Small animal PET as non-invasive tool for preclinical imaging Marta Oteo Vives Biomedical Applications of Radioisotopes and Pharmacokinetic Unit

Small animal PET as non-invasive tool for preclinical imaging  Preclinical imaging - Animal models - Major challenge for small animal imaging  Available imaging modalities  Preclinical PET equipment design  Small animal PET as a tool for quick and cheaper translational research  PET tracer development  MicroPET imaging examples Cracow PET Symposium 23/09/2014 2(C) Marta Oteo, CIEMAT, Madrid

Why do we need preclinical imaging on living animals?  Non-invasive in vivo validation of the candidate drugs and probes (observing multi-scale changes, from organ, tissue, cell, down to molecular level induced by physiological, pathological or pharmacological effects) is critical prior to perform human trials.  In vitro and ex vivo systems lack the interacting physiological factors present in vivo, facilitating investigation of systemic aspects of physiological processes and disease What small animal models are commonly used?  Mouse is the most used, followed by rat Mouse is the ideal model:  Prolific (fast breeding cycle)  Inexpensive to house  Reproductive and nervous system are like those of humans  Same diseases as humans  99% homology with human genome  Big advances in mouse genomics  Wide range of animal models of human disease  Rat is commonly used in Neuroscience (because of the bigger size of its brain) Cracow PET Symposium 23/09/2014 3(C) Marta Oteo, CIEMAT, Madrid

Spatial resolution Sensitivity Signal/Noise What is the major challenge for small animal imaging? To visualize anatomical structures and monitor physiological activities on such a small scale High resolution imaging modalities are required Cracow PET Symposium 23/09/2014 4(C) Marta Oteo, CIEMAT, Madrid

Available small animal imaging modalities Multimodality systems provide functional and anatomical information PET/CT, PET/MR, SPECT/CT, SPECT/MR Jürgen K.William et all (2008). Molecular imaging in drug developement. Nature Reviews CT imaging SPECT imaging PET imaging Ultrasound imaging Magnetic resonance imaging Optical imaging Cracow PET Symposium 23/09/2014 5(C) Marta Oteo, CIEMAT, Madrid

Cracow PET Symposium 23/09/2014 (C) Marta Oteo, CIEMAT, Madrid6 Comparative spatial resolution of clinical and preclinical imaging modalities and associated design refinements Fabian Kiessling and Bernd J. Pichler. “Small Animal imaging” Basics and Practical Guide. ISBN:

Performance parameters and logistical features of small-animal imaging modalities Cracow PET Symposium 23/09/2014 7(C) Marta Oteo, CIEMAT, Madrid

Clinical PET equipments Preclinical PET equipments  To improve detector instrumentation and overall system design: novel detector geometry ( ring diameter / detector size) new scintillators reconstruction methods: iterative algorithms  Low positron range  Radiotracer specific activity To spatial resolution and sensitvity: Cracow PET Symposium 23/09/2014 8(C) Marta Oteo, CIEMAT, Madrid

Characteristics of preclinical PET Scanners Cracow PET Symposium 23/09/2014 9(C) Marta Oteo, CIEMAT, Madrid Claudia Kuntner and David Stout. Frontiers in Physics. February 2014 | Volume 2 | Article 12

Preclinical PET imaging Clinical PET imaging Translational research Probes or labeled drugs evaluation and characterization in vivo (pharmacodynamics and pharmacokinetics) -quicker translation to clinical practice -better scientific foundation -more rapid elimination of ineffective compounds -reduced number of experimental animals Identification of the target molecule Find a probe that binds specifcally to the target Radioactive labeling of the probe In vitro tests (binding affinity, stability etc.) In vivo experiments Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Positron Emitter (PET) Half life 18 F 1.83h 124 I100.3h 68 Ga 1.13h 64 Cu 12.7h 76 Br 16.2h 86 Y 14.7h 89 Zr 78.4h Labeling strategies:  Direct (halogens)  Indirect (metals) : using chelators Main goal in radiotracer development Specific probes Peptides mAb: Immuno-PET -fast blood clearance -rapid tissue penetration -Low antigenicity -high specificity -low blood clearance -high tissue penetration -immunogenic -Diagnosis -Treatment “THERANOSTICS” mAb peptide Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Cracow PET Symposium 23/09/2014 (C) Marta Oteo, CIEMAT, Madrid Ga Applications 68 Ge/ 68 Ga generator GMP compliant Eckert & Ziegler

Radioisotopes more suitable for ImmunoPET: 124 I (103 h) – For Ab that do not became internalized (not residualizing) 89 Zr (78,4 h) – For Ab that became internalized (residualizing)  Combines the high resolution and sensitivity of a PET camera with the unique ability of a mAbs to selectively bind specific antigens.  Application in diagnostic as well as in prognostic and therapeutic oncology Immuno-PET Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Melanoma overexpressing MC1R (  -MSH receptor) A C B Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid MC1R (melanocortin -1 receptor)  -MSH (  - melanocyte-stimulating hormone)

PET detection of pulmonary NETs overexpressing SSTR using SST analogs. Lung Cancer transgenic mouse model Developed at Molecular Oncology Unit (CIEMAT) 18 F-FDG 68 Ga-DOTATATE Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Detection of NETs (Meningioma) overexpressing SSTR using SST analogs Mouse model s.c. implanted with CH157-MN (Meningioma cell line) Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Detection of NETs (Pheochromocytoma) overexpressing SSTR using SST analogs Mouse model s.c. implanted with PC-12 (Pheochromocytoma rat cell line) 68 Ga-DOTATATE Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Immuno-PET 89 Zr-DFO-anti-MMP14 Nude mice Implanted (s.c) with the glioblastoma cell line U87-MG Two weeks later: 1-2 mg mAb/Kg ( µCi) PET performed at different times post-administration Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Immuno-PET Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Concluding remark PET molecular imaging allows for the non-invasive assessment of biological and biochemical processes in living subjects, contributing to improve our understanding of disease and drug activity during preclinical and clinical drug development. Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid

Cracow PET Symposium 23/09/ (C) Marta Oteo, CIEMAT, Madrid Biomedical Applications of Radioisotopes and Pharmacokinetic Unit (CIEMAT)