title: Systemic Endoradiotherapy with Carrier-Added 4-[(131)I]Iodo-L-Phenylalanine: Clinical Proof-of-Principle in Refractory Glioma.
abstract: OBJECTIVE
  To explore feasibility, tolerability, dosimetry and probable efficacy of intravenous endoradiotherapy with carrier-added 4-[(131)I]iodo-L-phenylalanine (c.a. (131)I-IPA) in refractory high-grade glioma.
  
  
  METHODS
  Two male patients (45 and 50 years), with long-standing, extensively pre-treated gliomas and evidence of progression underwent single intravenous injections of 2 and 4 GBq of c.a. (131)I-IPA, respectively. Tumour targeting was verified by (131)I-IPA single-photon emission computed tomography (SPECT). Metabolic and morphological changes indicative of tumour response were assessed by sequential [(18)F]fluoroethyltyrosine ((18)F-FET) positron emission tomography (PET) and contrast-enhanced magnetic resonance imaging (MRI) following therapy. Further monitoring included clinical state, safety laboratory, quality of life and dosimetry. Absorbed mean organ and whole-body doses were determined according to the Medical Internal Radiation Dose (MIRD) scheme using OLINDAEXM based on serial planar scintigraphy.
  
  
  RESULTS
  Both patients tolerated the treatment well. No evidence of acute or delayed organ toxicity was observed. (131)I-IPA accumulated in the tumour recurrences identified by MRI/(18)F-FET. In patient 1, PET showed progressively decreasing maximum standardised uptake values (SUVmax) over 10 months, indicating metabolic response, paralleled by reduced contrast enhancement and tumour volume on MRI. Progression occurred 18 months after therapy. Treatment was repeated using 6.6 GBq of (131)I-IPA, to which no response was observed. Patient 2, followed-up for 3 months after therapy, showed stable disease on MRI and PET. Mean absorbed whole body doses ranged from 0.13 to 0.17 mSv/MBq, with the highest absorbed organ doses to kidneys, bladder and heart (0.86-1.23; 0.49-0.6 and 0.45-0.56 mSv/MBq).
  
  
  CONCLUSIONS
  Systemic endoradiotherapy using up to 6.6 GBq of c.a.(131)I-IPA is not associated with clinically detectable toxicity. Measurable anti-tumour effects in gliomas were observed. (131)I-IPA warrants further evaluation as glioma therapy.
authors.affiliation: Department of Nuclear Medicine/PET Centre, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99437 Bad Berka, Germany.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Baum
authors.affiliation: ABX-CRO Advanced Pharmaceutical Services, Forschungsgesellschaft m.b.H, 01307 Dresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kluge
authors.affiliation: Department of Nuclear Medicine, Laboratory of Radiopharmaceutical Chemistry, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany.
authors.forename: Franz Josef
authors.initials: FJ
authors.lastname: Gildehaus
authors.affiliation: ABX-CRO Advanced Pharmaceutical Services, Forschungsgesellschaft m.b.H, 01307 Dresden, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Bronzel
authors.affiliation: ABX-CRO Advanced Pharmaceutical Services, Forschungsgesellschaft m.b.H, 01307 Dresden, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Schmidt
authors.affiliation: Department of Nuclear Medicine/PET Centre, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99437 Bad Berka, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Schuchardt
authors.affiliation: Department of Nuclear Medicine/PET Centre, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99437 Bad Berka, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Senftleben
authors.affiliation: Department of Nuclear Medicine, Experimental Nuclear Medicine and Radiopharmacy, University of Würzburg, 97080 Würzburg, Germany.
authors.forename: Samuel
authors.initials: S
authors.lastname: Samnick
keywords: Carrier-added 4-[131I]iodo-L-phenylalanine; Dosimetry; Glioma; Human; Intracellular; Molecular endoradionuclide therapy