pathogens such as fungi, for example, would greatly facilitate the introduction of RIT into the clinic.

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Comparison of therapeutic efficacy and biodistribution of 213Bi- and 211Atlabeled monoclonal antibody MX35 in an ovarian cancer model Anna M. E. Gustafssona, Tom Bäcka, Jörgen Elgqvistb, Lars Jacobssona, Ragnar Hultbornb, Per Albertssonb, Alfred Morgensternc, Frank Bruchertseiferc, Holger Jensend and Sture Lindegrena a

Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden b Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden c European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe, Germany d PET and Cyclotron Unit, Rigshospitalet, Copenhagen, Denmark

Anna Gustafsson Department of Radiation Physics, Sahlgrenska University Hospital SE-413 45 Gothenburg, Sweden Telephone: +46 (0)31 342 97 36 E-mail: [email protected]

Introduction: The purpose of this study was to compare the therapeutic efficacy and biodistribution of the monoclonal antibody MX35 labeled with either 213Bi or 211At, both αemitters, in an ovarian cancer model. Our aims were to find out if the biodistributions of the radiolabeled immunoconjugates would differ and if the different physical properties of 213Bi and 211At, e.g. the different half-lives and the different path lengths of their emitted αparticles, would result in different therapeutic outcomes. The therapeutic efficacy experiment was performed in mice at two different stages of tumor development. Methods: One hundred female nude BALB/c (nu/nu) mice were inoculated intraperitoneally (i.p.) with human ovarian cancer cells (OVCAR-3). Two weeks later, forty of these mice were injected i.p. with ~2.7 MBq of 213Bi-MX35 (n=20) or ~0.44 MBq of 211At-MX35 (n=20). Four weeks after inoculation, a second group of forty OVCAR-3-inoculated mice were injected with the same activities of 213Bi-MX35 (n=20) or 211At-MX35 (n=20). Control mice (n=20) received no treatment. The presence of tumors and ascites was investigated eight weeks after therapy. Biodistributions of i.p-injected 213Bi-MX35 and 211At-MX35 were studied in tumor-free nude BALB/c (nu/nu) mice (n=16). Results: The animals injected with 213Bi-MX35 or 211At-MX35 two weeks after cell inoculation had tumor-free fractions (TFFs) of 0.60 and 0.90, respectively. The untreated reference group had a TFF of 0.20. The groups treated with 213Bi-MX35 or 211At-MX35 four weeks after inoculation both had TFFs of 0.25, and the reference animals all exhibited evidence of disease. The biodistributions of 213Bi-MX35 and 211At-MX35 were very similar to each other and displayed no alarming activity levels in the investigated organs. Conclusions: Micrometastatic growth of an ovarian cancer cell line was reduced in nude mice after treatment with 213Bi-MX35 or 211At-MX35. Treatment with 211At-MX35 provided a nonsignificantly better result for the chosen activity levels. The radiolabeled MX35 did not accumulate to a high extent in the investigated organs, and no considerable signs of toxicity were observed.

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Avidin-conjugated MX35 and 211At-labelled, biotinylated poly-L-lysine for pretargeted intraperitoneal α-radioimmunotherapy Sofia HL Frost, MSc1*, Tom Bäck1, Holger Jensen, PhD2, Ragnar Hultborn, MD, PhD3, Lars Jacobsson, PhD1, and Sture Lindegren, PhD1 1

Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden 2 Cyclotron and PET Unit, KF-3982, Rigshospitalet, Copenhagen, Denmark 3 Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden *Correspondence to: Sofia Frost Department of Radiation Physics, Sahlgrenska University Hospital SE-413 45 Gothenburg, Sweden Telephone: +46 (0)31 342 97 35 E-mail: [email protected]

Purpose Pretargeted α-radioimmunotherapy is a potentially efficient technique for treating disseminated cancer. We performed a study where an avidin-coupled, monoclonal antibody, (avidin-MX35; specific for ovarian cancer cells) and an astatine-211-labeled, biotinylated, succinylated poly-L-lysine (211At-B-PLsuc) were administered in mice to assess the potential efficacy for intraperitoneal (i.p.) therapy of microscopic tumours. Our aims were to determine a timeline for pretargeted radioimmunotherapy (PRIT) using these substances, and to estimate the maximum tolerable activity (MTA). Methods 125 I-labelled avidin-MX35 and 211At-B-PLsuc were administered i.p. in nude mice, and their distributions were studied in various tissues at different time points after injection. The effect of blocking unspecific uptake of free astatine using sodium perchlorate was also studied. Mean absorbed doses were estimated from organ uptake of 211At-B-PLsuc. In addition, myelotoxicity studies were performed after administration of different levels of activities of 211 At-B-PLsuc. Results Low blood content of both 125I-avidin-MX35 and 211At-B-PLsuc was observed, indicating fast clearance. The sodium perchlorate blocking was efficient, and the highest 211At uptake was found in kidneys at 1 h p.i. Some 211At activity was accumulated in red bone marrow (RBM). Mean absorbed doses of particular interest were 2.3 Gy/MBq for kidneys, 0.4 Gy/MBq for blood, and 0.9 Gy/MBq for RBM. An absorbed dose of 0.9 Gy to RBM was found to be safe. These results indicated that RBM would be the main dose-limiting organ in the proposed pretargeting scheme, and that blood data alone was inadequate for predicting its absorbed dose. Conclusions To achieve a favourable activity distribution and avoid major toxicities in PRIT using these substances, at least 1.0 MBq of 211At-B-PLsuc can be injected 24 h after i.p. administration of avidin-MX35. Our results provide a basis for future i.p. PRIT studies of microscopic ovarian cancer in mice.

