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Holmium-166 radioembolization for the treatment of patients with liver metastases: design of the phase I HEPAR trial.

Smits ML, Nijsen JF, van den Bosch MA, Lam MG, Vente MA, Huijbregts JE, van het Schip AD, Elschot M, Bult W, de Jong HW, Meulenhoff PC, Zonnenberg BA - J. Exp. Clin. Cancer Res. (2010)

Bottom Line: Previous studies have demonstrated the safety of 166Ho-PLLA-MS radioembolization ( 166Ho-RE) in animals.Prior to treatment, in addition to the standard technetium-99m labelled macroaggregated albumin ( 99mTc-MAA) dose, a low radioactive safety dose of 60-mg 166Ho-PLLA-MS will be administered.Based on preclinical studies, it is expected that 166Ho-RE has a safety and toxicity profile comparable to that of 90Y-RE.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, E01,132, 3584 CX Utrecht, The Netherlands.

ABSTRACT

Background: Intra-arterial radioembolization with yttrium-90 microspheres ( 90Y-RE) is an increasingly used therapy for patients with unresectable liver malignancies. Over the last decade, radioactive holmium-166 poly(L-lactic acid) microspheres ( 166Ho-PLLA-MS) have been developed as a possible alternative to 90Y-RE. Next to high-energy beta-radiation, 166Ho also emits gamma-radiation, which allows for imaging by gamma scintigraphy. In addition, Ho is a highly paramagnetic element and can therefore be visualized by MRI. These imaging modalities are useful for assessment of the biodistribution, and allow dosimetry through quantitative analysis of the scintigraphic and MR images. Previous studies have demonstrated the safety of 166Ho-PLLA-MS radioembolization ( 166Ho-RE) in animals. The aim of this phase I trial is to assess the safety and toxicity profile of 166Ho-RE in patients with liver metastases.

Methods: The HEPAR study (Holmium Embolization Particles for Arterial Radiotherapy) is a non-randomized, open label, safety study. We aim to include 15 to 24 patients with liver metastases of any origin, who have chemotherapy-refractory disease and who are not amenable to surgical resection. Prior to treatment, in addition to the standard technetium-99m labelled macroaggregated albumin ( 99mTc-MAA) dose, a low radioactive safety dose of 60-mg 166Ho-PLLA-MS will be administered. Patients are treated in 4 cohorts of 3-6 patients, according to a standard dose escalation protocol (20 Gy, 40 Gy, 60 Gy, and 80 Gy, respectively). The primary objective will be to establish the maximum tolerated radiation dose of 166Ho-PLLA-MS. Secondary objectives are to assess tumour response, biodistribution, performance status, quality of life, and to compare the 166Ho-PLLA-MS safety dose and the 99mTc-MAA dose distributions with respect to the ability to accurately predict microsphere distribution.

Discussion: This will be the first clinical study on 166Ho-RE. Based on preclinical studies, it is expected that 166Ho-RE has a safety and toxicity profile comparable to that of 90Y-RE. The biochemical and radionuclide characteristics of 166Ho-PLLA-MS that enable accurate dosimetry calculations and biodistribution assessment may however improve the overall safety of the procedure.

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Scanning electron microscope image of holmium microspheres.
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Figure 1: Scanning electron microscope image of holmium microspheres.

Mentions: Using the solvent evaporation technique, non-radioactive holmium-165 ( 165Ho) and its acetylacetonate complex (HoAcAc) can be incorporated into the poly(L-lactic acid) matrix to form microspheres (Figure 1). Subsequently, the non-radioactive 165Ho-PLLA-MS can be made radioactive by neutron activation in a nuclear facility and form 166Ho-PLLA-MS. Neutron-activated 166Ho has a half-life of 26.8 hours and is a beta emitter (Eβmax = 1.85 MeV) that also emits gamma photons (Eγ = 81 keV) suitable for single photon emission computed tomography (SPECT) (Table 1).