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Radioimmunotherapy with astatine-211 (211At)-labeled anti-CD45 monoclonal antibody (mAb) as nonmyeloablative conditioning in dog leukocyte antigen (DLA)-identical bone marrow transplantation Brenda M Sandmaier, MD1,2, Brian T Kornblit, MD, PhD1, Yun Chen, MD1, Hirohisa Nakamae, MD, PhD1, Donald K Hamlin3, Erlinda B Santos1, Rainer Storb, MD1,2, and D Scott Wilbur, PhD3 1

Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA; 2Dept. of Medicine, University of Washington, Seattle, WA; 3Department of Radiation Oncology, University of Washington, Seattle, WA; Nonmyeloablative conditioning for allogeneic hematopoietic cell transplantation (HCT) is a curative treatment option for various malignant hematologic diseases in older or medically infirm patients. However, treatment related toxicities and relapse are still major causes of morbidity and mortality. In an effort to increase irradiation of target tissues and reduce early or late toxic effects of external beam γ-irradiation, we have investigated the use of radioimmunotherapy (RIT) as conditioning for allogeneic HCT. Previously we demonstrated that anti-CD45 mAb labeled with bismuth-213 (213Bi), could replace 2 Gy total body irradiation (TBI) in nonmyeloablative conditioning of dogs transplanted with marrow from DLA-identical littermates (Blood, 2002;100:318). However, due to lack of availability and cost of 213Bi for the amounts needed for the translation of the 213Bi-labeled mAb into clinical trials, we investigated the use of 211At as an alternative α-particle-emitting isotope. 211At is readily available in quantities that can be scaled up for clinical trials at considerably lower cost, and the longer half-life (211At, 7.2 hrs; 213Bi, 46 min) allows longer exposure of target organs and delivery of sufficient radiation in a single infusion. Before the transition to 211At-based RIT was made, the two isotopes were compared in a murine model, which showed that the myelosuppressive effects and toxicity profile of 211At-labeled anti-CD45 mAb was comparable and possibly superior to 213Bi (Cancer Research, 2009;69:2408). In the current study, 211At was linked to anti-CD45 mAb through a conjugated closo-decaborate(2-) derivative. Biodistribution in a dog showed that the spleen received the highest dose of radioactivity, 0.3% injected dose per gram of organ (%ID/g) while kidney and liver received 0.03 and 0.10 %ID/g, respectively. Dose finding and toxicity studies were performed in 6 dogs receiving 211At-labeled anti-CD45 mAb in doses between 100 and 619 µCi/kg . All dogs experienced dose-dependent myelosuppression but recovered from the neutrophil (range, 0-1485/µL) and lymphocyte nadirs (range, 34-272/µL) without hematopoietic cell rescue. The two dogs treated with the highest doses of 211At–labeled anti-CD45 mAb (458 and 619 µCi/kg) experienced liver failure with ascites 17 to 20 weeks post-treatment. The dogs treated with 100 to 405 µCi/kg only experienced transient elevations of hepatic enzymes, and no macroscopic or histologic evidence of organ toxicity, including renal or hepatic, was observed at necropsy after 1 year of follow-up. Subsequently 8 dogs were transplanted with marrow from DLA-identical littermates with doses of 155-625 µCi/kg 211At on 0.5 mg/kg anti-CD45 mAb administered on day -3 as conditioning. Post-transplant immunosuppression consisted of mycophenolate mofetil and cyclosporin for 28 and 35 days, respectively. All dogs engrafted, and currently 5 of 8 dogs are alive after 24 to 52 weeks of follow-up. Two dogs were euthanized in good condition after 1 year of follow-up, and 1 dog (treated with the lowest dose of 155 µCi/kg) was euthanized in good condition after 12 weeks due to rejection after initial engraftment followed by autologous reconstitution. In the dogs with sustained engraftment, maximum and current/final donor chimerisms in mononuclear cells were 55%-100% and 27%-66%, respectively. No renal toxicity and only clinically irrelevant transient increases in hepatic enzymes were observed. Immune reconstitution was prompt with normal T and natural killer cell function by day 60. Upon necropsy no macroscopic or histologic evidence of organ toxicity was observed. In conclusion, our study demonstrated that low-dose RIT with 211At labeled anti-CD45 mAb could replace TBI in DLA-identical transplantation. At doses above 155 µCi/kg, 211At-labeled anti-CD45 mAb provided sufficient immunosuppression to enable stable mixed chimerism with only minimal toxicity, making it a candidate for future clinical trials of nonmyeloablative transplantation.

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Preclinical evaluation of 227Th- and 177Lu-labeled-trastuzumab in mice with HER-2 Positive Ovarian Cancer Xenografts Nasir Abbas*1 · Øyvind S. Bruland2,3 · Ellen Mengshoel Brevik4 · Jostein Dahle1 1

Dept. of Radiation Biology, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 2 Faculty of Medicine, University of Oslo, Box 1074 Blindern, 0316 Oslo, Norway. 3 Dept. of Oncology, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 4 Algeta ASA, Kjelsås, 0411 Oslo, Norway.

Purpose: The aim of the present study was to compare the biodistribution, normal tissue toxicity and therapeutic effect of the low dose rate alpha-particle emitting radioimmunoconjugate 227Th-trastuzumab and the low dose rate beta-particle emitting radioimmunoconjugate 177Lu-trastuzumab in mice with HER2-expressing ovarian cancer xenografts. Methods: Thorium-227 and 177Lu was conjugated to trastuzumab (Herceptin®) and injected intravenously in mice bearing SKOV-3 xenografts. The biodistribution was determined at different time points after injection. Inhibition of growth of ovarian cancer xenografts was measured after single injection of 227Th-trastuzumab, 227Th-rituximab, 177Lu-trastuzumab, cold trastuzumab, and NaCl. The toxicity of 227Th-trastuzumab and 177Lu-trastuzumab was evaluated by measurement of body weight, white blood cell counts, clinical chemistry parameters and histological examination of tissue specimens. Results: Absorbed radiation dose to tumor was 4 Gy after administration of 400 kBq/kg Th-trastuzumab and 72 MBq/kg 177Lu-trastuzumab, respectively. A significant anti-tumor effect of 227Th-trastuzumab at injected dosages of 400 and 600 kBq/ kg on SKOV-3 xenografts was observed as compared to untreated control, cold trastuzumab, 72 MBq/kg of 177 Lu-trastuzumab and 600 kBq/kg of 227Th-rituximab (non-specific targeting). Survival of mice at dosage of 400 kBq/kg and 600 kBq/kg of 227Th-trastuzumab was significantly improved compared to control and all other treatments (p-value < 0.05, Kaplan Meier). Both tumor growth and survival of mice treated with cold trastuzumab, 72 MBq/kg of 177Lutrastuzumab and 600 kBq/kg of 227Th-rituximab (non-specific targeting) was similar to untreated controls. Treatment related toxicity was not observed in any group except for a transient decrease of white blood cells between 3 to 9 weeks after treatment with 400 and 600 kBq/kg of 227Th-trastuzumab. 227

Conclusions: The α-radioimmunoconjugate 227Th-trastuzumab effectively delayed tumor growth and prolonged survival of mice as compared with β-emitting 177Lu-trastuzumab, administered at the same absorbed radiation dose to tumor. This new therapeutic approach can be a promising treatment alternative for micro-metastatic ovarian cancers.

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Alpha-emitting effect of radioimmunoconjugate on vascular network of SKOV-3 xenografts in athymic nude mice studied by dynamic contrastenhanced magnetic resonance imaging Helen Heyerdahl1, Kathrine Røe1, Ellen Mengshoel Brevik2, Jostein Dahle1 1

Dept. of Radiation Biology, Oslo University Hospital, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. 2 Algeta ASA, Box 54 Kjelsås, 0411 Oslo, Norway.

Objectives: Mechanisms of action for low dose rate radioimmunotherapy by 227Thmonoclonal antibodies are not fully understood. Radioimmunotherapy inhibits tumor growth in animal models where the tumor size is about 100 times the range of the alpha particles. In this study dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) was used to investigate the effect of 227Th-trastuzumab therapy on tumor vasculature by studying pharmacokinetic parameters derived from DCEMR-images of HER2-expressing human subcutaneous tumor xenografts in mice. Methods: Human SKOV-3 HER2-expressing ovarian cancer xenografts were grown bilaterally in athymic nude mice. When tumor diameter reached 8 mm, mice were treated with either 227Th-trastuzumab at a dose of 1000 kBq/kg body weight (n=18 tumors) or 100 µl NaCl (control group, n=16 tumors). T1-weighted DCEMRI was performed before treatment and 1, 2, and 3 weeks after start of therapy. Time-intensity curves in the tumor were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared to the parameters from the control tumors. Results: Significant increase in the mean values of the parameter kep (the rate constant between the extracellular extravascular space and the plasma, p