Holmium-166 radioembolization for the treatment of patients with liver metastases: design of the phase I HEPAR trial.

Smits ML, Nijsen JF, van den Bosch MA, Lam MG, Vente MA, Huijbregts JE, van het Schip AD, Elschot M, Bult W, de Jong HW, Meulenhoff PC, Zonnenberg BA - J. Exp. Clin. Cancer Res. (2010)

Scanning electron microscope image of holmium microspheres.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2903532&req=5

Figure 1: Scanning electron microscope image of holmium microspheres.
Mentions: Using the solvent evaporation technique, non-radioactive holmium-165 ( 165Ho) and its acetylacetonate complex (HoAcAc) can be incorporated into the poly(L-lactic acid) matrix to form microspheres (Figure 1). Subsequently, the non-radioactive 165Ho-PLLA-MS can be made radioactive by neutron activation in a nuclear facility and form 166Ho-PLLA-MS. Neutron-activated 166Ho has a half-life of 26.8 hours and is a beta emitter (Eβmax = 1.85 MeV) that also emits gamma photons (Eγ = 81 keV) suitable for single photon emission computed tomography (SPECT) (Table 1).

Bottom Line: Previous studies have demonstrated the safety of 166Ho-PLLA-MS radioembolization ( 166Ho-RE) in animals.Prior to treatment, in addition to the standard technetium-99m labelled macroaggregated albumin ( 99mTc-MAA) dose, a low radioactive safety dose of 60-mg 166Ho-PLLA-MS will be administered.Based on preclinical studies, it is expected that 166Ho-RE has a safety and toxicity profile comparable to that of 90Y-RE.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, E01,132, 3584 CX Utrecht, The Netherlands.

ABSTRACT

Background: Intra-arterial radioembolization with yttrium-90 microspheres ( 90Y-RE) is an increasingly used therapy for patients with unresectable liver malignancies. Over the last decade, radioactive holmium-166 poly(L-lactic acid) microspheres ( 166Ho-PLLA-MS) have been developed as a possible alternative to 90Y-RE. Next to high-energy beta-radiation, 166Ho also emits gamma-radiation, which allows for imaging by gamma scintigraphy. In addition, Ho is a highly paramagnetic element and can therefore be visualized by MRI. These imaging modalities are useful for assessment of the biodistribution, and allow dosimetry through quantitative analysis of the scintigraphic and MR images. Previous studies have demonstrated the safety of 166Ho-PLLA-MS radioembolization ( 166Ho-RE) in animals. The aim of this phase I trial is to assess the safety and toxicity profile of 166Ho-RE in patients with liver metastases.

Methods: The HEPAR study (Holmium Embolization Particles for Arterial Radiotherapy) is a non-randomized, open label, safety study. We aim to include 15 to 24 patients with liver metastases of any origin, who have chemotherapy-refractory disease and who are not amenable to surgical resection. Prior to treatment, in addition to the standard technetium-99m labelled macroaggregated albumin ( 99mTc-MAA) dose, a low radioactive safety dose of 60-mg 166Ho-PLLA-MS will be administered. Patients are treated in 4 cohorts of 3-6 patients, according to a standard dose escalation protocol (20 Gy, 40 Gy, 60 Gy, and 80 Gy, respectively). The primary objective will be to establish the maximum tolerated radiation dose of 166Ho-PLLA-MS. Secondary objectives are to assess tumour response, biodistribution, performance status, quality of life, and to compare the 166Ho-PLLA-MS safety dose and the 99mTc-MAA dose distributions with respect to the ability to accurately predict microsphere distribution.

Discussion: This will be the first clinical study on 166Ho-RE. Based on preclinical studies, it is expected that 166Ho-RE has a safety and toxicity profile comparable to that of 90Y-RE. The biochemical and radionuclide characteristics of 166Ho-PLLA-MS that enable accurate dosimetry calculations and biodistribution assessment may however improve the overall safety of the procedure.

Show MeSH
Related in: MedlinePlus